PSI 3.0L PFI Maintenace Section B Psi_3.0l_shop_opm Shop Opm

User Manual: psi_3.0l_shop_opm

Open the PDF directly: View PDF .
Page Count: 385

Download
Open PDF In Browser	View PDF

Original Issue
Dated January 2006
Publication Number PSI3P0LPFI-B

PSI 3.0L PFI CERTIFIED ENGINE
SERVICE MANUAL

MANUAL SECTIONS
Description

Page

Maintenance

1-1

Base Engine Repair

2-1

Dual Fuel System Description of Operation

3-1

Fuel System Component Remove & Replace 4-1
Dual Fuel System Diagnosis

5-1

Electrical

6-1

Diagnostic Trouble Codes

7-1

No part of this publication may be reproduced without the written
permission of Power Solutions, Inc. At the time of publication, all of
the information included in this publication is accurate to the best
of our knowledge. Power Solutions, Inc., cannot be responsible for
information that has changed after this book was published.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

MAINTENANCE SECTION 1-1

PSI 3.0L PFI
MAINTENANCE SECTION
Table Of Contents
Description

Page

V-Belts..........................................................................................................................1-2
Serpentine Belts...........................................................................................................1-3
Cooling System............................................................................................................1-3
Engine Electrical System.............................................................................................1-4
Engine Crankcase Oil..................................................................................................1-5
LPG Storage Cylinder and Fuel Filter..........................................................................1-7
Electronic Pressure Regulator (EPR)...........................................................................1-8
Gasoline Fuel Pressure and Temperature Manifold.....................................................1-9
Draining “Heavy Ends” (Oil) Build-Up from EPR.........................................................1-9
LPG Fuel Mixer and Electronic Throttle.....................................................................1-10
Gasoline Fuel Rail and Injectors................................................................................1-11
Three-Way Catalyst Mufﬂer........................................................................................1-11
Recommended Maintenance Schedule.....................................................................1-13

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

MAINTENANCE SECTION 1-2

MAINTENANCE
The maintenance of the engine and its related components is critical to the life of the engine and optimum
performance during its useful life. All engines require a certain amount of maintenance. The suggested
maintenance requirements are contained in this section. Industrial engines operate in various environmental
conditions and various temperature variations. This is a recommended guide line only each user must assess
there own operational usage and determine an appropriate schedule. In addition the owner may have installed
additional equipment to the vehicle may also increase the requirements for service on certain components.
Therefore the owner and the service agent should review the operating condition of the equipment and
determine if more frequent inspections and maintenance cycles maybe required.

MAINTENANCE OF THE BELTS

The engine installed in this equipment may use one or both accessory drive belt conﬁgurations. The drive
belt may be incorporated to drive the water pump, alternator and additional pumps or devices. It is important
to note, the drive belts is an integral part of the cooling and charging systems and should be inspected at a
minimum prescribe in the regular maintenance schedule. Where environmental and operational are more
severe more frequent maintenance is required.
When inspecting the belts check for:
•

Cracks or breaks

•

Chunking of the belt

•

Splits

•

Material hanging from the belt

•

Glazing and hardening

•

Damaged or improperly aligned pulleys

•

Improperly performing tensioner

V-BELT SYSTEMS
Check the belt tensioner by pressing down on the midway point of the longest stretch between pulleys. The
belt should not depress beyond 13mm (1/2 inch). If the depression is more than allowable adjust the tension.
NOTE: Do not over tighten the belt as doing so could cause premature failures in other belt driven
components.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

MAINTENANCE SECTION 1-3

SERPENTINE BELT SYSTEM
Serpentine belts utilize a spring loaded tensioner which keeps the belt properly adjusted. Serpentine belts
should be checked according to the maintenance schedule in this section.
IMPORTANT: The engine manufacturer does not recommend the use of “belt dressing” or “anti
slipping agents” on either belt conﬁguration.
COOLING SYSTEM

It is important to remember that the cooling system of the engine be maintained properly to insure the longevity
of the engine. Maintenance of the cooling system is critical to not only the cooling system but the fuel system
as well. The LPG vaporizer is connected into the cooling system. Low coolant levels and restricted or radiators
plugged with debris can impact the performance of the fuel system. Therefore proper maintenance of the
cooling system should include removing dust, dirt and debris from the radiator core on regular intervals. To
properly maintain the cooling system follow the recommended maintenance schedule in this section.
Cooling system inspections should be performed as prescribe. When inspecting the cooling system check for
the following:
•

Plugged or restricted radiator core clean with compressed air, blow dust and debris from the core and fan
shroud

•

Check the radiator cap to insure the cap is sealing replace if necessary

•

Check for coolant leaks at the radiator tank seams and inlet joints, repair if necessary

•

Check for leaks at the radiator hose connections tighten hose clamps if necessary

•

Check radiator and regulator coolant hoses for swelling separation, cracks or deterioration in the hoses or
hardening if any of these conditions exists replace the hose

•

Check Coolant level if add a mixture of 50% coolant and 50% water, do not add just water

•

Replaced coolant per the recommended maintenance schedule

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

MAINTENANCE SECTION 1-4

Checking the Coolant Level
Check the coolant in the recovery tank. Add coolant as required refer to the vehicle operator manual for more
information on the coolant reserve tank
NOTE: The engine manufacturer and the fuel system supplier DO NOT recommend the use of “stop leak”
additives to temporarily repair leaks. This stop leak can cause slug build up in the regulator coolant line and
cause harm to the regulator.
If the radiator requires repair insure that radiator repair does not result in a signiﬁcant loss of cooling capacity.
The engine manufacturer recommends the cooling system be ﬁlled with a 50/50 mixture of antifreeze and
water. The use of DexCool “Long Life” type coolant (orange) is required. The use of ethylene glycol based
coolant (green) may contribute to premature wear of seals and moving parts in the engine’s cooling system
ENGINE ELECTRICAL SYSTEM MAINTENANCE
The engine electrical system incorporates computers and micro processors to control the engine ignition,
fuel control, and emissions. Due to the sensitivity of the computers to good electrical connections periodic
inspection of the electrical wiring is necessary. When inspecting the electrical system use the following:
•

Check and clean the battery terminal connections and insure the connections are tight

•

Check the battery for any cracks or damage to the case

•

Check the Positive and Negative battery cables for any corrosion build up, rubbing or chafﬁng, check
connection on the chassis to insure they are tight

•

Check the entire engine wire harness for rubbing chafﬁng, cuts or damaged connections, repair if
necessary

•

Check all wire harness connectors to insure they are fully seated and locked

•

Check ignition coil and spark plug cables for hardening, cracking, chafﬁng, separation, split boot covers
and properly ﬁtted

•

Replace spark plugs at the proper intervals as prescribe in the recommended maintenance

•

Check to make sure all electrical components are ﬁtted securely

•

Check the instrument panel to insure all warning lights are functioning, MIL, oil pressure and temperature
gauges are registering

ENGINE CRANKCASE OIL

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

MAINTENANCE SECTION 1-5

To achieve proper engine performance and durability, it is important that you use only engine lubricating oils of
the correct quality in your engine. Proper quality oils also provide maximum efﬁciency for crankcase ventilation
systems. Use only oils displaying the American Petroleum Institute (API) “Starburst” Certiﬁcation Mark ‘FOR
GASOLINE ENGINES’ on the container.
Gasoline engines that are converted to run on LPG or NG MUST use oils labeled ‘FOR GASOLINE ENGINES.’
Do not use oils that are formulated for Diesel engines.
ENGINE OIL VISCOSITY SELECTION
Multi-Viscosity oils are recommended. SAE 10W-30 is recommended in climates that range from 0°F and
above. For climates that consistently fall below 0°F, SAE 5W-30 is recommended.
IMPORTANT:
Oils containing solid additives, non detergent oils, or low quality oils are not recommended by the
engine manufacturer.
USE OF SUPPLEMENTAL ADDITIVES
Oils recommended by the engine manufacturer already contain a balanced additive treatment. The use of
supplemental additives which are added to the engine oil by the owner is not necessary and may be harmful to
the engine. The engine manufacturer, fuel system supplier and the engine distributor do not review, approve or
recommend such products.
SYNTHETIC OILS
Synthetic oils have been available for use in industrial engines for a relatively long period of time. Synthetic oils
may offer advantages in cold temperature pumpability and high temperature oxidations resistance. However,
synthetic oils have not proven to provide operational or economic beneﬁts over conventional petroleum-based
oils in industrial engines. Their use does not allow the extension of oil change intervals.
CHECKING/FILLING ENGINE OIL LEVEL

IMPORTANT: Care must be taken when checking the engine oil level. Oil level must be maintained
between the “ADD” mark and “FULL” mark on the dipstick. To ensure that you are not getting a false
reading, make sure the following steps are taken to before check the oil level

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

MAINTENANCE SECTION 1-6

1. Stop the engine if in use
2. Allow sufﬁcient time (approximately 5 minutes) for the oil to drain back into the oil pan
3. Remove the dipstick. Wipe with a clean cloth or paper towel and reinstall. Push the dipstick all the way
into the dipstick tube
4. Remove the dipstick and note the oil level
5. Oil level must be between the “FULL” and “ADD” marks

Engine Oil Dip Stick

Figure 2

6. If the oil level is below the “ADD” mark, proceed to Step 7 an 8 and reinstall the dipstick into the dipstick
tube
7. Remove the oil ﬁlter cap from the valve rocker arm cover
8. Add the required amount of oil to bring the level up to but not over “FULL” mark on the dipstick
9. Reinstall the oil ﬁll cap to the valve rocker cover and wipe away any excess oil
CHANGING THE ENGINE OIL
IMPORTANT:
When changing the oil, always change the oil ﬁlter. Change oil when the engine is warm from operation
as the oils will ﬂow freely and carry away more impurities.
To change the oil use the following steps
1. Start the engine and run until it reaches normal operating temperature
2. Stop the engine
3. Remove the drain plug and allow the oil to drain
4. Remove and discard the oil ﬁlter and its sealing ring

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

MAINTENANCE SECTION 1-7

5. Coat the sealing ring on the ﬁlter with clean engine oil and wipe the sealing surface on the ﬁlter
mounting surface to remove any dust, dirt and debris. Tighten the ﬁlter securely (follow the ﬁlter
manufacturers instructions). Do not over tighten.
6. Check the sealing ring on drain plug for any damage, replace if necessary, wipe the plug with a clean
rag, and wipe the sealing surface on the pan and reinstall the pan plug. Do not over tighten
7. Fill the crankcase with oil
8. Start the engine and check for oil leaks
9. Stop the engine and check the oil level to insure the oil level is at “FULL”
10. Dispose of the oil and ﬁlter in a safe manner.
FUEL SYSTEM INSPECTION AND MAINTENANCE
The propane fuel system installed on this industrial engine has been designed to meet the emission standards
applicable for the engine size for model year. To insure that the engine continues to meet the regulatory
requirements follow the recommended maintenance schedule contained within this section.
INSPECTION AND MAINTENANCE OF THE FUEL STORAGE CYLINDER
The fuel storage cylinder should be inspected daily or at the beginning of each shift for any external leaks,
external damage, adequate fuel supply and insure the manual service valve is open. Fuel storage cylinders
should always be securely mounted, inspect the securing straps for damage and that the securing devices are
closed and locked. Check to insure that the fuel storage cylinder is properly positioned in the locating pin in the
tank collar on all horizontally mounted tanks this will insure that the tank pressure relief device will always be in
the correct position to function if required.
When refueling or exchanging a cylinder check the quick ﬁll valve for thread damage. Insure that the O-ring
seal is in place check the O-ring for cracks, separation or chunking; replace the O-ring if necessary before
refueling. Check the service line quick coupler for any thread damage. Check the coupler O-ring for cracks,
separation or chunking; replace the O-ring if necessary before refueling.
IMPORTANT: When refueling the cylinder, clean both the ﬁll hose and the tank connector with a clean
cloth to remove any dust, dirt or debris to prevent contamination of the fuel system.
FUEL FILTER MAINTENANCE
The emissions certiﬁed fuel system utilizes inline fuel ﬁlters to remove dirt and debris from both the gasoline
and propane fuel systems. These ﬁlters require periodic maintenance refer to the recommended maintenance
schedule. When inspecting the fuel ﬁlters check the following:
•

Check for any fuel leaks at the inlet and outlet ﬁttings

•

Check to make sure the ﬁlter is securely mounted

•

Check for any external damage or distortion, if damaged replace the ﬁlter element

To replace the ﬁlters use the following steps:

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

MAINTENANCE SECTION 1-8

1. Move the equipment to a well ventilated area and insure there are no external ignition sources
2. On Propane units start the engine and close the manual valve on the cylinder and run the engine until
the engine runs out of fuel.
3. Remove and replace the fuel ﬁlter
4. Leak check the connections with a soapy solution or electronic leak detector
5. On Gasoline fuel pumps with integrated fuel ﬁlters or screens located in the tank follow the OEM
recommended procedures for pump removal
6. On externally mounted ﬁlters close the manual valve at the gasoline tank to prevent fuel from draining
from the tank.
7. Drain any excess fuel into an approved container and replace the ﬁlter
8. After replacing the ﬁlter start the engine and leak check all connections

PROPANE ELECTRONIC PRESSURE REGULATOR (EPR) MAINTENANCE
The emission certiﬁed propane fuel system utilizes a speciﬁcally designed pressure regulator which reduces
the high pressure propane fuel to a lower pressure fuel which can be consumed in the engine. The EPR is
made up of two separate components a pressure regulator and an electronic control unit or voice coil. The
regulator is a two stage pressure regulator. The ﬁrst stage or primary stage reduces the tank pressure to a
pressure of 6-34 kPa (1-5 PSI). The second stage portion of the regulator is controlled by the voice coil portion
of the regulator and regulates the amount of fuel to be delivered to the mixer.
The regulator portion of the EPR can be serviced with parts supplied by the OEM, refer to servicing the
pressure regulator in the Fuel System R&R section of this manual.
When inspecting the EPR check for the following items:
•

Check for any fuel leaks at the inlet and outlet ﬁttings

•

Check for any fuel leaks at the connecting seams of the regulator body

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

MAINTENANCE SECTION 1-9

•

Check the inlet and outlet coolant ﬁttings at the regulator body

•

Check the inlet and outlet coolant lines for hardening, cracking, chafﬁng or splits. If any of these
conditions exist replace the coolant lines

•

Check the inlet and outlet coolant line hose clamps at each connection, tighten if necessary

•

Check the CAN connection on the electronic control section to insure it is seated and locked

•

Check to make sure the EPR assembly is securely mounted to the rubber isolators

•

Check the rubber isolators for cracking, hardening or separation

GASOLINE FUEL PRESSURE & TEMPERATURE MANIFOLD
The emission certiﬁed gasoline system utilizes a pressure and temperature manifold assembly device which
allows the fuel pressure to be maintained at the injectors and returns any unused fuel back into the tank.
This device prevents large amounts of fuel from being returned to the tank which would cause the fuel to be
agitated. Excessively agitating fuel causes large amounts of vapor to be built up in the fuel tank. Therefore the
gasoline pressure and temperature manifold assembly is critical to preventing heavy vapor build up in the tank.
When inspecting the gasoline pressure and temperature manifold assembly check the following items:
•

Check for any fuel leaks at the inlet and outlet ﬁtting on the regulator

•

Check the inlet and outlet hoses or fuel lines for any rubbing chafﬁng or external damage

•

Check the electrical connection at the sensor to insure the connector is seated and locked

•

Check to make sure the assembly is securely mounted

DRAINING OIL BUILD UP FROM THE PROPANE REGULATOR
During the course of normal operation oils or “heavy ends” may build inside the primary and secondary
chambers of the propane pressure regulator. These oils and heavy ends may be a result of poor fuel quality,
contamination of the fuel supply chain, or regional variation in the make up of the fuel. If the build up of the oil
is signiﬁcant this can effect the operation of the fuel control system. The recommended maintenance schedule
recommends periodic draining of the oil from the regulator. More frequent draining may be required if the fuel
supply has been contaminated.
Use the following procedure to drain the regulator:
IMPORTANT: For best results warm the engine to operating temperature before draining as this will
allow the oils to be liquid and ﬂow freely from the regulator.
1. Move the equipment to a well ventilated area and insure there are no external ignition sources.
2. Start the engine and bring to operationing temperature.
3. With the engine running close the manual tank valve and run the engine out of fuel.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

MAINTENANCE SECTION 1-10

4. Switch the Key to the Off position once the engine stops.
5. Disconnect the electrical connection to the LPG fuel temperature sesnor in the auxilliary fuel port of the
EPR.
6. Remove the retainer clip for the LPG fuel temperature sensor and remove the sesnor from the regulator
body. Note: Have a small container ready to collect oil that will drain freely from the regulator at this
point.
7. Once all of the oil has been drained, reinstall the LPG fuel temperature sensor and recoonectthe
electrical connector.
8. Re-open the fuel tank manual valve.
9. Start the engine and verify all connections.
10. Dispose of any oil in a safe and proper fashion.

AIR FUEL MIXER AND THROTTLE CONTROL DEVICE INSPECTION
The air fuel mixer component ﬁtted to the emission certiﬁed engines have been speciﬁcally designed and
calibrated to meet the regulatory requirements applicable for the engine.
The mixer can be serviced using parts supplied by the OEM, refer to servicing the mixer in the Fuel System
R&R section of this manual.
When inspecting the mixer check for the following items:
•

Check for any leaks at the inlet ﬁtting

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

MAINTENANCE SECTION 1-11

•

Check the air inlet connection to insure the clamp is tight and sealed

•

Check the vapor hose from the regulator to the mixer for kinks, collapsing, cracks, splitting, chafﬁng or
loose connections, replace of any of these conditions are present

•

Check the mixer mounting at the throttle control device to insure there are no vacuum leaks

•

Check to make sure the mixer is securely attached

•

Check the air cleaner element and replace if necessary

THROTTLE CONTROL INSPECTION
The throttle control device utilized on this industrial engine is an Electronic Throttle Control (ETC) device.
The ETC receives electrical signals and sends signals to the ECM. Therefore it is important that the electrical
connector be securely in place and locked.
In addition to controlling engine speed and load correction the ETC acts as the connecting mechanism
between the mixer and the manifold. Any vacuum leaks below the mixer can cause loss of fuel control when
operating on propane. Always insure that the throttle connecting screws are securely fastened.
When inspecting the throttle body check for the following items:
•

Check the throttle body connections to the mixer and manifold or adaptors is securely attached

•

Check for any vacuum leaks below the mixer

•

Check the ETC electrical connections and insure they are fully seated and locked

GASOLINE FUEL RAIL AND INJECTORS
The dual fuel system utilizes both a propane fuel system and a base gasoline fuel system to operate. The
emission certiﬁed engine gasoline fuel system utilizes a port injection fuel system and a common rail for fuel
delivery.
When inspecting the gasoline injectors and fuel rails check for the following items
•

Check the fuel supply hoses for cracking, chafﬁng, loose connections, or any external damage and replace
if any of these conditions exists

•

Check the fuel rail to insure the rail is securely attached

•

Check the injector for any leaks at the inlet or outlet points on the injector

•

Check the each injector electrical connector to make sure the connector is fully seated and locked

EXHAUST SYSTEM AND CATALYTIC CONVERTOR INSPECTION AND MAINTENANCE
The exhaust system on this emission certiﬁed engine contains a Heated Exhaust Gas Sensor (HEGO) before
the catalyst as well as after the catalyst. The pre catalyst sensor is used to provide fuel correction information
to the ECM. The Post Catalyst sensor provides input to the ECM as the effectiveness of the fuel control
system.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

MAINTENANCE SECTION 1-12

It is important to insure that the HEGO sensors are properly operating. As well visual inspection of the catalyst
can provide insight as to over fueling condition within the fuel system.
When inspecting the exhaust system check for the following:
•

Check the exhaust manifold connection to insure they are tight and no exhaust leaks are present

•

Check the exhaust pipe to manifold to insure the bolts are tight and the connection is sealed

•

Check the exhaust pipe for any external damage, holes or crushed pipes which may cause exhaust gas
ﬂow restriction. Exhaust gas restriction generally cause the manifold and or exhaust pipes to turn blue.

•

Check to make sure the exhaust pipe is securely attached at all hangers and supports

•

Check the Catalyst to insure that the catalyst is securely attached at all hangers and supports

•

Check both the HEGO sensor electrical connections to insure they are fully seated and locked

•

Check for any HEGO wiring damage which may have been caused by heat or external interference

•

Check the tail pipe for any damage and that the opening is not crushed or restricting ﬂow

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

MAINTENANCE SECTION 1-13

Recommended Maintenance Schedule
GASOLINE AND LPG CERTIFIED ENGINE MAINTENANCE REQUIREMENTS
Install
Date

Interval Hours

Daily 200 400 800 1000 1250 1500 1750 2000
General Maintenance Section
Visual check for leaks
X
Check engine oil level
X
Check coolant level
X
Every 150 hours or 120 days of operation
Change engine oil and ﬁlter
Prior to any service or maintenance activity
Check LPG/Gas system for leaks
Inspect accessory drive belts
X
X
Inspect electrical system
X
Inspect all vacuum lines and ﬁtting
X
Engine Coolant Section
Every 100 hours or 60 days of operation
Clean debris from radiator core
Change coolant
X
Inspect coolant hoses for cracks,
swelling or deterioration
X
X
Engine Ignition System
Inspect Battery case for damage
X
X
Check all electrical connectors
X
X
Replace Spark Plug Wires
X
Replace Distributor Cap & Rotor
X
Replace spark plug wires
X
Fuel System Maintenance
Replace fuel ﬁlter (Gas & LPG)
X
X
Inspect lock off for leaks & closing
X
Check LPG/Gas regulator pressure
X
Leak check LPG/Gas fuel lines
X
Inspect/Drain EPR-LPR for oil build
Every 150 hours or 120 days of operation
up
Annually or every 2000 hours
Inspect LPR for coolant leaks
Check air induction for leaks
X
Check manifold for vacuum leaks
X
Replace PCV Valve
X
Check injector & rails for leaks
X
Every
200
hours,
or
every
100
hours
in
dusty
environment
Inspect air cleaner
Every 400 hours, or every 200 hours in dusty environment
Replace ﬁlter element
Engine Exhaust System
Inspect exhaust manifold for leaks
X
Inspect exhaust piping for leaks
X
Inspect catalyst inlet and outlet
X
Check HEGO sensors connections
X
The maintenance schedule represents manufacturers recommended maintenance intervals to maintain
proper engine/equipment function. Speciﬁc state and federal regulations may require equipment operators
to conduct comprehensive engine/equipment inspections at more periodic intervals than those speciﬁed
above.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-1

Base Engine Section Table of Contents
Speciﬁcations ............................................................4
Fastener Tightening Speciﬁcations ............................4
Sealers, Adhesives and Lubricants ...............................4
Engine Mechanical Speciﬁcations (1 of 2) ....................5
Engine Mechanical Speciﬁcations (2 of 2) ....................6
Diagnostic Information and Procedures ..................7
Base Engine Noise Diagnosis .......................................7
Engine Compression Test..............................................8
Engine Noise Diagnosis ................................................8
Knocks Cold and Continues for 2 to 3 Minutes .............8
Knocks on Start-Up but Only Lasts a Few Seconds .....8
Knocks at Idle Hot .........................................................8
Valve Train Diagnosis ....................................................8
Oil Consumption Diagnosis ...........................................8
Low or No Oil Pressure Diagnosis and Testing .............9
Oil Leak Diagnosis ........................................................9
Block Explode #1 Disassembled View (1 of 4) ............10
Block Explode #2 Disassembled View (2 of 4) ...........12
Head Explode Disassembled View (3 of 4) .................14
Oil Pump Explode Disassembled View (4 of 4) ...........15
Draining Fluids, Oil Filter and Fuel Pump Cover
Removal .................................................................16
Engine Flywheel Removal ...........................................17
Fuel Rail Removal .......................................................17
Distributor/High Voltage Switch (HVS) Removal .........18
Ignition Coil Module Assembly Removal .....................18
Oil Level Indicator and Tube Removal ........................19
Lift Bracket Removal ...................................................19
Spark Plug Removal ....................................................19
Intake/Exhaust Manifold Removal ...............................20
Intake/Exhaust Manifold Disassemble and
Assemble ...............................................................20
Intake/Exhaust Manifold Clean and Inspect ................20
Coolant Inlet and Coolant Thermostat Removal..........21
Water Pump Removal .................................................21
Crankshaft Pulley Removal .........................................21
Valve Rocker Arm Cover Removal ..............................22
Pushrod Cover Removal .............................................22
Fuel Rail Bracket Removal ..........................................22
Valve Rocker Arm and Pushrod Removal ...................23
Measuring Camshaft Lobe Lift ....................................23
Valve Train Components Inspect (Cylinder Head).......24
Valve Lifter Removal....................................................24
Cylinder Head Removal ..............................................25
Oil Pan Removal .........................................................25
Oil Pump Removal ......................................................25
Engine Front Cover Removal ......................................26
Measuring Crankshaft and Camshaft Sprocket
Runout ...................................................................26
Measuring Timing Sprocket Teeth Backlash................27
Crankshaft Sprocket Removal .....................................27
Camshaft Removal ......................................................27
Crankshaft and Camshaft Sprocket Inspect ................28
Timing Gear Oil Nozzle Removal ................................28
Piston, Connecting Rod and Bearing Removal ...........29
Crankshaft and Bearings Clean and Inspect (Connecting
Rod Bearing Clearance) ........................................30

Crankshaft Rear Oil Seal and Housing Removal ........32
Crankshaft , Bearings and Bearing Cap Removal .......33
Crankshaft and Bearings Clean and Inspect ...............33
Crankshaft and Bearings Clean and Inspect
(Main Bearing Clearance) ......................................35
Camshaft Bearing Removal ........................................38
Distributor Lower Bushing and Thrust Washer
Removal .................................................................39
Oil Filter Bypass Valve Removal and Installation ........39
Cylinder Block Clean and Inspect ...............................40
Cylinder Bore Measurements ......................................40
Cylinder Boring and Honing ........................................41
Distributor Lower Bushing and Thrust Washer
Installation ..............................................................42
Piston and Connecting Rod Disassemble ...................42
Piston and Connecting Rod Clean and Inspect ...........43
Piston Selection ...........................................................45
Piston and Connecting Rod Assemble ........................46
Camshaft and Bearings Clean and Inspect .................47
Camshaft Sprocket and Retainer Removal and
Installation ..............................................................49
Camshaft Bearing Installation .....................................50
Oil Pump Disassemble ................................................51
Oil Pump Clean and Inspect ........................................52
Oil Pump Assemble .....................................................53
Cylinder Head Disassemble ........................................54
Cylinder Head Clean and Inspect ................................55
Valve Guide Reaming/Valve and Seat Grinding ..........58
Rocker Arm Stud Removal and Installation .................59
Cylinder Head Assemble .............................................60
Service Prior to Assembly ...........................................61
Crankshaft, Bearings and Bearing Cap Installation .....61
Crankshaft Rear Oil Seal and Housing Installation .....62
Piston, Connecting Rod and Bearing Installation ........63
Timing Gear Oil Nozzle Installation .............................65
Crankshaft Sprocket Installation ..................................65
Camshaft Installation ...................................................65
Engine Front Cover and Oil Seal Installation ..............66
Oil Pump Installation ...................................................67
Oil Pan Installation ......................................................67
Crankshaft Pulley Installation ......................................68
Cylinder Head Installation ...........................................68
Fuel Rail Inspection and Installation ............................69
Cylinder Head Torque Sequence.................................69
Valve Lifter Installation.................................................69
Valve Rocker Arm and Pushrod Installation ................70
Pushrod Cover Installation ..........................................71
Valve Rocker Arm Cover Installation ...........................72
Oil Level Indicator and Tube Installation .....................72
Water Pump Installation ..............................................72
Coolant Inlet and Coolant Thermostat Housing
Installation ..............................................................73
Intake/Exhaust Manifold Installation ............................73
Spark Plug Installation .................................................73
Lift Bracket Installation ................................................74
Ignition Coil Module Assembly Installation ..................74
Distributor/High Voltage Switch Installation .................75

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-2

Base Engine Section Table of Contents
Engine Flywheel Installation ........................................76
Engine Block Coolant Plug/Oil Filter/Crankshaft Position
Sensor and Fuel Pump Cover Installation .............76
Description and Operation ......................................78
Engine Component Description ...................................78
Engine Block ...............................................................78
Cylinder Head ..............................................................78
Crankshaft ...................................................................78
Camshaft .....................................................................78
Pistons and Connecting Rods .....................................78
Valve Train ...................................................................78
Lubrication ...................................................................79
Thread Repair .............................................................79
Cleanliness and Care ..................................................80
Replacing Engine Gaskets ..........................................80
Use of RTV and Anaerobic Sealer...............................80
Separating Parts ..........................................................81
Tools and Equipment ...................................................81
Special Tools and Equipment ......................................82

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-3

3.0L
NOTICE: Always use the correct fastener in the proper location. When you replace a fastener, use ONLY the exact
part number of that application.
General Motors will call out those fasteners that require a replacement after removal. General Motors will also call
out the fasteners that require thread lockers or thread sealant.
UNLESS OTHERWISE SPECIFIED, Do Not use supplemental coatings (paints, greases or other corrosion inhibitors)
on threaded fasteners or fastener joint interfaces. Generally, such coating adversely affect the fastener torque and
the joint clamping force, and may damage the fastener.
When you install fasteners, use the correct tightening sequence and speciﬁcations.
Following these instructions can help you avoid damage to parts and systems.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-4

Engine Mechanical - 3.0L
Speciﬁcations
Application
Camshaft Retainer Bolts
Coolant Temperature Sensor
Connecting Rod Cap Nuts
Crankshaft Main Bearing Cap Bolts
Crankshaft Position Sensor Retaining Bolt
Crankshaft Rear Oil Seal Retainer Bolts
Cylinder Head Bolts
Distributor Hold Down Bolt
Flywheel Bolts
Front Cover Bolts
Fuel Pump Cover Bolts
Fuel Rail to Fuel Rail Bracket Bolts
Ignition Coil Bracket Attaching Bolts
Ignition Coil Module to Bracket Bolts
Intake to Exhaust Manifold Attaching Nuts and Bolt
Intake/Exhaust Manifold to Head (2 center)
Intake/Exhaust Manifold to Head (outer)
Lift Bracket Bolts
Oil Level Bracket Nut
Oil Pan Nuts (rear)
Oil Pan Bolts (to crankcase)
Oil Pan Bolts (to front cover)
Oil Pan Studs to Oil Seal Retainer or Crankcase
Oil Pump Cover
Oil Pump to Block
Oil Pump Pickup
Pushrod Cover Bolts
Rocker Arm Cover Bolts
Spark Plugs
Thermostat Housing Bolt
Water Outlet Housing Bolts
Water Pump Bolts

GM Part Number
1052080
1052080
1052914
1052365
1052080
1052080

Type of Material
Sealant
Sealant
Sealant
Lubricant
Sealant
Sealant

N•m
N
m
9
20
61
85
10
15
135
33
100
9
19
12
25
2
47
50
50
34
9
19
11
5
2
8
13
7
9
7
20
38
28
20

Lb Ft

Lb In
80

15
45
63
89
133
100
24
74
80
14
106
18
18
35
37
37
25
80
168
97
44
18
71
115
62
80
62
15
28
21
15

Application
Rear camshaft bearing hole plug
Cylinder head bolt threads
Oil pan sealing surfaces
Valve train component prelube
Valve rocker arm stud threads
Oil level indicator tube

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Application

BASE ENGINE SECTION 2-5
Metric

English

General Data
Engine Type
Displacement

L4
3.0L

181 CID

Bore

101.60 mm

4.000 in

Stroke

91.44 mm

3.60 in

Compression Ratio

9.25:1

Firing Order

1-3-4-2

Spark Plug Gap

0.9 mm

0.035 in

Spark Plug Platinum Gap

1.28 mm

0.050 in

41.4 kPa at
1,000 engine rpm

6.0 psig at
1,000 engine rpm

124.1 kPa at
2,000 engine rpm

18.0 psig at
2,000 engine rpm

165.5 kPa at
4,000 engine rpm

24.0 psig at
4,000 engine rpm

Lubrication System
Oil Pressure (Minimum - Hot)

Oil Capacity (With Oil Filter Change)

3.81

Oil Pump Type

4.00 qts
Gear Driven

Cylinder Block
Bore Diameter

101.5746-101.6508 mm

3.9990-4.0020 in

Bore Out-of-Round Production

0.0254 mm (Maximum)

0.001 in (Maximum)

Bore Out-of-Round Service Limit

0.0508 mm (Maximum)

0.002 in (Maximum)

Bore Taper Thrust Side Production

0.0127 mm (Maximum)

0.0005 in (Maximum)

Bore Taper Thrust Side Service Limit

0.0254 mm (Maximum)

0.001 in (Maximum)

Bore Taper Relief Side Production

0.0127 mm (Maximum)

0.0005 in (Maximum)

Bore Taper Relief Side Service Limit

0.0254 mm (Maximum)

0.001 in (Maximum)

0.05 mm (Maximum)

0.002 in (Maximum)

Runout - Rear Face of Block to Crankshaft Center Line
Piston
Piston-To-Bore Clearance Production

0.0635-0.0889 mm

0.0025-0.0035 in

0.0889 mm

0.0035 in (Maximum)

Piston Compression Ring Groove Clearance Production Top

0.03048-0.07366 mm

0.0012-0.0029 in

Piston Compression Ring Groove Clearance Production 2nd

0.03048-0.07366 mm

0.0012-0.0029 in

0.09906 mm (Maximum)

0.0039 in (Maximum)

Piston-To-Bore Clearance Service Limit
Piston Rings

Piston Compression Ring Groove Clearance Service Limit
Piston Compression Ring Gap Top Production *

0.254-0.508 mm

0.01-0.02 in

Piston Compression Ring Gap 2nd Production *

0.4318-0.635 mm

0.017-0.025 in

Piston Compression Ring Gap Top Service Limit *

0.88 mm (Maximum)

0.035 In (Maximum)

Piston Compression Ring Gap 2nd Service Limit *

0.88 mm (Maximum)

0.035 in (Maximum)

Piston Oil Ring Groove Clearance Production
Piston Oil Ring Groove Clearance Service Limit
Piston Oil Ring Gap Production *
Piston Oil Ring Gap Service Limit *

0.0254-0.1524 mm

0.001-0.006 in

0.1778 mm (Maximum)

0.007 in (Maximum)

0.25-0.76 mm

0.01-0.03 in

1.016 mm (Maximum)

0.04 in (Maximum)

23.545-23.548 mm

0.9270-0.927 in

Piston Pin
Diameter
Clearance in Piston Production

0.00762-0.01651 mm

0.0003-0.00065 in

Clearance in Piston Service Limit

0.0254 mm (Maximum)

0.001 in (Maximum)

Fit in Connecting Rod

0.02032-0.050292 mm
(Interference)

0.0008-0.00198 in
(Interference)

* Measured in cylinder bore

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-6

Crankshaft
Crankshaft Journal Diameter (All)

58.3666-58.4047 mm

2.2979-2.2994 in

Crankshaft Journal Taper Production

0.005 mm (Maximum)

0.0002 in (Maximum)

Crankshaft Journal Taper Service Limit

0.0254 mm (Maximum)

0.001 in (Maximum)

Crankshaft Journal Out-of-Round Production

0.005 mm (Maximum)

0.0002 in (Maximum)

Crankshaft Journal Out-of-Round Service Limit

0.0254 mm (Maximum)

0.001 in (Maximum)

Crankshaft Bearing Clearance Production #1 - #4

0.0254-0.06096 mm

0.001-0.0024 in

Crankshaft Bearing Clearance Production #5

0.0406-0.0889 mm

0.0016-0.0035 in

Crankshaft Bearing Clearance Service Limit #1 - #4

0.0254-0.0635 mm

0.001-0.0025 in

Crankshaft Bearing Clearance Service Limit #5

0.0381-0.0889 mm

0.0015-0.0035 in

Crankshaft End Play
Crankshaft Sprocket Runout

0.05-0.1524 mm

0.002-0.006 in

0.07 mm (Maximum)

0.003 in (Maximum)

Connecting Rod
Connecting Rod Journal Diameter

53.2892-53.3273 mm

2.0980-2.0995 in

Connecting Rod Journal Taper Production

0.00762 mm (Maximum)

0.0003 in (Maximum)

Connecting Rod Journal Taper Service Limit

0.0254 mm (Maximum)

0.001 in (Maximum)

Connecting Rod Journal Out-of-Round Production

0.005 mm (Maximum)

0.0002 in (Maximum)

Connecting Rod Journal Out-of-Round Service Limit

0.0254 mm (Maximum)

0.001 in (Maximum)

Rod Bearing Clearance Production

0.04318-0.06858 mm

0.0017-0.0027 in

0.0762 mm (Maximum)

0.003 in (Maximum)

0.1524-0.4318 mm

0.006-0.017 in

Journal Diameter (Industrial)

47.452-47.478 mm

1.8682-1.8692 in

Journal Diameter (Marine)

47.440-47.490 mm

1.8677-1.8697 in

End Play

0.0762-0.2032 mm

0.003-0.008 in

Camshaft Sprocket Runout

0.1 mm (Maximum)

0.004 in (Maximum)

Rod Bearing Clearance Service Limit
Rod Side Clearance
Camshaft

Timing Sprocket Teeth Backlash

0.10-0.15 mm

0.004-0.006 in

Lobe Lift Intake (Industrial)

5.516-5.791 mm

0.2172-0.2280

Lobe Lift Exhaust (Industrial)

5.516-5.791 mm

0.2172-0.2280

Lobe Lift Intake (Marine)

6.400-6.45 mm

0.2520-0.2539

Lobe Lift Exhaust (Marine)

6.400-6.45 mm

0.2520-0.2539

±0.0254 mm

±0.001 in

Lobe Lift Service Limit
Valve System
Valve Lifter

Hydraulic

Valve Rocker Arm Ratio

1.75:1

Valve Lash

Half to One Turn Down From Zero Lash

Face Angle

45 Degrees

Seat Angle
Seat Runout

46 Degrees
0.05 mm (Maximum)

0.002 in (Maximum)

Seat Width Intake

1.27-1.778 mm

0.050-0.070 in

Seat Width Exhaust

1.524-2.032 mm

0.060-0.080 in

0.0254-0.06858 mm

0.001-0.0027 in

Stem Clearance Intake Production
Stem Clearance Exhaust Production

0.01778-0.06858 mm

0.0007-0.0027 in

Stem Clearance Intake Service Limit

0.09398 mm (Maximum)

0.0037 in (Maximum)

0.1193 mm (Maximum)

0.0047 in (Maximum)

Stem Clearance Exhaust Service Limit
Valve Spring Free Length

52.299 mm

2.059 in

Valve Spring Pressure Closed

444-490 N at 40.89 mm

100-110 lb at 1.61 in

Valve Spring Pressure Open

925-987 N at 30.99 mm

208-222 lb at 1.22 in

Valve Spring Installed Height Intake

41.91 mm

1.65 in

Valve Spring Installed Height Exhaust

41.91 mm

1.65 in

Valve Lift Intake

11.25 mm

0.443 in

Valve Lift Exhaust

11.25 mm

0.443 in

Cylinder Head Deck (measured within a 152.4 mm (6.0 in) area)

0.0762 mm

0.003 in

Cylinder Head Deck (measuring the overall length of the cylinder head)

0.1778 mm

0.007 in

Cylinder Head Warpage

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-7

Step

Action

Value

Yes

1. With the engine running, try to determine if the noise is
timed to the crankshaft speed or the camshaft speed.
2. Using a timing light, two knocks per ﬂash is the
crankshaft or one knock per ﬂash is the camshaft.
Is the noise timed to the crankshaft speed?

—

Go to Step 2

Go to Step 3

1. Remove the rod bearings and inspect the bearings and
the journals for wear.
2. If the parts are OK, remove the crankshaft and inspect
the main bearings and journals for wear.
3. Replace the parts as necessary.
Does the engine continue to knock?

—

Go to Step 3

System OK

Check to see if the noise is timed to the camshaft speed.
Is the noise timed to the camshaft speed?

—

Go to Step 5

Go to Step 4

1. Inspect for loose accessory attachments, the ﬂywheel.
2. Tighten or adjust as necessary.
Does the engine continue to knock?

—

Go to Step 5

System OK

1. Remove the pushrod cover.
• Refer to Pushrod Cover Removal.
2. Rotate the engine and measure the lifter movement in
the bore.
3. Compare the measurement with the speciﬁcations in
Engine Mechanical Speciﬁcations.
Is the camshaft within speciﬁcations?

—

Go to Step 7

Go to Step 6

Replace the camshaft. Refer to Camshaft Removal and
Installation.
Does the engine continue to knock?

—

Go to Step 7

System OK

1. Remove the rocker arms, the pushrods and the lifters.
2. Inspect the parts for excessive wear or damage.
3. Replace the parts as necessary.
Are the repairs complete?

—

System OK

—

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-8

Engine Compression Test

•

Perform the following steps in order to conduct a compression
test:

Improper oil viscosity. Install recommended oil
viscosity for expected temperatures.

•

Excessive piston to bore clearance.

Conduct the following steps in order to check cylinder
compression:

•

Excessive piston pin to piston clearance.

1.1.

Engine should be at room temperature.

•

Excessive crankshaft end clearance.

1.2.

Disconnect the two electrical connectors from
the distributor.

•

Excessive crankshaft bearing clearance.

1.3.

Remove the spark plugs.

1.4.

Throttle plates should be wide open.

1.5.

Battery should be at or near full charge.

For each cylinder, crank engine through four
compression strokes.

The lowest cylinder reading should not be less than
70% of the highest.

No cylinder reading should be less than 689 kPa
(100 psi).

Important: The results of a compression test will fall into the
following categories:
1.

Normal — Compression builds up quickly and evenly to
speciﬁed compression on each cylinder.

Piston Rings — Compression low on ﬁrst stroke. Tends
to build up on the following strokes but does not reach
normal. Improves considerably with addition of oil.

Valves — Compression low on ﬁrst stroke. Does not
tend to build up on the following strokes. Does not
improve much with addition of oil. Use approximately
three squirts from a plunger-type oiler.

Knocks at Idle Hot
•

Detonation or spark knock. Check operation of ignition
controls or knock sensor circuit.

•

Loose ﬂywheel bolts.

•

Exhaust leak at manifold. Tighten the exhaust
manifold bolts and/or replace the gasket.

•

Excessive connecting rod bearing clearance. Replace
the bearings as necessary.

•

Excessive piston pin clearance.

•

Excessive crankshaft thrust bearing clearance.

•

Bent connecting rod.

Valve Train Diagnosis
A light tapping at one-half engine speed or any varying
frequency, can indicate a valve train problem. These tapping
noises increase with engine speed.
Before attempting to judge the valve train noises, thoroughly
warm up the engine. By doing this you will bring all engine
components to a normal state of expansion. Also, run the engine
at various speeds and listen for engine noise. The causes of the
valve train noise include the following conditions:
•

Incorrectly adjusted valve lash.

Engine Noise Diagnosis

•

Low oil pressure.

There are four steps to diagnosing engine noise. You must
determine the following conditions:

•

Loose valve rocker arm attachments.

•

Worn valve rocker arm and/or pushrod.
Broken valve spring.

•

Type of noise.

•

The exact operating condition under which the noise
exists.

•

Sticking valves.

•

Lifters worn, dirty or faulty.

•

Determine the rate and location of the noise.

•

Camshaft lobes worn.

•

Compare the sounds in other engines to make sure
you are not trying to correct a normal condition.

•

Worn valve guides.

•

Worn or damaged valve keys.

•

Bent pushrods.

Identify the type of noise. For example, a light rattle or low
rumble.
Remember, engine noises are generally synchronized to either
engine speed (caused by the crankshaft, pistons or connecting
rods) or one-half engine speed (valve train noise). Try to
determine the rate at which the noise is occurring.
Knocks Cold and Continues for 2 to 3 Minutes
•

Engine ﬂywheel contacting the splash shield.
Reposition the splash shield.

•

Loose or broken crankshaft balancer or drive
pulleys. Tighten or replace as necessary.

•

Excessive piston to bore clearance. Replace the
piston.

•

Cold engine knock usually disappears when
the speciﬁc cylinder secondary ignition circuit is
grounded out. Cold engine piston knock which
disappears in 1.5 minutes should be considered
acceptable.

Knocks on Start-Up but Only Lasts a Few Seconds

Oil Consumption Diagnosis
Excessive oil consumption (not due to leaks) is the use of 1.9L
(2 qts.) or more of engine oil within 50 hours of use. The causes
of excessive oil consumption include the following conditions:
•

External oil leaks. Tighten bolts and/or replace gaskets
and oil seals as necessary.

•

Incorrect oil level or improper reading of oil level
indicator. With the engine at a level surface, allow
adequate drain down time and check for the correct oil
level.

•

Improper oil viscosity. Use a recommended SAE
viscosity for the prevailing temperatures.

•

Continuous high speed operation and/or severe
usage.

•

Crankcase ventilation system restrictions or
malfunctioning components. Possible improper PCV
valve.

•

Valve guides and/or valve stem oil seals worn, or

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

•

BASE ENGINE SECTION 2-9

the seal omitted. Ream guides and install oversize
service valves and/or new valve stem oil seals.

Perform the following steps in order to use the black light and
dye method:

Piston rings broken, improperly installed, worn or
not seated properly. Allow adequate time for rings to
seat. Replace broken or worn rings as necessary.

Tools Required

Piston improperly installed or mis-ﬁtted.

Low or No Oil Pressure Diagnosis and Testing
•

Low oil level. Fill to full mark on oil level indicator.

•

Incorrect or malfunctioning oil pressure switch.

•

Incorrect or malfunctioning oil pressure gauge.

•

Improper oil viscosity for the expected temperature.

•

Oil pump worn or dirty.

•

Malfunctioning oil pump pressure regulator valve.

•

Plugged oil ﬁlter.

•

Oil pump screen loose, plugged or damaged.

•

Excessive bearing clearance. Replace as
necessary.

•

Cracked, porous or restricted oil galleys. Repair or
replace the engine block.

J 39400 Leak Detector
1.

Pour speciﬁed amount of dye into the leaking
component.

Run the engine under normal operating conditions as
directed by the J 39400.

Direct the light toward the suspected area. The dyed
ﬂuid will appear as a yellow path leading to the source.

Repairing the Leak
Once the origin of the leak has been pinpointed and traced
back to its source, the cause of the leak must be determined in
order for it to be repaired properly. If a gasket is replaced, but
the sealing surface is damaged, the new gasket will not repair
the leak. Before attempting to repair a leak, be sure that the
gasket and sealing surfaces are correct.
Perform the following steps in order to check for gasket leaks:
1.

Inspect the ﬂuid level/pressure for being too high.

Check the crankcase ventilation system for restrictions
or malfunctioning components.

Inspect for improperly tightened fasteners or dirty/
damaged threads.

Oil Leak Diagnosis

Look for warped ﬂanges or sealing surfaces.

Most ﬂuid oil leaks are easily located and repaired by visually
ﬁnding the leak and replacing or repairing the necessary parts.
On some occasions a ﬂuid leak may be difﬁcult to locate or
repair.

Check for scratches, burrs or other damage to the
sealing surface.

Look for a damaged or worn gasket.

Check for cracking or porosity of the component.

Check for use of an improper sealant used (where
applicable).

•

Oil galley plugs missing or incorrectly installed.
Install the plugs or repair as necessary.

•

Oil diluted by moisture or unburned fuel mixtures.

Use the following steps in order to ﬁnd the leak:
1.

Identify the ﬂuid, determine whether it is engine oil,
transmission ﬂuid or power steering ﬂuid.

At what point is the ﬂuid leaking from? After running the
engine at normal operating temperature, place a large
sheet of paper under the engine. After a few minutes,
you should be able to ﬁnd the approximate location of
the leak by the drippings on the paper.

Visually check around the suspected component.
Check around the gasket mating surfaces for leaks. A
mirror is useful for ﬁnding leaks in areas that are hard to
reach.

If the leak still cannot be found, it may be necessary to
clean the suspected area with a degreaser, steam or
spray solvent. Clean the area well, then dry the area.
Run the engine for several minutes at normal operating
temperature and varying speeds. After running the
engine, visually check the suspected area. If you still
cannot locate the leak, try using the powder or black
light and dye method.

Perform the following steps in order to perform the powder
method:
1.

Clean the suspected area.

Apply an aerosol-type powder (such as foot powder) to
the suspected area.

Run the engine under normal operating conditions.

Visually inspect the suspected area. You should be able
to trace the leak path over the white powder surface to
the source.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Block Explode #1

BASE ENGINE SECTION 2-10

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-11

Disassembled View (1 of 4)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42

VALVE ROCKER ARM COVER BOLT
VALVE ROCKER ARM COVER REINFORCEMENT
VALVE ROCKER ARM COVER
OIL FILLER CAP
VALVE ROCKER ARM COVER GASKET
EFE VALVE THERMOSTAT
INTAKE MANIFOLD
INTAKE MANIFOLD NUT
INTAKE/EXHAUST MANIFOLD CLAMP
INTAKE/EXHAUST MANIFOLD WASHER
INTAKE/EXHAUST MANIFOLD BOLT
INTAKE/EXHAUST MANIFOLD GASKET
EFE VALVE SPRING
EFE VALVE WEIGHT
EXHAUST MANIFOLD
INTAKE/EXHAUST MANIFOLD BOLT
EXHAUST MANIFOLD STUD
INTAKE/EXHAUST MANIFOLD GASKET
CYLINDER HEAD BOLT
CYLINDER HEAD
CYLINDER HEAD GASKET
LIFT BRACKET
LIFT BRACKET BOLT
WATER OUTLET HOUSING BOLTS
WATER OUTLET HOUSING
WATER OUTLET HOUSING GASKET
COOLANT THERMOSTAT
THERMOSTAT HOUSING
THERMOSTAT HOUSING BOLTS
THERMOSTAT HOUSING GASKET
COOLANT TEMPERATURE SENSOR
ENGINE BLOCK
WATER PUMP GASKET
WATER PUMP
WATER PUMP BOLT
WATER PUMP BOLT
PUSHROD COVER GASKET
PUSHROD COVER
PUSHROD COVER BOLT
VALVE LIFTER
ENGINE BLOCK COOLANT PLUG
PUSHROD COVER STUD

43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83

FUEL PUMP COVER BOLT
FUEL PUMP COVER
FUEL PUMP COVER GASKET
CRANKSHAFT POSITION SENSOR O-RING
CRANKSHAFT POSITION SENSOR
CRANKSHAFT POSITION SENSOR RETAINING BOLT
ENGINE BLOCK COOLANT PLUG
DISTRIBUTOR/HIGH VOLTAGE SWITCH (HVS)
DISTRIBUTOR (EST)
DISTRIBUTOR GASKET
DISTRIBUTOR HOLD DOWN
DISTRIBUTOR HOLD DOWN BOLT
OIL LEVEL INDICATOR TUBE BRACKET RETAINING NUT
OIL LEVEL INDICATOR TUBE BRACKET WASHER
OIL LEVEL INDICATOR TUBE
OIL LEVEL INDICATOR
IGNITION COIL BRACKET BOLT
IGNITION COIL
IGNITION CONTROL MODULE HEAT SINK
IGNITION CONTROL MODULE
IGNITION CONTROL MODULE BOLTS
IGNITION COIL WASHER (EST)
IGNITION COIL BOLT (EST)
PRIMARY IGNITION COIL HARNESS (EST)
IGNITION COIL (EST)
IGNITION COIL WIRE
SPARK PLUG WIRE RETAINER
SPARK PLUG WIRE HARNESS
SPARK PLUG
VALVE PUSHROD
VALVE ROCKER ARM
VALVE ROCKER ARM BALL
VALVE ROCKER ARM NUT
FUEL RAIL BRACKET
FUEL RAIL BRACKET WASHER
FUEL INJECTOR TO CYLINDER HEAD O-RING
FUEL INJECTOR
FUEL INJECTOR RETAINING CLIP
FUEL INJECTOR TO RAIL O-RING
FUEL RAIL
FUEL RAIL TO BRACKET BOLTS

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Block Explode #2

BASE ENGINE SECTION 2-12

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47

ENGINE BLOCK
PISTON PIN
PISTON RING KIT
PISTON
CONNECTING ROD
CONNECTING ROD BOLT
CONNECTING ROD BEARING KIT
CONNECTING ROD CAP
CONNECTING ROD NUT
OIL NOZZLE
CAMSHAFT BEARINGS
CAMSHAFT
CAMSHAFT RETAINER
CAMSHAFT SPROCKET
CAMSHAFT RETAINER BOLT
CAMSHAFT WOODRUFF KEY
CRANKSHAFT PULLEY
ENGINE FRONT COVER SEAL
ENGINE FRONT COVER BOLT
ENGINE FRONT COVER
ENGINE FRONT COVER GASKET
CRANKSHAFT SPROCKET
CRANKSHAFT KEYWAY
OIL PUMP
OIL PUMP BOLT
CRANKSHAFT BEARING KIT
CRANKSHAFT
CRANKSHAFT BEARING CAP
CRANKSHAFT BEARING CAP BOLT
OIL PAN GASKET
OIL PAN
OIL PAN WASHER
OIL PAN BOLT
OIL DRAIN PLUG WASHER
OIL DRAIN PLUG
CRANKSHAFT REAR OIL SEAL HOUSING PIN
CRANKSHAFT REAR OIL SEAL HOUSING
CRANKSHAFT REAR OIL SEAL HOUSING STUD
CRANKSHAFT REAR OIL SEAL HOUSING BOLT
CLUTCH PILOT BEARING
ENGINE FLYWHEEL BOLT
ENGINE FLYWHEEL
CRANKSHAFT REAR OIL SEAL
CRANKSHAFT REAR OIL SEAL HOUSING BOLT
CRANKSHAFT REAR OIL SEAL HOUSING GASKET
CAMSHAFT REAR BEARING HOLE PLUG
ENGINE BLOCK CORE PLUG

BASE ENGINE SECTION 2-13

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Head Explode

1
2
3
4
5
6
7
8
9
10
11
12
13
14

CYLINDER HEAD
VALVE ROCKER ARM STUD
VALVE STEM KEY
VALVE SPRING CAP (MPFI)
VALVE SPRING (MPFI)
VALVE STEM OIL SEAL (MPFI)
EXHAUST VALVE
INTAKE VALVE
VALVE STEM KEY
VALVE SPRING CAP
VALVE STEM OIL SHIELD
VALVE SPRING
VALVE STEM OIL SEAL
VALVE ROTATOR CAP EXHAUST

BASE ENGINE SECTION 2-14

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

1
2
3
4
5
6
7
8
9
10

DRIVE GEAR
DRIVEN GEAR
OIL PRESSURE RELIEF VALVE
OIL PRESSURE RELIEF VALVE SPRING
OIL PUMP SCREEN
OIL PUMP
OIL PUMP COVER GASKET
OIL PUMP COVER
OIL PUMP COVER WASHER
OIL PUMP COVER BOLT

BASE ENGINE SECTION 2-15

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-16

Draining Fluids, Oil Filter and Fuel Pump Cover
Removal
1. Remove the oil pan drain plug and allow the oil to drain.

VE005-3L

2. Remove the oil ﬁlter.

VE006-3L

3. Remove the fuel pump cover bolts (1), cover (2), and
gasket (3).

VE133-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-17

4. Remove the left rear engine block coolant plug (4) and
allow the coolant to drain.
5. Remove the crankshaft position sensor retaining bolt (3).
6. Remove the crankshaft position sensor (2), (MPFI engine
only).

VE008-3L

Engine Flywheel Removal
Important: Note the position and direction of the engine
ﬂywheel before removal. The ﬂywheel center alignment hole
is a tapered ﬁt to the crankshaft. The engine ﬂywheel must be
reinstalled to the original position and direction.
1. Remove the engine ﬂywheel bolts.
2. Remove the engine ﬂywheel.

VE009-3L

Fuel Rail Removal
1. Remove the fuel rail mounting bolts (1).
2. Remove the fuel rail and injector assembly (2).

VE130-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-18

Distributor/High Voltage Switch (HVS) Removal
1. Disconnect the secondary ignition wires (1) from the
spark plugs and the ignition coil.
2. Remove the distributor hold down bolt (5).
3. Remove the distributor/high voltage switch (HVS) (2), and
gasket (3).
4. distributor (6) and primary ignition harness for EST

VE010-3L

Ignition Coil Module Assembly Removal
1. Remove the ignition coil bracket attaching bolts (1).
2. Remove the ignition coil and module assembly (2).
3. Remove the ignition coil bolt (8), washer (7) and ignition
coil (6) for EST models.

VE011-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-19

Oil Level Indicator and Tube Removal
1. Remove the oil level indicator from the tube.
2. Remove the oil level indicator tube retaining nut and
washer.
3. Remove the oil level indicator from the block, and the
washer from the stud.

VE128-3L

Lift Bracket Removal
1. Remove the lift bracket bolts.
2. Remove the lift bracket.

VE012-3L

Spark Plug Removal
1. Remove the spark plugs.

VE013-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-20

Intake/Exhaust Manifold Removal (Industrial)
1. Remove the intake/exhaust manifold bolts.
2. Remove the intake/exhaust manifold.
3. Remove the intake/exhaust manifold gaskets.

VE014-3L

Intake/Exhaust Manifold Disassemble and
Assemble (Industrial)
If necessary to replace either the intake or exhaust manifold,
separate them as follows:
1. Remove the one attaching bolt and the two nuts at the
center of the assembly.
2. Reassemble manifolds using a new gasket.
Tighten
Tighten the bolts to 27-34 N•m (20-25 lb ft).

VE015-3L

Intake/Exhaust Manifold Clean and Inspect
(Industrial)
Clean and inspect the following areas:
• The manifold bolts and studs.
• All manifold sealing surfaces.
• Any old RTV from the manifold.

VE016-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-21

Water Outlet and Thermostat Removal (Industrial)
1.
2.
3.
4.
5.

Remove the two water outlet housing bolts (1).
Remove the water outlet housing (2).
Remove the thermostat (4) and gasket (3).
Discard the water outlet housing gasket.
Remove the coolant temperature sensor (7) (MPFI engine
only).
6. Remove the thermostat housing bolts (6).
7. Remove the thermostat housing (5) and gasket (8).
8. Discard the thermostat housing gasket.

VE129-3L

Water Pump Removal
Make sure the coolant is drained.
1. Remove the water pump bolts.
2. Remove the water pump and gasket.
3. Discard the water pump gasket.
4. Inspect the water pump for the following:
• Gasket sealing surfaces for excessive scratches or
gouges.
• Excessive side-to-side play in the hub shaft.
• Leakage at the water inlet housing or rear cover
gaskets areas.
• Leakage at the water pump vent hole.
A stain around the vent hole is acceptable. If leakage
occurs at the vent hole with the engine running and the
cooling system pressurized, replace the pump.

VE017-3L

Crankshaft Pulley Removal
Tools Required
• J 24420-C Universal Crankshaft Pulley Remover
1. Use the J 24420-C in order to remove the crankshaft
pulley.

VE018-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-22

Valve Rocker Arm Cover Removal
1. Remove the valve rocker arm cover bolts.
2. Remove the valve rocker arm cover.
3. Remove the gasket/sealer.

VE019-3L

Fuel Rail Bracket Removal
1. Remove two cylinder head bolts and washers retaining
the fuel rail bracket.
2.. Remove the fuel rail bracket.

VE131-3L

Pushrod Cover Removal
1. Remove the pushrod cover bolts.
2. Remove the pushrod cover.
3. Remove the gasket/sealer.

VE020-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-23

Valve Rocker Arm and Pushrod Removal
1. Remove the following components from the cylinder
head:
1.1. The valve rocker arm nuts (1).
1.2. The valve rocker arm balls (2).

VE021-3L

Measuring Camshaft Lobe Lift
Tools Required
• J 8520 Camshaft Lobe Lift Indicator
1. Position the J 8520 with the ball socket adapter on the
valve pushrod. Be sure that the valve pushrod is in the
valve lifter socket.
2. Slowly rotate the crankshaft until the valve lifter roller is
on the heel of the cam lobe. The valve pushrod will be in
its lowest position.
3. Set the J 8520 on zero.
4. Slowly rotate the crankshaft until the valve pushrod is
raised fully.
5. Compare the total lift shown on the J 8520 with the
speciﬁcations. Refer to Engine Mechanical Speciﬁcations.
6. Remove the J 8520.
VE022-3L

2. Remove the valve pushrods.
3. Place the following parts in a rack so that they can be
reinstalled in their original locations:
• The valve rocker arms.
• The valve rocker arm balls.
• The valve pushrods.

VE023-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-24

Valve Train Components Inspect (Cylinder Head)
Inspect the following areas:
• The valve rocker arms and ball at the mating surfaces.
These surfaces should be smooth and free of scoring
or other damage.
• The valve pushrod sockets and valve stem mating
surfaces. These surfaces should be smooth with no
scoring or exceptional wear.
• The valve pushrods for bends or scored ends.

VE024-3L

Valve Lifter Removal
Tools Required
• J 3049 Valve Lifter Remover (Plier Type)
• J 9290-01 Valve Lifter Remover (Slide Hammer Type)
1. Use the J 3049 in order to remove the valve lifters.

VE025-3L

2. If the valve lifters cannot be removed with the J 3049 use
the J 9290-01 in order to remove the valve lifters.

VE026-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-25

Cylinder Head Removal
1. Remove the cylinder head bolts.
Notice: After removal, place the cylinder head on two wood
blocks to prevent damage.
2. Remove the cylinder head.
3. Remove the gasket.
4. Discard the gasket

VE027-3L

Oil Pan Removal
1.
2.
3.
4.

Remove the oil pan bolts.
Remove the oil pan.
Remove the gasket.
Discard the gasket.

VE028-3L

Oil Pump Removal
1. Remove the bolts that attach the oil pump to the engine
block.
2. Remove the oil pump and gasket.
3. Discard the gasket.

VE029-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-26

Engine Front Cover Removal
1.
2.
3.
4.

Remove the engine front cover bolts.
Remove the engine front cover.
Remove the gasket.
Discard the gasket.

VE030-3L

5. Remove the oil seal from the front cover.
6. Clean the engine front cover in solvent.
7. Inspect the engine front cover for damage to the gasket
surface or the oil seal surface.

VE031-3L

Measuring Crankshaft and Camshaft Sprocket
Runout
Tools Required
• J 8001 Dial Indicator
1. Use the J 8001 in order to measure the crankshaft and
camshaft sprocket runout. Refer to Engine Mechanical
Speciﬁcations.
2. If the sprocket runout exceeds speciﬁcations, clean and
remove any burrs from the shaft or replace the sprocket.

VE032-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-27

Measuring Timing Sprocket Teeth Backlash
Tools Required
• J 8001 Dial Indicator
1. Use the J 8001 in order to measure the backlash
between the timing sprocket teeth.
2. Refer to Engine Mechanical Speciﬁcations.

VE033-3L

Crankshaft Sprocket Removal
Tools Required
• J 6978-E Crankshaft Sprocket Puller
1. Use the J 6978-E in order to remove the crankshaft
sprocket.
2. If necessary, remove the crankshaft keys.

VE034-3L

Camshaft Removal
1. Remove the two camshaft retainer bolts, working through
the holes in the camshaft sprocket.

VE035-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-28

Important: All camshaft journals are the same diameter, so
care must be used in removing the camshaft to avoid damage
to the bearings.
2. Carefully rotate and pull the camshaft out of the bearings.

VE125-3L

Crankshaft and Camshaft Sprocket Inspect
•
•
•

The camshaft and crankshaft sprockets for wear.
One edge of worn teeth or that are no longer
concentric.
The valley between worn teeth.

VE126-3L

Timing Gear Oil Nozzle Removal
1. Remove the oil nozzle with pliers.

VE127-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-29

Piston, Connecting Rod and Bearing Removal
Tools Required
• J 5239 Connecting Rod Guide Tool
• J 24270 Ridge Reamer
1. Remove the ring ridge as follows:
1.1. Turn the crankshaft until the piston is at the bottom
of the stroke.
1.2. Place a cloth on top of the piston.
1.3. Use the J 24270 to remove the cylinder ring ridge.
1.4. Turn the crankshaft so the piston is at the top of the
stroke.
1.5. Remove the cloth.
1.6. Remove the cutting debris.

VE036-3L

Important: Place matchmarks or numbers on the connecting
rods and the connecting rod caps. Upon removal of the piston
and connecting rod assembly, install the connecting rod caps to
the matching connecting rods.
2. Remove the connecting rod nuts.
3. Remove the connecting rod cap.
4. Remove the connecting rod bearings.
• Keep bearings with the original connecting rod and
connecting rod cap.
• Wipe the oil from the bearings.
• Wipe the oil from the crankpins.

VE037-3L

5. Use the J 5239 in order to remove the connecting rod
and the piston out of the engine block.
6. Use a hammer and tap lightly on the end of the
connecting rod guide tool to remove the piston and
connecting rod assembly from the cylinder bore.

VE038-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-30

Crankshaft and Bearings Clean and Inspect
(Connecting Rod Bearing Clearance)
Important: Connecting rod bearings are a precision insert type.
Connecting rods are of a powdered metal design and cannot
be shimmed or ﬁled for bearing ﬁt. If clearances are found to be
excessive, a new bearing and/or connecting rod are required.
Do not rotate the crankshaft while gauging plastic is between
the crankshaft journal and the bearing surface.
1. Remove the connecting rod nuts.
2. Remove the connecting rod cap and bearing.

VE037-3L

3. Inspect the crankshaft bearings for craters or pockets.
Flattened sections on the bearing halves also indicate
fatigue.

VE039-3L

4. Inspect the crankshaft bearings for excessive scoring or
discoloration.
5. Inspect the crankshaft bearings for dirt or debris
imbedded into the bearing material.

VE040-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-31

6. Install the gauging plastic (1) onto the connecting rod
bearing journal. Install the gauging plastic the full width of
the journal.

VE041-3L

7. Install the connecting rod cap and bearing.
Tighten
Tighten the nuts evenly to 61 N•m (45 lb ft).

VE037-3L

8. Remove the connecting rod nuts.
9. Remove the connecting rod cap and bearing.

VE037-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-32

10. Measure the gauging plastic at its widest area using the
scale supplied with the plastic gauging kit.
11. Compare the measurements to Engine Mechanical
Speciﬁcations.

VE042-3L

Crankshaft Rear Oil Seal and Housing Removal
1. Remove the crankshaft rear oil seal housing bolts.
2. Remove the crankshaft rear oil seal housing, seal and
gasket.

VE043-3L

3. Remove the crankshaft rear oil seal from the crankshaft
rear oil seal housing.

VE044-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-33

Crankshaft , Bearings and Bearing Cap Removal
1. Remove the crankshaft bearing cap bolts.
2. Remove the crankshaft bearing caps.

VE045-3L

3. Remove the crankshaft.
4. Remove the crankshaft bearings from the bearing caps
(lower bearings) and from the engine block (upper
bearings).

VE046-3L

Crankshaft and Bearings Clean and Inspect
Tools Required
• J 7872 Magnetic Base Indicator Set
Caution: Wear safety glasses in order to avoid eye damage.
1. Clean the crankshaft in solvent.
2. Inspect the crankshaft oil passages for restrictions.
3. Dry the crankshaft with compressed air.
4. Inspect the crankpins for scoring or wear.
5. Inspect the reluctor wheel teeth for damage or warpage.

VE047-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-34

5. Inspect the crankshaft bearings for craters or pockets.
Flattened sections on the bearing halves also indicate
fatigue.

VE039-3L

6. Inspect the crankshaft bearings for excessive scoring or
discoloration.
7. Inspect the crankshaft bearings for dirt or debris imbedded
into the bearing material.

VE040-3L

8. Inspect the crankshaft bearings for improper seating
indicated by bright, polished sections of the bearing.
• If the lower half of the bearing is worn or damaged,
both the upper and lower halves must be replaced.

VE048-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-35

9. Measure the crankpins for out-of-round, taper or
undersize with a micrometer. Refer to Engine Mechanical
Speciﬁcations.

VE049-3L

10. Support the crankshaft front and rear journals on Vblocks.
11. Measure the crankshaft run-out at front and rear
intermediate journals with J 7872. Refer to Engine
Mechanical Speciﬁcations.
12. Replace or recondition crankshaft if measurements are

VE050-3L

Crankshaft and Bearings Clean and Inspect (Main
Bearing Clearance)
Important: Crankshaft main bearings are a precision insert
type. Main bearing caps are machined with the engine block for
proper clearance and cannot be shimmed or ﬁled for bearing ﬁt.
Crankshaft bearing clearances are critical. If the clearances are
found to be excessive, new bearings and/or engine block and
cap repair may be required.
Do not rotate the crankshaft while gauging plastic is between
the crankshaft journal and the bearing surface.
1. Remove the crankshaft bearing cap bolts.
2. Remove the crankshaft bearing caps.

VE045-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-36

3. Install gauging plastic (1) onto the crankshaft journal.
Install the gauging plastic the full width of the crankshaft
bearing journal.

VE051-3L

4. Install the bearing, bearing cap and bolts.
Tighten
Tighten the crankshaft bearing cap bolts to 85 N•m (63 lb ft).

VE045-3L

5. Remove the crankshaft bearing cap bolts.
6. Remove the crankshaft bearing caps.

VE045-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-37

7. Measure the gauging plastic at its widest area using the
scale supplied with the plastic gauging kit.
8. Compare the measurements to Engine Mechanical
Speciﬁcations.
• If the gauging plastic shows irregularity in the journal
exceeding 0.025 mm (0.001 in), remove the crankshaft
and measure the journal with a micrometer.
• If the clearance is greater than Engine Mechanical
Speciﬁcations, select and install an undersized bearing
set. Measure the clearance with gauging plastic.
• If clearance cannot be brought to speciﬁcations,
grind the crankshaft for use with the next undersized

VE052-3L

9. Use a dial indicator or feeler gauge in order to measure
end play between the front of the rear of the crankshaft
bearing cap and the crankshaft thrust surface in order to
determine the crankshaft end play.
10. If you use a feeler gauge, measure between the
thrust surface of the crankshaft bearing and the
crankshaft. Refer to Engine Mechanical Speciﬁcations.

VE053-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-38

Camshaft Bearing Removal

VE054-3L

Tools Required
• J 6098-01 Camshaft Bearing Remover/Installer
1. Remove the camshaft rear bearing hole plug.
2. Use the J 6098-01 in order to remove the inner camshaft
bearings. Repeat the following procedure for each of the
inner camshaft bearings:
2.1. With the nut (4) and the thrust washer (3) installed
to the end of the puller screw threads, index the
pilot (2) in the camshaft front bearing and install the
puller screw through the pilot (2) and the bearing to
be removed.
2.2. Install the bearing tool (1) with the shoulder toward
the bearing.
2.3. Using two wrenches, hold puller screw (5) while you
turn the nut (4) in order to draw the bearing out of
the bore.
2.4. When the bearing has been pulled from the bore,
remove the bearing tool and the bearing from the
puller screw.
2.5. Index the pilot in the rear camshaft bearing in order
to remove the rear inner camshaft bearing.

3. Use the J 6098-01 in order to remove the front and rear
camshaft bearings.
3.1. Assemble the bearing tool to the driver.
3.2. Drive the front and rear camshaft bearings out of
the block bore. Drive inward toward the center of
the engine block.

VE055-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-39

Distributor Lower Bushing and Thrust Washer
Removal
Tools Required
• J 9534 Distributor Lower Bushing Remover
• J 6585 Slide Hammer
1. Install the J 9534 into the distributor lower bushing.
2. Use the J 6585 in order to remove the bushing.

VE056-3L

3. Use a drift punch up through the bushing bore in order to
drive the thrust washer (if installed) out of the bore.
4. Clean the bushing bore in the cylinder block and inspect
for burrs or damage.

VE057-3L

Oil Filter Bypass Valve Removal and Installation
1.
2.
3.
4.

Check the spring and ﬁber valve for operation.
Inspect for a cracked or broken valve.
Use a screwdriver in order to pry the valve out.
Use a 9/16 in thin-wall deep socket in order to tap the
new bypass valve in place.

VE058-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-40

Cylinder Block Clean and Inspect
1. Clean the following areas:
• The engine block in solvent, removing all sludge, dirt
or debris
Caution: Wear safety glasses in order to avoid eye damage.
• Dry the block with compressed air.
• The gasket surfaces.
• The coolant passages.
• The oil passages.
• The main bearing caps.
• All threaded bolt holes.
2. Inspect the following areas:
• The cylinder walls for excessive scratches, gouging or
ring ridge.
• The coolant jackets for cracks.
• The valve lifter bores for excessive scoring or wear.
• The crankshaft bearing webs for cracks.
• The gasket sealing surfaces for excessive scratches or
gouging.
• The oil passages for restrictions.
• All threaded bolt holes for thread damage.

VE059-3L

Cylinder Bore Measurements
Tools Required
• J 8087 Cylinder Bore Gauge
1. Use the J 8087 in order to check cylinder bore taper and
out-of-round as follows:
1.1. Set the gauge so that the thrust pin must be forced
in about 1/4 in to enter the gauge in the cylinder
bore.
1.2. Center the gauge in the cylinder and turn the dial to
“0.”
1.3. Work the gauge up and down to determine the
taper.
1.4. Turn the gauge to different point around the cylinder

VE060-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Cylinder Boring and Honing
Boring Procedure
1. Before you start the honing or reboring process,
measure all new pistons with the micrometer,
contacting at points exactly 90° from the piston
pin centerline. Refer to Piston Selection. Select
the smallest piston for the piston ﬁtting. Slightly
varied pistons in a set may provide correction, in
case the ﬁrst piston is too loosely ﬁtted.
2. Before you use any type of boring bar, ﬁle the top
of the cylinder block in order to remove any dirt
or burrs. If you do not check the cylinder block,
the boring bar may be tilted, this could result in
the rebored cylinder wall being at incorrect right
angles from the crankshaft.
3. Carefully follow the instructions furnished by the
manufacturer regarding the use of the equipment.
4. When you rebore cylinders, make sure all
crankshaft bearing caps are in place. Tighten
the bearing caps to the proper torque in order to
avoid distortion of the bores in the ﬁnal assembly.
The crankshaft must be clear of the boring cutter
when you bore each cylinder. Cover or tape the
crankshaft bearings and other internal parts to
protect during the boring or honing process.
Honing Procedure
1. When honing the cylinders, follow the
manufacturer’s recommendations for use,
cleaning and lubrication. Use only clean, sharp
stones of the proper grade for the amount of
material you remove. Dull, dirty stones cut
unevenly and generate excessive heat. When
using coarse or medium-grade stones, leave
sufﬁcient metal so that all stone marks may be
removed with the ﬁne stones you use for ﬁnishing
in order to provide for proper clearance.
2. During the honing process, thoroughly clean the
cylinder bore. Check for a correct ﬁt of the piston
you select for the individual cylinder.
3. When honing to eliminate taper in the cylinder,
make full strokes of the hone in the cylinder.
Repeatedly check the measurement at the top,
the middle and the bottom of the bore.
Notice: Handle the pistons with care. Do not force the
pistons through the cylinder until you hone the cylinder
to the correct size. The piston can be distorted through
careless handling.
4. When ﬁnished honing a cylinder bore to ﬁt a
piston, move the hone up and down at a sufﬁcient
speed to obtain very ﬁne, uniform surface ﬁnish

8.
9.

10.
11.

BASE ENGINE SECTION 2-41
marks in a cross hatch pattern at 45-65 degrees.
The ﬁnish marks should be clean but not sharp.
The ﬁnish marks should be free from imbedded
particles and torn or folded metal.
By measuring the piston to be installed at the
sizing point speciﬁed and by adding the average
of the clearance speciﬁcation, you can determine
the ﬁnish hone cylinder measurement. Refer to
Engine Mechanical Speciﬁcations. Measure the
block and the piston at normal room temperature.
True up the reﬁnished cylinder bores to have less
than the speciﬁed out-of-round or taper. You must
ﬁnal hone each bore in order to remove all stone
or cutter marks and in order to provide a smooth
surface.
For piston-to-bore tolerance speciﬁcations, Refer
to Engine Mechanical Speciﬁcations.
After ﬁnal honing and before the piston is
checked for ﬁt, clean the bores with hot water and
detergent. Scrub the bores with a stiff bristle brush
and rinse the bores thoroughly with hot water. Do
not allow any abrasive material to remain in the
cylinder bores. This abrasive material will wear
the new rings, the cylinder bores and the bearings
lubricated by the contaminated oil. After you wash
the bore, brush the dry bore clean with a powerdriven ﬁber brush.
Permanently mark the piston for the cylinder to
which the piston has been ﬁtted.
Apply clean engine oil to each bore in order to

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-42

Distributor Lower Bushing and Thrust Washer
Installation
Tools Required
• J 9535 Distributor Lower Bushing Installer
1. Use the J 9535 in order to drive the thrust washer (if
removed) into the cylinder block.
2. Use the J 9535 with the driver-bolt in the driver handle.

VE061-3L

3. Install the driver into the new bushing from the large
inside diameter.
4. Drive the new bushing into the cylinder block until the
J 9535 bottoms against the cylinder block.

VE062-3L

Piston and Connecting Rod Disassemble
Tools Required
• J 24086-C Piston Pin Removal Set
1. Remove the piston rings from the pistons.

VE063-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-43

2. Remove the pin from the piston.
Notice: After the J 24086-C Installer bottoms on the support
assembly, do not exceed 34,475 kPa (5000 psi) or the tool may
be damaged.

VE064-3L

Piston and Connecting Rod Clean and Inspect
1. Clean the piston ring grooves with a groove cleaner.

Caution: Wear safety glasses in order to avoid eye damage.
2. Clean the connecting rod in cleaning solvent.
3. Clean the varnish from the piston skirts and the pins with
cleaning solvent
4. Dry the components with compressed air.
5. Do not use a wire brush in order to clean any part of the
piston.
6. Clean the piston oil ring holes and the slots.
7. Inspect the connecting rod for twisting, nicks and cracks.
Replace any damaged connecting rods.
8. Inspect the pistons for the following conditions:
• Cracked ring lands, skirts or pin bosses.
• Nicks or spurs in the grooves that may cause binding.
• Warped or worn ring lands.
• Scuffed or damaged skirts.
• Eroded areas at the top of the piston.
• Worn piston bores and piston pins.
9. Replace pistons that are damaged or show signs of
excessive wear.

VE065-3L

VE066-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-44

10. Measure the pin bore-to-piston clearance.
10.1. The piston pin bores and the piston pins must be
free of varnish or scufﬁng when being measured.
10.2. Use a micrometer in order to measure the piston

VE067-3L

10.3. Use an inside micrometer in order to measure the
piston pin bore. Replace the piston and piston pin if
the clearance is in excess of 0.0254 mm (0.001 in).
10.4. Match the piston and piston pin. Do not service
separately.

VE068-3L

11. Measure the piston compression ring end gap.
Important: Fit each compression ring to the cylinder in which it
will be used.
11.1. Place the compression ring into the cylinder bore.
11.2. Push the compression ring into the cylinder bore
approximately 6.5 mm (0.25 in) above the ring
travel. The ring must be square to the cylinder wall.
11.3. Use a feeler gauge in order to measure the end
gap.
11.4. Select another size ring set if the end gap exceeds

VE069-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-45

12. Measure the piston ring side clearance.
12.1. Roll the piston ring entirely around its ring groove
on the piston.
12.2. Dress the groove with a ﬁne cut ﬁle if the ring
groove causes binding.
12.3. Replace the piston ring if a distorted piston ring
causes binding.

VE070-3L

12.4. Use a feeler gauge in order to measure the side
clearance of the piston ring and groove.
12.5. Try another piston ring if the side clearance is too
small.

VE071-3L

Piston Selection
Important: Measurements of all components should be taken
with the components at normal room temperature.
For proper piston ﬁt, the engine block cylinder bores must not
have excessive wear or taper.
A used piston and pin set may be reinstalled if, after cleaning
and inspection, they are within speciﬁcations.
1. Inspect the engine block cylinder bore. Refer to Cylinder
Block Clean and Inspect.
2. Inspect the piston and piston pin. Refer to Piston and
Connecting Rod Clean and Inspect.
3. Use a boring gauge in order to measure the cylinder bore
diameter at a point of 66 mm (2.5 in) from the top of the
cylinder bore.

VE060-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-46

4. Measure the bore gauge with a micrometer and record
the reading.

VE072-3L

5. With a micrometer or caliper at a right angle to the piston,
measure the piston 11 mm (0.433 in) from the bottom of
the skirt.
6. Subtract the piston diameter from the cylinder bore
diameter in order to determine piston-to-bore clearance.
7. For proper piston-to-bore clearance, Refer to Engine
Mechanical Speciﬁcations.
8. If the proper clearance cannot be obtained, select another
piston and measure for the clearances. If the proper ﬁt
cannot be obtained, the cylinder bore may require boring
or honing. Refer to Cylinder Boring and Honing.
9. When the piston-to-cylinder bore clearance is within
speciﬁcations, permanently mark the top of the piston for
installation to the proper cylinder.

VE073-3L

Piston and Connecting Rod Assemble
Tools Required
• J 24086-C Piston Pin Removal Set
Important: When assembling the piston and connecting rod,
the ﬂange or the heavy side on the connecting rod must face
toward the front of the piston (stamped arrow in top of the piston
head).
1. Install the piston pin and connecting rod assembly.
1.1. Lubricate the piston pin holes in both the piston and
the connecting rod assembly.
1.2. Press the piston pin into the piston and connecting
rod assembly using the J 24086-C.
1.3. Inspect for freedom of movement of the piston on

VE064-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-47

2. Install the piston rings onto the piston.
The marked side of the piston rings must face toward the top of
the piston.

VE123-3L

3. Use the following procedure in order to locate the piston
ring gaps:
3.1. Install the oil ring spacer in groove and insert antirotation tang in oil hole.
3.2. Hold the spacer ends together and install lower oil
ring rail with the gap properly located.
3.3. Install the upper oil ring rail with the gap properly
located.
3.4. Flex the oil ring assembly to make sure the rings
are free.
3.5. Install the lower compression ring.
3.6. Install the upper compression ring.

VE074-3L

Camshaft and Bearings Clean and Inspect
Tools Required
• J 7872 Magnetic Base Indicator Set
Caution: Wear safety glasses in order to avoid eye damage.
1. Clean the camshaft in solvent.
2. Dry the camshaft with compressed air.
3. Inspect the camshaft bearing journals for scoring or
excessive wear.
4. Inspect the camshaft valve lifter lobes for scoring or
excessive wear.
5. Inspect the camshaft retainer plate for wear.

VE075-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-48

6. Inspect the camshaft bearings for proper ﬁt in the engine
block. Camshaft bearings have an interference ﬁt to the
engine block and should not be loose in their engine
block bearing bores.
7. Inspect the camshaft bearings for excessive wear or
scoring. Bearings with excessive wear or scoring must be
replaced.

VE076-3L

8. Measure the camshaft for out-of-round, taper or
undersize with a micrometer. Refer to Engine Mechanical
Speciﬁcations.

VE077-3L

9. Support the camshaft front and rear journals on V-blocks.
10. Measure the camshaft run-out at the intermediate journal
with J 7872. Refer to Engine Mechanical Speciﬁcations.
11. Replace camshaft if measurements are not within
speciﬁcations.

VE078-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-49

Camshaft Sprocket and Retainer Removal and
Installation
Removal
Tools Required
• J 791 Camshaft Sprocket Remover
1. If the inspection indicated that the camshaft, gear and
retainer were in good condition, the camshaft end
play should be checked. Refer to Engine Mechanical
Speciﬁcations.

VE079-3L

2. If the inspection indicated that the camshaft, gear or
retainer should be replaced, the gear must be removed
from the camshaft as follows:
2.1. Place the camshaft through the J 791.
2.2. Place the end of the remover on the table of a
press and press the camshaft out of the gear.
Important:
The retainer must be positioned so that the woodruff key in the
camshaft does not damage it when the camshaft is pressed out
of the gear. Also, support the hub of the gear or the gear will be
seriously damaged.

VE080-3L

Installation
1. Install the camshaft sprocket, retainer and gear spacer
ring to the camshaft as follows:
1.1. Firmly support the camshaft at the back of the front
journal in an arbor press.
1.2. Place the gear spacer ring and retainer over the
end of the camshaft and install the woodruff key in
the camshaft keyway.
1.3. Align the sprocket keyway with the woodruff key
in the camshaft and press it onto the shaft until it
bottoms against the gear spacer ring.

VE081-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-50

Camshaft Bearing Installation

VE055-3L

VE054-3L

Tools Required
• J 6098-01 Camshaft Bearing Installer
Important:
• A loose camshaft bearing may be caused by an
enlarged, out of round or damaged engine block
bearing bore.
• The outer front and rear camshaft bearings must be
installed ﬁrst. These bearings serve as guides for the
tool pilot and help center the inner bearings during the
installation process.
• The camshaft bearing oil holes must align with the
oil galleys in the engine block. An improperly aligned
camshaft bearing oil galley hole will restrict oil ﬂow to
the bearing and camshaft journal.
1. Use the J 6098-01 in order to install the front and rear
camshaft bearings:
1.1. Assemble the bearing tool to the driver handle.
1.2. Align the oil holes.
1.3. Drive the front and the rear camshaft bearings
inward toward the center of the engine block.

2. Use the J 6098-01 in order to install the inner camshaft
bearings. Repeat the following steps for each of the inner
camshaft bearings:
2.1. With the nut (4) and the thrust washer (3) installed
to the end of the puller screw threads, index the
pilot in the camshaft front bearing and install the
puller screw through the pilot (2).
2.2. Index the camshaft bearing in the bore. Make sure
you align the oil galley holes.
2.3. Install the puller screw through the bearing bore
and bearing to be installed and assemble bearing
tool (1) to the puller screw with the shoulder toward
the bearing. Make sure that enough threads are
engaged.
2.4. Using two wrenches, hold the puller screw (5) while
you turn the nut in order to draw the bearing into
the bore. When the bearing has been pulled into
the bore, remove the bearing tool and the puller
screw and check the alignment of the bearing oil
hole to the bore oil hole.
3. Install a new camshaft rear bearing hole plug. Coat the
plug outside diameter with GM P/N 1052080 sealant, or
the equivalent.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-51

Oil Pump Disassemble
1. If necessary, remove the oil pump screen.
• The oil pump screen has a press ﬁt in to the pump
cover.
• Do not remove the screen from the pipe. The pipe and

VE082-3L

2. Remove the cover bolts.
3. Remove the pump cover.

VE083-3L

4. Remove the drive gear (2) and the driven gear (1).
Matchmark the gear teeth for assembly.

VE084-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-52

5. Remove the following items:
• The retaining pin (1).
• The pressure relief valve spring (3).
• The pressure relief valve (2).

VE085-3L

Oil Pump Clean and Inspect

VE086-3L

Important: The internal parts of the oil pump are not serviced
separately. If the oil pump components are worn or damaged,
replace the oil pump as an assembly.
The oil pump pipe and screen are to be serviced as an
assembly. Do not attempt to repair the wire mesh portion of the
pipe and screen assembly.
1. Clean all of the parts in cleaning solvent.
Caution: Wear safety glasses in order to avoid eye damage.
2. Dry the parts with compressed air.
3. Inspect the following areas:
• The oil pump housing and cover for cracks, scoring,
casting imperfections and damaged threads.
• The drive gear shaft (If the shaft is loose in the oil
pump housing, replace the oil pump).
• The pressure relief valve for scoring and sticking
(Burrs may be removed with a ﬁne oil stone).
• The pressure relief valve spring for loss of tension.
• The oil pump screen for broken wire mesh or
looseness (If the pipe is loose or has been removed
from the screen, the oil pump screen must be
replaced).
• The gears for chipping, galling and wear.
Important: If the drive gear and driveshaft are worn,
replace the entire oil pump.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-53

Oil Pump Assemble
Tools Required
• J 21882 Oil Suction Pipe Installer
Important: Replace the pressure relief valve spring when you
reuse the oil pump.
1. Install the following items:
• The pressure relief valve (2).
• The pressure relief valve spring (3).
• The retaining pin (1).

VE085-3L

2. Coat the drive gear, the driven gear and the housing gear
surfaces with clean engine oil.
3. Install the drive gear (2) and the driven gear (1) into the
pump body. Align the matchmarks on the gears. Install the
smooth side of the gear toward the pump cover.

VE084-3L

4. Install the pump cover.
5. Install the cover bolts.
Tighten
Tighten the bolts to 8 N•m (71 lb in).

VE083-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-54

6. Inspect the pump for smoothness of operation by turning
the oil pump driveshaft by hand.
7. Install the oil pump screen.
7.1. If removed, replace the oil pump screen. The oil
pump screen must have a good press ﬁt into the oil
pump body.
7.2. Mount the oil pump in a soft jawed vise.
7.3. Apply sealer to the end of the pipe.
7.4. Use the J 21882 and a soft-faced hammer in order
to tap the oil pump screen into the pump body. The
screen must align parallel with the bottom of the oil
pan when it is installed.

VE087-3L

Cylinder Head Disassemble
Tools Required
• J 8062 Valve Spring Compressor
Important: Mark, organize or sort the cylinder head
components for assembly. Return the components to their
original location during assembly.
1. Measure the valve spring installed height using a ruler.
Measure from the machined surface of the cylinder
head to the top of the valve spring cap. Refer to Engine
Mechanical Speciﬁcations

VE088-3L

2. Use the J 8062 in order to compress the valve springs.

VE089-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-55

3. Remove the valve stem keys (1).
4. Remove the cap from the valve spring ( 2&6).
5. Remove the valve stem oil shield (3).
6. Remove the valve spring (4).
7. Remove the valve stem oil seal (5).
8. Remove the valve (7&8).
Important: Place the valves in a rack in the proper sequence
so that you can install them in the same order.

VE090-3L

Cylinder Head Clean and Inspect
Tools Required
• J 8089 Carbon Remover Brush
• J 9666 Valve Spring Tester
• J 8001 Dial Indicator
Caution: Wear safety glasses in order to avoid eye damage.
1. Use the J 8089 in order to clean the carbon from the
combustion chambers and the valve ports. Be careful not
to scuff the chamber.
2. Clean the following areas:
2.1. The carbon and the sludge from the valve pushrods
and the valve rocker arms.
2.2. The valve stems and heads on a bufﬁng wheel.
2.3. The cylinder head and engine block gasket
surfaces.
2.4. The bolt holes and threads in the cylinder head and

VE091-3L

3. Inspect the following areas:
3.1. The cylinder head for cracks in the exhaust ports
and the combustion chambers.
3.2. The cylinder head for external cracks in the water
chamber.
3.3. The valves for burned heads, cracked faces or
damaged stems.

VE092-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-56

4. Use the J 9666 and a ﬂex bar torque wrench in order to
measure the valve spring pressure.
• Replace the valve spring if the spring pressure is less
than 444 N (100 lb.) at 40.9 mm (1.61 in). Refer to
Engine Mechanical Speciﬁcations.

VE093-3L

VE094-3L

5. Excessive valve stem-to-bore clearance will cause
excessive oil consumption and may cause a valve to
break. Insufﬁcient clearance will result in noisy and
sticky functioning of the valve and will disturb the engine
assembly smoothness.
5.1. Install the valve into the guide.
5.2. Install the J 8520 onto the cylinder head.
5.3. Locate the indicator so that the movement of the
valve stem from side to side (crosswise to the
cylinder head) will cause a direct movement of the
indicator stem.
5.4. The indicator stem must contact the side of the
valve stem just above the valve guide.
5.5. Drop the valve head about 1.6 mm (0.0064 in) off
the valve seat.
5.6. Use light pressure and move the valve stem from
side to side in order to obtain a clearance reading.
5.7. If the valve stem to guide clearance is excessive,
the valve must be replaced and/or the guide must
be repaired to obtain the proper clearances. Refer
to Engine Mechanical Speciﬁcations.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-57

6. Inspect the valve springs for squareness.

VE095-3L

7. Measure the valve seat runout.
• Use the J 8001 in order to check the valve seat
runout.
• The valve seats should be concentric to within 0.0508

VE096-3L

8. Measure the cylinder head for warpage with a straight
edge and a feeler gauge. A cylinder head with excessive
warpage must be repaired or replaced. Refer to Engine
Mechanical Speciﬁcations.

VE097-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-58

Valve Guide Reaming/Valve and Seat Grinding
1. Ream the valve guides for oversize valves if the
clearance exceeds the speciﬁcations.
2. Service valves are available in the standard and 0.038
mm (0.015 in).
3. Ream the valve guide bores for the service valves as
necessary.

VE098-3L

4. Reconditioning the valve seats is very important.
5. Recondition the valve seat after reaming the valve guide
bores or installing the new valve guides.
• The valves must seat perfectly for the engine to deliver
optimum power and performance.
• Cooling the valve heads is another important factor.
Good contact between each valve and its seat in the
cylinder head is necessary to ensure that the heat in
the valve head is properly carried away.
• Regardless of what type of equipment is used, it is
essential that the valve guide bores are free from
carbon or dirt to ensure the proper centering of the
pilot in the guide.
• The valve seats should be concentric to within 0.0508
mm (0.002 in) total indicator reading.
VE096-3L

6. Reface pitted valves on a valve refacing machine in order
to ensure the correct relationship between the head and
the stem.
• Replace the valves that show excessive wear or are
warped.
• Replace the valve if the edge of the head is less than
0.8 mm (0.031 in) thick after grinding.
• Several different types of equipment are available
for reconditioning valves and valve seats. Use the
manufacturers recommendations of equipment to
obtain the proper results.

VE099-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-59

Rocker Arm Stud Removal and Installation
Tools Required
• J 5802-01 Rocker Arm Stud Remover
• J 6880 Rocker Arm Stud Installer
Rocker arm studs with damaged threads or with loose ﬁt in
cylinder head should be replaced with new, oversize studs.
1. Remove the old stud by placing J 5802-01 over the stud,
installing nut and ﬂat washer and removing the stud by
turning out.

VE100-3L

2. Ream the hole for the oversize stud.
Important: Do not attempt to install an oversize stud without
reaming the stud hole.

VE101-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-60

3. Coat the press-ﬁt area of the stud with Perfect Seal.
4. Install the new stud, using J 6880 as a guide.

VE102-3L

Cylinder Head Assemble
Tools Required
• J 8062 Valve Spring Compressor
• J 42073 Valve Stem Oil Seal Installer
1. Install the valve (7&8) into the proper port.
2. Lubricate oil seal (5) with clean engine oil.
3. Install the oil seal onto the valve stem. MPFI models
require the use of J 42073 to install the valve stem seals.
4. Install the valve spring (4).
5. Install the valve stem oil shield (3), some models.
6. Install the cap on the valve spring (2&6).

VE090-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-61

Caution: Wear safety glasses in order to avoid eye damage.
7. Use the J 8062 in order to compress the valve spring.
8. Install the valve stem keys.
8.1. Use grease to hold the keys in place while
disconnecting the J 8062.
8.2. Make sure that the keys seat properly in the upper
groove of the valve stem.
8.3. Tap the end of the valve stem with a plastic-faced
hammer in order to seat the keys if necessary.

VE089-3L

Service Prior to Assembly
•

•

Dirt or debris will cause premature wear of the rebuilt
engine. Clean all components. Refer to Cleanliness
and Care.
Use the proper tools to measure components when
checking for excessive wear. Components that are
not within the manufacturers speciﬁcations must be
repaired or replaced.
When components are reinstalled into an engine,
return the components to their original location,
position and direction. Refer to Separating Parts.
During assembly, lubricate all moving parts with
clean engine oil or engine assembly lubricant (unless
otherwise speciﬁed). This will provide initial lubrication
when the engine is ﬁrst started. Refer to Sealers,
Adhesives and Lubricants.

Crankshaft, Bearings and Bearing Cap
Installation
Important
• Crankshaft bearing caps must be installed to the
proper location and direction.
• When installing the crankshaft bearings, align the
locating tabs on the bearings with the locating notches
in the engine block journal bore and the bearing cap.
• Always install crankshaft bearings with their machined
partner. Do not ﬁle bearings or mix bearing halves.
1. Install the crankshaft bearings into the engine block and
the crankshaft bearing caps.
2. Coat the crankshaft bearings with clean engine oil.
3. Install the crankshaft.
VE046-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-62

4. Install the crankshaft bearing caps with the crankshaft
bearings.
5. Be sure that the cap directional arrows point toward the
front of the engine block and the cap is in its original
position.
6. Install the crankshaft bearing cap bolts.
7. Thrust the crankshaft rearward in order to set and align
the thrust bearings and the bearing caps.
8. Thrust the crankshaft forward in order to align the rear
faces of the rear crankshaft bearings.
Tighten
Tighten all of the bolts to 85 N•m (63 lb ft).

VE045-3L

Crankshaft Rear Oil Seal and Housing Installation
Tools Required
• J 35621 Crankshaft Rear Oil Seal Installer
Important: Always use a new crankshaft rear oil seal and new
crankshaft rear oil seal housing gasket when you install the
crankshaft rear oil seal housing.
1. Install the new gasket and the crankshaft rear oil seal
housing on to the studs.
2. Install the rear oil seal housing nuts and bolts.
Tighten
Tighten the crankshaft rear oil seal housing bolts to 15 N•m
(133 lb in).

VE103-3L

3. Coat the new oil seal entirely with clean engine oil.
4. Install the seal onto the J 35621.
5. Install the J 35621 onto the rear of the crankshaft.
Tighten the screws snugly in order to ensure that the seal
will be installed squarely over the crankshaft.
6. Install the crankshaft rear oil seal onto the crankshaft and
into the crankshaft rear oil seal housing. Tighten the wing
nut on the J 35621 until the oil seal bottoms.
7. Remove the J 35621 from the crankshaft rear oil seal
housing.

VE104-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-63

Piston, Connecting Rod and Bearing Installation
Tools Required
• J 5239 Guide Set
• J 8037 Piston Ring Compressor
Important
• The piston and cylinder bore have been measured
and the bore has been sized for the proper clearance.
Install the piston and connecting rod assembly into the
proper cylinder bore.
• The piston alignment mark MUST face the front of the
engine block.
1. Lubricate the following components with clean engine oil:
• The piston.
• The piston rings.
• The cylinder bore.
• The bearing surfaces.
2. Install the connecting rod bearing into the connecting rod
and bearing cap.
3. Install the J 5239 onto the connecting rod.
4. Install the J 8037 or equivalent onto the piston and
compress the piston rings.

VE124-3L

5. Install the piston assembly into its matched bore with the
stamped arrow facing forward.
6. Use the J 8037 and the J 5239 and lightly tap the top of
the piston with a wooden hammer handle.
• Hold the J 8037 ﬁrmly against the engine block until
all of the piston rings enter the cylinder bore.
• Use the J 5239 in order to guide the connecting rod
onto the crankshaft journal.

VE105-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-64

7. Remove the J 5239.

VE038-3L

8. Install the connecting rod cap and nuts.
Tighten
Tighten the nuts evenly to 61 N•m (45 lb ft).

VE037-3L

8. When all of the connecting rod bearings are installed,
tap each connecting rod assembly lightly parallel to the
crankpin in order to make sure that they have clearance.
9. Use a feeler gauge or a dial indicator in order to measure
the side clearance between the connecting rod caps.
Refer to Engine Mechanical Speciﬁcations.

VE106-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-65

Timing Gear Oil Nozzle Installation
1. Drive the new nozzle in place (oil hole facing up) with a
suitable light plastic or rubber hammer.

VE127-3L

Crankshaft Sprocket Installation
Tools Required
• J 5590 Crankshaft Sprocket Installer
1. Install the keys into the crankshaft keyways.
2. Use the J 5590 in order to install the crankshaft sprocket.

VE107-3L

Camshaft Installation
Important: If camshaft replacement is required, the valve lifters
must also be replaced.
1. Carefully rotate and install the camshaft into the engine.
2. Install the two camshaft retainer bolts working through
the holes in the camshaft sprocket. Be sure to align the
camshaft and the crankshaft sprocket alignment marks.
Tighten
Tighten the camshaft retainer bolts to 9 N•m (80 lb in).

VE108-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-66

Engine Front Cover and Oil Seal Installation
Tools Required
• J 35468 Engine Front Cover Aligner and Oil Seal
Installer
1. Use the J 35468 in order to install the engine front cover
oil seal.

VE109-3L

2. Install the engine front cover gasket.
3. Install the engine front cover and bolts.
Tighten
Tighten engine front cover bolts to 9 N•m (80 lb in).

VE030-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-67

Oil Pump Installation
Important: Inspect the oil pump and engine block oil galley
passages. These surfaces must be clear and free of debris or
restrictions.
1. Install the oil pump.
2. Install the bolts that attach the oil pump to the engine
block.
Tighten

VE110-3L

Oil Pan Installation
Important: Apply the sealer 25 mm (1.0 in) in either direction
of the radius cavity of the junctions.
1. Apply a small amount of sealer, GM P/N 1052914 or
equivalent, 10 mm (0.393 in) wide and 20 mm (0.787 in)
long at the engine front cover to engine block junction.
2. Apply a small amount of sealer, GM P/N 1052914 or
equivalent, 25 mm (1.0 in) long at the crankshaft rear oil
seal housing to engine block junction.
3. Install the new oil pan gasket.
4. Install the oil pan.
5. Install the nuts and bolts to the oil pan.
Tighten
Tighten the rear oil pan nuts to 19 N•m (168 lb in).
Tighten the oil pan bolts to the crankcase to 11 N•m (97 lb in).
Tighten the oil pan bolts to the front cover to 5 N•m (44 lb in).
Tighten the oil pan studs to the oil seal retainer to 2 N•m

VE111-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-68

Crankshaft Pulley Installation
Tools Required
• J 8792 Crankshaft Pulley Installer
1. Coat the front cover oil seal contact area of the crankshaft
pulley with clean engine oil.
2. Assemble the J 8792 as shown.

VE112-3L

3. Install the J 8792 onto the crankshaft pulley.
4. Position the pulley on the crankshaft and drive into
position until it bottoms against the crankshaft sprocket.

VE113-3L

Cylinder Head Installation
1. Install the new cylinder head gasket over the locating
pins.
2. Install the cylinder head over the locating pins and the
gasket.
3. Install the fuel rail bracket with two cylinder bolts and
washers, ﬁnger tight.

VE114-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-69

Fuel Rail Inspection and Installation
1. Remove the fuel injector retaining clip (6), and remove
the fuel injectors (4).
2. Inspect the fuel injectors (4) and the fuel injector O-rings
(3, 5), replace if necessary.
3. Install the fuel injectors (4) into the fuel rail (2).
4. Install the fuel injector retaining clips (6).
5. Install the fuel rail assembly (2) and secure to the fuel rail
bracket with the fuel rail bracket bolts (1).
Tighten
Tighten the fuel rail to fuel rail bracket bolts to 12 N•m (106 lb

VE132-3L

Cylinder Head Torque Sequence
1. With the fuel rail bracket and fuel rail installed, tighten all
cylinder head bolts.
Tighten
Tighten the cylinder head bolts in sequence to 135 N•m
(100 lb ft).

VE115-3L

Valve Lifter Installation
1. Coat the bottom of the valve lifters with prelube, GM P/N
03755008 or equivalent.
2. If reusing the valve lifters, install in their original location.
3. Install the valve lifters.

VE116-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-70

Valve Rocker Arm and Pushrod Installation
Important: Be sure to keep parts in order. Parts must be
installed from where they were removed.
1. Install the valve pushrods. Be sure that the valve
pushrods seat in the valve lifter sockets.

VE023-3L

2. Install the following components:
2.1. The valve rocker arms (3).
2.2. The valve rocker arm balls (2). Lubricate the rocker
arm balls with clean engine oil.
2.3. The valve rocker arm nuts (1).

VE021-3L

VE117-3L

3. Adjust the valve rocker arm nuts as follows:
3.1. Turn the crankshaft until the mark on the crankshaft
pulley lines up with “0” on the timing tab and
number 1 cylinder is at top dead center.
3.2. Place ﬁngers on the number 1 valves as the
mark approaches “0.” If the valves move as the
mark approaches “0,” the engine is on number 4
top dead center and should be rotated one more
revolution in order to reach number 1 top dead
center.
3.3. With the engine at number 1 top dead center, adjust
the following valves:
– The exhaust valves 1, 3
– The intake valves 1, 2
3.4. Adjust the correct valves as follows:
3.4.1. Back off the valve rocker arm nut until the
lash is felt in the valve pushrod.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
3.4.2.

3.5.

3.6.

Tighten the valve rocker arm nut until all
the lash is removed.
3.4.3. Zero lash can be felt by moving the valve
pushrod up and down between your
thumb and foreﬁnger until there is no more
movement.
3.4.4. When all the free play is gone, tighten the
valve rocker arm nut 1 additional turn (360
degrees).
Turn the crankshaft 1 revolution until the mark on
the crankshaft pulley lines up with “0” on the timing
tab. This is number 4 top dead center.
With the engine at number 4 top dead center, adjust
the following valves:
– The exhaust valves 2, 4
– The intake valves 3, 4
3.6.1. Back off the valve rocker arm nut until the
lash is felt in the valve pushrod.
3.6.2. Tighten the valve rocker arm nut until all
the lash is removed.
3.6.3. Zero lash can be felt by moving the valve
pushrod up and down between your
thumb and foreﬁnger until there is no more
movement.
3.6.4. When all the free play is gone, tighten the
valve rocker arm nut 1 additional turn (360
degrees).

BASE ENGINE SECTION 2-71

VE117-3L

Pushrod Cover Installation
1. Install the pushrod cover gasket/sealer.
2. Install the pushrod cover.
3. Install the pushrod cover bolts.
Tighten
Tighten the pushrod bolts to 9 N•m (80 lb in).

VE118-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-72

Valve Rocker Arm Cover Installation
1. Install the valve rocker arm cover gasket/sealer.
2. Install the valve rocker arm cover.
3. Install the valve rocker arm bolts.
Tighten
Tighten the valve rocker arm cover bolts to 7 N•m (62 lb in).

VE019-3L

Oil Level Indicator and Tube Installation
1.
2.
3.
4.

Install one washer on the oil level tube stud.
Apply sealer to oil level indicator tube.
Install the oil level indicator tube into the engine block.
Use a light plastic or rubber hammer in order to tap the
tube until it seats in the engine block.
5. Install the washer and oil level tube retaining nut.
Tighten
Tighten the retaining nut to 9 N•m (80 lb in).
6. Install the oil level indicator into the tube.

VE120-3L

Water Pump Installation
1. Position the water pump and NEW gasket to the engine
block.
2. Install the water pump bolts.
Tighten
Tighten the water pump bolts to 20 N•m (15 lb ft).

VE017-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-73

Water Outlet and Thermostat Installation
1. Position the thermostat housing (5) and NEW gasket (8)
to the engine block.
2. Install the thermostat housing bolts (6).
Tighten
Tighten the thermostat housing bolts to 38 N•m (28 lb ft).
3. Install the thermostat (4) and NEW gasket (3) on the
thermostat housing (5).
4. Install the water outlet housing (2).
5. Install the water outlet housing bolts (1).
Tighten
Tighten the water outlet housing bolts to 28 N•m (21 lb ft).
6. Apply thread sealer then install the engine coolant
temperature sensor (7).
Tighten
Tighten the coolant temperature sensor to 20 N•m (15 lb ft).

VE129-3L

Intake/Exhaust Manifold Installation
1. Install the intake/exhaust manifold gasket over the
locating pins on the cylinder head.
2. Install the bolts and clamps while holding the manifold in
place.
Tighten
Tighten the four center bolts to 50 N•m (37 lb ft).
Tighten the end bolts to 50 N•m (37 lb ft).

VE014-3L

Spark Plug Installation
1. Check spark plug gap.
Platinum plug: 1.28 mm (.050 in)
Standard plug: 0.90 mm (.035 in)
2. Install the spark plugs.
Tighten
Tighten the spark plugs to 20 N•m (15 lb ft).

VE013-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-74

Lift Bracket Installation
1. Install the lift bracket.
2. Install the lift bracket bolts.
Tighten
Tighten the lift bracket bolts to 34 N•m (25 lb ft).

VE012-3L

Ignition Coil Module Assembly Installation
1. Install the ignition coil and module assembly.
2. Some models use EST ignition coil (6) only.
3. Install the ignition coil bracket bolts (1).
Tighten
Tighten the attaching bolts to 25 N•m (18 lb ft).

VE011-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-75

Distributor/High Voltage Switch (HVS) Installation
Important: To ensure correct ignition timing, the distributor
must be installed in the correct position. Position the engine at
top dead center on number one cylinder. The distributor cap
must be removed in order to position the rotor when installing
the distributor.
1. Install the distributor (2) and new gasket (3), making sure
the distributor rotor is pointing to number one tower on
the distributor cap.
2. Some models use the EST distributor (6) and primary
ignition harness (7).
3. Install the distributor hold down (4) and bolt (5).
Tighten
Tighten the hold down bolt to 33 N•m (24 lb ft).

VE010-3L

4. Connect the secondary ignition wires (1) to the spark
plugs and the ignition coil. See diagram for speciﬁc

VE010-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-76

Engine Flywheel Installation
Important: Note the position and direction of the engine
ﬂywheel before removal. The ﬂywheel center alignment hole
is a tapered ﬁt to the crankshaft. The engine ﬂywheel must be
reinstalled to the original position and direction. The engine
ﬂywheel will not initially seat against the crankshaft ﬂange, but
will be pulled onto the crankshaft by the engine ﬂywheel bolts.
1. Install the engine ﬂywheel.
2. Install the engine ﬂywheel bolts.
Tighten
Tighten the ﬂywheel bolts to 100 N•m (74 lb ft).

VE009-3L

Engine Block Coolant Plug/Oil Filter/Crankshaft
Position Sensor and Fuel Pump Cover Installation
1. Apply thread sealer and install the left rear engine block
coolant plug (4).
2. Inspect the crankshaft position sensor O-ring (1) for
damage, replace if necessary. Lubricate the O-ring with
clean oil.
3. Install the crankshaft position sensor (2).
4. Install the crankshaft position sensor retaining bolt (3).
Tighten
Tighten the crankshaft position sensor retaining bolt to 10 N•m
(89 lb in).

VE008-3L

5. Apply clean oil to the oil ﬁlter gasket and install the oil

VE006-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-77

6. Install the fuel pump cover gasket/sealer (3).
7. Install the fuel pump cover (2).
8. Install the fuel pump cover bolts (1).
Tighten
Tighten the fuel pump cover bolts to 19 N•m (14 lb ft).

VE133-3L

9. Install the oil pan drain plug.

VE005-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-78

Description and Operation
Engine Component Description
Engine Block
The engine block has four cylinders arranged in an “in-line” construction. Starting at the front of the engine, the
cylinders are numbered 1-2-3-4. The ﬁring order of the cylinders is 1-3-4-2. The cylinders are encircled by coolant
jackets.
Cylinder Head
The cylinder head has one intake and one exhaust valve per cylinder. A spark plug is located between the valves
in the side of the cylinder head. The valve guides are integral and the valve rocker arms are retained on individual
threaded studs.
Crankshaft
The crankshaft is cast nodular iron and is supported by ﬁve crankshaft bearings. The bearings are retained by
crankshaft bearing caps that are machined with the engine block for proper alignment and clearances.
Camshaft
A billet steel one piece camshaft is supported by four full round, sleeve-type bearings. These bearings are a press
ﬁt into the engine block. The camshaft timing sprocket is mounted to the front of the camshaft and is driven the
crankshaft sprocket.
Pistons and Connecting Rods
The pistons are made of cast-aluminum alloy using two compression rings and one oil control ring assembly. The
piston pins are a press ﬁt in the connecting rods and a ﬂoating ﬁt in the pistons.
Valve Train
The valve train is a ball-pivot type. Motion is transmitted from the camshaft through the valve lifter and valve pushrod
to the valve rocker arm. The valve rocker arm pivots on its ball and transmits the camshaft motion to the valve.
The valve lifters keep all parts of the valve train in constant contact. Each lifter acts as an automatic adjuster and
maintains zero lash in the valve train. This eliminates the need for periodic valve adjustment.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Lubrication
The oil pump is gear driven from the camshaft. Oil is
drawn from the oil pan through a pickup screen and
tube. The gear type oil pump has a pressure regulator
valve which controls the lubrication system pressure by
bypassing excess oil back to the oil pan sump.
Pressurized oil from the oil pump ﬂows to the full ﬂow
ﬁlter. A bypass valve allows oil to bypass the ﬁlter if it
becomes clogged or restricted. Oil then ﬂows into an
oil passage that runs along the right side of the block
and intersects the lifter bosses. Oil from this passage
is routed to the crankshaft main bearings and camshaft
bearings through smaller drilled passages. Oil is
supplied to the connecting rod bearings by holes drilled
in the crankshaft. Oil is supplied to the rocker arms
through holes in the hydraulic lifters which feed oil up
the pushrods to the rocker arms. The oil is metered by
discs under the pushrod seat.
Many internal engine parts have no direct oil feed and
are supplied by either gravity or splash from other
direct feed components. Timing gears are lubricated
by oil supplied through a passage from the front of the
camshaft to a calibrated nozzle above the crankshaft
gear.

Thread Repair
Tools Required
General purpose thread repair kits. These kits are

BASE ENGINE SECTION 2-79

available commercially
Caution: Wear safety glasses in order to avoid eye
damage.
1. Determine the size, pitch and depth of the
damaged thread. If necessary, adjust the stop
collars on the cutting tool and tap to the required
depth.
2. Drill out the damaged thread. Clean out any chips.
3. Avoid any buildup of chips. Back out the tap every
few turns and remove the chips.

4. Tap the hole. Lubricate the tap with light engine
oil. Clean the thread.
VE122-3L

5.Thread the insert onto the mandrel of the installer.
Engage the tang of the insert onto the end of the
mandrel.
Important: The insert should be ﬂush to one turn below
the surface.
6. Lubricate the insert with light engine oil (except
when installing in aluminum) and install the insert.
7. If the tang of the insert does not break off when

VE121-3L

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
backing out the installer, break the tang off with a
drift.

Cleanliness and Care
•

•
•

•

•
•

Throughout this section, it should be
understood that proper cleaning and protection
of machined surfaces and friction areas is part
of the repair procedure. This is considered
standard shop practice even if not speciﬁcally
stated.
When any internal engine parts are serviced,
care and cleanliness is important.
When components are removed for service,
they should be marked, organized or retained
in a speciﬁc order for reassembly. Refer to
Separating Parts.
At the time of installation, components should
be installed in the same location and with the
same mating surface as when removed.
An engine is a combination of many machined,
honed, polished and lapped surfaces with
tolerances that are measured in millimeters or
thousandths of an inch. These surfaces should
be covered or protected to avoid component
damage.
A liberal coating of clean engine oil should be
applied to friction areas during assembly.
Proper lubrication will protect and lubricate
friction surfaces during initial operation.

Replacing Engine Gaskets
1. Gasket reuse and applying sealants:
• Do not reuse any gasket unless speciﬁed.
• Gaskets that can be reused will be identiﬁed in
the service procedure.
• Do not apply sealant to any gasket or sealing
surface unless speciﬁed in the service
procedure.
2. Separating components:
• Use a rubber mallet to separate components.
• Bump the part sideways to loosen the
components.
• Bumping should be done at bends or
reinforced areas to prevent distortion of the
parts.
3. Cleaning gasket surfaces:
• Remove all gasket and sealing material from
the part using a plastic or wood scraper (if
required).
• Care must taken to avoid gouging or scraping
the aluminum sealing surfaces.
• Do not use any other method or technique to
remove sealant or gasket material from a part.
• Do not use abrasive pads, sand paper or

BASE ENGINE SECTION 2-80

power tools to clean gasket surfaces.
– These methods of cleaning can cause
damage to the component sealing
surfaces.
– Abrasive pads also produce a ﬁne grit
that the oil ﬁlter cannot remove from the
oil.
– This grit is abrasive and has been
known
to cause internal
engine damage.
4. Assembling components:
• When assembling components, use only the
sealant speciﬁed or equivalent in the service
procedure.
• Sealing surfaces should be clean and free of
debris or oil.
• Speciﬁc components such as crankshaft oil
seals or valve stem oil seals may require
lubrication during assembly.
• Components requiring lubrication will be
identiﬁed in the service procedure.
• When applying sealant to a component, apply
the amount speciﬁed in the service procedure.
• Do not allow the sealant to enter into any blind
threaded holes, as it may prevent the bolt
from clamping properly or cause component
damage when tightened.
• Tighten bolts to speciﬁcations. Do not
overtighten.

Use of RTV and Anaerobic Sealer
Important: Three types of sealer are commonly used
in engines. These are RTV sealer, anaerobic gasket
eliminator sealer and pipe joint compound. The correct
sealer and amount must be used in the proper location
to prevent oil leaks. DO NOT interchange the three
types of sealers. Use only the speciﬁc sealer or the
equivalent as recommended in the service procedure.
Pipe Joint Compound
• Pipe joint compound is a pliable sealer that
does not completely harden. This type sealer
is used where two nonrigid parts (such as the
oil pan and the engine block) are assembled
together.
• Do not use pipe joint compound in areas where
extreme temperatures are expected. These
areas include: exhaust manifolds, head gasket
or other surfaces where gasket eliminator is
speciﬁed.
• Follow all safety recommendations and
directions that are on the container.
• To remove the sealant or the gasket material,

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Refer to Replacing Engine Gaskets.
• Apply a continuous bead of pipe joint
compound to one sealing surface. Sealing
surfaces to be resealed must be clean and dry.
• Tighten the bolts to speciﬁcations. Do not
overtighten.
RTV Sealer
• Room Temperature Vulcanizing (RTV) sealant
hardens when exposed to air. This type sealer
is used where two nonrigid parts (such as the
oil pan and the engine block) are assembled
together.
• Do not use RTV sealant in areas where
extreme temperatures are expected. These
areas include: exhaust manifolds, head gasket
or other surfaces where gasket eliminator is
speciﬁed.
• Follow all safety recommendations and
directions that are on the container.
• To remove the sealant or the gasket material,
Refer to Replacing Engine Gaskets.
• Apply RTV to a clean surface. Use a bead size
as speciﬁed in the service procedure. Run the
bead to the inside of any bolt holes. Do not
allow the sealer to enter any blind threaded
holes, as it may prevent the bolt from clamping
properly or cause damage when the bolt is
tightened.
• Assemble components while RTV is still wet
(within three minutes). Do not wait for RTV to
skin over.
• Tighten the bolts to speciﬁcations. Do not
overtighten.
Anaerobic Sealer
• Anaerobic gasket eliminator hardens in
the absence of air. This type sealer is used
where two rigid parts (such as castings) are
assembled and no sealer or gasket is readily
noticeable, the parts were probably assembled
using a gasket eliminator.
• Follow all safety recommendations and
directions that are on the container.
• To remove the sealant or the gasket material,
Refer to Replacing Engine Gaskets.
• Apply a continuous bead of gasket eliminator
to one ﬂange. Surfaces to be resealed must be
clean and dry.
• Spread the sealer evenly with your ﬁnger to get
a uniform coating on the sealing surface. Do
not allow the sealer to enter any blind threaded

BASE ENGINE SECTION 2-81

•
•

holes, as it may prevent the bolt from clamping
properly or cause damage when the bolt is
tightened.
Tighten the bolts to speciﬁcations. Do not
overtighten.
After properly tightening the fasteners, remove
the excess sealer from the outside of the joint.

Separating Parts
Important: Many internal engine components will
develop speciﬁc wear patterns on their friction surfaces.
When assembling the engine, internal components
MUST be separated, marked or organized in a way to
ensure reinstallation to original location and position.
Mark or identify the following components:
• Piston and the piston pin.
• Piston assembly to the speciﬁc cylinder bore.
• Piston rings to the speciﬁc piston assembly
and cylinder bore.
• Connecting rod to the crankshaft journal.
• Connecting rod to bearing cap.
• Crankshaft main and connecting rod bearings.
• Camshaft and valve lifters.
• Valve lifters, guides, pushrods, pivot supports
and rocker arms.
• Valve to the valve guide.
• Valve spring and shim .
• Engine block main bearing cap location and
direction.
• Oil pump drive and driven gears.

Tools and Equipment
Special tools are listed and illustrated throughout this
section with a complete listing at the end of the section.
These tools (or their equivalents) are specially designed
to quickly and safely accomplish the operations for
which they are intended. The use of these special
tools will also minimize possible damage to engine
components. Some precision measuring tools are
required for inspection of certain critical components.
Torque wrenches and a torque angle meter are
necessary for the proper tightening of various fasteners.
To properly service the engine assembly, the following
items should be readily available:
• Approved eye protection and safety gloves.
• A clean, well-lit work area.
• A suitable parts cleaning tank.
• A compressed air supply.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Special Tools and Equipment

BASE ENGINE SECTION 2-82

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-83

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-84

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

BASE ENGINE SECTION 2-85

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DUAL FUEL DESCRIPTION OF OPERATION 3-1

PSI 3.0L PFI
DUAL FUEL SYSTEM
DESCRIPTION OF OPERATION
Table Of Contents
Description

Page

Typical Dual Fuel System Schematic...........................................................................3-2
Dual Fuel System Overview.........................................................................................3-3
LPG Storage Tank........................................................................................................3-3
LPG Service Line.........................................................................................................3-4
Fuel Filters...................................................................................................................3-4
Electronic Fuel Lock.....................................................................................................3-4
Electronic Pressure Regulator (EPR)...........................................................................3-5
Low Pressure Regulator...............................................................................................3-5
LPG Mixer....................................................................................................................3-6
Electronic Throttle Control (ETC).................................................................................3-6
Three-Way Catalytic Mufﬂer.........................................................................................3-7
Engine Control Module (ECM).....................................................................................3-8
Heated Exhaust Gas Oxygen Sensor (HEGO)............................................................3-9
Gasoline Fuel Storage Tank.......................................................................................3-10
Gasoline Fuel Pump...................................................................................................3-10
Gasoline Fuel Pressure & Temperature Manifold......................................................3-10
Fuel Injector Rail........................................................................................................3-11
Fuel Injector...............................................................................................................3-11

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DUAL FUEL DESCRIPTION OF OPERATION 3-2

DESCRIPTION AND OPERATION OF THE FUEL SYSTEMS

Figure 1 - Typical IMPCO Dual Fuel System Schematic

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DUAL FUEL DESCRIPTION OF OPERATION 3-3

DUAL FUEL SYSTEM
The IMPCO Dual Fuel system is designed to offer the operator the ability to operate the vehicle on either
gasoline or LPG by positioning a selector switch in the operator’s platform. When the operator places the
selector switch in the gasoline mode the gasoline fuel pump is energized when the operator places the ignition
key in the, key ON engine off (KOEO) or the key ON engine run (KOER) modes. While in the gasoline mode
the LPG fuel lock-off is isolated and will not energize. In addition the gasoline injector circuit is enabled and
injector pulses are provided to each injector and the ECM calibration for gasoline is also enabled. When the
operator selects the LPG mode the Low Pressure LPG lock-off is energized when the operator places the
ignition key in the (KOEO) or the (KOER) modes and fuel from the LPG tank ﬂows to the Electronic Pressure
Regulator (EPR). During the (KOEO) or the (KOER) the EPR receives and electronic signal to position the
secondary lever for the start or run positions and when the engine begins to crank the mixer air valve will
rise and fuel will begin ﬂowing to engine. During this mode the gasoline fuel pump is isolated and will not be
activated during the (KOEO) or the (KOER) modes. The primary components of the gasoline dual fuel system
are the gasoline fuel storage tank, electric fuel pump and ﬁlter, fuel supply line, injector rail and injectors and
the fuel pressure regulator. The primary components of the LPG dual fuel system are the LPG fuel storage
tank, in-fuel ﬁlter, LPG Low Pressure lock-off, Electronic Pressure Regulator (EPR) and the fuel mixer module.
The LPG fuel system operates at pressures which range from 355.60 mm (14.0 inches) of water column up to
21.5 BAR (312 psi).
Components which are shared by both systems include the Electronic Throttle Control (ETC), Three Way
Catalytic (TWC) converter and the ECM. The ECM contains a dual calibration one which controls the gasoline
fuel system during gasoline operation and a calibration which controls the LPG fuel system during LPG
operation. The block diagram above Figure 1 identiﬁes the major components identiﬁed in this section and the
placement, pressure and circuit relationship to the ECM.

LPG FUEL TANK
Propane is stored in the fuel tank as a liquid. The approximate pressure of the fuel in the tank is 16.5 bar (240
psi) when the tank is full at an ambient temperature of 27° C (81°F). The boiling point, (temperature at which
the liquid fuel becomes vapor) is approximately -40° C (-40° F). When the fuel changes from liquid to vapor
the fuel expands and creates pressure inside the tank. When the tank service valve is opened the pressure
inside the tank forces the liquid fuel out though the pick up tube located near the bottom of the fuel cylinder.
Because the Propane is stored under pressure the tank is equipped with a safety valves which are normally
set at 25.8 bar (375 psi) to prevent tank rupture due to over-pressurization of the cylinder. The service valve
mounted in the end of the cylinder controls the ﬂow of fuel from the tank. By turning the handle to its “open”
position, fuel ﬂows out of the tank and into the service line. The service valve is also equipped with a safety
feature called an “excess ﬂow check valve”. This feature reduces the ﬂow from the service valve in the event
of a rupture of the fuel line or any down stream component.

Figure 2
Typical Propane Cylinders

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DUAL FUEL DESCRIPTION OF OPERATION 3-4

SERVICE LINE
Propane ﬂows from the fuel tank to the electric lock via the service line. The service line is connected to
the tank utilizing a quick coupler. The other end of the service line is connected to a “bulkhead connector”
mounted on the equipment sheet metal. This bulkhead connector allows for a safe means of passing
through the equipment’s engine compartment sheet metal and into the engine compartment. If a bulkhead
connector is used a pressure relief device is mounted in the service line or the connector itself to prevent over
pressurization of the service line. The service line is made of high pressure hose with special material or
possibly tubing which is friendly to the LPG fuel and should always be replaced with an OEM supplied part.

FUEL FILTER
Propane fuel like all other motor fuels is subject to contamination from outside sources. Refueling of the
equipment’s tank and removal of the tank from the equipment can inadvertently introduce dirt and other
foreign matter into the fuel system. It is therefore necessary to ﬁlter the fuel prior to entering the fuel system
components down stream of the tank. An inline fuel ﬁlter has been installed in the fuel system to remove the
dirt and foreign matter from the fuel. The inline ﬁlter is replaceable as a unit only. Maintenance of the ﬁlter
is critical to proper operation of the fuel system and should be replaced as deﬁned in the Recommended
Maintenance Schedule. In severe operating condition more frequent replacement of the ﬁlter may be
necessary.

Figure 3
Inline Fuel Filter

ELECTRIC LOCK OFF
The Electric Lock Off device is an integrated assembly. The electric lock assembly is a 12 volt normally closed
valve. The solenoid is mounted to the valve body. When energized the solenoid opens the valve and allows
the Propane fuel to ﬂow through the device. The valve opens during cranking and run cycles of the engine.
The lock off supply voltage is controlled by the engine control module (ECM).

Figure 4
Electric Fuel Lock Off

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DUAL FUEL DESCRIPTION OF OPERATION 3-5

EPR ASSEMBLY
The EPR assembly is a combination Low Pressure Regulator and a Voice Coil Assembly. The Voice coil
is an electronic actuator which is controlled by an internal microprocessor. The microprocessor provides
output data to the ECM and receives input data over a CAN BUS connection. The internal microprocessor
receives electrical signals from the Fuel Pressure Sensor FPS and the Fuel Temperature Pressure FTP
and communicates the data to the ECM. The ECM uses the FPS and FTP data to calculate the location
of the secondary lever in the LPR and sends that data back to the EPR via the CAN BUS. The internal
microprocessor in the EPR will than output a signal, which causes the voice coil to move and position the
secondary lever to the correct location.

Figure 5
EPR Assembly

LOW PRESSURE REGULATOR (LPR)
The LPR is a combination vaporizer, pressure regulating device. The LPR is a negative pressure two stage
regulator that is normally closed when the engine is not running. When the engine is cranking or running a
partial vacuum is created in the fuel line which connects the regulator to the mixer. This partial vacuum opens
the regulator permitting fuel to ﬂow to the mixer.
Propane fuel enters the primary port of the LPR and passes through the primary jet and into the primary/
exchanger chamber. As the propane passes through the heat exchanger the fuel expands and creates
pressure inside the chamber. The pressure rises as the fuel expands when the pressure rises above 10.34
kpa (1.5 psi), sufﬁcient pressure is exerted on the primary diaphragm to cause the diaphragm plate to pivot and
press against the primary valve pin thus closing off the ﬂow of fuel. This action causes the ﬂow of fuel into the
regulator to be regulated.
When the engine is cranking, sufﬁcient vacuum will be introduce into the secondary chamber from the mixer
drawing the secondary diaphragm down onto the spring loaded lever and opening the secondary valve
allowing vaporized fuel to pass to the mixer. This mechanical action in conjunction with the EPR reactions
causes the downward action on the secondary lever causing it to open wider allowing more fuel to ﬂow to the
mixer.

Figure 5
Low pressure regulators

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DUAL FUEL DESCRIPTION OF OPERATION 3-6

AIR FUEL MIXER
The air valve mixer is an air-fuel metering device and is completely self-contained. The mixer is an air valve
design, utilizing a relatively constant pressure drop to draw fuel into the mixer from cranking to full load. The
mixer is mounted in the air stream ahead of the throttle control device.
When the engine begins to crank it draws in air with the air valve covering the inlet, negative pressure begins
to build. This negative pressure signal is communicated to the top of the air valve chamber through 4 vacuum
ports in the air valve assembly. A pressure/force imbalance begins to build across the air valve diaphragm
between the air valve vacuum chamber and the atmospheric pressure below the diaphragm. The air valve
vacuum spring is calibrated to generate from 101.6 mm (4.0 inches) of water column at start to as high as
355.60 mm (14.0 inches) of water column at full throttle. The vacuum being created is referred to as Air Valve
Vacuum (AVV). As the air valve vacuum reaches 101.6mm (4.0 inches) of water column, the air valve begins
to lift against the air valve spring. The amount of AVV generated is a direct result of the throttle position. At
low engine speed the air valve vacuum is low and the air valve position is low thus creating a small venturi
for the fuel to ﬂow. As the engine speed increase the AVV increases and the air valve is lifted higher thus
creating a much larger venturi. This air valve vacuum is communicated from the mixer venture to the LPR
secondary chamber via the low pressure fuel supply hose. As the AVV increases in the secondary chamber
the secondary diaphragm is drawn further down forcing the secondary valve lever to open wider.

Figure 6
Air Fuel Mixer

ELECTRONIC THROTTLE CONTROL (ETC)
Engine speed and load control is maintained by an ETC device. Speed and load control are determined by the
ECM. Defaults programmed into the ECM software and throttle position sensors allow the ECM to maintain
safe operating control over the engine. The Electronic Throttle Control device or “throttle body assembly” is
connected to the intake manifold of the engine. The electronic throttle control device utilizes an electric motor
connected to the throttle shaft. When the engine is running electrical signals are sent from the equipment
controls to the engine ECM when the operator depresses an equipment function switch. The ECM then sends
an electrical signal to the motor on the electronic throttle control to increase or decrease the angle of the
throttle blade thus increasing or decreasing the air/fuel ﬂow to the engine.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DUAL FUEL DESCRIPTION OF OPERATION 3-7

The electronic throttle control device also incorporates two internal Throttle Position Sensors (TPS) which
provide output signals to the ECM as to the location of the throttle shaft and blade. The TPS information is
used by the ECM to correct for speed and load control as well as emission control.

Figure 8
ETC throttle control device

THREE-WAY CATALYTIC MUFFLER
The emission certiﬁed engine has been designed and calibrated to meet the emission standards in effect for
2006. To help meet the emission requirements the vehicle has been equipped with a Three Way Catalytic
(TWC) mufﬂer. The catalyst mufﬂer is a three way catalyst, sound damping and spark arresting unit. Besides
controlling the noise created from the combustion process, and preventing sparks from escaping from
the exhaust system the most important function is treating the exhaust gases which are created from the
combustion process. The three-way catalyst consists of a honeycomb coated with a mixture of platinum,
palladium, and rhodium. The hot gases ﬂow through the catalyst sections where an oxidation and reduction
reactions take place. These chemical reactions reduce the amount of CO, HC and NOX in the engines
exhaust. The Exhaust gas then ﬂows through the outlet.

Figure 9
Three way catalytic converter

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DUAL FUEL DESCRIPTION OF OPERATION 3-8

ENGINE CONTROL MODULE
To obtain maximum effect from the catalyst and accurate control of the air fuel ratio the emission certiﬁed
engine is equipped with an onboard computer or Engine Control Unit (ECM). The ECM is a 32 bit controller
which receives in-put data from sensors ﬁtted to the engine and fuel system and then out-puts various signals
to control engine operation.
One speciﬁc function of the controller is to maintain “closed loop fuel control”. Closed loop fuel control is
accomplished when the exhaust gas oxygen sensor (HEGO) mounted in the exhaust system sends a voltage
signal to the controller. The controller then calculates any correction that may need to be made to the air fuel
ratio. The controller then out-puts signals to the EPR to correct the amount of fuel being supplied to the mixer.
At the same time the ECM may correct the throttle blade position to correct speed and load of the engine.
The controller also performs diagnostic functions on the fuel system and notiﬁes the operator of malfunctions
by turning on a Malfunction Indicator Light (MIL) mounted in the dash. Malfunctions in the system are
identiﬁed by a Diagnostic Code number. In addition to notifying the operator of the malfunction in the system
the controller also stores the information about the malfunction in its memory. A technician can than utilize a
computerized diagnostic tool to retrieve the stored diagnostic code and by using the diagnostic charts in this
manual determine the cause of the malfunction. In the event a technician does not have the computerized
diagnostic tool the MIL light can be used to identify the diagnostic code. By following speciﬁc steps the
technician can activate the “blink” feature and count the number of blinks to determine the diagnostic code
number to locate the fault in the system.

Figure 10
LPG Engine Control Unit (ECM)

Figure 11
ECM Assembly

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DUAL FUEL DESCRIPTION OF OPERATION 3-9

HEATED EXHAUST GAS OXYGEN SENSOR
On the 2006 fuel system equipped on your vehicle there are two, Heated Exhaust Gas Oxygen Sensor
(HEGO). The pre-catalyst HEGO is mounted in the exhaust system downstream of the engine. The precatalyst HEGO is used to measure the amount of oxygen present in the exhaust stream and communicate that
to the ECM via an electrical signal. The amount of oxygen present in the exhaust stream indicates whether
the fuel air ratio is to rich or to lean. If the HEGO sensor signal indicates that the exhaust stream is to rich the
ECM will decrease or lean the fuel mixture during engine operation, if the mixture is to lean the ECM will richen
the mixture. The ECM continuously monitors the HEGO sensor output if a rich or lean condition is present for
an extended period of time and the ECM cannot correct the condition the ECM will set a diagnostic code and
turn on the MIL light in the dash.
The second HEGO is the Post-catalyst monitoring sensor. The sensor is mounted in the exhaust system after
the catalyst. The Post-catalyst HEGO measure the amount of oxygen in the exhaust system after the catalyst
treatment has been completed. The Post-catalyst sends the electronic signal to the ECM. If the ECM detects
that the catalytic action in the mufﬂer is not sufﬁcient and fuel correction cannot correct the malfunction the MIL
light is illuminated in the dash and a DTC code will be set.

Figure 12
Heated Exhaust Gas Oxygen Sensor (HEGO)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DUAL FUEL DESCRIPTION OF OPERATION 3-10

GASOLINE MULTI POINT FUEL INJECTION SYSTEM (MPFI)
The primary components of the Gasoline Multi Point Fuel Injection (MPFI) fuel system are the gasoline fuel tank, electric
fuel pump, fuel pressure and temperature sensor manifold, fuel ﬁlter and fuel rail.

GASOLINE FUEL STORAGE TANK
The gasoline fuel storage tank location may very on equipment applications. The fuel tank may be integrated into the
chassis frame or may be a stand alone vessel mounted on the equipment. For precise location for the equipment application refer to the OEMs vehicle manual.

GASOLINE FUEL PUMP
The Gasoline is stored as a liquid in the fuel tank and in drawn into the fuel system by a 12 volt electric fuel pump.
Depending on the vehicle application the fuel pump may be mounted in the fuel tank or as a stand alone component. In
either case the fuel pump will receive a signal from the ECM at Key On to prime the fuel system for approximately 2 seconds prior to start. Priming of the fuel system provides for a quicker start, when the engine begins to crank. Consult the
OEM for the location of the fuel pump.

GASOLINE PRESSURE AND TEMPERATURE SENSOR MANIFOLD
This engine is equipped with a fuel injector rail that does not have a pressure regulator or a return circuit to the fuel tank.
Fuel pressure for this engine is regulated by the engine’s ECM. The ECM receives fuel pressure and temperature feedback from the gasoline fuel sensor manifold and uses this information to control the ground side of the fuel pump. Fuel
pressure is regulated by the ECM pulse width modulating (PWM) the fuel pump. The fuel pressure and temperature sensor manifold has a return or “bleed” circuit that connects back to the equipment fuel tank. This circuit is used to bleed off
any vapor that develops in the line and returns a small amount of fuel to the tank. The fuel comes from the fuel tank and
passes through the fuel pump. Fuel exits the fuel pump, passes through the ﬁlter and then enters the fuel pressure and
temperature manifold assembly. Fuel ﬂows through the feed ciruit and is delivered to the fuel injector rail. Fuel that enters the bleed circuits through the by-pass valve in the manifold is returned to the fuel tank.

Gasoline Fuel Pressure and Temperature
Manifold Assembly

FUEL FILTER

After the fuel is drawn into the fuel pump, the fuel ﬂows through the gasoline fuel ﬁlter. The fuel ﬁlter will trap small particles. The fuel passes through the ﬁlter to remove debris which prevents the fuel pressure and temperature manifold
and fuel injectors from becoming damaged. Maintenance of the fuel ﬁlter is required as indicated in the Recommended
Maintenance Schedule. A more frequent replacement of the ﬁlter may be required if the equipment operates in a dusty or
dirty environment.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DUAL FUEL DESCRIPTION OF OPERATION 3-11

FUEL INJECTOR RAIL
The fuel ﬂows from the fuel pressure and temperature manifold assembly to the fuel rails where the fuel is delivered to the
fuel injectors. The fuel rail also contains a Schrader valve which is utilized to test the regulated pressure of the fuel system.

FUEL INJECTOR
The fuel supply is maintained on the top of the injector from the injector rail. The injector is fed a “pulse” signal through
the wire harness which causes the injector to open. During regular operating conditions the ECM controls the opening
and duration of opening of the injector. During lower RPM operation the injector signals or “pulses” are less frequent then
when the engine is operating at higher RPMs. The certiﬁed engine has been calibrated to deliver the precise amount of
fuel for optimum performance and emission control.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

FUEL SYSTEM R&R SECTION 4-1

PSI 3.0L PFI
FUEL SYSTEM REMOVE & REPLACE SECTION
Description

Table Of Contents

Page

LPG Fuel Filter............................................................................................................4-2
Electronic Pressure Regulator Assembly (EPR)..........................................................4-3
Pressure Regulator Section.........................................................................................4-5
TMAP Sensor...............................................................................................................4-5
Electronic Throttle Control Assembly............................................................................4-6
LPG Fuel Mixer Assembly............................................................................................4-7
Coolant Hose...............................................................................................................4-8
LPG Vapor Hose..........................................................................................................4-8
ECM.............................................................................................................................4-8
HEGO Sensor..............................................................................................................4-9
Three-Way Catalyst Mufﬂer..........................................................................................4-9

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

FUEL SYSTEM R&R SECTION 4-2

REPAIR INSTRUCTIONS
PROPANE FUEL SYSTEM PRESSURE RELIEF
CAUTION: The propane fuel system operates at pressures up to 21.5 BAR (312 psi). To minimize the risk of ﬁre
and personal injury, relieve the propane fuel system pressure (where applicable) before servicing the propane fuel
system components.
To relieve propane fuel system pressure:
1. Close the manual shut-off valve (MSV) on the propane fuel tank.
2. Start and run the vehicle until the engine stalls.
3. Turn the ignition switch OFF.
Important
• Residual vapor pressure will be present in the fuel system. Ensure the work area is well ventilated before disconnecting
any fuel line.

PROPANE FUEL SYSTEM LEAK TEST
CAUTION: Never use an open ﬂame of any type to check for propane fuel system leaks.
Always inspect the propane fuel system for leaks after performing service. Check for leaks at the ﬁttings of the serviced
or replaced component. Use a commercially available liquid leak detector or an electronic leak detector. When using both
methods, use the electronic leak detector ﬁrst to avoid contamination by the liquid leak detector.
Figure 1
Filter Lock Assembly

PROPANE FUEL FILTER REPLACEMENT
(FIGURE 1)
Removal Procedure
1.Relieve the propane fuel system pressure. Refer to Propane Fuel System Pressure Relief.
2.

Disconnect the negative battery cable.

Slow loosen the Filter housing retaining bolt and retain.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
4.

Pull the ﬁlter housing down from the Electric lock off assembly

Locate Filter magnet and retain

Remove the ﬁlter from the housing

Remove and discard the housing seal

Remove and discard the retaining bolt seal.

Remove and discard mounting plate to lock off O-ring seal

FUEL SYSTEM R&R SECTION 4-3

Installation Procedure
•

Important: Be sure to reinstall the ﬁlter magnet into the housing before installing new seal

Install the mounting plate to lock off O-ring seal

Install the retaining bolt seal

Install the housing seal

Drop the magnet into the bottom of the ﬁlter housing

Install the ﬁlter into the housing

Install the retaining bolt into the ﬁlter housing

Install the ﬁlter up to the bottom of the electric lock off

Tighten the ﬁlter retain bolt to speciﬁcation
Tighten
12 Nm (106 in lbs).

Open manual shut-off valve.

Start the vehicle and leak check the propane fuel system at each serviced ﬁtting Refer to Propane Fuel System Leak
Test..

FIGURE 2
EPR Assembly

ELECTRONIC PRESSURE REGULATOR (EPR) ASSEMBLY REPLACEMENT
(FIGURE 2)
The EPR assembly is a made up of two separate components. The Voice Coil Section is not serviceable and can only be
replaced as an assembly. The pressure regulator section is serviceable and will be detailed in this section.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

FUEL SYSTEM R&R SECTION 4-4

EPR Assembly Removal Procedure
1. Relieve the propane fuel system pressure. Refer to Propane Fuel System Pressure Relief.
2. Disconnect the negative battery cable.
3. Slowly remove the fuel inlet ﬁtting at the Electric Lock Off
NOTE: Residual vapor pressure will be present in the fuel system.
4. Disconnect the electrical connector to the Electric Lock off
5. Remove the Electric Lock Off from the regulator
6. Remove the lock pin from the vapor ﬁtting on the regulator housing and remove the ﬁtting and hose and retain the pin
7. Remove the lock pin from the pressure sensor on the regulator housing and remove the Sensor and retain the pin
8. Using a clamp pliers pinch off the hoses on the coolant lines to the regulator
9. Remove the lock pin from both the water ﬁttings on the regulator housing and remove the ﬁttings and hoses and retain
the pin
10. Disconnect the EPR electrical connector
11. Remove the (3) three nuts from the EPR isolators and the EPR mounting bracket
12. Remove the EPR from the bracket
13. Remove the (3) three mounting isolators
Installation Procedure
Important
• Do not use Teﬂon tape on any fuel ﬁtting. Use a liquid pipe thread sealant when installing ﬁttings.
• Check all the O-rings on the vapor and water ﬁttings for any damage replace if necessary
• Lube all the O-rings with an O-ring lube before installing.
1. Install the three (3) rubber isolators to the bottom of the EPR
2. Install the EPR assembly to the bracket and tighten the retaining nuts
NOTE: Do not over tighten the isolators and cause a separation of the isolators
3. Install the fuel temperature sensor into the regulator opening and lock in place with the locking pin, connect the
electrical connector
4. Insert the fuel vapor line and ﬁtting into the regulator port and lock in place with the locking pin
5. Install both the water hoses and ﬁttings into the regulator and lock in place with the locking pin remove the clamp
pliers from the hoses
6. Install the electric lock off into the regulator inlet and tighten into proper location, connect the electrical connector
7. Connect the fuel supply line and tighten until fully seated
8. Connect the EPR electrical connector
9. Open the manual valve
10. Start the vehicle and leak check the propane fuel system at each serviced ﬁtting Refer to Propane Fuel System Leak
Test.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Pressure Regulator Section Removal

FUEL SYSTEM R&R SECTION 4-5

Figure 3
Pressure Regulator Section

1. Remove the EPR refer to EPR Removal Procedure
2. Remove the six (6) regulator to voice coil screws using the special tool and separate the regulator from the actuator.
IMPORTANT: DO NOT REMOVE THE SECONDARY DIAPHRAGM RETAINING PLATE AND DIAPHRAGM THIS WILL
VOID THE WARRANTY OF THE ACTUATOR SECTION.
Installation Procedure
1. Install the regulator to the actuator section using the six (6) retaining screws and tighten to speciﬁcation.
Tighten
8 Nm (70 in lbs).
2. Install the EPR refer to EPR Installation

TEMPERATURE MANIFOLD ABSOLUTE PRESSURE (TMAP) SENSOR
(Figure 4)
Removal Procedure
1. Disconnect the TMAP electrical connector
2. Remove the two retaining bolts
3. Remove the TMAP
Installation Procedure
•

Apply a small amount of O-ring lubricant before installation
1. Install in reverse order
2. Tighten retaining bolts
Tighten
7 Nµ (62 lb-in)
3. Start the vehicle
Figure 4
TMAP Sensor & Electronic Throttle Control (ETC)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

FUEL SYSTEM R&R SECTION 4-6

ELECTRONIC THROTTLE CONTROL REPLACEMENT
(FIGURE 4)
Removal Procedure
1.
2.
3.
4.
5.
6.
7.
8.
9.

Disconnect the negative battery cable.
Remove the air intake duct.
Release the hose clamp on the vapor fuel line and remove the vapor hose
Disconnect the TMAP electrical connector
Disconnect the electronic throttle control device connector
Remove the manifold to throttle body adapter bolts and remove the throttle body mixer assembly
Pull the throttle body assembly from the adapter
Remove electronic throttle control device
Remove the O-rings gasket and discard

Installation Procedure
Important
• Lightly Lubricate the both the O-rings of the throttle control device to adapter
1. Install the O-ring (32501097) on throttle body. Press it down to the bottom of the surface.

2. Install the two quad seals (33000599). Install one seal at a time to insure the seal does not roll. The seal must sit ﬂat
on the throttle body.

3. Attach mixer and throttle body together. The two parts do not bolt together; they will be secured when you mount it on
the intake. Notice the orientation of the air inlet and throttle body cover.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

FUEL SYSTEM R&R SECTION 4-7

4. Place gasket on intake manifold and attach mixer/throttle assembly to manifold.

Figure 4A
Mixer Assembly

MIXER REPLACEMENT
(FIGURE 4A)
1. Remove the Throttle control device Refer to Electronic Throttle Body Replacement
2. Remove the four (4) bolts to the throttle control device to mixer adapter bolts
3. Remove and discard the mixer to adapter gasket.
Installation Procedure
Important
• Cover Throttle body adapter opening to prevent debris from entering engine until reassembly
1. Install Mixer to adapter gasket onto the mixer
2. Install the mixer to the throttle control device to mixer adapter and secure with the 4 retaining screws
Tighten
9 N•m (80 lb-in)
3. Install Throttle body Refer to Electronic Throttle Control Device Replacement
4. Start the engine and leak check all ﬁttings and connections

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

FUEL SYSTEM R&R SECTION 4-8

COOLANT HOSE REPLACEMENT
1. Drain the coolant
2. Using a hose clamp pliers disconnect both hose clamps on each hose
3. Remove the hose from each of the ﬁttings
NOTE: Use hose material and lengths speciﬁed by the OEM
4. Install the hose clamps to each hose and set the clamp back on each hose to make installation easier
5. Fit the hose to the ﬁttings
6. Secure by positioning each of the clamps

VAPOR HOSE REPLACEMENT
1. Using a hose clamp pliers disconnect both hose clamps
2. Remove the vapor hose form each ﬁtting
Installation Procedure
Important
• Vapor supply hose is speciﬁcally designed, DO NOT use hose material or length other than the OEM speciﬁed
parts
3. Install hose clamps and set back on each hose
4. Reinstall the vapor hose to
5. Reset clamps
6. Start engine and check for leaks

each ﬁtting

ENGINE CONTROL MODULE REPLACEMENT
1.
2.
3.
4.

Disconnect Negative battery cable
Remove controller from mounting bracket
Push connector lock back to unlock connector
Unplug controller and remove

Installation Procedure
Important
• Controller is calibrated for each engine verify you have the correct controller
5.
6.
7.
8.
9.
10.
11.
12.

Plug connector into controller
Push lock into place
Mount controller into mounting bracket
Reconnect the battery cable
Install Diagnostic service tool
Start engine
Check for any DTC codes and clear
Verify engine is in closed loop and no MIL lights are present

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

FUEL SYSTEM R&R SECTION 4-9

HEATED EXHAUST GAS OXYGEN SENSOR REPLACEMENT
1. Disconnect Negative battery cable
2. Disconnect the O2 sensor electrical connector
3. Using a O2 Sensor socket remove the O2 Sensor and discard
Installation Procedure
Important
• Before install the O2 sensor lubricate threads with anti-seize compound GM P/N 5613695 or equivalent.
Avoid getting compound on the sensor tip
4. Install O2 sensor
Tighten
41 N•m (30 lb-ft)
5. Start engine
6. Check for any DTC codes and clear
7. Verify engine is in closed loop and no MIL lights are present

THREE WAY CATALYTIC CONVERTER MUFFLER REPLACEMENT
1. Remove the TWC mufﬂer using the OEM end product processes
Installation Procedure
Important
• The Three Way Catalytic converter is speciﬁcally designed to meet the emission control of the certiﬁed
engine. Use only the OEM speciﬁed parts
2. Install the TWC mufﬂer using the OEM end product processes

3. Inspect and replace any gaskets and/or sealing rings as necessary
4. Start engine
5. Check for any DTC codes and clear
6. Verify engine is in closed loop and no MIL lights are present

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

FUEL SYSTEM DIAGNOSIS 5- 1

PSI 3.0L PFI
FUEL SYSTEM DIAGNOSIS SECTION
Table Of Contents

Description
Page
Fuel System Description..............................................................................................5-2
Diagnostic Aids.............................................................................................................5-3
LPG Fuel System Diagnosis........................................................................................5-4
Symptom Diagnosis.....................................................................................................5-8

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Fuel SYSTEM DIAGNOSIS SECTION 5- 2

LPG Fuel System Diagnosis

Fuel System Description
To maintain fuel and emission control on the LPG fuel system the Engine Control Units (ECM) relies on numerous engine sensor and output data from the Electronic Pressure Regulator (EPR). The ECM will then determine the target fuel calibration and command the EPR to reposition the voice coil to the proper position which,
subsequently reposition the secondary lever in the pressure regulator to maintain proper control. The EPR and
ECM will continue to communicate back and forth during normal operation.
In the event that the EPR fails to communicate or the Communications Area Network (CAN) cable fails to transmit data the regulator will operate in an open loop conﬁguration. As the air valve vacuum in the mixer venturi is
communicated to the secondary chamber of the regulator the secondary diaphragm will be drawn in a downwards motion. This downward motion will cause the secondary lever to open thus allowing more fuel to enter
the mixer.
In the (LPR) the fuel is vaporized and the pressure reduced in two stages. The ﬁrst stage reduces the pressure to approximately 6.8 to 20.6 kPa (1.0 to 3.0 psi). The second stage reduces the pressure to approximately
negative 1.5” of water column.
The fuel is then drawn from the secondary chamber of the LPR by the vacuum generated by air ﬂowing through
the mixer. This vacuum signal is also used to generate lift for the mixer air valve. This vacuum signal is most
commonly referred to as air valve vacuum. In the mixer, the fuel mixes with the air entering the engine. This air/
fuel mixture is then drawn into the engine for combustion.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

FUEL SYSTEM DIAGNOSIS 5- 3

Diagnostic Aids
This procedure is intended to diagnose a vehicle operating on LPG. If the vehicle will not continue to run on
LPG, refer to Hard Start for preliminary checks. Before proceeding with this procedure, verify that the vehicle
has a sufﬁcient quantity of fuel and that liquid fuel is being delivered to the LPR. Also, ensure that the manual
shut off valve on the LPG tank is fully opened and that the excess ﬂow valve has not been activated.
Tools Required:
• 7/16 Open end wrench (for test port plugs)
• DVOM (GM J 39200, Fluke 88 or equivalent).
• 12 volt test light
Diagnostic Scan Tool
• Diagnostic Display tool.
Pressure Gauges
• IMPCO ITK-3 Test kit
• Water Column Gauge / Manometer (GM 7333-6 or equivalent).
• 0-10 PSI Gauge
Test Description
The numbers below refer to step numbers on the diagnostic table.
5. This step determines if the LPR requires replacement
6. This step determines if the problems are in the mechanical side of the Pressure Regulator or the Electronic
Voice Coil
10. This step determines if the Mixer requires replacement
14. This step determines if the Lock Off requires replacement
17. This step determines if the Fuel Filter requires replacement.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1
2

LPG Fuel System Diagnosis

Action
Were you referred to this procedure by a DTC
diagnostic chart?
Perform the On Board Diagnostic (OBD) System
Check.

Are any DTCs present in the ECM?
Verify that the LPG fuel tank has a minimum of 1/4
tank of fuel, that the manual valve is open and the
tank quick connect is fully engaged
Does the vehicle have fuel?
1. Connect a water column gauge or a
manometer to the secondary test port of the
low pressure regulator (LPR).
2. Start the engine and allow it to reach operating
temperature.
Does the engine start and run?
With the engine idling, observe the pressure
reading for the LPR secondary pressure.

Fuel SYSTEM DIAGNOSIS SECTION 5- 4

Is the fuel pressure within the speciﬁed range?
1. Disconnect the EPR electrical connectors.

Yes

Go to Step 3

Go to Step 2

Go to the
applicable DTC
Table

Go to Step 3

__
Go to Step 4

-.5” to
-2.5” w.c

Go to Step 5

Go to Step 8

Go to Step 25

Go to Step 6

Go to Fuel
Control System
Diagnosis

Go to Step 7

Go to Step 26

Go to Step 22

Go to Step 12

Go to Step 9

Note: This
6

action will cause a DTC to be
set by the ECM
2. With the engine idling observe the
pressure reading on the secondary test
port.

Value(s)
__

Is the fuel pressure WITHIN the speciﬁed range?
1. Inspect the air intake stream between the mixer
assembly and the throttle body for leaks.
2. Inspect the fuel hose connection between
the LPR and mixer assembly for damage or
leakage.
3. Inspect any vacuum hoses for leaks

-.5” to
-2.5” w.c

Was a problem found and corrected?

1. Connect a water column gauge or a
manometer to the secondary test port of the
low pressure regulator (LPR).
2. Crank the engine and observe the pressure
reading for the LPR secondary pressure.
Does the fuel pressure indicate a vacuum is
present?

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step

Action
1. Remove Air induction hose to the mixer
2. Observe the air valve for movement while the
engine is cranking.
Note: Movement of the air valve will be minimal at
cranking speeds.

FUEL SYSTEM DIAGNOSIS 5- 5
Value(s)

Was a problem found and repaired?
1. Connect a 0-10 psi gauge to the primary test
port of the low pressure regulator (LPR).
2. Crank the engine and observe the pressure
reading for the LPR primary pressure.

1. Turn OFF the ignition.
2. Disconnect the LPL connector.
3. Install a test light between the pins of the LPL
connector.
4. Crank the engine. The test light should
illuminate.

Go to Step 10

Go to Step 26

Go to Step 24

Go to Step 26

Go to Step 12

Go to Step 22

Go to Step 13

Go to Step 14

Go to Step 16

Go to Step 15

Go to Step 23

Go to Step 17

1- 3 PSI

Does the test light illuminate?
Using a DVOM, check the resistance of the low
pressure lock-off (LPL).
Is the resistance within the speciﬁed range?
1. Turn the ignition OFF.
2. Close the manual shut-off valve on the LPG
tank.

Go to Step 11

Was a problem found and repaired?
Inspect the fuel hose connection between the LPR
and the mixer assembly for damage or leakage.

Is the fuel pressure ABOVE the speciﬁed
value?

Does the air valve move when the engine is
cranked?

1. Inspect the air intake stream to the mixer assembly and the throttle body for
vacuum leaks.
2. Inspect the vacuum hoses from the mixer for proper connection and condition.

Yes

CAUTION: When disconnecting LPG fuel lines, liquid LPG may be present. Perform this step in a well
ventilated area.

12 Ω - 16

3. Loosen the fuel inlet hose ﬁtting at the inlet of
the LPL.
Was fuel present when the ﬁtting was loosened?

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step

Action
1. Turn OFF the ignition.
2. Connect the test light to chassis ground and
probe pin A of the LPL connector.
3. Crank the engine. The test light should
illuminate.

Fuel SYSTEM DIAGNOSIS SECTION 5- 6
Value(s)

The fuel supply system or hoses are
plugged or restricted, locate and repair the
problem.

Go to Step 20

Go to Step 21

Go to Step 19

Go to Step 18

Was a problem found?
18

Does the test light illuminate?
1. Remove the LPG fuel ﬁlter / LPL.
2. Remove the ﬁlter from the LPL.
3. Empty the contents of the inlet side of the LPG
fuel ﬁlter onto a clean surface.
4. Inspect the contents of the LPG fuel ﬁlter for an
excessive amount of foreign material or water.
If necessary, locate and repair the source of
contamination.
5. Verify the LPG fuel ﬁlter is not restricted or
plugged.

Yes

__
Go to Step 26

Is the action complete?
19

Replace the fuel ﬁlter. Refer to Fuel Filter
Replacement.

__
Go to Step 26

Is the action complete?
20

Repair the open in the lock-off ground circuit.

__
Go to Step 26

Is the action complete?
21

Repair the open in the lock-off power circuit.

Is the action complete?
Replace the low pressure regulator (LPR). Refer to
Low Pressure Regulator Replacement.

Is the action complete?
Replace the lock-off. Refer to Lock-off
Replacement.

Is the action complete?
Replace the mixer assembly. Refer to Fuel Mixer
Replacement.
Is the action complete?

__
Go to Step 26

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step

FUEL SYSTEM DIAGNOSIS 5- 7

Action
The fuel supply system is operating normally, if a
failure of the control solenoids is suspected. Refer
to Fuel Control System Diagnosis.

Value(s)

Yes

1. Install the test plug in the LPR secondary chamber.
2. If you were sent to this routine by another diagnostic chart, return to the previous diagnostic procedure.

System OK

Is the action complete?
1. Disconnect all test equipment
2. Install the primary and secondary test port plugs.
3. Start the engine.
4. Using SNOOP or equivalent, leak check the
test port plugs.
Is the action complete?

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Fuel SYSTEM DIAGNOSIS SECTION 5- 8

Symptom Diagnosis
Checks
Before Using This Section

Important Preliminary Checks

Action
Before using this section, you should have performed On Board Diagnostic
Check and determined that:
1. The Control Module and MIL (Malfunction Indicator Lamp) are
operating correctly.
2. There are no Diagnostic Trouble Codes (DTCs) stored, or a DTC
exists but without a MIL.

LPG Fuel System Check

Several of the following symptom procedures call for a careful visual and
physical check. The visual and physical checks are very important. The
checks can lead to correcting a problem without further checks that may save
valuable time.
1. Verify the customer complaint.
2. Locate the correct symptom table.
3. Check the items indicated under that symptom.
4. Operate the vehicle under the conditions the symptom occurs. Verify
HEGO switching between lean and rich.
IMPORTANT!

Visual and Physical Checks

•

Normal HEGO switching indicates the LPG fuel system is in closed
loop and operating correctly at that time.
Check all ECM system fuses and circuit breakers.

•

Check the ECM ground for being clean, tight and in its proper location.

•

Check the vacuum hoses for splits, kinks and proper connections.

•

Check thoroughly for any type of leak or restriction.

•

Check for air leaks at all the mounting areas of the intake manifold
sealing surfaces.

•

Check for proper installation of the mixer module assembly.

•

Check for air leaks at the mixer assembly.

•

Check the ignition wires for the following conditions:

•

−

Cracking

−

Hardness

−

Proper routing

−

Carbon tracking

Check the wiring for the following items:
−

•

Proper connections, pinches or cuts.

The following symptom tables contain groups of possible causes for each
symptom. The order of these procedures is not important. If the scan tool
readings do not indicate the problems, then proceed in a logical order,
easiest to check or most likely to cause ﬁrst.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Intermittent

Checks

FUEL SYSTEM DIAGNOSIS 5- 9
Action

DEFINITION: The problem may or may not turn ON the Malfunction Indicator Lamp (MIL) or store a Diagnostic Trouble
Code (DTC).
Preliminary Checks
• Refer to Important Preliminary Checks.
•

Do not use the DTC tables. If a fault is an intermittent, the use of the DTC
tables may result in the replacement of good parts.
Faulty electrical connections or wiring can cause most intermittent problems.

•

Check the suspected circuit for the following conditions:

•
Faulty Electrical Connections or
Wiring

•

−

Faulty fuse or circuit breaker

−

Connectors poorly mated

−

Terminals not fully seated in the connector (backed out)

−

Terminals not properly formed or damaged

−

Terminal to wires poorly connected

−

Terminal tension insufﬁcient.

Carefully remove all the connector terminals in the problem circuit in order
to ensure the proper contact tension. If necessary, replace all the connector
terminals in the problem circuit in order to ensure the proper contact tension.

Checking for poor terminal to wire connections requires removing the
terminal from the connector body.
If a visual and physical check does not locate the cause of the problem, drive the
vehicle with a scan tool. When the problem occurs, an abnormal voltage or scan
reading indicates the problem may be in that circuit.
The following components can cause intermittent MIL and no DTC(s):
•

Operational Test
Intermittent Malfunction Indicator
Lamp (MIL)

Loss of DTC Memory

•

A defective relay, Control Module driven solenoid, or a switch that can cause
electrical system interference. Normally, the problem will occur when the
faulty component is operating.

•

The improper installation of electrical devices, such as lights, 2-way radios,
electric motors, etc.

•

The ignition secondary voltage shorted to a ground.

•

The Malfunction Indicator Lamp (MIL) circuit or the Diagnostic Test Terminal
intermittently shorted to ground.

• The Control Module grounds.
To check for the loss of the DTC Memory:
1.

Disconnect the TMAP sensor.

Idle the engine until the Malfunction Indicator Lamp illuminates.

The ECM should store a TMAP DTC. The TMAP DTC should remain in the
memory when the ignition is turned OFF. If the TMAP DTC does not store and
remain, the ECM is faulty.
Additional Checks

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Fuel SYSTEM DIAGNOSIS SECTION 5- 10

No Start

Checks
Action
DEFINITION: The engine cranks OK but does not start.
Preliminary Checks
• Refer to Important Preliminary Checks.
Control Module Checks
• If a scan tool is available:
•

Sensor Checks

Fuel System Checks

Ignition System Checks

Check for proper communication with both the ECM

•

Check the fuse in the ECM battery power circuit. Refer to Engine
Controls Schematics.

•

Check battery power, ignition power and ground circuits to the ECM.
Refer to Engine Control Schematics. Verify voltage and/or continuity for
each circuit.

•

Check the TMAP sensor.

•

Check the Magnetic pickup sensor (RPM).

.
Important:: A closed LPG manual fuel shut off valve will create a no start
condition.
•

Check for air intake system leakage between the mixer and the throttle
body.

•

Verify proper operation of the low pressure lock-off solenoids.

•

Check the fuel system pressures. Refer to the LPG Fuel System
Diagnosis.

•

Check for proper mixer air valve operation.

Note: LPG being a gaseous fuel requires higher secondary ignition system
voltages for the equivalent gasoline operating conditions.
•

Check for the proper ignition voltage output with J 26792 or the
equivalent.

•

Verify that the spark plugs are correct for use with LPG (R42LTS)

•

Check the spark plugs for the following conditions:
−

Wet plugs

−

Cracks

−

Wear

−

Improper gap

−

Burned electrodes

−

Heavy deposits

•

Check for bare or shorted ignition wires.

•

Check for loose ignition coil connections at the coil.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Checks
Engine Mechanical Checks

Action
Important: The LPG Fuel system works on a fumigation principle of fuel
introduction and is more sensitive to intake manifold leakage than the
gasoline fuel supply system.
•

Exhaust System Checks

FUEL SYSTEM DIAGNOSIS 5- 11

•

Check for the following:
−

Vacuum leaks

−

Improper valve timing

−

Low compression

−

Bent pushrods

−

Worn rocker arms

−

Broken or weak valve springs

−
Worn camshaft lobes.
Check the exhaust system for a possible restriction:
−

Inspect the exhaust system for damaged or collapsed pipes

−

Inspect the mufﬂer for signs of heat distress or for possible
internal failure.

Check for possible plugged catalytic converter. Refer to Restricted
Exhaust System Diagnosis

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Fuel SYSTEM DIAGNOSIS SECTION 5- 12

Hard Start

Checks
Action
DEFINITION: The engine cranks OK, but does not start for a long time. The engine does eventually run, or may
start but immediately dies.
Preliminary Checks
• Refer to Important Preliminary Checks.
Checks
Sensor Checks

Fuel System Checks

Ignition System Checks

•
•

Make sure the vehicle’s operator is using the correct starting procedure.
Check the Engine Coolant Temperature sensor with the scan
tool. Compare the engine coolant temperature with the ambient air
temperature on a cold engine. IF the coolant temperature reading is
more than 5 degrees greater or less than the ambient air temperature
on a cold engine, check for high resistance in the coolant sensor circuit.
Refer to DTC 111

•

Check the Crankshaft Position (CKP) sensor.

• Check the Throttle position (TPS) sensor.
Important: A closed LPG manual fuel shut off valve will create an extended
crank OR no start condition.
•

Verify the excess ﬂow valve in the LPG manual shut-off valve is not
tripped.

•

Check mixer module assembly for proper installation and leakage.

•

Verify proper operation of the low pressure lock-off solenoids.

•

Verify proper operation of the EPR

•

Check for air intake system leakage between the mixer and the throttle
body.

•

Check the fuel system pressures. Refer to the Fuel System Diagnosis.

Note: LPG being a gaseous fuel requires higher secondary ignition system
voltages for the equivalent gasoline operating conditions.
•

Check for the proper ignition voltage output with J 26792 or the
equivalent.

•

Verify that the spark plugs are correct for use with LPG (R42LTS)

•

Check the spark plugs for the following conditions:
−

Wet plugs

−

Cracks

−

Wear

−

Improper gap

−

Burned electrodes

−

Heavy deposits

•

Check for bare or shorted ignition wires.

•

Check for moisture in the distributor cap if applicable.

•

Check for loose ignition coil connections.

Important:
1. If the engine starts but then immediately stalls, Check the Crankshaft
Position (CKP).
2. Check for improper gap, debris or faulty connections.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Checks
Engine Mechanical Checks

Action
Important: The LPG Fuel system works on a fumigation principle of fuel
introduction and is more sensitive to intake manifold leakage than the
gasoline fuel supply system.
•

Exhaust System Checks

•
•

•
Additional Checks

FUEL SYSTEM DIAGNOSIS 5- 13

•

Check for the following:
−

Vacuum leaks

−

Improper valve timing

−

Low compression

−

Bent pushrods

−

Worn rocker arms

−

Broken or weak valve springs

−

Worn camshaft lobes. Ref

Check the intake and exhaust manifolds for casting ﬂash.
Check the exhaust system for a possible restriction:
−

Inspect the exhaust system for damaged or collapsed pipes

−

Inspect the mufﬂer for signs of heat distress or for possible
internal failure.

Check for possible plugged catalytic converter. Refer to Restricted
Exhaust System Diagnosis or Exhaust System in the GM Base Engine
Service Manual

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Fuel SYSTEM DIAGNOSIS SECTION 5- 14

Cuts Out, Misses

Checks
Action
DEFINITION: A surging or jerking that follows engine speed, usually more pronounced as the engine load
increases which is not normally felt above 1500 RPM. The exhaust has a steady spitting sound at idle, low speed,
or hard acceleration for the fuel starvation that can cause the engine to cut-out.
Preliminary Checks
• Refer to Important Preliminary Checks.
Ignition System Checks
• Start the engine.

Engine Mechanical Checks

Fuel System Checks

Additional Check

•

Wet down the secondary ignition system with water from a spray bottle,
and look/listen for arcing or misﬁring as you apply water.

•

Check for proper ignition output voltage with spark tester J 26792.

•

Check for a cylinder misﬁre.

•

Verify that the spark plugs are correct for use with LPG (R42LTS)

•

Remove the spark plugs in these cylinders and check for the following
conditions:
•

Insulation cracks

•

Wear

•

Improper gap

•

Burned electrodes

•

Heavy deposits

•

Visually/Physically inspect the secondary ignition for the following:

•

Ignition wires for arcing, cross-ﬁring and proper routing

•

• Ignition coils for cracks or carbon tracking
Perform a cylinder compression check.

•

Check the engine for the following:
−

Improper valve timing

−

Bent pushrods

−

Worn rocker arms

−

Worn camshaft lobes.

−

Broken or weak valve springs.

•
•

Check the intake and exhaust manifold passages for casting ﬂash.
Check the fuel system - plugged fuel ﬁlter, low fuel pressure, etc. Refer to
LPG Fuel System Diagnosis.

•

Check the condition of the wiring to the low pressure lock-off solenoid.

Check for Electromagnetic Interference (EMI).
•

EMI on the reference circuit can cause a missing condition.

•

Monitoring the engine RPM with a scan tool can detect an EMI.

•

A sudden increase in the RPM with little change in the actual engine
RPM, indicates EMI is present.

•

If the problem exists, check the routing of the secondary wires and
the ground circuit.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

FUEL SYSTEM DIAGNOSIS 5- 15

Hesitation, Sag, Stumble

Checks
Action
DEFINITION: The vehicle has a momentary lack of response when depressing the accelerator. The condition can
occur at any vehicle speed. The condition may cause the engine to stall if it’s severe enough.
Preliminary Checks
Refer to Important Preliminary Checks.
Fuel System Checks
• Check the fuel pressure. Refer to LPG Fuel System Diagnosis.

Ignition System Checks

Additional Check

•

Check for low fuel pressure during a moderate or full throttle acceleration.
If the fuel pressure drops below speciﬁcation, there is possibly a faulty
low pressure regulator or a restriction in the fuel system.

•

Check the Manifold Absolute Pressure (MAP) sensor response and
accuracy.

•

Check LPL electrical connection

•

Check the mixer air valve for sticking or binding.

•

Check the mixer module assembly for proper installation and leakage.

• Check the EPR electrical connections.
Note: LPG being a gaseous fuel requires higher secondary ignition system
voltages for the equivalent gasoline operating conditions. If a problem is
reported on LPG and not gasoline, do not discount the possibility of a LPG
only ignition system failure and test the system accordingly.
•

Check for the proper ignition voltage output with J 26792 or the
equivalent.

•

Verify that the spark plugs are correct for use with LPG (R42LTS)

•

Check for faulty spark plug wires

•

Check for fouled spark plugs.

•
•

Check for manifold vacuum or air induction system leaks

•

Check the generator output voltage.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Fuel SYSTEM DIAGNOSIS SECTION 5- 16

Backﬁre

Checks
Action
DEFINITION: The fuel ignites in the intake manifold, or in the exhaust system, making a loud popping noise.
Preliminary Check
• Refer to Important Preliminary Checks.
Ignition System Checks
Important!
LPG, being a gaseous fuel, requires higher secondary ignition system
voltages for the equivalent gasoline operating conditions. The ignition
system must be maintained in peak condition to prevent backﬁre.

Engine Mechanical Check

•

Check for the proper ignition coil output voltage using the spark tester
J26792 or the equivalent.

•

Check the spark plug wires by connecting an ohmmeter to the ends of
each wire in question. If the meter reads over 30,000 ohms, replace the
wires.

•

Check the connection at each ignition coil.

•

Check for deteriorated spark plug wire insulation.

•

Check the spark plugs. The correct spark plugs for LPG are (R42LTS)

•

Remove the plugs and inspect them for the following conditions:
−

Wet plugs

−

Cracks

−

Wear

−

Improper gap

−

Burned electrodes

−

Heavy deposits

Important!
The LPG Fuel system works on a fumigation principle of fuel
introduction and is more sensitive to intake manifold leakage than a
gasoline fuel supply system.
•

•
Fuel System Checks

•

Check the engine for the following:
−

Improper valve timing

−

Engine compression

−

Manifold vacuum leaks

−

Intake manifold gaskets

−

Sticking or leaking valves

−

Exhaust system leakage

Check the intake and exhaust system for casting ﬂash or other
restrictions.
Perform a fuel system diagnosis. Refer to LPG Fuel System Diagnosis.
Diagnosis

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

FUEL SYSTEM DIAGNOSIS 5- 17

Lack of Power, Sluggishness, or Sponginess

Checks
Action
DEFINITION: The engine delivers less than expected power. There is little or no increase in speed when partially
applying the accelerator pedal.
Preliminary Checks
• Refer to Important Preliminary Checks.

Fuel System Checks

•

Refer to the LPG Fuel system OBD System Check

•

Compare the customer’s vehicle with a similar unit. Make sure the
customer has an actual problem. Do not compare the power output of the
vehicle operating on LPG to a vehicle operating on gasoline as the fuels
do have different drive feel characteristics

•

Remove the air ﬁlter and check for dirt or restriction.

•

Check the vehicle transmission Refer to the OEM transmission
diagnostics.
Check for a restricted fuel ﬁlter, contaminated fuel, or improper fuel
pressure. Refer to LPG Fuel System Diagnosis.

•
•

Check for the proper ignition output voltage with the spark tester J 26792
or the equivalent.

•

Check for proper installation of the mixer module assembly.

•

Check all air inlet ducts for condition and proper installation.

•

Check for fuel leaks between the LPR and the mixer.

•

Verify that the LPG tank manual shut-off valve is fully open.

•

Verify that liquid fuel (not vapor) is being delivered to the LPR.

Sensor Checks

•

Check the Heated Exhaust Gas Oxygen Sensor (HEGO) for
contamination and performance. Check for proper operation of the MAP
sensor.

Exhaust System Checks

•
•

Check for proper operation of the TPS sensor.
Check the exhaust system for a possible restriction:

Engine Mechanical Check

Additional Check

−

Inspect the exhaust system for damaged or collapsed pipes

−

Inspect the mufﬂer for signs of heat distress or for possible
internal failure.

−

Check for possible plugged catalytic converter.

Check the engine for the following:
•

Engine compression

•

Valve timing

•
•

Improper or worn camshaft. Refer to Engine Mechanical in the Service
Manual.
Check the ECM grounds for being clean, tight, and in their proper
locations.

•

Check the generator output voltage.

•

If all procedures have been completed and no malfunction has been
found, review and inspect the following items:

•

Visually and physically, inspect all electrical connections within the
suspected circuit and/or systems.

•

Check the scan tool data.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Fuel SYSTEM DIAGNOSIS SECTION 5- 18

Poor Fuel Economy

Checks
Action
DEFINITION: Fuel economy, as measured by refueling records, is noticeably lower than expected. Also, the
economy is noticeably lower than it was on this vehicle at one time, as previously shown by an by refueling
records.
Preliminary Checks
• Refer to Important Preliminary Checks.
Checks
•

Check the air cleaner element (ﬁlter) for dirt or being plugged.

•

Visually (Physically) check the vacuum hoses for splits, kinks, and proper
connections.

•

Check the operators driving habits for the following items:
−

Is there excessive idling or stop and go driving?

−

Are the tires at the correct air pressure?

−

Are excessively heavy loads being carried?

−

Is their often rapid acceleration?

•

Suggest to the owner to ﬁll the fuel tank and to recheck the fuel economy.

•
Fuel System Checks

•

Suggest that a different operator use the equipment and record the
results.
Check the LPR fuel pressure. Refer to LPG Fuel System Diagnosis.
Diagnosis

Sensor Checks
Ignition System Checks

•
•
•

Check the fuel system for leakage.
Check the Temperature Manifold Absolute Pressure (TMAP) sensor.
Verify that the spark plugs are correct for use with LPG (R42LTS)

•

Check the spark plugs. Remove the plugs and inspect them for the
following conditions:

•

Cooling System Checks

•

Additional Check

•
•

−

Wet plugs

−

Cracks

−

Wear

−

Improper gap

−

Burned electrodes

−

Heavy deposits

Check the ignition wires for the following items:
−

Cracking

−

Hardness

− Proper connections
Check the engine thermostat for always being open or for the wrong heat
range
Check the transmission shift pattern. Refer to the OEM Transmission
Controls section the Service Manual.
Check for dragging brakes.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

FUEL SYSTEM DIAGNOSIS 5- 19

Rough, Unstable, or Incorrect Idle, Stalling

Checks
Action
DEFINITION: The engine runs unevenly at idle. If severe enough, the engine or vehicle may shake. The
engine idle speed may vary in RPM. Either condition may be severe enough to stall the engine.
Preliminary Check
• Refer to Important Preliminary Checks.
Sensor Checks
• Check for silicon contamination from fuel or improperly used sealant. The
sensor will have a white powdery coating. The sensor will result in a high
but false signal voltage (rich exhaust indication). The ECM will reduce
the amount of fuel delivered to the engine causing a severe driveability
problem.

Fuel System Checks

Ignition System Checks

•

Check the Heated Exhaust Gas Oxygen Sensor (HEGO) performance:

•
•

Check the Temperature Manifold Absolute Pressure (TMAP) sensor
response and accuracy.
Check for rich or lean symptom that causes the condition. Drive the vehicle
at the speed of the complaint. Monitoring the oxygen sensors will help
identify the problem.

•

Check for a sticking mixer air valve.

•

Verify proper operation of the EPR.

•

Perform a cylinder compression test. Refer to Engine Mechanical in the
Service Manual.

•

Check the LPR fuel pressure. Refer to the LPG Fuel System Diagnosis.

•
•

Check mixer module assembly for proper installation and connection.
Check for the proper ignition output voltage using the spark tester J26792
or the equivalent.

•

Verify that the spark plugs are correct for use with LPG (R42LTS)

•

Check the spark plugs. Remove the plugs and inspect them for the
following conditions:
−

Wet plugs

−

Cracks

−

Wear

−

Improper gap

−

Burned electrodes

−

Blistered insulators

−

Heavy deposits

Check the spark plug wires by connecting an ohmmeter to the ends of each
wire in question. If the meter reads over 30,000 ohms, replace the wires.
Important: The LPG Fuel system works on a fumigation principle of fuel
introduction and is more sensitive to intake manifold leakage than the gasoline
fuel supply system.
•

Additional Checks

•

Check for vacuum leaks. Vacuum leaks can cause a higher than normal idle
and low throttle angle control command.

•

Check the ECM grounds for being clean, tight, and in their proper locations.

•

Check the battery cables and ground straps. They should be clean and
secure. Erratic voltage may cause all sensor readings to be skewed
resulting in poor idle quality..

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Checks
Engine Mechanical Check

•

Fuel SYSTEM DIAGNOSIS SECTION 5- 20

Action
Check the engine for the following:
−

Broken motor mounts

−

Improper valve timing

−

Low compression

−

Bent pushrods

−

Worn rocker arms

−

Broken or weak valve springs

−

Worn camshaft lobes

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

FUEL SYSTEM DIAGNOSIS 5- 21

Surges/Chuggles

Checks
Action
DEFINITION: The engine has a power variation under a steady throttle or cruise. The vehicle feels as if it speeds
up and slows down with no change in the accelerator pedal.
Preliminary Checks
• Refer to Important Preliminary Checks.
Sensor Checks
Fuel System Checks

Ignition System Checks

Additional Check

• Be sure the driver understands the Torque Converter Clutch operation.
Check the Heated Exhaust Gas Oxygen Sensor (HEGO) performance.
• Check for Rich or Lean symptom that causes the condition. Drive the
vehicle at the speed of the complaint. Monitoring the oxygen sensors will
help identify the problem.
•

Check the fuel pressure while the condition exists. Refer to LPG Fuel
System Diagnosis.

•

Verify proper fuel control solenoid operation.

•

Verify that the LPG manual shut-off valve is fully open.

•
•

Check the in-line fuel ﬁlter for restrictions.
Check for the proper ignition output voltage using the spark tester J26792
or the equivalent.

•

Verify that the spark plugs are correct for use with LPG (R42LTS)

•

Check the spark plugs. Remove the plugs and inspect them for the
following conditions:
−

Wet plugs

−

Cracks

−

Wear

−

Improper gap

−

Burned electrodes

−

Heavy deposits

−
•

Check the Crankshaft Position (CKP) sensor.
Check the ECM grounds for being clean, tight, and in their proper
locations.

•

Check the generator output voltage.

•

Check the vacuum hoses for kinks or leaks.

•

Check Transmission

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

ELECTRICAL SECTION 6-1

PSI 3.0L PFI
ELECTRICAL SECTION
Table Of Contents
Description

Page

Wire Harness Repairs..................................................................................................6-2
ECM Heder Connector ................................................................................................6-5
Customer Interface Connector Pin-Out........................................................................6-6
Fuse and Relay Center Layout....................................................................................6-7
Engine Wire Harness Schematic.................................................................................6-8
Diagnostic Service Tool (DST) Installation.................................................................6-10
USB Driver Installation...............................................................................................6-14
Running the DST and Connecting to an Engine........................................................6-16
DST Screen Descriptions...........................................................................................6-19
Running the Data Plotter and Logger.........................................................................6-22
Malfunction Indicator Lamp (MIL) & Diagnostic Trouble Codes (DTC)......................6-28
Blink Code Procedure................................................................................................6-29

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

ON-VEHICLE SERVICE WIRE HARNESS
REPAIR
The ECM/PCM harness electrically connects the ECM/
PCM to the various solenoids, electrically and sensors in
vehicle engine and passenger compartment.
Wire harnesses should be replaced with proper part number harnesses. When signal wires are spliced, into a harness, use wire with high temperature insulation only.
With the low current and voltage levels found in the system,
it is important that the best possible bond at all wire splices
be made by soldering the splices, as shown in Figure 3-20.
Molded on connectors require complete replacement of the
connector. This means splicing a new connector assembly
into the harness.
Refer to Figure 1 for wiring diagrams.

CONNECTORS AND TERMINALS
Use care when probing a connector or replacing terminals
in them. It is possible to short between opposite terminals.
If this happens to the wrong terminal pair, it is possible to
damage certain components. Always use jumper wires between connectors, for circuit checking. NEVER probe

ELECTRICAL SECTION 6-2
through the Weather-Pack seals. Use tachometer adapter
J 35812, or equivalent, which provides an easy hook up of
the tach. lead. The connector test adapter kit J 35616, or
equivalent, contains an assortment of ﬂexible connectors,
used to probe terminals during diagnosis. Fuse remover and
test tool BT 8616, or equivalent, is used for removing a fuse
and to adapt fuse holder, with a meter, for diagnosis.
When diagnosing, open circuits are often difﬁcult to locate
by sight, because oxidation, or terminal misalignment are
hidden by the connectors. Merely wiggling a connector on
a sensor, or in the wiring harness, may correct the open
circuit condition. This should always be considered, when
an open circuit, or failed sensor is indicated. Intermittent
problems may, also, be caused by oxidized or loose connections.
Before making a connector repair, be certain of the type of
connector. Weather-Pack and Compact Three connectors
look similar, but are serviced differently.

Figure 1

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

ELECTRICAL SECTION 6-3

Micro-Pack
Refer to Figure 2 and repair procedure for replacement
of a :Micro-Pack terminal.

Metri-Pack
Some connectors use terminals called Metri-Pack
Series 150. (Figure 3). ‘These may be used at the coolant sensor, as well as TBI units.
They are also called “Pull-To-Seat” terminals, because,
to install a terminal on a wire, the wire is ﬁrst inserted
through the seal (5) and connector (4). The terminal is
then crimped on the wire and the terminal pulled back
into the connector to seat it in place.

To remove a terminal:
1. Slide the seal back on the wire.

FIGURE 2 MICRO_PACK CONNECTOR

2. Insert tool (3) BT-8518, or J 35689, or equivalent,
as shown in insert “A” and “B,” to release the terminal locking tab (2).
3. Push the wire and terminal out through the connector.
If reusing the terminal, reshape the locking tang (2).

FIGURE 2 METR-PACK SERIES 150 TERMINAL REMOVAL

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

ELECTRICAL SECTION 6-4

Weather-Pack
A Weather-Pack connector can be identiﬁed by a rubber seal,
at the rear of the connector. This connector, which is used in the
engine compartment, protects against moisture and dirt, which
could create oxidation and deposits on the terminals. This protection is important, because of the very low voltage and current
levels found in the electronic system.
Repair of a Weather-Pack terminal is shown in Figure 4. Use
tool J 28742, or BT8234-A to remove the pin and sleeve terminals.
If removal is attempted with an ordinary pick, there is a good
chance that the terminal will be bent, or deformed. Unlike standard blade type terminals, these terminals cannot be straightened once they are bent.
Make certain that the connectors are properly seated and all of
the sealing rings in place, when connecting leads. The hinge
type ﬂap provides a backup, or secondary locking feature for the
connector. They are used to improve the connector reliability by
retaining the terminals, if the small terminal lock tangs are not
positioned properly.
Weather-Pack connections cannot be replaced with standard
connections. Instructions are provided with Weather-Pack connector and terminal packages.
FIGURE 4 WEATHER PACK TERMINAL REPAIR

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

ECM Header Connector Pin-Out

ELECTRICAL SECTION 6-5

ECM Header Connector Termnial Identiﬁcation

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Customer Interface Connector Pin-Out

ELECTRICAL SECTION 6-6

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

ELECTRICAL SECTION 6-7

Engine Wire Harness Fuse and Relay Center Layout

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

ELECTRICAL SECTION 6-8

Engine Wiring Schematic - Part A

C003

C002

C004

C005

C007
C009
C001

C012

C013

C017

C025

C028

C029

C030

C031

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

ELECTRICAL SECTION 6-9

Engine Wiring Schematic - Part B

C006

C005

C008

C007

C010

C011
C014
C015
C016

017
C018
C020/C021
C026
C027

C022
C023

C024

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

ELECTRICAL SECTION 6-10

Diagnostic Service Tool Installation Instructions
Before installing the DST software, please be sure your computer meets the minimum system requirements.
Supported operating systems are:
Windows XP
Windows 2000
Windows 98SE (Second Edition)
Minimum processor speed:
Pentium II 450 MHz
Minimum RAM requirement:
Windows XP
Windows 2000
Windows 98SE

256 MB
128 MB
128 MB

* At least one available RS232 serial or USB port.
* USB Driver does not support Windows 98SE (Second Edition)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

•

Open the DST folder

• Open the Latest_GCP_Display folder

ELECTRICAL SECTION 6-11

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

ELECTRICAL SECTION 6-12

•

Double click on “setup.exe” (application ﬁle) to start the windows installer. If a previous version of
the GCP software is installed, the uninstaller will remove the previous version and exit. You will be
required to start the installer again to install the new version.

•

Click next to continue

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

•

Click next to continue

•

Click next to continue

•

Click the “ﬁnish” box to complete the installation.

ELECTRICAL SECTION 6-13

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

ELECTRICAL SECTION 6-14

Once installed, the software can be accessed from
Start Menu → Programs → GCP Display → GCP Display

Installing the USB Adapter Driver
If your computer does not have an RS232 serial port, you will need to install the USB adapter driver. The
installation of this driver is similar to the GCP display.

•

Open the DST folder

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

•

Open the “USB Driver” folder

ELECTRICAL SECTION 6-15

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
•

ELECTRICAL SECTION 6-16

Double click on “setup.exe” (application ﬁle) and follow the on screen prompts.

Password Login
Figure 1 shows the password dialog box, which is displayed when a software session begins. Login can be
accomplished in two ways.
1. Enter an ‘All S/N Password’ which is applicable to all ECMs of a given original equipment manufacture
(OEM).
2. Enter a ‘Single S/N Password’ and corresponding serial number for a single ECM. A Single Serial
Number password is only applicable for the speciﬁc ECM serial number it applies to, and is useful for
authorizing service personnel to make changes or view information for a single ECM for which they
would otherwise not have access to.
In most instances the top “all” serial number boxes should be used for password entry. In this case, do not
check the single serial number box. Each password is a 16-character alpha-numeric string speciﬁc to each
customer and determines which pages and variables are visible through the software. Passwords are assigned
to an OEM by PSI and may change periodically. Check the “save password” box to automatically retain the
password for future use.

Figure 1: Populated Password Dialog Box
Password Dialog Box Functions
•

Clear Password Button- Erases the current password from the password ﬁeld

•

Paste Password Button- Allows the user to copy a 16-character string from any word processor and paste
the string in the password ﬁeld

•

Single Serial Number Access Checkbox- Tells the software that the password is applicable for single serial
number access

•

Serial Number Field- Only applicable when Single Serial Number Access Checkbox is checked. The entry
ﬁeld must be populated for the 6-digit serial number for which the Single Serial Number Access password

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

ELECTRICAL SECTION 6-17

applies (NOTE: Leading zeros included in the serial number are not required).
•

Save Password and S/N Checkbox- Retains the password, and serial number (if applicable) for the next
software session.

Should an invalid password be entered, the error prompt shown in ﬁgure (2) will be
and the software will not load. This prompt signiﬁes the following:

displayed

•

The All S/N password is invalid

•

The Single S/N password is incorrect for the Single Serial Number entered

•

An All S/N password is entered for Single Serial Number use

•

The Single Serial Number password is valid, however, the Single Serial Number Access Checkbox
is not checked

Figure 2: Password Error Prompt
If the Single S/N password entered is correct for the software but does not match the entered S/N of the targeted

ECM, the prompt in Figure 3 will be displayed.

Figure 3: Incorrect Serial Number Message
Figure 4 shows the communication status if a valid software password is entered when attempting to connect
to an ECM with a different key. In this instance the software will load but will not connect to the target (ECM).

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

ELECTRICAL SECTION 6-18

Figure 4: Not Authorized to Connect Message
In the event you receive this error message call your OEM support group for more information.

Connecting the PC to the Engine Control System
A laptop computer is the required tool for performing proper diagnostic testing of the engine control and fuel
system. A laptop computer, with the system diagnostic cable and diagnostic software, is used to read and clear
Diagnostic Trouble codes. It is also used to monitor sensor and actuator values. The DST software also performs
several special tests.
•

Connect the system diagnostic cable to the RS232 port on the back of the computer. If you do not have
a RS232 port, use the USB to RS232 adapter supplied in the IMPCO ITK test kit. Be sure to install the
USB driver to enable the USB adapter for use with your computer.

•

Connect the diagnostic cable to the DLC (diagnostic link connector) labeled C016 in the electrical
schematic. The DLC is located on the engine harness. The new 8 pin DLC requires the use of the 4 to 8
pin adapter included in the late model ITK test kits.

•

Turn the computer ON.

•

Start Windows.

•

From the start menu select Programs → GCP Display → GCP Display and enter password

•

Place the ignition key in the ON position.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

ELECTRICAL SECTION 6-19

Within several seconds the system Gauge screen should now appear and a green banner in the upper left
hand will read “Connected”.

DST Service Screens

Gauge Screen
Provides system data in large easy to read displays. Displays ECM conﬁguration information for the ECM
software, hardware, serial numbers and calibration dates.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

ELECTRICAL SECTION 6-20

Multi Engine Page
The multi engine page provides a convenient way to access system voltages and sensor inputs for multiple
engine installations. It also includes system status on power derate modes.
This screen has limited use for single engine applications.

Test Screen
Provides diagnostic information voltages and sensor outputs and includes diagnostic engine tools such as
spark and injector kill controls. Please note that not all features are available for all applications. Disabled item
menus are grayed out or rendered inoperative

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

ELECTRICAL SECTION 6-21

Spark Kill
The spark kill mode allows the technician to disable the ignition on individual cylinders. If the Spark Kill
diagnostic mode is selected with the engine running below 1000 RPM, the minimum throttle command will lock
into the position it was in when the test mode was entered. If the Spark System Test mode is selected with
the engine running above 1000 RPM, the throttle will continue to operate normally. Disabling Ignition Outputs
to disable the ignition system for an individual cylinder, use the mouse to highlight the “Spark Kill” button and
select the desired coil. The spark output can be re-enabled by using the mouse to highlight the “Spark Kill”
button and selecting “Normal”. If the engine is running below 1000 RPM, the spark output will stay disabled
for 15 seconds and then re-set. If the engine is running above 1000 RPM, the spark output will stay disabled
for 5 seconds and then re-set. This test mode has a timeout of 10 minutes. Record the rpm drop related to
each spark output disabled. The Spark outputs are arranged in the order which the engine ﬁres, not by cylinder
number.
Injector Kill
The Injector Kill mode is used to disable individual fuel injectors. If the Injector Kill mode is selected with the
engine running below 1000 RPM, the minimum throttle command will lock into the position it was in when the
test mode was entered. If the Injector Kill mode is selected with the engine running above 1000 RPM, the
throttle will continue to operate normally. To disable an injector, use the mouse to select the desired injector.
The word “Normal” will change to the Injector you have selected. The injector driver can be re-enabled by
selecting again. If the engine is running below 1000 RPM, the injector driver will stay disabled for 15 seconds
and then re-set. If the engine is running above 1000 RPM, the injector driver will stay disabled for 5 seconds
and then re-set. Record the change in rpm while each driver is disabled.
DBW Test Mode
The DBW (Drive by Wire) test mode allows the technician to control the throttle directly with the foot pedal
or throttle input and is used during the diagnostic routines speciﬁed for FPP and TPS for systems that use
DBW control. FPP position displays the current position of the foot pedal as a percentage. FPP volts display
the voltage which the ECM is reading from the FPP sensor. TPS Command displays the commanded throttle
position expressed as a percentage, which is being sent to the throttle. TPS Position is the actual percent of
throttle opening being sent to the ECM from the throttle. TPS volts display the actual TPS signal voltage the
ECM is receiving from the throttle. To select this test mode the engine must be off and the key must be in the
ON position
External Power Test
The external power test manually activates relays (relay power, fuel pump, and drive-by wire power)
controlled by the ECM while the engine is in the “Stopped” or “Running” states. Reverts to normal operation if
“Automatic” state is selected or ignition voltage is cycled from high to low.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

ELECTRICAL SECTION 6-22

Faults Page
Stores DTC codes that may have occurred in the past (Historic Faults) or current set codes (Active Faults).
Includes useful system voltages and senor readings used while working with the fuel and emission trouble
shooting charts. Shows power derate mode status. To erase a historic DTC code, double click on the code with
the left mouse button. Then choose to “erase all codes” or only selected codes in the pop up box.

Plot/Log Menu Functions
The Plot/Log menu allows the user to graphically plot or numerically log variables that have been tagged
for plotting/logging. To plot or log variables, a tag must be assigned to each variable of interest. A variable
is tagged for plotting/logging through a single right-mouse click in the variable’s vicinity. Once a variable
has been tagged for plotting/logging it is highlighted in green. Figure 5 shows an example of variables that
have been tagged. A maximum of twenty (20) variables may be tagged for logging and a maximum of ten
(10) variables may be tagged for plotting. The maximum achievable sample frequency/minimum period is
dependent on the number of variables tagged.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Figure 5: Tagged Variables for Plot/Log

ELECTRICAL SECTION 6-23

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

ELECTRICAL SECTION 6-24

Once the variables have been tagged as highlighted by the green color ﬁll, select the “Plot/Log”
function in the top menu bar as shown below in ﬁgure 6.

Figure 6

•

Select “Plot Tags” to open the snapshot window
Other functions available from the Plot/Log menu include:

•

Clear Tags: Releases all plot/log variables.

•

Plot Tags (Ctrl + P, or P): Graphically plot all tagged variables.

•

Load Plot Setup: Loads and tags variables for plotting/logging that have been stored in a plot ﬁle (.plt).

•

Log Tags (Ctrl + L): Numerically log all variables that have been tagged for plotting/logging

Once the Plot Tags menu item has been selected, tagged variables are graphically plotted in a strip chart
interface. An example of a plot is shown in Figure 7. Capabilities of the plotter are outlined in Table 1.
Start/Stop Button
Save Button

Load Plot Button

Start or stop plotting of selected variables
Save plotted data displayed in the plot to a comma-separated value
ﬁle (CSV) on the PC hard drive. Format must not be altered if the
Load function is to be used.
Convert the plot into a snapshot that may be panned, zoomed,
scrolled, and saved
Close the DST Plot interface
Load tags from a previously saved plot (.plt) ﬁle to allow for similar
plots and logs to be generated
Load a previously saved plot from the PC into the DST Plot interface

Variable Selector Menu

Selects the active variable for axis scaling

Snapshot Button
Close Button
Load Setup Button

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

ELECTRICAL SECTION 6-25

Single Shot Acquisition
Checkbox*

When checked, this does not allow the plot to scroll past the ‘Time
Interval’ thereby preserving plotted data for post-processing.

Exclusive Serial Use
Checkbox*

When checked, this allows exclusive serial communication for the
plot variables. Other variables on the active page are not updated.

Min Y Value Field**
Max Y Value Field**
Sample Interval (ms) Field**

Specify the minimum Y-axis scaling for the active variable
Specify the maximum Y-axis scaling for the active variable
Deﬁne the sample period for recording and display Frequency (hz.)
= 1000/Sample Interval (ms)
Time Interval (s) Field**
Deﬁnes the total sample acquisition time for the plot.
*Accessible only when plotter is not running.
Table 1

Variable selector

Figure 7 DST Plot

•
•

Click on the start button to start the DST plot function.
Click on the variable selector button to view selected sensors

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

ELECTRICAL SECTION 6-26

Figure 8: DST Plot Snapshot

•

Click on the “Save” button to save the snapshot as a ﬁle.

To replay the saved ﬁle, open the edis_saplot program from the windows start menu.

•

Start Menu → Programs → GCP Display → edis_saplot

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

ELECTRICAL SECTION 6-27

DST Plot Interface Functions
A graphic tool incorporated in the plotter is the snapshot function. This function allows data collected in a plot
to be transferred into a second window for quick graphical post-processing. The snapshot allows the user to
zoom in/out, pan left/right, and move cursors along the signal traces to measure the variable values in virtual
real-time. An example of a snapshot is shown in Figure 8. Any CSV ﬁle in plot format (.plt) may be loaded into
the snapshot. Table 2 outlines the available hot key functions of the snapshot screen.

Snapshot Hot Key Functions

Command

Function
Snap closest cursor to data
Move/pan plot along y axis
Move/pan plot along t axis
Zoom plot in and out in y axis
Zoom plot in and out in t axis
Resize plot to default settings
Zoom out by 10%
Zoom in by 10%
Toggle to previous cursor
Toggle to next cursor
Follow selected data along trace
Follow selected data along trace
Move 10 points along trace
Move 10 points along trace
Go to ﬁrst visible point on current plot
Advance to last visible point on current plot
Toggle between traces/variables
Table 2

DST Logger
Another data capture function incorporated in the software is the DST logger. This tool serves as a PC data
logger for any variable available in the ECM through the interface software. Figure 9 shows the interface
display for conﬁguring the DST Log. The interface allows the user to create the ﬁle’s ﬁlename, set the sample
rate for acquisition, set the time interval for sampling, and display the progress of acquisition. A maximum
of twenty (20) variables may be tagged for the log. The amount of data stored is only limited by available PC
RAM. The resulting text ﬁle may then be viewed by any standard Windows text editor/reader program. To
create a log ﬁle select the “Log Tags” in the drop down menu as shown in ﬁgure 6.

Figure 9: DST Log Interface

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

ELECTRICAL SECTION 6-28

Malfunction Indicator Lamp (MIL)
The engine control system has built-in diagnostics for system trouble shooting. The system has a dash mounted
malfunction indicator lamp (MIL) that provides indications of an emissions related problem. Most engine control
system related problems that affect emissions or driveability of the vehicle will set a (DTC) diagnostic trouble
code and illuminate the Malfunction Indicator Lamp.
The MIL serves as notiﬁcation to the operator of a problem related to the emission control system so the driver
can arrange for service as soon as possible. It will also display DTC’s that have been stored due to a system
malfunction.
The MIL should illuminate when the key is in the on position and the engine is not running. This feature veriﬁes
that the lamp is in proper working order. If the lamp does not illuminate with the vehicle key on/engine off, repair
it as soon as possible. Once the engine is in start or run mode, the MIL should turn off. If the lamp remains on
while the engine is in the start or run mode a diagnostic trouble code may be set.
Diagnostic Trouble Codes (DTC)
Diagnostic Trouble Codes are set when the ECM (Electronic Control Module) runs a diagnostic self test and the
test fails. When a DTC is set, the ECM will illuminate the MIL on the instrument panel and also save the DTC
in memory. The ECM will continue to run the self test. If the system continues to fail the test, the lamp will stay
illuminated and the DTC is stored as an active DTC. If the self test runs and passes, the DTC will be stored as
historic DTC. All DTC’s are stored as historic faults until they are cleared. Most DTC’s will automatically clear
from memory if the DTC does not reset within 50 to 100 consecutive engine run cycles.
While a Diagnostic Trouble Code is current for a sensor, the ECM may assign a default “limp home” value and
use that value in its control algorithms. All of the system diagnostic self-tests run continuously during normal
vehicle operation.
The Diagnostic Trouble Codes can be read by using either the MIL lamp or a laptop computer. Diagnostic Trouble
Codes can be cleared from memory with a laptop computer, or by turning the ignition key to the OFF position and
removing the ECM power fuse (F2) for 15 seconds.
If more than one DTC is detected, start the diagnostic repair with the lowest DTC number set. Diagnose each
problem to correction unless directed to do otherwise by the diagnostic chart. The DTC’s are numbered in order
of importance. Having DTC 112 and DTC122 both concerning the oxygen sensor, it is possible that by repairing
DTC 112 ﬁrst, the problem causing the DTC 122 may also be corrected.
Diagnostic test charts contained in this manual refer to the DST to be connected and in the “System Data Mode”.
This simply means that the DST is connected and communicating with the PC. In some instances the chart will
call out a special test mode. An example of this would be instructions for the DST to be connected and in the
DBW (drive by wire) mode. Always be sure to follow the special instructions to avoid a false diagnosis of fuel
system components.
DLC Communication Error
The ECM 5 volt reference circuit powers the diagnostic link cable. In the event that the 5 volt reference signal
is open or shorted to ground, you will not be able to connect to the system. If you are unable to connect, follow
the quick checks listed below:

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

ELECTRICAL SECTION 6-29

Be sure you are using the correct password and latest software for the system you are connecting to.
Check the ECM system power and ground circuits. Refer to DTC 562 for the power schematic. Also check for
+12 volts switched power at ECM pin 45 with the ignition key on.
Check for power at the DLC connector for + 5 volts between pin 1 (BLK /LT GRN) and pin 2
(LT GRN RED) with the ignition key in the on position.
You may still be able to retrieve a code using the blink code function if none of the above recommendations
prove useful. In the event of a 5 volt reference signal malfunction, DTC 642 or DTC 643 should set. If you ﬁnd
one of these codes using the blink code function, follow the DTC diagnostic chart recommendations for that
speciﬁc DTC.
Blink Code Function
Although the DST is considered a required tool to access the DTC codes, codes may be retrieved without a
laptop computer using the blink code function. To enable this function follow the steps below:
•

Jump pins 1 and 4 at the DLC connector C016.

•

Turn the ignition key to the on position

•

The system will now enter the self diagnostic blink code mode. Be ready with pen and paper to write
down any codes that may be stored.

•

The ECM will ﬂash the MIL indicator with a pause between represented numbers that represent DTC
codes. The sequence starts with code 1654. Code 1654 conﬁrms the system has entered the blink
code mode. The ECM will ﬂash code 1654 (3) times before displaying the actual DTC code that may be
set.

Example:
One short blink (pause) six short blinks (pause) ﬁve short blinks (pause) four short blinks.
•

If no DTC codes are found, the ECM will continue to ﬂash 1654 only. This means no stored DTC codes
were found.
Intermittent Problems

Intermittent fuel system problems can prove to be the most challenging to repair. It is most important to
remember when looking to ﬁnd the cause of these problems, to operate the system in the condition when and
where the problem occurs. An example of this would be, if the DST showed a lean fuel mixture at full load, one
of the ﬁrst things to look at would be the fuel pressure. The fuel pressure would need to be monitored while
the machine is operating at full load, not at idle because the leaning effect does not occur at idle. Electrical
problems should be treated the same way. One excellent tool for ﬁnding intermittent electrical problems is the
DST plot/log function. Set up the plot for the code that sets. An example of this would be if an intermittent IAT
code set, tag the IAT voltage and watch the plot. While watching the plot, agitate the electrical wire connection
at the sensor and ECM connector. The resolution of the plot screen is such that you will be able to see any
unstable voltages that you would otherwise not see with a standard DVOM.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

ELECTRICAL SECTION 6-30

Caution should be used when pressure washing the under hood of any electrical system. Avoid direct pressure
spray on the system electrical connectors. They are splash proof, but if water is sprayed directly at the
connector moisture can become trapped behind the connector seal and cause serious system problems.
Extra care must be taken when probing electrical pins and terminals. Do not bend or spread these terminals as
this can also be a source of intermittent problems cause by improper handling of these connectors.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-1

PSI 3.0L PFI
DIAGNOSTIC TROUBLE CODE SECTION
Table Of Contents
Description
Page
DTC to SPN/FMI Cross Reference Chart....................................................................7-4
OBD System Check.....................................................................................................7-5
DTC 16 Crank Never Synced at Start - SPN/FMI 636:8..............................................7-6
DTC 91 Fuel Pressure Sensor Voltage Low - SPN/FMI 94:4.....................................7-11
DTC 92 Fuel Pressure Sensor Voltage High - SPN/FMI 94:3....................................7-14
DTC 107 MAP Low Voltage - SPN/FMI 106:4............................................................7-17
DTC 108 BP High Pressure - SPN/FMI 106:16.........................................................7-21
DTC 111 IAT Higher Than Expected 1 - SPN/FMI 105:15..........................................7-23
DTC 112 IAT Low Voltage - SPN/FMI 105:4.............................................................7-25
DTC 113 IAT High Voltage SPN/FMI 105:3..............................................................7-28
DTC 116 ECT higher Than Expected 1 - SPN/FMI 110:15.......................................7-31
DTC 117 ECT Low Voltage - SPN/FMI 110:4............................................................7-33
DTC 118 ECT High Voltage - SPN/FMI 110:3...........................................................7-35
DTC 121 TPS 1 Lower Than TPS 2 - SPN/FMI 51:1...............................................7-38
DTC 122 TPS 1 Signal Low Voltage - SPN/FMI 51:4..............................................7-41
DTC 123 TPS 1 Signal High Voltage - SPN/FMI 51:3...............................................7-44
DTC 127 IAT Higher Than Expected 2 - SPN/FMI 105:0...........................................7-47
DTC 129 BP Low Pressure - SPN/FMI 108:1...........................................................7-49
DTC 134 EGO 1 Open/Inactive - SPN/FMI 724:10...................................................7-51
DTC 154 EGO 2 Open/Inactive - SPN/FMI 520208:10.............................................7-54
DTC 171 Adaptive Learn High Gasoline - SPN/FMI 520200:0.................................7-57
DTC 172 Adaptive Learn Low Gasoline - SPN/FMI 520200:1..................................7-60
DTC 182 Gasoline Temperature Sensor Low Voltage - SPN/FMI 174:4..................7-62
DTC 183 Gasoline Temperature Sensor High Voltage - SPN/FMI 174:3..................7-65
DTC 187 LPG Fuel Temperature Low Voltage - SPN/FMI 520240:4.......................7-68
DTC 188 LPG Fuel Temperature High Voltage - SPN/FMI 520240:3......................7-71
DTC 217 ECT Higher Than Expected 2 - SPN/FMI 110:0........................................7-74
DTC 219 Max Govern Speed Override - SPN/FMI 515:15.......................................7-76
DTC 221 TPS 1 Higher Than TPS 2 - SPN/FMI 51:0...............................................7-78
DTC 222 TPS 2 Signal Low Voltage - SPN/FMI 520251:4.......................................7-81
DTC 223 TPS 2 Signal High Voltage - SPN/FMI 520251:3.......................................7-83

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-2

Table Of Contents
Description
Page
DTC 261 Injector Driver 1 Open - SPN/FMI 651:5....................................................7-86
DTC 262 Injector Driver 1 Shorted - SPN/FMI 651:5.................................................7-89
DTC 264Injector Driver 2 Open - SPN/FMI 652:5.....................................................7-92
DTC 265 Injector Driver 2 Shorted - SPN/FMI 652:6.................................................7-95
DTC 267 Injector Driver 3 Open - SPN/FMI 653:5....................................................7-98
DTC 268 Injector Driver 3 Shorted - SPN/FMI 653:6...............................................7-101
DTC 270 Injector Driver 4 Open - SPN/FMI 654:5...................................................7-104
DTC 271 Injector Driver 4 Shorted - SPN/FMI 654:6...............................................7-107
DTC 336 Crank Sync Noise - SPN/FMI 636:2........................................................7-110
DTC 337 Crank Loss - SPN/FMI 636:4...................................................................7-113
DTC 341 Cam Sync Noise - SPN/FMI 723:2..........................................................7-116
DTC 342 Camshaft Sensor Loss - SPN/FMI 723:4.................................................7-119
DTC 420 Gasoline Catalyst Monitor - SPN/FMI 520211:10.....................................7-122
DTC 524 Oil Pressure Low - SPN/FMI 100:1..........................................................7-123
DTC 562 System Voltage Low - SPN/FMI 168:17..................................................7-126
DTC 563 System Voltage High - SPN/FMI 168:15..................................................7-128
DTC 601 Flash Checksum Invalid - SPN/FMI 628:13.............................................7-130
DTC 604 RAM Failure - SPN/FMI 630:12...............................................................7-132
DTC 606 COP Failure - SPN/FMI 629:31...............................................................7-134
DTC 642 External 5V Reference Low - SPN/FMI 1079:4.......................................7-136
DTC 643 External 5V Reference High - SPN/FMI 1079:3......................................7-139
DTC 685 Power Relay Open - SPN/FMI 1485:5....................................................7-141
DTC 686 Power Relay Shorted - SPN/FMI 1485:4.................................................7-144
DTC 687 Power Relay Short to Power - SPN/FMI 1485:3......................................7-146
DTC 1111 Fuel Rev Limit - SPN/FMI 515:16...........................................................7-149
DTC 1112 Spark Rev Limit - SPN/FMI 515:0..........................................................7-151
DTC 1151 Closed Loop Multiplier High LPG - SPN/FMI 520206:0.........................7-153
DTC 1152 Closed Loop Multiplier Low LPG - SPN/FMI 520206:1..........................7-155
DTC 1155 Closed Loop Multilier High Gasoline - SPN/FMI 520204:0....................7-157
DTC 1156 Closed Loop Multiplier Low Gasoline - SPN/FMI 520204:1...................7-159
DTC 1161 Adaptive Learn High LPG - SPN/FMI 520202:0.....................................7-161
DTC 1162 Adaptive Learn Low LPG - SPN/FMI 520202:1.....................................7-164
DTC 1165 LPG Catalyst Monitor - SPN/FMI 520213:10........................................7-167
DTC 1171 LPG Pressure Higher Than Expected - SPN/FMI 520260:0...................7-168
DTC 1172 LPG Pressure Lower Than Expected - SPN/FMI 520260:1...................7-170
DTC 1173 EPR Comm Lost - SPN/FMI 520260:31................................................7-172

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-3

Table Of Contents

Description
Page
DTC 1174 EPR Voltage Supply High - SPN/FMI 520260:3....................................7-176
DTC 1175 EPR Voltage Supply Low - SPN/FMI 520260:4.....................................7-178
DTC 1176 EPR Internal Acuator Fault - SPN/FMI 520260:12.................................7-181
DTC 1177 EPR Internal Circuitry Fault - SPN/FMI 520260:12................................7-183
DTC 1178 EPR Internal Comm Fault - SPN/FMI 520260:12..................................7-185
DTC1612 RTI 1 Loss - SPN/FMI 629:31.................................................................7-187
DTC 1613 RTI 2 Loss - SPN/FMI 629:31................................................................7-189
DTC 1614 RTI 3 Loss - SPN/FMI 629:31................................................................7-191
DTC 1615 A/D Loss - SPN/FMI 629:31...................................................................7-193
DTC 1616 Invalid Interupt - SPN/FMI 629:31.........................................................7-195
DTC 1626 CAN Tx Failure - SPN/FMI 639:12........................................................7-197
DTC 1627 Can Rx Failure - SPN/FMI 639:12.........................................................7-200
DTC 1628 CAN Address Conﬂict Failure - SPN/FMI 639:13.................................7-203
DTC 1629 Loss of TSC 1 - SPN/FMI 639:31...........................................................7-205
DTC 2111 Unable to Reach Lower TPS - SPN/FMI 51:7........................................7-207
DTC 2112 Unable to Reach Higher TPS - SPN/FMI 51:7.......................................7-210
DTC 2229 BP High Pressure - SPN/FMI 108:0......................................................7-213

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-4

DTC Code to SPN:FMI Code Cross Reference
DTC Code

Description

SPN Code

FMI Code

DTC Code

Description

SPN Code

Crank Never Synced at Start

636

524

Oil Pressure Low

100

FMI Code
1

Fuel Pump Low Voltage

562

System Voltage Low

168

Fuel Pump High Voltage

563

System Voltage High

168

107

MAP Low Voltage

106

601

Flash Checksum Invalid

628

108

MAP High Pressure

106

604

RAM Failure

630

111

IAT Higher Than Expected 1

105

606

COP Failure

629

112

IAT Low Voltage

105

642

External 5V Reference Low

1079

113

IAT High Voltage

105

643

External 5V Reference High

1079

116

ECT Higher Than Expected 1

110

685

Power Relay Open

1485

117

ECT Low Voltage

110

686

Power Relay Shorted

1485

118

ECT High Voltage

110

687

Power Relay Short to Power

1485

121

TPS 1 Lower Than TPS 2

1111

Fuel Rev Limit

515

122

TPS 1 Signal Voltage Low

1112

Sparl Rev Limit

515

123

TPS 1 Signal Voltage High

1151

Closed Loop Multiplier High LPG

520206

127

IAT Higher Than Expected 2

105

1152

Closed Loop Multiplier Low LPG

520206

129

BP Low Pressure

108

1155

Closed Loop Multiplier High Gasoline

520204

134

EGO 1 Open/Inactive

724

1156

Closed Loop Multiplier Low Gasoline

520204

154

EGO 2 Open/Inactive

520208

1161

Adaptive Learn High LPG

520202

171

Adaptive Learn High Gasoline

520200

1162

Adaptive Learn Low LPG

520202

172

Adaptive Learn Low Gasoline

520200

1165

LPG Cat Monitor

520213

182

Fuel Temp Gasoline Low Voltage

174

1171

LPG Pressure Higher Than Expected

520260

183

Fuel Temp Gasoline High Voltage

174

1172

LPG Pressure Lower Than Expected

520260

187

Fuel Temp LPG Low Voltage

520240

1173

EPR Comm Lost

520260

188

Fuel Temp LPG High Voltage

520240

1174

EPR Voltage Supply High

520260

217

ECT Higher Than Expected 2

110

1175

EPR Voltage Supply Low

520260

219

Max Govern Speed Override

515

1176

EPR Internal Actuator Fault

520260

221

TPS 2 Signal Voltage Low

1177

EPR Internal Circuitry Fault

520260

222

TPS 2 Signal Low Voltage

520251

EPR Internal Comm Fault
RTI 1 loss

520260
629

12
31
31

223

TPS 2 Signal High Voltage

520251

1178
1612

261

Injector Driver 1 Open

651

1613

RTI 2 Loss

629

262

Injector Driver 1 Shorted

651

1614

RTI 3 Loss

629

264

Injector Dirver 2 Open

652

1615

A/D Loss

629

265

Injector Driver 2 Shorted

652

1616

Invalid Interupt

629

267

Injector Driver 3 Open

653

1625

Shutdown Request

1384

268

Injector Driver 3 Shorted

653

1626

CAN Tx Failure

639

270

Injector Driver 4 Open

654

1627

CAN Rx Failure

639

271

Injector Driver 4 Shorted

654

1628

CAN Address Conflict Failure

639

336

Crank Sync Noise

636

1629

Loss of TSC 1

639

31
7

337

Crank Loss

636

2111

Unable to Reach Lower TPS

341

Cam Sync Noise

723

2112

Unable to Reach Higher TPS

342

Cam Sensor Loss

723

2135

TPS 1/2 Simulataneous Voltages

420

Gasoline Cat Monitor

520211

2229

BP Pressure High

108

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-5

OBD System Check/ MIL (Malfunction Indicator Lamp)

Circuit Description
The Spectrum Fuel system is equipped with OBD (On-Board Diagnostics). The system has a dash mounted MIL
(Malfunction Indicator Lamp) for the indication of system problems. Engine control system problems that affect exhaust
emissions of the vehicle will set a DTC (Diagnostic Trouble Code). The ECM will then provide a path to ground and
illuminate the MIL.
The MIL serves as notiﬁcation of an emissions related problem. The MIL also has the ability to ﬂash DTC codes in what
is referred to the blink code mode. It will display DTC’s that have been stored due to a system malfunction. The following
DTC charts in this manual will instruct the technician to perform the OBD system check. This simply means to verify the
operation of the MIL. The lamp should illuminate when the key is in the ON position, and the engine is not running. This
feature veriﬁes that the lamp is in proper working order. If the lamp does not come on with the vehicle key on/engine off,
repair it as soon as possible. Once the engine is in start or run mode, the lamp should go off. If the lamp stays on while
the engine is in the start or run mode, a current diagnostic trouble code may be set or a problem may exist with the MIL
electrical wiring.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1
2

Action
• Key ON Engine OFF
Does the MIL illuminate?
•
•

OBD System Check

Start the engine
Does the MIL lamp turn off?

Key ON engine OFF
Check for voltage between MIL power source
and engine ground
Do you have voltage?

MIL is working
properly. OBD
System Check
is complete
Go to Step (4)

Go to Step (10)

Key OFF
Disconnect ECM wire harness connector
C001
• Using a DVOM check for continuity between
MIL side of connector C011 and ECM pin 80
Do you have continuity?
• Inspect the MIL lamp socket, connector C011
and ECM pin 80 for damage, corrosion or
contamination
Did you ﬁnd a problem?

Go to Step (6)

Go to Step (8)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (1)

Go to Step (7)

Go to Step (9)

Repair open
circuit in
connector
C022

Repair the
damaged
socket or
terminal as
required.
Refer to
Wiring Repairs
in Engine
Electrical.
-

Repair the
wire harness
open circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

• Replace ECM
Is the replacement complete?
Back probe both MIL and ECM side of
terminal G in connector C011
• Using a DVOM check for continuity through
connector C011
Do you have continuity?
Inspect the MIL lamp socket, connector C011
and ECM terminal 80 for damage, corrosion
or contamination
Did you ﬁnd a problem?
•

No
Go to Step (3)

Go to step (1)

•

Yes
Go to Step (2)

Replace MIL lamp
Did that solve the problem?
•
•

Value(s)

Repair MIL
voltage source.
Refer to OEM
body and
chassis wiring
diagrams
Go to Step (5)

•
•

DIAGNOSTIC TROUBLE CODES 7-6

Active DTC (Diagnostic trouble code) is stored in
memory. Proceed with DTC diagnosis. If no active
DTC is found in ECM memory return to this page
Step (11)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step

•
•
•
•

Action
Key OFF
Disconnect ECM wire harness connector
C001
Using a DVOM check for continuity between
ECM terminal 80 and battery voltage
Do you have continuity?

DIAGNOSTIC TROUBLE CODES 7-7
Value(s)

Yes
Repair the
shorted to
ground circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

No
Go to Step (7)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-8

DTC 16-Never Crank Synced At Start SPN/FMI 636:8

Conditions for setting the DTC
•
•
•
•

Crankshaft Position sensor
Check Condition- Engine cranking
Fault Condition- Cranking RPM above 90 and more than 4 cranking revolutions without sync
MIL Command-ON

Circuit Description
The CKP (crankshaft position sensor) is a magnetic transducer mounted on the engine block adjacent to a pulse wheel
located on the crankshaft. It determines crankshaft position by monitoring the pulse wheel. The Crankshaft Position sensor
is used to measure engine RPM and its signal is used to synchronize the ignition and fuel systems. This fault will set one or
more crank re-sync occur within 800 ms.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

DTC 16- Never Crank Synced At Start SPN/FMI 636:8

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

Check to be sure that the ECM ground
terminals C014 and C023 are clean and tight.
Are terminals C014 and C023 clean and tight?

Key OFF
Disconnect the CKP sensor connector C017
Using a DVOM check for voltage output
directly from the CKP sensor while cranking
the engine
• Do you have voltage output?
Key OFF
Disconnect ECM connector C001
Using a DVOM check for continuity between CKP
connector pin A and ECM connector pin 21
Do you have continuity between them?
•
•
•

•
•
•
•

Yes
Go to Step (2)
Go to Step (3)

•

DIAGNOSTIC TROUBLE CODES 7-9

Over .5 volts

Go to Step (4)

Go to Step (5)

•

Using a DVOM check for continuity between CKP
connector pin B and ECM connector pin 22
Do you have continuity between them?

Go to Step (6)

•

Inspect the CKP connector C017 pins for damage,
corrosion or contamination
Did you ﬁnd a problem?

•

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Repair the
shorted circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

Inspect the ECM connector C001 pins 21 and 22
for damage, corrosion or contamination
Did you ﬁnd a problem?

Using a DVOM check for continuity between ECM
connector pins 21 and 22 to engine ground
Do you have continuity?

No
Go to OBD
System Check
Section
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (11)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (7)

Go to step (8)

Go to Step (10)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
9
10
11

Action
• Replace CKP sensor
Is the replacement complete?
• Replace ECM
• Is the replacement complete?
• Key OFF
• Inspect the pulse wheel and CKP sensor
for mechanical damage, corrosion or
contamination.
Did you ﬁnd a problem?
Remove all test equipment except the DST.
Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-16 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•

DIAGNOSTIC TROUBLE CODES 7-10
Value(s)

Yes
Go to Step (12)

No
-

Go to Step (12)

Repair the
component
as necessary.
Refer to
Engine Repairs
in Engine
Section
System OK

Go to Step (9)

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-11

DTC 91-Gasoline Fuel Pressure Sensor Low Voltage SPN/FMI 94:4

Conditions for Setting the DTC
•
•
•
•

Gasoline fuel pressure sensor voltage
Fuel pressure sensor voltage less than .2v for 1s
MIL-On for active fault and for 2 seconds after active fault
Adaptive-disabled for the remainder of key cycle

Circuit Description
Note: The fuel pressure and temperature sensor is wired via Equipment Manufacturer supplied harness jumper.
The terminals A, B, C, D & 19, 20, 48, 54 are engine wiring harness terminals at the fuel sensor interface
connector C002 and the ECM header connector C001. You may need to consult additional wiring information
supplied by the OEM. The fuel pump pressure sensor voltage is read at less than .2v. This indicates abnormally
low fuel pressure or a low voltage fault from the sensor or circuit.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-12

DTC 91- Gasoline Fuel Pressure Sensor Low Voltage SPN/FMI 94:4

Step
1

Action
Did you perform the On-Board (OBD) System
Check?

Value(s)
-

Yes
Go to Step (2)
Go to Step (3)

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section

Go to Step (4)

Go to step (8)

Repair the
circuit as
necessary.
Refer to
Wiring
Repairs
in Engine
Electrical.
Go to Step (6)

Go to step (5)

• Key On, Engine running.
• DST (Diagnostic Scan Tool) connected in
System Data Mode
Using a DVOM, check for voltage at connector
C002 terminal D by back probing to ground. Is
voltage 0.2v or less with the engine idling?
3

•
•

Key OFF
Disconnect the gasoline fuel pressure sensor
jumper harness connector C002 from the
engine wiring harness
Key On
Using a DVOM, check for voltage between
connector C002 terminal C and ground.

Is voltage 4.5 volts or greater?
4

•

Inspect fuel pressure and temperature
sensor connector and pins for corrosion,
contamination or mechanical damage. Check
for opens or shorts in OEM supplied jumper
harness to sensor
Any problems found?

•
•
•

•

Key OFF
Disconnect ECM connector C001
Check for continuity between gasoline
pressure sensor connector terminal D and
ECM pin 54.
Do you have continuity between them?
Check for continuity between fuel pressure
sensor connector terminal C and ECM pin 19

Do you have continuity between them?

Go to step (7)

Repair the
circuit as
necessary.
Refer to
Wiring
Repairs
in Engine
Electrical.
Repair the
circuit as
necessary.
Refer to
Wiring
Repairs
in Engine
Electrical.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
7

•

Action
Check for continuity between fuel pressure
sensor connector terminal A and ECM pin 20

DIAGNOSTIC TROUBLE CODES 7-13
Value(s)

Yes
Go to step
(11)

Do you have continuity between them?

•
•
•

Key Off
Disconnect ECM header connector C001
Check for continuity between pressure
sensor connector C002 terminal C and ECM
connector terminal 19.

Do you have continuity?
• Inspect ECM and gasoline pressure
sensor connector (C002) terminals for
corrosion, contamination or mechanical
damage
Any problems found?

Replace ECM. Refer to ECM replacement
in the Engine Controls Section.
Is the replacement complete?

Replace fuel pressure and temperature
sensor
Is the replacement complete?

•
•

•

•
•
•

Remove all test equipment except the DST.
Connect any disconnected components,
fuses, etc.
Using the DST clear DTC information from the
ECM.
Turn the ignition OFF and wait 30 seconds.
Start the engine and operate the vehicle to full
operating temperature

Observe the MIL
Observe engine performance and driveability
After operating the engine within the test
parameters of DTC-91 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•
•

Go to Step (9)

Repair the
circuit as
necessary.
Refer to
Wiring
Repairs
in Engine
Electrical.
Go to step
(12)

Go to step
(12)

System OK

No
Repair the
circuit as
necessary.
Refer to
Wiring
Repairs
in Engine
Electrical.
Repair the
circuit as
necessary.
Refer to
Wiring
Repairs
in Engine
Electrical.
Go to Step
(10)

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-14

DTC 92-Gasoline Fuel Pressure Sensor High Voltage SPN/FMI 94:3

Conditions for Setting the DTC
•
•
•
•

Gasoline fuel pressure sensor voltage
Fuel pressure sensor voltage greater than 4.8v for 1s
MIL-On for active fault and for 2 seconds after active fault
Adaptive-disabled for the remainder of key cycle

Circuit Description
Note: The fuel pressure and temperature sensor is wired via Equipment Manufacturer supplied harness jumper.
The terminals A, B, C, D & 19, 20, 48, 54 are engine wiring harness terminals at the fuel sensor interface
connector C002 and the ECM header connector C001. You may need to consult additional wiring information
supplied by the OEM. The fuel pressure sensor voltage is read at greater than 4.8v. This indicates abnormally
high fuel pressure or a high voltage fault from the sensor or circuit.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-15

DTC 92- Gasoline Fuel Pressure Sensor High Voltage SPN/FMI 94:3

Step
1

Action
Did you perform the On-Board (OBD) System
Check?

Value(s)
-

Yes
Go to Step (2)
Go to Step (3)

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section

Go to Step (4)

Go to step (8)

Repair the
circuit as
necessary.
Refer to
Wiring
Repairs
in Engine
Electrical.
Go to Step (6)

Go to step (5)

•
•

Key OFF
Disconnect the gasoline fuel pressure sensor
jumper harness connector C002 from the
engine wiring harness
Key On
Using a DVOM, check for voltage between
connector C002 terminals C and A.

Is voltage 4.5 volts or greater?
4

•

•
•
•

•

Do you have continuity between them?

Go to step (7)

Repair the
circuit as
necessary.
Refer to
Wiring
Repairs
in Engine
Electrical.
Repair the
circuit as
necessary.
Refer to
Wiring
Repairs
in Engine
Electrical.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
7

•

Action
Check for continuity between fuel pressure
sensor connector terminal A and ECM pin 20

DIAGNOSTIC TROUBLE CODES 7-16
Value(s)

Yes
Go to step
(11)

Do you have continuity between them?

•
•
•

Key Off
Disconnect ECM header connector C001
Check for continuity between pressure
sensor connector C002 terminal A and ECM
connector terminal 20.

Do you have continuity?
• Inspect ECM and gasoline pressure
sensor connector (C002) terminals for
corrosion, contamination or mechanical
damage
Any problems found?

Replace ECM. Refer to ECM replacement
in the Engine Controls Section.
Is the replacement complete?

Replace fuel pressure and temperature
sensor
Is the replacement complete?

•
•

•

•
•
•

Observe the MIL
Observe engine performance and driveability
After operating the engine within the test
parameters of DTC-92 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•
•

Go to Step (9)

Repair the
circuit as
necessary.
Refer to
Wiring
Repairs
in Engine
Electrical.
Go to step
(12)

Go to step
(12)

System OK

No
Repair the
circuit as
necessary.
Refer to
Wiring
Repairs
in Engine
Electrical.
Repair the
circuit as
necessary.
Refer to
Wiring
Repairs
in Engine
Electrical.
Go to Step
(10)

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-17

DTC 107- MAP Low Voltage SPN/FMI 106:4

Conditions for Setting the DTC
•
•
•
•
•
•

Manifold Absolute Pressure Sensor
Check Condition-Engine cranking or running
Fault Condition-MAP voltage less than 0.05 with throttle position greater than 2% and engine RPM less than 7000.
MIL-ON
Adaptive-Disabled for the remainder of key on cycle
Fueling is based on RPM and TPS Limp-Home Condition during this fault.

Circuit Description
The Manifold Absolute Pressure sensor is a pressure transducer connected to the intake manifold. It is used to
measure the pressure of air in the manifold prior to induction. The pressure reading is used in conjunction with other
inputs to estimate the airﬂow rate to the engine, which determines the fuel ﬂow rate. This fault will set when the MAP
reading is lower than the sensor should normally produce. When this fault is set the Adaptive Learn will be disabled for
the remainder of the key on cycle and the MIL will be on.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

DIAGNOSTIC TROUBLE CODES 7-18

DTC 107- MAP Low Voltage SPN/FMI 106:4

Action
Did you perform the On-Board (OBD) System
Check?

Value(s)
-

Yes
Go to Step (2)
Go to Step (3)

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section

Go to Step (4)

Go to step (8)

Repair the
circuit as
necessary.
Refer to
Wiring
Repairs
in Engine
Electrical.
Go to Step (6)

Go to step (5)

• Key On, Engine running.
• DST (Diagnostic Scan Tool) connected in
System Data Mode
Does DST display MAP voltage of 0.05 or less
with the engine idling?
3

•
•
•
•

Key OFF
Disconnect the TMAP sensor connector C007
from the wiring harness
Jump the 5 volt reference pin 3 and MAP
signal circuit pin 4 together
Key ON

Does the DST display MAP voltage of 4.5 volts or
greater?
4

•

Inspect TMAP connector and pins for
corrosion, contamination or mechanical
damage
Any problems found?

•
•
•

•

Key OFF
Disconnect ECM connector C001
Check for continuity between TMAP sensor
connector signal pin 4 and ECM MAP signal
pin 7.
Do you have continuity between them?

Check for continuity between TMAP sensor
connector 5 volt supply signal pin 3 and ECM
5 volt supply pin 19
Do you have continuity between them?

Go to step (7)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
7

•

Action
Check for continuity between TMAP sensor
connector ground pin 1 and ECM sensor
ground pin 20
Do you have continuity between them?

Probe MAP connector signal circuit pin 4 with
a test light connected to battery voltage

Does the DST display MAP voltage of 4.0 or
greater?
• Key OFF
• Disconnect ECM connector
• Check for continuity between TMAP sensor
connector pin 3 and ECM 5 volt reference pin
19.
Do you have continuity between them?
• Check for continuity between TMAP sensor
connector 5 volt reference pin 3 and engine
ground
Do you have continuity?

Inspect ECM and TMAP wire harness
connector and terminals for corrosion,
contamination or mechanical damage
Any problems found?

Replace ECM. Refer to ECM replacement
in the Engine Controls Section.
Is the replacement complete?

•
•

•

Disconnect ECM connector
Check for continuity between TMAP sensor
connector signal circuit pin 4 and ECM signal
pin 7
Do you have continuity between them?

DIAGNOSTIC TROUBLE CODES 7-19
Value(s)

Yes
Go to step
(17)

Go to Step (9)

Go to step
(10)

Repair the
circuit as
necessary.
Refer to
Wiring
Repairs
in Engine
Electrical.
Repair the
circuit as
necessary.
Refer to
Wiring
Repairs
in Engine
Electrical.
Go to step
(17)

Go to Step
(14)

No
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to step (13)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step
(11)

Go to Step
(16)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
14

Action
Check for continuity between TMAP sensor
connector signal pin 4 and engine ground
Do you have continuity?

•

Inspect ECM connector and wire harness
connector terminals for corrosion,
contamination or mechanical damage
Any problems found?

Replace ECM. Refer to ECM replacement
in the Engine Controls Section.
Is the replacement complete?

• Replace TMAP sensor
Is the replacement complete?

•
•

•

•
•
•

Observe the MIL
Observe engine performance and driveability
After operating the engine within the test
parameters of DTC-107 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•
•

DIAGNOSTIC TROUBLE CODES 7-20
Value(s)

Yes
Repair the
circuit as
necessary.
Refer to
Wiring
Repairs
in Engine
Electrical.
Repair the
circuit as
necessary.
Refer to
Wiring
Repairs
in Engine
Electrical.
Go to Step
(18)

No
Go to step (15)

Go to step
(18)

System OK

Go to Step
(16)

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-21

DTC 108-MAP High Pressure SPN/FMI 106:16

Conditions for Setting the DTC
•
•
•
•
•

Barometric pressure check
Check condition-engine running and greater than 1800 RPM
Fault Condition-MAP greater than 17 psia withTPS less than 10% and RPM greater than 1800
MIL-On for active fault and for 4 seconds after active fault
Adaptive-disabled for the remainder of key cycle

Circuit Description
The MAP (Manifold Absolute Pressure) is estimated from the TMAP sensor. The MAP pressure value is used for
fuel, airﬂow and spark calculations. This fault will set in the event the MAP value is greater than 17 psia when the
TPS is less than 10% with engine speed greater than 1800.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

DIAGNOSTIC TROUBLE CODES 7-22

DTC 108- MAP High Pressure SPN/FMI 106:16

Action
Did you perform the On-Board (OBD) System
Check?

Value(s)
-

Yes
Go to Step (2)
Go to step (3)

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section

Go to step (4)

Go to step (6)

Go to step (5)

Go to step (8)

Go to step (6)

Go to Step
(10)

Go to step (7)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
-

Key On, Engine running at full operating
temperature.
• DST (Diagnostic Scan Tool) connected in
System Data Mode
•

Does DST display MAP pressure of 17.0 psia or
greater with the engine running above 1800 RPM?
3

4
5

• Key OFF
• Disconnect the TMAP sensor connector C007
• Key ON
Does the DST display MAP pressure less than 0.05
psia?
• Probe TMAP connector ground pin 1 with a test
light connected to battery voltage.
Does the test light come on?
• Check TMAP mechanical vacuum connection for
correct mounting or possible damage causing
leakage.
Is the TMAP sensor mechanical connection Ok?
• Key OFF
• Disconnect ECM connector and inspect
terminals for damage corrosion or contamination.
Is the connection Ok?

Replace TMAP sensor. Is the repair complete?

Go to step (11)

•

Disconnect ECM connector and check for
continuity between TMAP connector sensor
ground pin 1 and ECM sensor ground pin 20.
Do you have continuity between them?

Go to step (9)

Replace ECM. Refer to ECM replacement in the
Engine Controls Section.
Is the replacement complete?
• Correct TMAP mechanical connection

Go to step (11)

Has the TMAP mechanical connection problem been
corrected?

System OK

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-23

DTC 111-IAT Higher Than Expected 1 SPN/FMI 105:15

Conditions for Setting the DTC
• Intake Air Temperature
• Check Condition-Engine Running
• Fault Condition-Intake Air Temperature greater than 200 degrees F. and engine RPM greater than 1300 for more than
60 seconds
• MIL-On
• Adaptive-Disabled during active fault
• Power Derate (Level 1)

Circuit Description
The TMAP is a combined IAT (Intake Air Temperature) and MAP (Manifold Absolute Pressure) sensor. A temperature
sensitive resistor is used in the TMAP located in the intake manifold of the engine. It is used to monitor incoming air
temperature, and the output in conjunction with other sensors is used to determine the airﬂow to the engine. The ECM
provides a voltage divider circuit so that when the air is cool, the signal reads higher voltage, and lower when warm.
The IAT is a calculated value based mainly on the IAT sensor at high airﬂow, and inﬂuenced more by the ECT (Engine
Coolant Temperature) at low airﬂow. This fault will set if the Intake Air Temperature is greater than 200 degrees F. and
engine rpm is greater than 1300 for more than 60 seconds. Power derate level one will be enforced during this fault
limiting the maximum throttle position to50%.

Diagnostic Aid
* This fault will set when inlet air is much hotter than normal. The most common cause of high inlet air temperature is a
problem with the inlet air system. Ensure that the air inlet is not obstructed, modiﬁed or damaged.
* Inspect the air inlet system for cracks or breaks that may allow unwanted under hood air in to the air inlet system.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-24

DTC 111-IAT Higher Than Expected 1 SPN/FMI 105:15
This fault will set when inlet air is much hotter than normal. The most common cause of high inlet air temperature is a
problem with the inlet air system. Ensure that the air inlet is not obstructed, modiﬁed or damaged.
•

Inspect the air inlet system for cracks or breaks that may allow unwanted under hood air in to the air inlet
system

•

If none of the above can be found, Follow the diagnostic steps for DTC
112-IAT Low Voltage

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-25

DTC 112-IAT Low Voltage SPN/FMI 105:4

Conditions for Setting the DTC
•
•
•
•
•

Intake Air Temperature
Check Condition Engine Cranking or Running
Fault Condition-IAT Sensor Voltage less than 0.05 for greater than 1 second
MIL-On during active fault and for 2 seconds after active fault
Adaptive-Disabled during active fault

Circuit Description
The TMAP is a combined IAT (Intake Air Temperature) and MAP (Manifold Absolute Pressure) sensor. A
temperature sensitive resistor is used in the TMAP located in the intake manifold of the engine. It is used to
monitor incoming air temperature, and the output in conjunction with other sensors is used to determine the
airﬂow to the engine. The ECM provides a voltage divider circuit so that when the air is cool, the signal reads
higher voltage, and lower when warm.
The IAT is a calculated value based mainly on the IAT sensor at high airﬂow, and inﬂuenced more by the ECT
(Engine Coolant Temperature) at low airﬂow. This fault will set if the signal voltage is less than 0.05 volts for 1
second anytime the engine is cranking or running. The ECM will use the default value for the IAT sensor in the
event of this fault.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

DIAGNOSTIC TROUBLE CODES 7-26

DTC 112- IAT VOLTAGE LOW SPN/FMI 105:4

Action
Did you perform the On-Board (OBD) System
Check?

Value(s)
_

Go to step
(3)

• Key On
• DST (Diagnostic Scan Tool) connected in
System Data Mode

Does DST display IAT voltage of 0.05 or less?
• Key Off
• Disconnect the TMAP sensor connector
C007
• Key ON
Does the DST display IAT voltage of 4.9 volts
or greater?
• Replace TMAP sensor.
Is the replacement complete?
• Key OFF
• Disconnect ECM wire harness connector
C001
• Check for continuity between TMAP sensor
connector ground pin 1 and TMAP sensor
connector signal pin 2
Do you have continuity between them?
• Check for continuity between TMAP
sensor connector signal circuit pin 2
and engine ground.
Do you have continuity?

Replace ECM. Refer to ECM
replacement in the Engine Controls
Section.
Is the replacement complete?
•

Yes
Go to Step
(2)

No
Go to OBD
System
Check
Section
Intermittent
problem
Go to
Intermittent
section

Go to step
(4)

Go to step
(5)

Go to Step
(9)
Repair the
circuit as
necessary.
Refer to
Wiring
Repairs
in Engine
Electrical.

Repair the
circuit as
necessary.
Refer to
Wiring
Repairs
in Engine
Electrical.
Go to step
(8)

Go to step
(6)

Go to step
(7)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
8

Action
Remove all test equipment except the DST.
Connect any disconnected components,
fuses, etc.
• Using the DST clear DTC information from
the ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to
full operating temperature
• Observe the MIL
• Observe engine performance and
driveability
• After operating the engine within the test
parameters of DTC-112 check for any
stored codes.
Does the engine operate normally with no
stored codes?
•
•

Value(s)

DIAGNOSTIC TROUBLE CODES 7-27
Yes
System OK

No
Go to OBD
System
Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-28

DTC 113-IAT High Voltage SPN/FMI 105:3

Conditions for Setting the DTC
•
•
•
•
•

Intake Air Temperature
Check Condition-Engine Running
Fault Condition-IAT Sensor Voltage greater than 4.95 for more than 1 second
MIL-On during active fault and for 2 seconds after active fault
Adaptive-Disabled during active fault

Circuit Description
The TMAP is a combined IAT (Intake Air Temperature) and MAP (Manifold Absolute Pressure) sensor. A
temperature sensitive resistor is used in the TMAP located in the intake manifold of the engine. It is used to
monitor incoming air temperature, and the output in conjunction with other sensors is used to determine the
airﬂow to the engine. The ECM provides a voltage divider circuit so that when the air is cool, the signal reads
higher voltage, and lower when warm.
The IAT is a calculated value based mainly on the IAT sensor at high airﬂow, and inﬂuenced more by the ECT
(Engine Coolant Temperature) at low airﬂow. This fault will set if the signal voltage is greater than 4.95 volts for
more than 1 second anytime the engine is running. The ECM will use a default value for the IAT sensor in the
event of this fault.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

DIAGNOSTIC TROUBLE CODES 7-29

DTC 113- IAT VOLTAGE HIGH SPN/FMI 105:3

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

• Key On
• DST (Diagnostic Scan Tool) connected in
System Data Mode
Does DST display IAT voltage of 4.95 or greater?
• Key Off
• Disconnect the TMAP sensor connector C007
and jump pins 1 and 2 together
• Key On
Does the DST display IAT voltage of 0.1 volts or less?
Key OFF
Jumper TMAP sensor connector signal pin 2 to
engine ground
• Key ON
• Does DST display IAT voltage of 0.1 volts or
less?
Replace TMAP sensor.
Is the replacement complete?
• Key OFF
• Disconnect the ECM wire harness connector
C001.
• Check for continuity between TMAP sensor
connector signal pin 2 and ECM IAT signal pin 39
Do you have continuity between them?
• Check for continuity between TMAP sensor
connector ground circuit pin 1 and ECM
sensor ground circuit pin 20
Do you have continuity between them?
•
•

5
6

• Replace ECM.
Refer to ECM replacement in the Engine Controls
Section.
Is the replacement complete?
• Re-check wire harness and TMAP sensor
connector for damage corrosion or contamination
Any problems found?

Yes
Go to Step (2)
Go to step (3)

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section

Go to step (9)

Go to step (4)

Go to Step (7)

Go to Step (6)

Go to Step (11)

Go to step (10)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
_

Go to step (10)

Go to step (11)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical

Go to Step (5)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
10

Action
Re-check wire harness and TMAP sensor
connectors for damage corrosion or
contamination
Any problems found?

•

Remove all test equipment except the DST.
Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-113 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•

DIAGNOSTIC TROUBLE CODES 7-30
Value(s)

Yes
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical
System OK

No
Go to Step (8)

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-31

DTC 116-ECT Higher Than Expected 1 SPN/FMI 110:15

Conditions for Setting the DTC
•
•
•
•
•
•

Engine Coolant Temperature
Check Condition-Engine Running
Fault Condition-Engine Coolant Temperature reading or estimate greater than 220 degrees F. for greater than 60
seconds
MIL-On
Power derate (level 1)
Adaptive-Disabled during active fault

Circuit Description
The ECT (Engine Coolant Temperature) sensor is a temperature sensitive resistor located in the engine coolant. sensor
that is located in the coolant passage. The ECT is used for engine airﬂow calculation, fuel enrichment, ignition timing
control and to enable certain other temperature dependant operations. This code set is designed to help prevent engine
damage from overheating. The ECM provides a voltage divider circuit so when the sensor reading is cool the sensor
reads higher voltage, and lower when warm. This fault will set when the coolant exceeds 225 degrees F. for more than
60 seconds with the engine speed over 1200 rpm. Power derate level one will be enforced during this fault limiting the maximum
throttle position to 50%.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1
2

DIAGNOSTIC TROUBLE CODES 7-32

DTC 116- ECT HIGHER THAN EXPECTED 1 SPN/FMI 110:15

Action
Did you perform the On-Board (OBD) System Check?
Key On
DST (Diagnostic Scan Tool) connected in
System Data Mode
• Warm Engine to normal operating temperature,
then run the engine above 1200 rpm for at least
60 seconds
Does DST display ECT temperature of 225 degrees
F. or greater with the engine running over 1200 rpm?
• Verify with a temperature gauge that the
engine coolant is over 225 degrees F.
Does the temperature gauge indicate 225 degrees F.
or greater?
Verify ECT circuit function. Follow diagnostic test
procedure for DTC117 ECT Low Voltage
•
•

Value(s)
-

Yes
Go to Step (2)
Go to Step (3)

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section

Repair Cooling
system.

Go to step (4)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-33

DTC 117-ECT Low Voltage SPN/FMI 110:4

Conditions for Setting the DTC
•
•
•
•
•

Engine Coolant Temperature
Check Condition-Engine Running
Fault Condition- ECT sensor voltage less than 0.05
MIL-On during active fault and for 2 seconds after active fault
Adaptive-Disabled during active fault

Circuit Description

The ECT (Engine Coolant Temperature) sensor is a temperature sensitive resistor located in the engine coolant passage.
It is used for the engine airﬂow calculation, gasoline cold enrichment and to enable other temperature dependant features.
The ECM provides a voltage divider circuit so that when the coolant is cool, the signal reads higher voltage, and lower
when warm. This fault will set if the signal voltage is less than 0.05 volts anytime the engine is running. The ECM will use
a default value for the ECT sensor in the event of this fault.
Temp
(deg F)
242.4
231.9
211.6
201.4
181.9
163.1
144.9
127.4
102.4
78.9
49.9
23.5
-5.7
-21.2
-30.8
-40.0

Ohms
101
131
175
209
302
434
625
901
1,556
2,689
5,576
11,562
28,770
49,715
71,589
99,301

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
1

DIAGNOSTIC TROUBLE CODES 7-34

DTC 117- ECT VOLTAGE LOW SPN/FMI 110:4

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
_

Yes
Go to Step (2)
Go to step (3)

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section

Go to step (4)

Go to step (5)

Go to Step (8)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

Go to step (6)

• Key On
• DST (Diagnostic Scan Tool) connected in
• System Data Mode
Does DST display ECT voltage of 0.05 or less?
3

4
5

7
8

• Key Off
• Disconnect the ECT wire harness connector
• Key ON
Does the DST display ECT voltage of 4.9 volts or
greater?
Replace ECT sensor.
Is the replacement complete?
• Key OFF
• Disconnect ECM wire harness connector
• Check for continuity between ECT sensor
connector signal pin A and ECT sensor ground
pin B
Do you have continuity between them?
• Check for continuity between ECT sensor
connector signal circuit pin A and engine ground.
Do you have continuity?

Replace ECM. Refer to ECM replacement in the
Engine Controls Section.
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
•
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-117 check for any stored
codes.
Does the engine operate normally with no stored
codes?

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

Go to step (8)
System OK

Go to step (7)

_
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-35

DTC 118-ECTHigh Voltage SPN/FMI 110:3

Conditions for Setting the DTC
•
•
•
•
•

Engine Coolant Temperature
Check Condition-Engine Running
Fault Condition-ECT sensor voltage exceeds 4.95 volts for greater than 1 second
MIL-On during active fault and for 2 seconds after active fault
Adaptive-Disabled during active fault

Circuit Description
The ECT (Engine Coolant Temperature) sensor is a temperature sensitive resistor located in the engine coolant passage.
It is used for the engine airﬂow calculation, gasoline cold enrichment and to enable other temperature dependant features.
The ECM provides a voltage divider circuit so that when the coolant is cool, the signal reads higher voltage, and lower when
warm. This fault will set if the signal voltage is greater than 4.95 volts for one second anytime the engine is running. The
ECM will use a default value for the ECT sensor in the event of this fault.
Temp
(deg F)
242.4
231.9
211.6
201.4
181.9
163.1
144.9
127.4
102.4
78.9
49.9
23.5
-5.7
-21.2
-30.8
-40.0

Ohms
101
131
175
209
302
434
625
901
1,556
2,689
5,576
11,562
28,770
49,715
71,589
99,301

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
1

DIAGNOSTIC TROUBLE CODES 7-36

DTC 118- ECT VOLTAGE HIGH SPN/FMI 110:3

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

Yes
Go to step (2)
Go to step (3)

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section

Go to step (4)

Go to Step (8)

Go to step (6)

Go to step (5)

Go to step (14)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to step (9)

Go to step (7)

Key On
DST (Diagnostic Scan Tool) connected in System
Data Mode
Does DST display ECT voltage of 4.95 or greater?
•
•

5
6

Key Off
Disconnect the ECT sensor connector C008 and
Jump terminals A and B together
• Key On
Does the DST display ECT voltage of 0.05 volts or
less?
• Using a DVOM check the resistance between the
two terminals of the ECT sensor and compare the
resistance reading to the chart
Is the resistance value correct?
•
•

• Replace ECT sensor
Is the replacement complete?
• Inspect the ECT wire harness connector terminals
A and B for damage, corrosion or contamination
Did you ﬁnd a problem?

•
•
•
•

8
9

Key OFF
Disconnect ECM wire harness connector C001
Inspect ECM connector pins 20 and 40 for
damage corrosion or contamination
Did you ﬁnd a problem?

Jumper the ECT signal pin A at the ECT
connector to engine ground
Does DST display ECT voltage of 0.05 or less?
• Key OFF
• Disconnect ECM wire harness connector
• Using a DVOM check for continuity between ECT
sensor ground pin B and ECM connector pin 20
Do you have continuity between them?
•

•

Inspect ECM connector pins 20 and 40 for
damage, corrosion or contamination

Did you ﬁnd a problem?

See
resistance
chart vs.
temperature
in the DTC
118 circuit
description

Go to step (10)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

Intermittent
problem
Go to
Intermittent
section
Go to step (12)
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (11)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
11
12

Action
• Replace ECM
Is the replacement complete?
• Key OFF
• Disconnect ECM wire harness connector
• Using A DVOM check for continuity between
ECT connector signal pin A and ECM connector
terminal 40
Do you have continuity between them?

•

Inspect ECM connector pins 20 and 40 for
damage, corrosion or contamination
Did you ﬁnd a problem?

•
•
•
•
•

Remove all test equipment except the DST.
Connect any disconnected components, fuses,
etc.
Using the DST clear DTC information from the
ECM.
Turn the ignition OFF and wait 30 seconds.
Start the engine and operate the vehicle to full
operating temperature

Observe the MIL
Observe engine performance and driveability
After operating the engine within the test
parameters of DTC-118 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•
•

DIAGNOSTIC TROUBLE CODES 7-37
Value(s)

Yes
Go to step (14)

No
-

Go to step (13)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (11)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
System OK

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-38

DTC 121-TPS 1 Lower Than TPS 2 SPN/FMI 51:1

Conditions for Setting the DTC
•
•
•
•
•

Throttle Position Sensor 1 & 2
Check Condition-Key On
Fault Condition-TPS 1 20% lower than TPS 2
MIL-On for remainder of key on cycle
Power Derate 1

Circuit description
There are two Throttle Position Sensors located within the throttle which use variable resistors to determine signal voltage
based on throttle plate position. TPS 1 will read low voltage when closed and TPS 2 will read high voltage when closed.
The TPS 1 and TPS 2 percentages are calculated from these voltages. Although the voltages are different, the calculated
values for the throttle position percentages should be very close to the same. The TPS values are used by the ECM to
determine if the throttle is opening as commanded.
This fault will set if TPS 1 is 20% (or more) lower than TPS 2. At this point the throttle is considered to be out of
speciﬁcation, or there is a problem with the TPS signal circuit. Power derate 1 will be enforced limiting the throttle to 50%
maximum. Low rev limit and forced idle will also be enforced during this fault.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1
2

DTC 121 TPS 1 Lower Than TPS 2 SPN/FMI 51:1

Action
Did you perform the On-Board (OBD) System Check?

Key OFF
Disconnect ECM wiring harness connector C001
Key ON
Using a DVOM check for voltage between ECM
connector TPS 1 signal pin 5 and engine ground
Do you have voltage?

Repair the
TPS 1 circuit
shorted to
voltage as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (6)

•

Yes
Go to Step (2)
Go to Step (3)

•
•
•
•

Value(s)
-

Key ON, Engine OFF
DST (Diagnostic Scan Tool) connected in
System Data Mode
Does the DST display more than a 20% difference
between TPS 1 and TPS 2 voltage?
• Key OFF
• Disconnect electronic throttle connector C025
• Key ON
• Change DST mode to DBW (drive by wire) test
mode
Is the voltage for TPS 1 less than 0.1 volts?
•
•

DIAGNOSTIC TROUBLE CODES 7-39

Jump TPS 1 signal pin 6 to the 5 volt reference
pin 3 at connector C025
Does DST display TPS 1 voltage over 4.95 volts
• Inspect wire terminals at throttle connector for
damage corrosion or contamination
Any problems found?

• Replace the electronic Throttle
Is the replacement complete?
• Key OFF
• Disconnect ECM wire harness connector C001
• Using a DVOM check for continuity between
throttle connector TPS 1 signal pin 6 and ECM
connector TPS 1 signal pin5
Do you have continuity between them?
• Using a DVOM check for continuity between
throttle connector signal ground pin 2 and ECM
connector signal ground pin 20
Do you have continuity between them?

Go to Step (5)

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section
Go to Step (4)

Go to Step (9)

Go to Step (8)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (12)

Go to Step (7)

Go to Step (9)

Repair the
open circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Repair the
open circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

Go to Step (10)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
10

11
12

Action
Inspect ECM connector terminals for damage
corrosion or contamination.
Any problems found?
•

• Replace ECM
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-121 check for any stored
codes.
Does the engine operate normally with no stored
codes?

DIAGNOSTIC TROUBLE CODES 7-40
Value(s)

Yes
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical
Go to Step (12)
System OK

No
Go to Step (11)

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-41

DTC 122-TPS 1 Signal Voltage Low SPN/FMI 51:4

Conditions for Setting the DTC
•
•
•
•
•

Throttle Position Sensor 1
Check Condition-Cranking or Running
Fault Condition-TPS sensor voltage less than 0.20 for more than .50 seconds
MIL-On during active fault
Power Derate 1

Circuit Description
There are 2 Throttle Position Sensors located within the throttle which use variable resistors to determine signal
voltage based on throttle plate position. TPS1 will read lower voltage when closed and TPS2 will read higher
voltage when closed. The TPS1 and TPS2 percentages are calculated from these voltages. Although the voltages
are different, the calculated values for the throttle position percentages should be very close to the same. The TPS
values are used by the ECM to determine if the throttle is opening as commanded. The TPS is not serviceable and
in the event of a failure the electronic throttle assembly must be replaced.
This fault will set if the TPS 1 voltage is less than 0.20 volts for more than .50 seconds. The MIL command in ON
and power derate level 1 will be enforced limiting maximum throttle to 50%.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1
2

6
7

DIAGNOSTIC TROUBLE CODES 7-42

DTC 122 TPS 1 Signal Voltage Low SPN/FMI 51:4

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

Yes
Go to Step (2)

Key ON, Engine OFF
DST (Diagnostic Scan Tool) connected in
DBW (Drive by Wire) throttle test mode
Does the DST display TPS 1 voltage of 0.20 volts or
less with the throttle closed?
• Slowly depress Foot Pedal while observing TPS 1
voltage
Does TPS 1 voltage ever fall below 0.20 volts?

Go to Step (4)

Key OFF
Disconnect the electronic throttle connector C025
Jump the 5 volt reference circuit pin 3 and TPS
1 signal circuit pin 6 together at the throttle
connector
• Key ON
Does DST display TPS 1voltage of 4.0 volts or
greater?
• Key OFF
• Disconnect ECM wire harness connector C001
Using a DVOM check continuity between TPS 1
connector C025 signal pin 6 and ECM connector TPS
1 signal pin 5
Do have continuity between them?
• Replace ECM
Is the replacement complete?
• Inspect the throttle wire harness connector
terminals for damage, corrosion or contamination
Did you ﬁnd a problem?

Go to Step (7)

•
•

•
•
•

• Replace the electronic throttle
Is the replacement complete?

Go to Step (4)

Go to Step (6 )

Go to Step (9)
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (9)

No
Go to OBD
System Check
Section
Go to Step (3)

Intermittent
problem
Go to
Intermittent
section
Go to Step (5)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (8)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
9

Action
Remove all test equipment except the DST.
Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-122 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•

DIAGNOSTIC TROUBLE CODES 7-43
Value(s)

Yes
System OK

No
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-44

DTC 123-TPS 1 Signal Voltage High SPN/FMI 51:3

Conditions for Setting the DTC
•
•
•
•
•

Throttle Position Sensor 1
Check Condition-Cranking or Running
Fault Condition-TPS sensor voltage exceeds 4.80 volts for more than .50 seconds
MIL-On during active fault
Power derate level 1

Circuit Description
There are 2 Throttle Position Sensors located within the throttle which use variable resistors to determine signal
voltage based on throttle plate position. TPS1 will read lower voltage when closed and TPS2 will read higher
voltage when closed. The TPS1 and TPS2 percentages are calculated from these voltages. Although the voltages
are different, the calculated values for the throttle position percentages should be very close to the same.
The TPS values are used by the ECM to determine if the throttle is opening as commanded. The TPS is not
serviceable and in the event of a failure the electronic throttle assembly must be replaced.
This fault will set if the TPS 1 voltage exceeds 4.80 volts for more than .50 seconds. The MIL command in ON and
power derate level 1 will be enforced limiting maximum throttle to 50%.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1
2

6
7

9
10

DIAGNOSTIC TROUBLE CODES 7-45

DTC 123 TPS 1 Signal Voltage High SPN/FMI 51:3

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

Yes
Go to Step (2)

Key ON, Engine OFF
DST (Diagnostic Scan Tool) connected
Does the DST display TPS 1 voltage of 4.8 volts or
greater with the throttle closed?
• Slowly depress Foot Pedal while observing TPS 1
voltage
Does TPS 1 voltage ever exceed 4.8 volts?

Go to Step (4)

• Key OFF
• Disconnect electronic throttle connector C025
• Key ON
Does DST display TPS 1 voltage less than 0.2 volts?
• Key OFF
• Disconnect ECM wire harness connector C001
• Key ON
• Using a DVOM check for voltage between TPS
1 signal at the ECM connector pin 5 and engine
ground

Go to Step (7)

•

Do you have voltage?
• Replace ECM
Is the replacement complete?
• Back probe sensor ground circuit at the ECM
side of the wire harness pin 20 with a test light
connected to battery voltage
Does the test light come on?
• Inspect the electronic throttle connector terminals
for damage, corrosion or contamination
Did you ﬁnd a problem?

• Replace the electronic throttle
Is the replacement complete?
• Key OFF
• Disconnect ECM connector C001
• Using a DVOM check for continuity between the
electronic throttle connector C025 sensor ground
pin 2 and ECM connector TPS 1 sensor ground
pin 20
Do have continuity between them?

Go to Step (4)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

No
Go to OBD
System Check
Section
Go to Step (3)

Intermittent
problem
Go to
Intermittent
section
Go to Step (5)

Go to Step (6)

Go to Step (11)

Go to Step (8)

Go to Step (10)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (11)

Go to Step (9)

Go to Step (6)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
11

Action
Remove all test equipment except the DST.
Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-123 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•

DIAGNOSTIC TROUBLE CODES 7-46
Value(s)

Yes
System OK

No
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-47

DTC 127-IAT Higher Than Expected 2 SPN/FMI 105:0

Conditions for Setting the DTC
•
•
•
•
•

Intake Air Temperature
Check Condition-Engine Running
Fault Condition-Intake Air Temperature greater than 200 degrees F. for more than
120 seconds with engine speed greater than 1300 RPM
MIL-On for active fault and for 15 seconds after active fault
Engine Shut Down

Circuit Description
The TMAP is a combined IAT (Intake Air Temperature) and MAP (Manifold Absolute Pressure) sensor. A
temperature sensitive resistor is used in the TMAP located in the intake manifold of the engine. It is used to
monitor incoming air temperature, and the output in conjunction with other sensors is used to determine the
airﬂow to the engine. The ECM provides a voltage divider circuit so that when the air is cool, the signal reads
higher voltage, and lower when warm.
This fault will set if the Intake Air Temperature is greater than 210 degrees F. for more than 120 seconds with
engine RPM greater than 1400. The MIL light command is on during this active fault and the engine will shut
down.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-48

DTC 127-IAT Higher Than Expected 2 SPN/FMI 105:0

Diagnostic Aid
This fault will set when inlet air is much hotter than normal. The most common cause of high inlet air temperature is
a problem with the inlet air system. Ensure that the air inlet is not obstructed, modiﬁed or damaged.
•

Inspect the air inlet system for cracks or breaks that may allow unwanted under hood air in to the air inlet
system

•

If none of the above can be found, follow the diagnostic steps for
DTC 112-IAT Low Voltage.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-49

DTC 129-BP Low Pressure SPN/FMI 108:1

Conditions for Setting the DTC
•
•
•
•
•

Barometric pressure check
Check condition-engine off and key on
Fault Condition-BP less than 8.3 PSIA
MIL-On for active fault and for 2 seconds after active fault
Adaptive-disabled for the remainder of key cycle

Circuit Description
The BP (Barometric Pressure) is estimated from the TMAP sensor. The barometric pressure value is used for fuel
and airﬂow calculations. This fault sets in the event the BP value is out of the normal operating range.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

DIAGNOSTIC TROUBLE CODES 7-50

DTC 129- BP Low Pressure SPN/FMI 108:1

Action
Did you perform the On-Board (OBD) System Check?

2
•
•
•

Value(s)
-

Yes
Go to Step (2)
Go to step (3)

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section

Go to Step (4)

System Ok

Go to OBD
System Check

Key On
DST (Diagnostic Scan Tool) connected in
System Data Mode

Does DST display MAP pressure of 8.3 PSIA or less?
3

• Replace TMAP sensor.
Is the repair complete?

•
•
•
•
•

Remove all test equipment except the DST.
Connect any disconnected components, fuses,
etc.
Using the DST clear DTC information from the
ECM.
Turn the ignition OFF and wait 30 seconds.
Start the engine and operate the vehicle to full
operating temperature

Observe the MIL
Observe engine performance and driveability
After operating the engine within the test
parameters of DTC-129 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•
•

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-51

DTC 134-EGO 1 Open/Lazy SPN/FMI 724:10

Conditions for Setting the DTC

•
•
•
•
•
•

Heated Oxygen Sensor
Check condition- Engine running
Fault condition- EGO 1 cold persistently more than 120 seconds
MIL- On during active fault and for 1 second after active fault
Adaptive- Disabled during active fault
Closed Loop- Disabled during active fault

Circuit Description
The EGO 1 sensor is used to determine if the fuel ﬂow to the engine is correct by measuring the oxygen content
in the exhaust gas. The ECM uses this information to correct the fuel ﬂow with the Closed Loop multiplier and the
Adaptive multiplier.
This fault will set if EGO 1 is cold, non-responsive, or inactive for more than 120 seconds.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

DIAGNOSTIC TROUBLE CODES 7-52

DTC 134-EGO 1 Open/Inactive SPN/FMI 724:10

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

Yes
Go to step (2)
Go to Step (3)

•
•

Key ON, Engine Running
DST (Diagnostic Scan Tool) connected in
System Data Mode
• Run engine to full operating temperature and
then idle for a minimum of 2 minutes

No
Go to OBD
System Check
Section
Intermittent
problem. See
Electrical
Section
Intermittent
Electrical
Diagnosis

Does DST display EGO 1 voltage ﬁxed between 0.4
and 0.5 volts after at least 2 minutes of idle run time?
3

•
•
•
•

Key OFF
Disconnect EGO 1 connector C006
Key ON
Using a DVOM check for voltage between
EGO 1 connector pins B and D

Go to step (8)

Go To Step (4)

Go to step (5)

Repair system
power relay
open circuit

Go to step (6)

Repair open
heater ground
circuit

Correct the
problem as
required see
Electrical
Section wire
harness repair

Go to step (7)

(Check must be made within 30 seconds or before
power relay shuts down)
Do you have voltage?
4

•
•
•

Key OFF
Using a DVOM check for voltage between
EGO 1 connector pin B and engine ground
Key ON

System
Voltage

(Check must be made within 30 seconds or before
power relay shuts down)
Do you have voltage?
5

Disconnect ECM connector C001
Using a DVOM check for continuity between
EGO 1 connector pin D and ECM connector
pin 72
Do you have continuity?
• Inspect wire harness connector C006 pins A
and D and C001 pins 1 and 72 for damage,
corrosion or contamination
Did You ﬁnd a problem?
•
•

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
7

Action
• Replace ECM
Is the replacement complete?

•
•
•

Key OFF
Disconnect ECM wire harness connector
C001
Using a DVOM check for continuity between
EGO 1 pin A and ECM connector pin 1

Do you have continuity?
• Using a DVOM check for continuity between
EGO 1 pin C and ECM connector pin 20

DIAGNOSTIC TROUBLE CODES 7-53
Value(s)

Yes
Go to step (11)
Go to step (9)

Repair open
EGO 1 circuit

Go to step (10)

Repair open
EGO 1 signal
ground

Do you have continuity?
10
11

•

Replace EGO 1 sensor

Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
Observe the MIL
Observe engine performance and driveability
After operating the engine within the test
parameters of DTC-134 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•
•

No
-

Go to step (11)
System Ok

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-54

DTC 154-EGO 2 Open/Inactive SPN/FMI 520208:10

Conditions for Setting the DTC

•
•
•
•
•
•

Heated Oxygen Sensor
Check condition- Engine running
Fault condition- EGO 2 cold persistently more than 120 seconds
MIL- On during active fault and for 1 second after active fault
Adaptive- Disabled during active fault
Closed Loop- Disabled during active fault

Circuit Description
The EGO 2 sensor is used to monitor the efﬁciency of the catalytic converter. The ECM compares the EGO 1 and
EGO 2 voltage signals to determine this. This fault will set if EGO 2 is cold, non-responsive, or inactive for more
than 120 seconds.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

DIAGNOSTIC TROUBLE CODES 7-55

DTC 154-EGO 2 Open/Inactive SPN/FMI 520208:10

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

Yes
Go to step (2)
Go to Step (3)

•
•

Key ON, Engine Running
DST (Diagnostic Scan Tool) connected in
System Data Mode
• Run engine to full operating temperature and
then idle for a minimum of 2 minutes

No
Go to OBD
System Check
Section
Intermittent
problem. See
Electrical
Section
Intermittent
Electrical
Diagnosis

Does DST display EGO 2 voltage ﬁxed between 0.4
and 0.5 volts after at least 2 minutes of idle run time?
3

•
•
•
•

Key OFF
Disconnect EGO 2 connector C005
Key ON
Using a DVOM check for voltage between
EGO 2 connector pins C and D

Go to step (8)

Go To Step (4)

Go to step (5)

Repair system
power relay
open circuit

Go to step (6)

Repair open
heater ground
circuit

Correct the
problem as
required see
Electrical
Section wire
harness repair

Go to step (7)

(Check must be made within 30 seconds or before
power relay shuts down)
Do you have voltage?
4

•
•
•

Key OFF
Using a DVOM check for voltage between
EGO 2 connector pin C and engine ground
Key ON

System
Voltage

(Check must be made within 30 seconds or before
power relay shuts down)
Do you have voltage?
5

Disconnect ECM connector C001
Using a DVOM check for continuity between
EGO 2 connector pin D and ECM connector
pin 73
Do you have continuity?
• Inspect wire harness connector C005 pins C
and D and C001 pins 2 and 73 for damage,
corrosion or contamination
Did You ﬁnd a problem?
•
•

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
7

Action
• Replace ECM
Is the replacement complete?

•
•
•

Key OFF
Disconnect ECM wire harness connector
C001
Using a DVOM check for continuity between
EGO 2 connector pin B and ECM connector
pin 2

Do you have continuity?
• Using a DVOM check for continuity between
EGO 2 pin A and ECM connector pin 20

DIAGNOSTIC TROUBLE CODES 7-56
Value(s)

Yes
Go to step (11)
Go to step (9)

Repair open
EGO 2 circuit

Go to step (10)

Repair open
EGO 2 signal
ground

Do you have continuity?
10
11

•

Replace EGO 2 sensor

Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
Observe the MIL
Observe engine performance and driveability
After operating the engine within the test
parameters of DTC-154 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•
•

No
-

Go to step (11)
System Ok

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-57

DTC 171-Adaptive Learn High Gasoline SPN/FMI 520200:0

Conditions for Setting the DTC
•
•
•

Heated Oxygen Sensor
Functional Fault-Adaptive multiplier out of range (greater than 30%)
MIL-On during active adaptive limit condition

Circuit Description
The EGO 1 sensor is used to determine if the fuel ﬂow to the engine is correct by measuring the oxygen content in the
exhaust gas. The ECM uses this information to correct the fuel ﬂow with the Closed Loop multiplier and the Adaptive
multiplier. This fault sets if the Adaptive multiplier exceeds the limits of normal operation.

Diagnostic Aid
Check for other DTC codes that may be set. Correct those starting with the lowest code set number before proceeding
with the diagnostic chart.
Oxygen Sensor Wire Heated Oxygen sensor wires may be mis-routed and contacting the exhaust manifold.
Vacuum Leaks Large vacuum leaks and crankcase leaks can cause a lean exhaust condition at especially at light load.
Injectors System will be lean if an injector driver or driver circuit fails open. The system will also be lean if an injector fails
in a closed manner or is dirty.
Fuel Pressure Low fuel pressure, faulty fuel injector or damaged fuel pump assembly can cause the fuel system to run
lean
Exhaust Leaks If there is an exhaust leak, outside air can be pulled into the exhaust and past the 02 sensor causing a
false lean condition.
Fuel Quality Contaminated or spoiled fuel can cause the fuel system to be lean.
Ground Problem Check ECM grounds.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
1
2

DIAGNOSTIC TROUBLE CODES 7-58

DTC 171 Adaptive Learn High Gasoline SPN/FMI 520200:0

Action
• Perform the On-Board (OBD) System Check?
Are any other DTCs present?

Value(s)

System
voltage

Yes
Go to Step (3)

No
Go to Step (2)

Go to Step (8)

Go to Step (4)

Go to Step (8)

Go to step (4)

Go to Step (5)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

Repair the
shorted circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

Go to Step (6)

Repair the
shorted circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (8)

Go to Step (7)

(CHECK MUST BE MADE WITHIN 30 SECONDS
OR BEFORE POWER RELAY SHUTS DOWN)
Do you have voltage?
5

Key OFF
Disconnect EGO 1 sensor wire harness
connector C006
• Disconnect ECM wire harness connector C001
• Key ON
• Using a high impedance DVOM check for
continuity between EGO 1 connector signal pin C
and engine ground
Do you have continuity?
• Using a high impedance DVOM check for
continuity between EGO 1 connector signal ground
pin D and EGO 1 signal pin C
• Do you have continuity?
•
•

• Replace EGO 1 sensor
Is the replacement complete?

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
8

Action
Remove all test equipment except the DST.
Connect any disconnected components, fuses, etc.
Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-171 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•
•

DIAGNOSTIC TROUBLE CODES 7-59
Value(s)

Yes
System OK

No
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-60

DTC 172-Adaptive Learn Low Gasoline SPN/FMI 520200:1

Conditions for Setting the DTC
•
•
•

Heated Oxygen Sensor
Functional Fault-Adaptive multiplier out of range (at limit of -30%)
MIL-On during active adaptive limit condition

Circuit Description
The EGO 1 sensor is used to determine if the fuel ﬂow to the engine is correct by measuring the oxygen content in the
exhaust gas. The ECM uses this information to correct the fuel ﬂow with the Closed Loop multiplier and the Adaptive
multiplier. This fault sets if the Adaptive multiplier exceeds the limits of normal operation.

Diagnostic Aid
Check for other DTC codes that may be set. Correct those starting with the lowest code set number before proceeding with the
diagnostic chart
Fuel System The system will be rich if an injector fails in an open manner. High fuel pressure due to a faulty fuel regulator or obstructed
fuel return line will cause the system to run rich.
Ignition noise open or poor ground circuit to or in the ignition system or ECM may cause EMI (Electromagnetic interference). This
noise could be interpreted by the ECM as ignition pulses, and the sensed RPM becomes higher than the actual speed. The ECM then
delivers too much fuel, causing the system to go rich.
TMAP Sensor A higher manifold pressure than normal can cause the system to go rich. Temporarily disconnecting the MAP Sensor will
allow the ECM to set a default value for MAP.
IAT Sensor Check for a shifted sensor that could cause the ECM to sense lower than actual temperature of incoming air. This can
cause a rich exhaust condition.
ECT Sensor Check for a skewed sensor that could cause the ECM to sense engine temperature cooler than it actually is. This could
also cause a rich exhaust condition.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1
2

5
6

DIAGNOSTIC TROUBLE CODES 7-61

DTC 172 Adaptive Learn Low Gasoline SPN/FMI 520200:1

Action
• Perform the On-Board (OBD) System Check?
Are any other DTCs present?

Visually and physically check the following items:
• The air intake duct for being collapsed or restricted
• The air ﬁlter for being plugged
• The EGO 1 sensor installed securely and the
wire leads not contacting the exhaust manifold or
ignition wires
• ECM grounds for being clean and tight. Refer to
Engine Electrical Power and Ground Distribution
• Fuel System Diagnostics. Refer to Fuel System
Diagnostics
Was a repair made?
• Diagnose any other DTC codes before proceeding
with this chart.
Have any other DTC codes been detected, diagnosed
and repaired?
• Key OFF
• Disconnect EGO 1 sensor wire harness connector
• Disconnect ECM wire harness connector C001
• Key ON
• Using a DVOM check for voltage at EGO 1
connector C006 signal pin C and engine ground
Do you have voltage?
• Replace EGO 1 sensor
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses, etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-172 check for any stored
codes.
Does the engine operate normally with no stored
codes?

Value(s)

Yes
Go to Step (3)

No
Go to Step (2)

Go to Step (6)

Go to Step (4)

Go to Step (6)

Go to step (4)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

Go to Step (5)

Go to Step (6)

System OK

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-62

DTC 182-Gasoline Fuel Temperature Sensor Low Voltage
SPN/FMI 174:4

Conditions for Setting the DTC
•
•
•

Gasoline fuel temperature sensor voltage
Fuel temperature sensor voltage greater than 0.05v for 1s
MIL-On for active fault and for 2 seconds after active fault

Circuit Description
Note: The fuel pressure and temperature sensor is wired via Equipment Manufacturer supplied harness jumper.
The terminals A, B, C, D & 19, 20, 48, 54 are engine wiring harness terminals at the fuel sensor interface
connector C002 and the ECM header connector C001. You may need to consult additional wiring information
supplied by the OEM. The gasoline fuel temperature sensor voltage is read at less than 0.05v. This indicates a
low voltage fault from the sensor or circuit.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

DIAGNOSTIC TROUBLE CODES 7-63

DTC 182- Gasoline Fuel Temperature Sensor Low Voltage
SPN/FMI 174:4

Action
Did you perform the On-Board (OBD) System
Check?

2
•
•
•

Value(s)
-

Yes
Go to Step (2)
Go to Step (3)

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section

Go to Step (4)

Go to step (8)

Go to Step (5)

Go to Step (7)

Go to Step (6)

Go to Step 7

Repair the
circuit as
necessary.
Refer to
Wiring
Repairs
in Engine
Electrical.
Go to Step (8)

Go to step
(11)

Key On, Engine running.
DST (Diagnostic Scan Tool) connected in
System Data Mode
Check voltage for AUX_PU3 raw on the Raw
Volts Page

Is voltage 0.050 volts or lower?
3

•
•

Key OFF
Disconnect the gasoline fuel pressure sensor
jumper harness connector C002 from the
engine wiring harness
Key On
Using a DVOM, check for voltage between
connector C002 terminal B and engine
ground.

Is voltage 4.95 volts or higher?
4

•

Using a DVOM check for voltage between fuel
pressure sensor connector C002 terminals A &
B.
Is voltage of 4.95 volts or higher

•

Jumper fuel pressure sensor connector C002
terminals A & B together.

Is voltage for AUX_PU3 raw .050 volts or less?
6

•

•
•
•

Key OFF
Disconnect ECM connector C001
Check for continuity between gasoline
pressure sensor connector terminal A and
ECM pin 20.
Do you have continuity between them?

Repair the
circuit as
necessary.
Refer to
Wiring
Repairs
in Engine
Electrical.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
8

•

Action
Check for continuity between fuel pressure
sensor connector terminal B and ECM pin 48

DIAGNOSTIC TROUBLE CODES 7-64
Value(s)

Yes
Go to step (9)

Do you have continuity between them?

Inspect ECM and gasoline pressure
sensor connector (C002) terminals for
corrosion, contamination or mechanical
damage
Any problems found?

Replace ECM. Refer to ECM replacement
in the Engine Controls Section.
Is the replacement complete?

Replace fuel pressure and temperature
sensor
Is the replacement complete?

•
•

•

•
•
•

Repair the
circuit as
necessary.
Refer to
Wiring
Repairs
in Engine
Electrical.
Go to step
(12)

Go to step
(12)

System OK

No
Repair the
circuit as
necessary.
Refer to
Wiring
Repairs
in Engine
Electrical.
Go to Step
(10)

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-65

DTC 183-Gasoline Fuel Temperature Sensor High Voltage
SPN/FMI 174:3

Conditions for Setting the DTC
•
•
•

Gasoline fuel temperature sensor voltage
Fuel temperature sensor voltage greater than 4.95v for 1s
MIL-On for active fault and for 2 seconds after active fault

Circuit Description
Note: The fuel pressure and temperature sensor is wired via Equipment Manufacturer supplied harness jumper.
The terminals A, B, C, D & 19, 20, 48, 54 are engine wiring harness terminals at the fuel sensor interface
connector C002 and the ECM header connector C001. You may need to consult additional wiring information
supplied by the OEM. The fuel temperature sensor voltage is read at greater than 4.95v. This indicates a high
voltage fault from the sensor or circuit.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

DIAGNOSTIC TROUBLE CODES 7-66

DTC 183- Gasoline Fuel Temperature Sensor High Voltage
SPN/FMI 174:3

Action
Did you perform the On-Board (OBD) System
Check?

2
•
•
•

Value(s)
-

Yes
Go to Step (2)
Go to Step (3)

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section

Go to Step (4)

Go to step (8)

Go to Step (5)

Go to Step (7)

Go to Step (6)

Go to Step (7)

Repair the
circuit as
necessary.
Refer to
Wiring
Repairs
in Engine
Electrical.

Go to step
(11)

Key On, Engine running.
DST (Diagnostic Scan Tool) connected in
System Data Mode
Check voltage for AUX_PU3 raw on the Raw
Volts Page

Is voltage 4.95 volts or higher?
3

•
•

Is voltage 4.95 volts or higher?
4

•

Using a DVOM check for voltage between fuel
pressure sensor connector C002 terminals A &
B.
Is voltage of 4.95 volts or higher

•

Jumper fuel pressure sensor connector C002
terminals A & B together.

Is voltage for AUX_PU3 raw .050 volts or less?
6

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
7

Action
Key OFF
Disconnect ECM connector C001
Check for continuity between gasoline
pressure sensor connector terminal A and
ECM pin 20.
Do you have continuity between them?

•
•
•

•

Check for continuity between fuel pressure
sensor connector terminal B and ECM pin 48

DIAGNOSTIC TROUBLE CODES 7-67
Value(s)

Yes
Go to Step (8)

Go to step (9)

Do you have continuity between them?

Inspect ECM and gasoline pressure
sensor connector (C002) terminals for
corrosion, contamination or mechanical
damage
Any problems found?

Replace ECM. Refer to ECM replacement
in the Engine Controls Section.
Is the replacement complete?

Replace fuel pressure and temperature
sensor
Is the replacement complete?

•
•

•

•
•
•

Repair the
circuit as
necessary.
Refer to
Wiring
Repairs
in Engine
Electrical.
Go to step
(12)

Go to step
(12)

System OK

No
Repair the
circuit as
necessary.
Refer to
Wiring
Repairs
in Engine
Electrical.
Repair the
circuit as
necessary.
Refer to
Wiring
Repairs
in Engine
Electrical.
Go to Step
(10)

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-68

DTC 187-LPG Fuel Temperature Sesnor Voltage Low
SPN/FMI 520240:4

Conditions for Setting the DTC
•
•
•
•
•

Fuel Temperature
Check Condition-Engine Running
Fault Condition-FT sensor voltage less than 0.050 volts
MIL-On during active fault and for 2 seconds after active fault
Adaptive-Disabled during active fault and for the remainder of
the key cycle

Circuit Description

Temperature Sensor Resistance
Temperature
Tolerance ± 10%
Degrees F.
Ohms
-40
99318
-20
48300
0
24705
20
13214
40
7357
60
4259
70
3284
80
2554
100
1582
120
1008
140
660.6
160
444.1
170
367.3
180
305.5
190
255.4
200
214.6
220
153.7

The FT (Fuel Temperature) sensor is a temperature sensitive resistor located near the fuel outlet of the electronic pressure
regulator. It is used to help determine fuel charge density for accurate fuel mixture control. The ECM provides a voltage
divider circuit so that when the sensor is cool the signal reads a higher voltage, and lower when warm. This fault will set if
the signal voltage is less than 0.050 volts anytime the engine is running.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

DIAGNOSTIC TROUBLE CODES 7-69

DTC 187- LPG Fuel Temperature Sensor Voltage Low
SPN/FMI 520240:4

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
_

Yes
Go to Step (2)
Go to step (3)

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section

Go to step (4)

Go to step (5)

Go to Step (8)

Repair the
shorted circuit
as Repairs
in Engine
Electrical.

Go to step (6)

• Key On
• DST (Diagnostic Scan Tool) connected in
• System Data Mode
Does DST display FT voltage of 0.050 or less?
3

4
5

• Key Off
• Disconnect the FT wire harness connector C003
• Key ON
Does the DST display FT voltage of 4.9 volts or
greater?
Replace FT sensor.
Is the replacement complete?
• Key OFF
• Disconnect ECM wire harness connector C001
• Check for continuity between FT sensor
connector signal pin A and FT sensor ground pin
B
Do you have continuity between them?
• Check for continuity between FT sensor
connector signal circuit pin A and engine ground.
Do you have continuity?

Replace ECM. Refer to ECM replacement in the
Engine Controls Section.
Is the replacement complete?

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

Go to step (8)

Go to step (7)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
8

•
•
•
•
•
•
•
•
•

Observe the MIL
Observe engine performance and driveability
After operating the engine within the test
parameters of DTC-187 check for any stored
codes.
Does the engine operate normally with no stored
codes?

DIAGNOSTIC TROUBLE CODES 7-70
Value(s)

Yes
System OK

No
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-71

DTC 188-LPG Fuel Temperature Sensor Voltage High
SPN/FMI 520240:3

Conditions for Setting the DTC
•
•
•
•
•

Fuel Temperature
Check Condition-Engine Running
Fault Condition-FT sensor voltage exceeds 4.950
MIL-On during active fault and for 2 seconds after active fault
Adaptive-Disabled during active fault and for the remainder of
the key cycle

Circuit Description
The FT (Fuel Temperature) sensor is a temperature sensitive resistor located near the fuel outlet of the electronic pressure
regulator. It is used to help determine fuel charge density for accurate fuel mixture control. The ECM provides a voltage
divider circuit so that when the sensor is cool the signal reads a higher voltage, and lower when warm. This fault will set if
the signal voltage is greater than 4.950 volts anytime the engine is running.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

DIAGNOSTIC TROUBLE CODES 7-72

DTC 188- FT Voltage High
SPN/FMI 520240:3

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

Yes
Go to Step (2)
Go to step (3)

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section

Go to step (4)

Go to Step (8)

Go to Step (6)

Go to step (5)

Go to Step (14)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (9)

Go to Step (7)

Key On
DST (Diagnostic Scan Tool) connected in System
Data Mode
Does DST display FT voltage of 4.95 or greater?
•
•

5
6

Key Off
Disconnect the FT sensor connector C003 and
jump connector terminals A and B together
• Key On
Does the DST display FT voltage of 0.05 volts or
less?
• Using a DVOM check the resistance between the
two terminals of the FT sensor and compare the
resistance reading to the chart
Is the resistance value correct?
•
•

• Replace FT sensor
Is the replacement complete?
• Inspect the FT sensor connector terminals for
damage, corrosion or contamination
Did you ﬁnd a problem?

•
•
•
•

8
9

Key OFF
Disconnect ECM wire harness connector
Inspect ECM connector pins 20 and 41 for
damage corrosion or contamination
Did you ﬁnd a problem?

Jump the FT signal pin A at the FT connector
C003 to engine ground
Does DST display FT voltage of 0.05 or less?
• Key OFF
• Disconnect ECM wire harness connector C001
• Using a DVOM check for continuity between FT
sensor ground pin B and ECM connector pin 20
Do you have continuity between them?
•

See
temperature
vs.
resistance
chart in
the DTC
188 circuit
description

Go to Step (10)

Intermittent
problem
Go to
Intermittent
section
Go to Step (12)
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
10

•

Action
Inspect ECM connector pins 20 and 41 for
damage, corrosion or contamination

Did you ﬁnd a problem?

11
12

• Replace ECM
Is the replacement complete?
• Key OFF
• Disconnect ECM wire harness connector C001
• Using a DVOM check for continuity between
FT connector signal pin A and ECM connector
terminal 41
Do you have continuity between them?

•

Inspect ECM connector pins 20 and 41 for
damage, corrosion or contamination
Did you ﬁnd a problem?

•
•
•
•
•
•
•
•
•

Remove all test equipment except the DST.
Connect any disconnected components, fuses,
etc.
Using the DST clear DTC information from the
ECM.
Turn the ignition OFF and wait 30 seconds.
Start the engine and operate the vehicle to full
operating temperature

Observe the MIL
Observe engine performance and driveability
After operating the engine within the test
parameters of DTC-188 check for any stored
codes.
Does the engine operate normally with no stored
codes?

DIAGNOSTIC TROUBLE CODES 7-73
Value(s)

Yes
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (14)

No
Go to Step (11)

Go to Step (13)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (11)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
System OK

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-74

DTC 217-ECT Higher Than Expected 2 SPN/FMI 110:0

Conditions for Setting the DTC
•
•
•
•
•

Engine Coolant Temperature
Check Condition-Engine Running
Fault Condition-Engine Coolant temperature reading or estimate greater than 235 deg. F for more than 60
seconds with the engine speed greater than 600 rpm
MIL-On
Engine Shut Down

Circuit Description
The ECT (Engine Coolant Temperature) sensor is a temperature sensitive resistor located in the engine coolant
passage. The ECT is used for engine airﬂow calculation, fuel enrichment, ignition timing control and to enable
certain other temperature dependant operations. This code set is designed to help prevent engine damage from
overheating. The ECM provides a voltage divider circuit so when the sensor reading is cool the sensor reads
higher voltage, and lower when warm. This fault will set when the coolant exceeds 250 degrees F. for more than
60 seconds with the engine speed over 1000 rpm. The engine will then shut down.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DTC 217 ECT Higher than expected 2 SPN/FMI 110:0

Step
1

Action
Did you perform the On-Board (OBD) System Check?

• Key On
• DST (Diagnostic Scan Tool) connected in
System Data Mode
• Operate the engine to attempt to recreate the
failure running the engine above 1000 rpm for at
least 60 seconds
•
Does DST display ECT temperature of 250
degrees F. or greater with the engine running
over 1000 rpm, and then shut down?
• Verify with a temperature gauge that the engine
coolant is over 250 degrees F.
Does the temperature gauge indicate 250 degrees F.
or greater?
Verify ECT circuit function. Follow diagnostic test
procedure for DTC-117 ECT Low Voltage

DIAGNOSTIC TROUBLE CODES 7-75

Value(s)
-

Yes
Go to Step (2)
Go to Step (3)

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section

Repair Cooling
system.

Go to step (4)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-76

DTC 219-Max Govern Speed Override SPN/FMI 515:15

Conditions for Setting the DTC
•
•
•
•

Max Govern Speed Override
Check Condition- Engine Running
Fault Condition- Engine RPM greater than 3200 for 2 seconds continuously
MIL- On during active fault

Circuit description
This fault will set anytime the engine RPM exceeds 3500 for 2 seconds or more
is ON during this active fault.

continuously. The MIL command

Diagnostic Aid
Always check for other stored DTC codes before using the following DTC chart for this code set. Repair any existing
codes starting with the lowest numerical code ﬁrst.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

DIAGNOSTIC TROUBLE CODES 7-77

DTC 219- Max Govern Speed Override SPN/FMI 515:15

• Key ON, Engine OFF
• DST connected
Are any other DTC codes present with DTC 219?

Go to Step (3)

No
Go to OBD
System Check
Section
Go to Step (4)

•

Diagnose and repair any other DTC codes stored
before proceeding with this chart.
Have any other DTC codes been diagnosed and
repaired?
• Check the service part number on the ECM to
ensure the correct calibration is in use
Is the Service Part Number Correct?
• Replace ECM with correct service part number
Is the replacement complete?
• Check the mechanical operation of the throttle
Is the mechanical operation of the throttle OK?
• Correct mechanical operation of the throttle. Refer
to Engine & Component section
Has the mechanical operation of the throttle been
corrected?
• Check engine for large manifold vacuum leaks.
Refer to Symptom Diagnostic section
Did you ﬁnd and correct the vacuum leak?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses, etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-219 check for any stored
codes.
Does the engine operate normally with no stored
codes?

Go to step (4)

4
5
6
7

8
9

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

Yes
Go to Step (2)

Go to Step (6)
Go to Step (9)
Go to Step (8)

Go to Step 5
Go to Step (7)

Go to step (9)

Go to Step (9)

Go to OBD
System Check
Section
Go to OBD
System Check

System OK

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-78

DTC 221-TPS 1 Higher Than TPS 2 SPN/FMI 51:0

Conditions for Setting the DTC
•
•
•
•
•

Throttle Position Sensor 1 & 2
Check Condition-Key On
Fault Condition-TPS 1 20% higher than TPS2
MIL-On for remainder of key on cycle
Engine Shutdown

Circuit Description
There are two Throttle Position Sensors located within the throttle which use variable resistors to determine
signal voltage based on throttle plate position. TPS 1 will read lower voltage when closed and TPS 2 will read
higher voltage when closed. The TPS 1 and TPS 2 percentages are calculated from these voltages. Although the
voltages are different, the calculated values for the throttle position percentages should be very close to the same.
The TPS values are used by the ECM to determine if the throttle is opening as commanded. The TPS is not
serviceable and in the event of a failure the electronic throttle assembly must be replaced. This fault will set if TPS
1 is 20% (or more) higher than TPS 2. At this point the throttle is considered to be out of speciﬁcation, or there is
a problem with the TPS signal circuit. The MIL command is ON and Power derate 1 will be enforced limiting the
throttle to 50% maximum

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1
2

DTC 221 TPS 1 Higher Than TPS 2 SPN/FMI 51:0

Action
Did you perform the On-Board (OBD) System Check?

Key OFF
Disconnect ECM wiring harness connector C001
Key ON
Using a DVOM check for voltage between ECM
connector TPS 1 signal pin 5 and engine ground
Do you have voltage?

Repair the
TPS 1 circuit
shorted to
voltage as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (6)

•

Yes
Go to Step (2)
Go to Step (3)

•
•
•
•

Value(s)
-

Key ON, Engine OFF
DST (Diagnostic Scan Tool) connected in
System Data Mode
Does the DST display more than a 20% difference
between TPS 1 and TPS 2?
• Key OFF
• Disconnect electronic throttle connector C025
• Key ON
• Change DST mode to DBW (drive by wire) test
mode
Is the voltage for TPS 1 less than 0.1 volts?
•
•

DIAGNOSTIC TROUBLE CODES 7-79

Go to Step (5)

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section
Go to Step (4)

Go to Step (9)

Go to Step (8)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (12)

Go to Step (7)

Go to Step (9)

Repair the
open circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Repair the
open circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

Go to Step (10)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
10

11
12

Action
Inspect ECM connector terminals for damage
corrosion or contamination.
Any problems found?
•

• Replace ECM
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-221 check for any stored
codes.
Does the engine operate normally with no stored
codes?

DIAGNOSTIC TROUBLE CODES 7-80
Value(s)

Yes
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical
Go to Step (12)
System OK

No
Go to Step (11)

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-81

DTC 222-TPS 2 Signal Voltage Low SPN/FMI 520251:4

Conditions for Setting the DTC
•
•
•
•
•

Throttle Position Sensor 2
Check Condition-Cranking or Running
Fault Condition-TPS 2 sensor voltage less than 0.200 volts for more than .500 seconds
MIL-ON during active fault
Engine Shutdown

Circuit Description
There are 2 Throttle Position Sensors located within the throttle which use variable resistors to determine signal
voltage based on throttle plate position. TPS1 will read lower voltage when closed and TPS2 will read higher
voltage when closed. The TPS1 and TPS2 percentages are calculated from these voltages. Although the voltages
are different, the calculated values for the throttle position percentages should be very close to the same.
The TPS values are used by the ECM to determine if the throttle is opening as commanded. The TPS is not
serviceable and in the event of a failure the electronic throttle assembly must be replaced.
This fault will set if the TPS 2 voltage is less than 0.200 volts for more than .500 seconds. The MIL command is
ON and power derate level 1 will be enforced limiting maximum throttle to 50%.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
1
2

6
7

8
9

DIAGNOSTIC TROUBLE CODES 7-82

DTC 222 TPS 2 Signal Voltage Low SPN/FMI 520251:4

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

Yes
Go to Step (2)

Key ON, Engine OFF
DST (Diagnostic Scan Tool) connected in
DBW (Drive by Wire) throttle test mode
Does the DST display TPS 2 voltage of 0.2 volts or
less with the throttle closed
• Slowly depress Foot Pedal while observing TPS 2
voltage
Does TPS 2 voltage ever fall below 0.2 volts?

Go to Step (4)

Key OFF
Disconnect electronic throttle connector C025
Jumper the 5 volt reference circuit pin 3 and
TPS 2 signal circuit pin 5 together at the throttle
connector
• Key ON
Does DST display TPS 2 voltage of 4.0 volts or
greater?
• Key OFF
• Disconnect ECM wire harness connector C001
Using a DVOM check continuity between TPS 2
connector signal pin 5 and ECM connector TPS 2
Signal pin 6
Do have continuity between them?
• Replace ECM
Is the replacement complete?
• Inspect the electronic throttle wire harness
connector terminals for damage, corrosion or
contamination
Did you ﬁnd a problem?

Go to Step (7)

•
•

•
•
•

• Replace the electronic throttle
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-222 check for any stored
codes.
Does the engine operate normally with no stored
codes?

Go to Step (4)

Go to Step (6 )

Go to Step (9)

No
Go to OBD
System Check
Section
Go to Step (3)

Intermittent
problem
Go to
Intermittent
section
Go to Step (5)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
-

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (9)

Go to Step (8)

System OK

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-83

DTC 223-TPS 2 Signal Voltage High SPN/FMI 520251:3

Conditions for Setting the DTC
•
•
•
•
•

Throttle Position Sensor 2
Check Condition-Cranking or Running
Fault Condition-TPS 2 sensor exceeds 4.80 volts for more than .50 seconds
MIL-On during active fault
Engine Shutdown

Circuit Description
There are 2 Throttle Position Sensors located within the throttle which use variable resistors to determine signal
voltage based on throttle plate position. TPS1 will read lower voltage when closed and TPS2 will read higher
voltage when closed. The TPS1 and TPS2 percentages are calculated from these voltages. Although the voltages
are different, the calculated values for the throttle position percentages should be very close to the same.
The TPS values are used by the ECM to determine if the throttle is opening as commanded. The TPS is not
serviceable and in the event of a failure the electronic throttle assembly must be replaced.
This fault will set if the TPS 2 voltage is greater than 4.80 volts for more than .50 seconds. The MIL command is
ON and power derate level 1 will be enforced limiting maximum throttle to 50%.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
1
2

6
7

9
10

DIAGNOSTIC TROUBLE CODES 7-84

DTC 223 TPS 2 Signal Voltage High SPN/FMI 520251:3

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

Yes
Go to Step (2)

Key ON, Engine OFF
DST (Diagnostic Scan Tool) connected in
DBW (Drive by Wire) throttle test mode
Does the DST display TPS 2 voltage of 4.8 volts or
greater with the throttle closed?
• Slowly depress Foot Pedal while observing TPS 2
voltage
Does TPS 2 voltage ever exceed 4.8 volts?

Go to Step (4)

• Key OFF
• Disconnect electronic throttle connector C025
• Key ON
Does DST display TPS 2 voltage less than 0.2 volts?
• Key OFF
• Disconnect ECM wire harness connector C001
• Key ON
• Using a DVOM check for voltage between
electronic throttle connector TPS 2 signal pin 5
and engine ground
Do you have voltage?
• Replace ECM
Is the replacement complete?
• Probe sensor ground circuit at the ECM side of
the wire harness pin 20 with a test light connected
to battery voltage
Does the test light come on?
• Inspect the electronic throttle wire harness
connector and terminals for damage, corrosion or
contamination
Did you ﬁnd a problem?

Go to Step (7)

•
•

• Replace electronic throttle
Is the replacement complete?
• Key OFF
• Disconnect ECM connector C001
• Using a DVOM check for continuity between
throttle connector C025 sensor ground pin 2 and
ECM connector sensor ground pin 20
Do have continuity between them?

Go to Step (4)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

No
Go to OBD
System Check
Section
Go to Step (3)

Intermittent
problem
Go to
Intermittent
section
Go to Step (5)

Go to Step (6)

Go to Step (11)

Go to Step (8)

Go to Step (10)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (11)

Go to Step (9)

Go to Step (6)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
11

Action
Remove all test equipment except the DST.
Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-223 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•

DIAGNOSTIC TROUBLE CODES 7-85
Value(s)

Yes
System OK

No
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-86

DTC 261 Injector Driver 1 (Cyl #1) Open SPN/FMI 651:5

Conditions for Setting the DTC
•
•
•
•
•
•

Injector loop open or driver circuit short
Check Condition-key on and engine running
Fault Condition-System voltage greater than 9 volts and injector low side less than 4 volts for 10 injector
ﬁrings
MIL-On for active fault and for 5 seconds after active fault
Adaptive-Disabled for remainder of key-on cycle
Closed Loop-Disabled during active fault

Circuit Description
This fault will set if the ECM detects low feedback voltage at the injector driver circuit while the injector drive circuit
is in the off-state and battery voltage is greater than 9 volts.

Diagnostic Aid
The injector driver numbers shown above are called out in respect to the engine ﬁring order. It is important to
know the engine ﬁring order when locating a speciﬁc injector at the engine block. Refer to engine ﬁring order in the
engine section of this manual.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
1

DIAGNOSTIC TROUBLE CODES 7-87

DTC 261 Injector Driver 1 (Cyl #1) Open SPN/FMI 651:5

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
_

Yes
Go to Step (2)
Go to step (3)

Key On, Engine Running
DST (Diagnostic Scan Tool) connected in system
data mode
• Clear System DTC 261
Does DTC 261 reset with the engine idling?
•
•

4
5

Key Off
Disconnect the wire harness connector C031 at
the number 1 injector.
• Using a high impedance DVOM, measure the
resistance between the (2) pins on the injector at
an ambient temperature of 58 to 88 degrees F.
Does the DVOM display a resistance value of 16
Ohms or less?
•
•

• Replace the Fuel Injector
Is the replacement complete?
• Measure the resistance between C031 injector
driver BRN/LT BLU wire and battery ground.
Does the DVOM display a resistance of 5.0 Ohms or
less?
•

Disconnect ECM connector C001

•

Measure the resistance between the injector
driver wire BRN/LT BLU and battery ground.

16 ohms or
less

•
•
•

Disconnect ECM wire harness connector C001
Using a DVOM measure the resistance between
the injector driver wire BRN/LT BLU and ECM
connector pin 61
Does the DVOM display a resistance of 5.0 Ohms
or less between them?

Check the injector connector and ECM
connector terminals for damage, corrosion or
contamination.
Any problems found?

Go to step (5)

Go to step (4)

Go to Step (11)

Go to Step (6)

Go to step (9)

Repair the
shorted injector
driver circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (8)

Go to Step (9)

5.0 Ohms

Does the DVOM display a resistance of 5.0 Ohms or
less?
7

5.0 Ohms

•

No
Go to OBD
System Check
Section
Intermittent
problem.
Go to
Intermittent
electrical
section

Repair the
open injector
driver circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

Repair the
open circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to step (10)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
9

10
11

DIAGNOSTIC TROUBLE CODES 7-88

Action
Disconnect ECM wire harness connector
C001
• Using a DVOM measure the resistance
between the injector connector C031 BRN/
LT BLU wire and ECM pin 61
Does the DVOM display a resistance of 5.0 Ohms or
less?

Value(s)

Replace ECM. Refer to ECM replacement in the
Engine Controls Section.
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-261 check for any stored
codes.
• Does the engine operate normally with no stored
codes?

•

Yes
Go to Step (8)

Go to step (11)
System OK

No
Repair the
open circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
_
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-89

DTC 262 Injector Driver 1 (Cyl #1) Shorted SPN/FMI 651:6

Conditions for Setting the DTC
•
•
•
•
•
•

Injector coil shorted
Check Condition-key on and engine running
Fault Condition-Battery voltage at ECM less than16 volts and injector on state low side greater than 4 volts for
10 injector ﬁrings
MIL-On for active fault and for 5 seconds after active fault
Adaptive-Disabled for remainder of key-on cycle
Closed Loop-Disabled during active fault

Circuit Description
This fault will set if the ECM detects high feedback voltage at the injector while the injector drive circuit is in the offstate with system battery voltage less than 16 volts.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

DIAGNOSTIC TROUBLE CODES 7-90

DTC 262 Injector Driver 1 (Cyl #1) Shorted SPN/FMI 651:6

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
_

Yes
Go to Step (2)
Go to step (3)

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section

Go to step (5)

Go to step (4)

Go to Step (8)

Repair the
shorted to
voltage injector
driver circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (8)

Go to Step (6)

Go to step (9)

• Key On, Engine Running
• DST (Diagnostic Scan Tool) connected in
System Data Mode
• Clear System DTC 262
Does DTC 262 reset with the engine idling?
3

4
5

Key Off
Disconnect the harness connector C031 from the
cylinder number 1 injector.
• Using a high impedance DVOM, measure the
resistance between the (2) pins of the injector
Does the DVOM display a resistance value of 5 ohms
or more?
• Replace the Fuel Injector
Is the replacement complete?
• Disconnect the ECM wire harness connector
C001
• Key ON
• Using a DVOM check for voltage between the
ECM connector pin 61 and engine ground
Does the DVOM display voltage?
•
•

• Replace Fuel Injector
Is the replacement complete?
Replace ECM. Refer to ECM replacement in the
Engine Controls Section.
Is the replacement complete?

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
8

•
•
•
•
•
•
•
•
•

Action
Remove all test equipment except the DST.
Connect any disconnected components, fuses,
etc.
Using the DST clear DTC information from the
ECM.
Turn the ignition OFF and wait 30 seconds.
Start the engine and operate the vehicle to full
operating temperature
Observe the MIL
Observe engine performance and driveability
After operating the engine within the test
parameters of DTC262 check for any stored
codes.
Does the vehicle engine normally with no stored
codes?
Remove all test equipment except the DST.
Connect any disconnected components, fuses,
etc.
Using the DST clear DTC information from the
ECM.
Turn the ignition OFF and wait 30 seconds.
Start the engine and operate the vehicle to full
operating temperature
Observe the MIL
Observe engine performance and driveability
After operating the engine within the test
parameters of DTC262 check for any stored
codes.
Does the engine operate normally with no stored
codes?

DIAGNOSTIC TROUBLE CODES 7-91
Value(s)

Yes
System OK

No
Go to Step (7)

System OK

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-92

DTC 264 Injector Driver 2 (Cyl #3) Open SPN/FMI 652:5

Conditions for Setting the DTC
•
•
•
•
•
•

Injector coil open or driver circuit short
Check Condition-key on and engine running
Fault Condition-Battery voltage at ECM greater than 9 volts and injector low side less than 4 volts for 10
injector ﬁrings
MIL-On for active fault and for 5 seconds after active fault
Adaptive-Disabled for remainder of key-on cycle
Closed Loop-Disabled during active fault

Circuit Description
This fault will set if the ECM detects low feedback voltage on the internal injector while the injector drive circuit is in
the off-state and battery voltage is greater than 9 volts.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
1

DIAGNOSTIC TROUBLE CODES 7-93

DTC 264 Injector Driver 2 (Cyl #3) Open SPN/FMI 652:5

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
_

Yes
Go to Step (2)
Go to step (3)

Key On, Engine Running
DST (Diagnostic Scan Tool) connected in system
data mode
• Clear System DTC 264
Does DTC 264 reset with the engine idling?
•
•

4
5

Key Off
Disconnect the wire harness connector C029 at
the cylinder number 3 injector.
• Using a high impedance DVOM, measure the
resistance between the (2) pins on the injector at
an ambient temperature of 58 to 88 degrees F.
Does the DVOM display a resistance value of 16
Ohms or less?
•
•

• Replace the Fuel Injector
Is the replacement complete?
• Measure the resistance between C029 injector
driver BRN/ LT GRN wire and battery ground.
Does the DVOM display a resistance of 5.0 Ohms or
less?
•

Disconnect ECM connector C001

•

Measure the resistance between the injector
driver wire BRN/ LT GRN and battery ground.

16 ohms or
less

•
•
•

Disconnect ECM wire harness connector C001
Using a DVOM measure the resistance between
the injector driver wire BRN/ LT GRN and ECM
connector pin 62
Does the DVOM display a resistance of 5.0 Ohms
or less between them?

Check the injector connector and ECM
connector terminals for damage, corrosion or
contamination.
Any problems found?

Go to step (5)

Go to step (4)

Go to Step (11)

Go to Step (6)

Go to step (9)

Repair the
shorted injector
driver circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (8)

Go to Step (9)

5.0 Ohms

Does the DVOM display a resistance of 5.0 Ohms or
less?
7

5.0 Ohms

•

No
Go to OBD
System Check
Section
Intermittent
problem.
Go to
Intermittent
electrical
section

Repair the
open injector
driver circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

Repair the
open circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to step (10)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
9

10
11

DIAGNOSTIC TROUBLE CODES 7-94

Action
Disconnect ECM wire harness connector
C001
• Using a DVOM measure the resistance
between the injector connector C029 BRN/
LT GRN wire and ECM pin 62
Does the DVOM display a resistance of 5.0 Ohms or
less?

Value(s)

Replace ECM. Refer to ECM replacement in the
Engine Controls Section.
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-264 check for any stored
codes.
• Does the engine operate normally with no stored
codes?

•

Yes
Go to Step (8)

Go to step (11)
System OK

No
Repair the
open circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
_
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-95

DTC 265 Injector Driver 2 (Cyl #3) Shorted SPN/FMI 652:6

Conditions for Setting the DTC
•
•
•
•
•
•

Injector coil shorted
Check Condition-key on and engine running
Fault Condition-Battery voltage at ECM less than 16 volts and injector on state low side greater than 4 volts
for 10 injector ﬁrings
MIL-On for active fault and for 5 seconds after active fault
Adaptive-Disabled for remainder of key-on cycle
Closed Loop-Disabled during active fault

Circuit Description
This fault will set if the ECM detects high feedback voltage at the injector while the injector drive circuit is in the offstate with system battery voltage less than 16 volts.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

DIAGNOSTIC TROUBLE CODES 7-96

DTC 265 Injector Driver 2 (Cyl #3) Shorted SPN/FMI 652:6

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
_

Yes
Go to Step (2)
Go to step (3)

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section

Go to step (5)

Go to step (4)

Go to Step (8)

Repair the
shorted to
voltage injector
driver circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (8)

Go to Step (6)

Go to step (9)

• Key On, Engine Running
• DST (Diagnostic Scan Tool) connected in
System Data Mode
• Clear System DTC 265
Does DTC 265 reset with the engine idling?
3

4
5

Key Off
Disconnect the harness connector C029 from the
cylinder number 3 injector.
• Using a high impedance DVOM, measure the
resistance between the (2) pins of the injector
Does the DVOM display a resistance value of 5 ohms
or more?
• Replace the Fuel Injector
Is the replacement complete?
• Disconnect the ECM wire harness connector
C001
• Key ON
• Using a DVOM check for voltage between the
ECM connector pin 62 and engine ground
Does the DVOM display voltage?
•
•

• Replace Fuel Injector
Is the replacement complete?
Replace ECM. Refer to ECM replacement in the
Engine Controls Section.
Is the replacement complete?

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
8

•
•
•
•
•
•
•
•
•

Action
Remove all test equipment except the DST.
Connect any disconnected components, fuses,
etc.
Using the DST clear DTC information from the
ECM.
Turn the ignition OFF and wait 30 seconds.
Start the engine and operate the vehicle to full
operating temperature
Observe the MIL
Observe engine performance and driveability
After operating the engine within the test
parameters of DTC265 check for any stored
codes.
Does the vehicle engine normally with no stored
codes?
Remove all test equipment except the DST.
Connect any disconnected components, fuses,
etc.
Using the DST clear DTC information from the
ECM.
Turn the ignition OFF and wait 30 seconds.
Start the engine and operate the vehicle to full
operating temperature
Observe the MIL
Observe engine performance and driveability
After operating the engine within the test
parameters of DTC265 check for any stored
codes.
Does the engine operate normally with no stored
codes?

DIAGNOSTIC TROUBLE CODES 7-97
Value(s)

Yes
System OK

No
Go to Step (7)

System OK

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-98

DTC 267 Injector Driver 3 (Cyl #4) Open SPN/FMI 653:5

Conditions for Setting the DTC
•
•
•
•
•
•

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
1

DIAGNOSTIC TROUBLE CODES 7-99

DTC 267 Injector Driver 3 (Cyl #4) Open SPN/FMI 653:5

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
_

Yes
Go to Step (2)
Go to step (3)

Key On, Engine Running
DST (Diagnostic Scan Tool) connected in system
data mode
• Clear System DTC 267
Does DTC 267 reset with the engine idling?
•
•

4
5

Key Off
Disconnect the wire harness connector C028 at
the cylinder number 4 injector.
• Using a high impedance DVOM, measure the
resistance between the (2) pins on the injector at
an ambient temperature of 58 to 88 degrees F.
Does the DVOM display a resistance value of 16
Ohms or less?
•
•

• Replace the Fuel Injector
Is the replacement complete?
• Measure the resistance between C028 injector
driver BRN/YEL wire and battery ground.
Does the DVOM display a resistance of 5.0 Ohms or
less?
•

Disconnect ECM connector C001

•

Measure the resistance between the injector
driver wire BRN/YEL and battery ground.

16 ohms or
less

•
•
•

Disconnect ECM wire harness connector C001
Using a DVOM measure the resistance between
the injector driver wire BRN/YEL and ECM
connector pin 63
Does the DVOM display a resistance of 5.0 Ohms
or less between them?

Check the injector connector and ECM
connector terminals for damage, corrosion or
contamination.
Any problems found?

Go to step (5)

Go to step (4)

Go to Step (11)

Go to Step (6)

Go to step (9)

Repair the
shorted injector
driver circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (8)

Go to Step (9)

5.0 Ohms

Does the DVOM display a resistance of 5.0 Ohms or
less?
7

5.0 Ohms

•

No
Go to OBD
System Check
Section
Intermittent
problem.
Go to
Intermittent
electrical
section

Repair the
open injector
driver circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

Repair the
open circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to step (10)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
9

10
11

DIAGNOSTIC TROUBLE CODES 7-100

Action
Disconnect ECM wire harness connector
C001
• Using a DVOM measure the resistance
between the injector connector C028 BRN/
YEL wire and ECM pin 63
Does the DVOM display a resistance of 5.0 Ohms or
less?

Value(s)

Replace ECM. Refer to ECM replacement in the
Engine Controls Section.
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-267 check for any stored
codes.
• Does the engine operate normally with no stored
codes?

•

Yes
Go to Step (8)

Go to step (11)
System OK

No
Repair the
open circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
_
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-101

DTC 268 Injector Driver 3 (Cyl #4) Shorted SPN/FMI 653:6

Conditions for Setting the DTC
•
•
•
•
•
•

Injector coil shorted
Check Condition-key on and engine running
Fault Condition-Battery voltage at ECM less than 16 volts and injector on state low side greater than 4 volts
for 10 injector ﬁrings
MIL-On for active fault and for 5 seconds after active fault
Adaptive-Disabled for remainder of key-on cycle
Closed Loop-Disabled during active fault

Circuit Description
This fault will set if the ECM detects high feedback voltage at the injector while the injector drive circuit is in the offstate with system battery voltage less than 16 volts.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

DIAGNOSTIC TROUBLE CODES 7-102

DTC 268 Injector Driver 3 (Cyl #4) Shorted SPN/FMI 653:6

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
_

Yes
Go to Step (2)
Go to step (3)

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section

Go to step (5)

Go to step (4)

Go to Step (8)

Repair the
shorted to
voltage injector
driver circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (8)

Go to Step (6)

Go to step (9)

• Key On, Engine Running
• DST (Diagnostic Scan Tool) connected in
System Data Mode
• Clear System DTC 268
Does DTC 268 reset with the engine idling?
3

4
5

7
8

Key Off
Disconnect the harness connector C028 from the
cylinder number 4 injector.
• Using a high impedance DVOM, measure the
resistance between the (2) pins of the injector
Does the DVOM display a resistance value of 5 ohms
or more?
• Replace the Fuel Injector
Is the replacement complete?
• Disconnect the ECM wire harness connector
C001
• Key ON
• Using a DVOM check for voltage between the
ECM connector pin 63 and engine ground
Does the DVOM display voltage?
•
•

• Replace Fuel Injector
Is the replacement complete?
Replace ECM. Refer to ECM replacement in the
Engine Controls Section.
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC268 check for any stored
codes.
• Does the vehicle engine normally with no stored
codes?

System OK

Go to Step (7)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
9

•
•
•
•
•
•
•
•
•

DIAGNOSTIC TROUBLE CODES 7-103
Value(s)

Yes
System OK

No
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-104

DTC 270 Injector Driver 4 (Cyl #2) Open SPN/FMI 654:5

Conditions for Setting the DTC
•
•
•
•
•
•

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
1

DIAGNOSTIC TROUBLE CODES 7-105

DTC 270 Injector Driver 4 (Cyl #2) Open SPN/FMI 654:5

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
_

Yes
Go to Step (2)
Go to step (3)

Key On, Engine Running
DST (Diagnostic Scan Tool) connected in system
data mode
• Clear System DTC 270
Does DTC 270 reset with the engine idling?
•
•

4
5

Key Off
Disconnect the wire harness connector C030 at
the Cylinder number 2 injector.
• Using a high impedance DVOM, measure the
resistance between the (2) pins on the injector at
an ambient temperature of 58 to 88 degrees F.
Does the DVOM display a resistance value of 16
Ohms or less?
•
•

• Replace the Fuel Injector
Is the replacement complete?
• Measure the resistance between C030 injector
driver BRN/WHT wire and battery ground.
Does the DVOM display a resistance of 5.0 Ohms or
less?
•

Disconnect ECM connector C001

•

Measure the resistance between the injector
driver wire BRN/WHT and battery ground.

16 ohms or
less

•
•
•

Disconnect ECM wire harness connector C001
Using a DVOM measure the resistance between
the injector driver wire BRN/WHT and ECM
connector pin 64
Does the DVOM display a resistance of 5.0 Ohms
or less between them?

Check the injector connector and ECM
connector terminals for damage, corrosion or
contamination.
Any problems found?

Go to step (5)

Go to step (4)

Go to Step (11)

Go to Step (6)

Go to step (9)

Repair the
shorted injector
driver circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (8)

Go to Step (9)

5.0 Ohms

Does the DVOM display a resistance of 5.0 Ohms or
less?
7

5.0 Ohms

•

No
Go to OBD
System Check
Section
Intermittent
problem.
Go to
Intermittent
electrical
section

Repair the
open injector
driver circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

Repair the
open circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to step (10)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
9

10
11

DIAGNOSTIC TROUBLE CODES 7-106

Action
Disconnect ECM wire harness connector
C001
• Using a DVOM measure the resistance
between the injector connector C030 BRN/
WHT wire and ECM pin 64
Does the DVOM display a resistance of 5.0 Ohms or
less?

Value(s)

Replace ECM. Refer to ECM replacement in the
Engine Controls Section.
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-270 check for any stored
codes.
• Does the engine operate normally with no stored
codes?

•

Yes
Go to Step (8)

Go to step (11)
System OK

No
Repair the
open circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
_
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-107

DTC 271 Injector Driver 4 (Cyl #2) Shorted SPN/FMI 654:6

Conditions for Setting the DTC
•
•
•
•
•
•

Injector coil shorted
Check Condition-key on and engine running
Fault Condition-Battery voltage at ECM less than 16 volts and injector on state low side greater than 4 volts
for 10 injector ﬁrings
MIL-On for active fault and for 5 seconds after active fault
Adaptive-Disabled for remainder of key-on cycle
Closed Loop-Disabled during active fault

Circuit Description
This fault will set if the ECM detects high feedback voltage at the injector while the injector drive circuit is in the offstate with system battery voltage less than 16 volts.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

DIAGNOSTIC TROUBLE CODES 7-108

DTC 271 Injector Driver 4 (Cyl #2) Shorted SPN/FMI 654:6

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
_

Yes
Go to Step (2)
Go to step (3)

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section

Go to step (5)

Go to step (4)

Go to Step (8)

Repair the
shorted to
voltage injector
driver circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (8)

Go to Step (6)

Go to step (9)

• Key On, Engine Running
• DST (Diagnostic Scan Tool) connected in
System Data Mode
• Clear System DTC 271
Does DTC 271 reset with the engine idling?
3

4
5

7
8

Key Off
Disconnect the harness connector C030 from the
cylinder number 2 injector.
• Using a high impedance DVOM, measure the
resistance between the (2) pins of the injector
Does the DVOM display a resistance value of 5 ohms
or more?
• Replace the Fuel Injector
Is the replacement complete?
• Disconnect the ECM wire harness connector
C001
• Key ON
• Using a DVOM check for voltage between the
ECM connector pin 64 and engine ground
Does the DVOM display voltage?
•
•

• Replace Fuel Injector
Is the replacement complete?
Replace ECM. Refer to ECM replacement in the
Engine Controls Section.
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC271 check for any stored
codes.
• Does the vehicle engine normally with no stored
codes?

System OK

Go to Step (7)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
9

•
•
•
•
•
•
•
•
•

DIAGNOSTIC TROUBLE CODES 7-109
Value(s)

Yes
System OK

No
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-110

DTC 336-Crank Sync Noise SPN/FMI 636:2

Conditions for setting the DTC
•
•
•
•

Crankshaft Position sensor
Check Condition- Engine cranking or running
Fault Condition- one or more invalid crank re-sync within 800 ms
MIL Command-ON

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

DTC 336- Crank Sync Noise SPN/FMI 636:2

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

Check to be sure that the ECM ground
terminals C014 and C023 are clean and tight.
Are terminals C014 and C023 clean and tight?

•
•
•
•

Yes
Go to Step (2)
Go to Step (3)

•

DIAGNOSTIC TROUBLE CODES 7-111

Over .5 volts

Go to Step (4)

Go to Step (5)

•

Using a DVOM check for continuity between CKP
connector pin B and ECM connector pin 22
Do you have continuity between them?

Go to Step (6)

•

Inspect the CKP connector C017 pins for damage,
corrosion or contamination
Did you ﬁnd a problem?

•

• Replace CKP sensor
Is the replacement complete?
• Replace ECM
• Is the replacement complete?

Inspect the ECM connector C001 pins 21 and 22
for damage, corrosion or contamination
Did you ﬁnd a problem?

Using a DVOM check for continuity between ECM
connector pins 21 and 22 to engine ground
Do you have continuity?

Go to Step (12)

No
Go to OBD
System Check
Section
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (11)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (7)

Go to step (8)

Go to Step (10)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
11

Action
Key OFF
Inspect the pulse wheel and CKP sensor for
mechanical damage, corrosion or
contamination.
Did you ﬁnd a problem?
•
•

Remove all test equipment except the DST.
Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-336 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•

DIAGNOSTIC TROUBLE CODES 7-112
Value(s)

Yes
Repair the
component
as necessary.
Refer to
Engine Repairs
in Engine
Section

No
Go to Step (9)

System OK

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-113

DTC 337-Crank Loss SPN/FMI 636:4

Conditions for setting the DTC
•
•
•
•

Crankshaft Position sensor
Check Condition- Engine cranking or running
Fault Condition- Three or more cam pulses without crank activity
MIL Command-ON

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
1

DTC 337- Crank Loss SPN/FMI 636:4

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

Check to be sure that the ECM ground
terminals C014 and C023 are clean and tight.
Are terminals C014 and C023 clean and tight?

•
•
•
•

Yes
Go to Step (2)
Go to Step (3)

•

DIAGNOSTIC TROUBLE CODES 7-114

Over .5 volts

Go to Step (4)

Go to Step (5)

•

Using a DVOM check for continuity between CKP
connector pin B and ECM connector pin 22
Do you have continuity between them?

Go to Step (6)

•

Inspect the CKP connector C017 pins for damage,
corrosion or contamination
Did you ﬁnd a problem?

•

• Replace CKP sensor
Is the replacement complete?
• Replace ECM
• Is the replacement complete?

Inspect the ECM connector C001 pins 21 and 22
for damage, corrosion or contamination
Did you ﬁnd a problem?

Using a DVOM check for continuity between ECM
connector pins 21 and 22 to engine ground
Do you have continuity?

Go to Step (12)

No
Go to OBD
System Check
Section
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (11)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (7)

Go to step (8)

Go to Step (10)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
11

Action
Key OFF
Inspect the pulse wheel and CKP sensor
for mechanical damage, corrosion or
contamination.
Did you ﬁnd a problem?
•
•

Remove all test equipment except the DST.
Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-337 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•

DIAGNOSTIC TROUBLE CODES 7-115
Value(s)

Yes
Repair the
component
as necessary.
Refer to
Engine Repairs
in Engine
Section
System OK

No
Go to Step (9)

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-116

DTC 341-Camshaft Sync Noise SPN/FMI 723:2

Conditions for Setting the DTC

•
•
•
•

Camshaft position sensor
Check Condition-Cranking or Running
Fault Condition- 1 invalid cam re-sync in 700ms or less
MIL-On

Circuit Description
The CMP (Camshaft Position Sensor) is used to synchronize the fuel and ignition systems. This fault will set if the ECM
detects erroneous pulses from the camshaft position sensor causing invalid cam re-sync.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

DIAGNOSTIC TROUBLE CODES 7-117

DTC 341- Camshaft Sensor Noise SPN/FMI 723:2

Action
Did you perform the On-Board (OBD) System Check?

•

•
•

•
•
•

Value(s)
-

Check that the ECM ground terminals C014 and
C023 are clean and tight
Are the ground terminals C014 and C023 clean and
tight?

Key On, Engine OFF
Disconnect the CMP (Camshaft position) Sensor
connector C019
• Using A DVOM check for voltage at the CMP
sensor connector pin C and engine ground
Do you have voltage?

•

Yes
Go to Step (2)
Go to Step (3)

5.0 volts

Go to Step (4

Key OFF
Disconnect ECM connector C001
Using a DVOM check for continuity between CMP
connector pin A and ECM connector pin 24
Do you have continuity between them?

Go to Step (5)

•

Using a DVOM check for continuity between CMP
connector pin B and ECM connector pin 25
Do you have continuity between them?

Go to Step (6)

•

Inspect the CMP connector terminals for damage,
corrosion or contamination
Did you ﬁnd a problem?

•

• Replace CMP sensor
Is the replacement complete?
• Replace ECM
• Is the replacement complete?

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (10)

Inspect the ECM connector C001 terminals 19, 24
and 25 for damage, corrosion or contamination
Did you ﬁnd a problem

Go to Step (11)

No
Go to OBD
System Check
Section
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (7)

Go to step (8)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
10

Action
Remove all test equipment except the DST.
Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-341 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•

Remove all test equipment except the DST.
Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-341 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•

DIAGNOSTIC TROUBLE CODES 7-118
Value(s)

Yes
System OK

No
Go to Step (9)

System OK

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-119

DTC 342-Camshaft Sensor Loss SPN/FMI 723:4

Conditions for Setting the DTC

•
•
•
•

CMP (Camshaft Position Sensor)
Check Condition-Engine Cranking or Running
Fault Condition-No cam pulse in 2 cycles with engine speed above 100 RPM
MIL-On

Circuit Description
The CMP (Camshaft Position Sensor) is used to synchronize the fuel and ignition systems. This fault will set if the ECM
does not detect a cam pulse in 2 engine cycles whenever the engine is cranking or running. The engine may not run with
this fault present.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
1

DIAGNOSTIC TROUBLE CODES 7-120

DTC 342-Camshaft Sensor Loss SPN/FMI 723:4

Action
Did you perform the On-Board (OBD) System Check?

•

•
•

•
•
•

Value(s)
-

Check that the ECM ground terminals C014 and
C023 are clean and tight
Are the ground terminals C014 and C023 clean and
tight?

Key On, Engine OFF
Disconnect the CMP (Camshaft position) Sensor
connector C019
• Using A DVOM check for voltage at the CMP
sensor connector pin C and engine ground
Do you have voltage?

•

Yes
Go to Step (2)
Go to Step (3)

5.0 volts

Go to Step (4)

Key OFF
Disconnect ECM connector C001
Using a DVOM check for continuity between CMP
connector pin A and ECM connector pin 24
Do you have continuity between them?

Go to Step (5)

•

Using a DVOM check for continuity between CMP
connector pin B and ECM connector pin 25
Do you have continuity between them?

Go to Step (6)

•

Inspect the CMP connector C019 terminals for
damage, corrosion or contamination
Did you ﬁnd a problem?

•

• Replace CMP sensor
Is the replacement complete?
• Replace ECM
• Is the replacement complete?

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (10)

Inspect the ECM connector C001 terminals 24,25
and 19 for damage, corrosion or contamination
Did you ﬁnd a problem

Go to Step (11)

Go to step (8)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
10

Action
Remove all test equipment except the DST.
Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-342 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•

Remove all test equipment except the DST.
Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-342 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•

DIAGNOSTIC TROUBLE CODES 7-121
Value(s)

Yes
System OK

No
Go to Step (9)

System OK

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-122

DTC 420 Gasoline Catalyst Monitor SPN/FMI 520211:10

Conditions for Setting the DTC
•
•
•
•
•

Catalyst Function
Check condition- Engine running
Fault condition- EGO 1 signal = EGO 2 signal for 100 updates
MIL- On during active fault and for 1 second after active fault
Adaptive- Disabled during active fault

Circuit Description
The ECM uses EGO 1 and EGO 2 sensor signals to diagnose problems with the catalyst mufﬂer. When the
signals for EGO 1 & EGO 2 are similar it may indicate a problem with the catalyst.

Diagnostic Aids
Always diagnose any other troubles, stored along with DTC 420 ﬁrst. Check for and eliminate any exhaust leaks
prior to replacing catalyst mufﬂer. Look for exhaust leaks at the catalyst mufﬂer inlet and tail pipes. Clear this
trouble code after repairing exhaust leaks, and recheck for code.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-123

DTC 524-Oil Pressure Low SPN/FMI 100:1

Conditions for Setting the DTC
•
•
•
•
•

Engine Oil Pressure low
Check Condition-Engine running for 30 seconds with RPM greater than 600
Fault Condition- closed circuit/voltage low less than 2.5 volts
MIL-On during active fault and for 3 seconds after active fault
Engine Shut Down

Circuit Description
The Oil Pressure Switch is used to communicate a low oil pressure condition to the ECM. Engine damage can occur if the
engine is operated with low oil pressure. The ECM uses an analog voltage input with an internal 5 volt reference. If the oil
pressure circuit is grounded, the input voltage will be near zero. If it is open, the input will be near 5 volts. The switch is
normally closed. This fault will set if the switch remains closed with the engine running. The MIL command is ON and the
engine will shut down in the event of this fault to help prevent possible engine damage.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1
2

5
6

DIAGNOSTIC TROUBLE CODES 7-124

DTC 524- Oil Pressure Low SPN/FMI 100:1

Action
Did you perform the On-Board (OBD) System Check?
•

Verify that the engine has oil pressure using a
mechanical oil pressure gauge before proceeding
with this chart. See Engine Speciﬁcations Section
1F.

Does the engine have oil pressure above 2 psi?
• Key On, Engine Running DST connected in
System Data Mode
• Clear DTC 524
• Warm the engine by idling until the ECT
temperature is above 160 degrees F. and has
been running for at least one minute
• Increase engine speed above 600 RPM
Does DTC 524 reset and cause the engine to shut
down?

Value(s)
-

Yes
Go to Step (2)
Go to Step (3)

Go to Step (4)

No
Go to OBD
System Check
Section
Repair faulty
Oiling System

Intermittent
problem
Go to
Intermittent
section

•
•

Key OFF
Disconnect oil pressure switch harness connector
C005
• Clear DTC 524
• Start engine, let idle for at least one minute with
ECT over 160 degrees F.
• Increase engine speed above 600 RPM
Does DTC 524 reset?

Go to Step (6)

Go to Step (5)

• Replace oil pressure switch
Is the replacement complete?
• Key OFF
• Disconnect ECM harness connector C001
• Using a DVOM check for continuity between oil
pressure switch connector LT GRN/BLK wire and
engine ground.
• Do you have continuity between them?
• Inspect ECM connector pin 37 for damage
corrosion or contamination
Did you ﬁnd a problem?

Go to Step (9)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (9)

Go to Step (7)

•
•

Replace ECM
Is the replacement complete?

Go to Step (8)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
9

Action
Remove all test equipment except the DST.
Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-524 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•

DIAGNOSTIC TROUBLE CODES 7-125
Value(s)

Yes
System OK

No
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-126

DTC 562-System Voltage Low SPN/FMI 168:17

Conditions for Setting the DTC
•
•
•
•
•

System Voltage to ECM
Check Condition-Key on with engine speed greater than 1500 RPM
Fault Condition-Battery voltage at ECM less than 9.0 volts for more than 5 seconds
MIL-On for active fault and for 10 seconds after active fault
Adaptive-Disabled and for the for remainder of key ON cycle

Circuit Description
The battery voltage powers the ECM and must be measured to correctly operate injector drivers, fuel trim valves and
ignition coils. This fault will set if the ECM detects system voltage less than 9.0 for 5 seconds or longer while the alternator
should be charging. The adaptive learn is disabled during this fault for the remainder of the key cycle.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

DIAGNOSTIC TROUBLE CODES 7-127

DTC 562- System Voltage Low SPN/FMI 168:17

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

Key On, Engine Running
DST (Diagnostic Scan Tool) connected in
System Data Mode
Does DST display system voltage greater than 9.0
volts?
•
•

Yes
Go to Step (2)

Intermittent
problem
Go to Engine
Electrical
Intermittent
section

Go to Step (4)

• Check battery condition
Is it OK?
• Check charging system
Is it Ok?

Go to Step (5)

•

Check the voltage at ECM connector C001 pins
60 and 79
• Measure voltage with DVOM between each pin
and engine ground
Is the voltage greater than 9.0 volts?

Repair ECM
Ground circuit.
Go to Power
and Ground
section
in engine
Electrical
Repair ECM
power circuit.
Go to Power
and Ground
section
in engine
Electrical
Go to Step (8)

System OK

Check the voltage at ECM connector pins
69 and 81
• Measure voltage with DVOM between each pin
and battery positive
Is the voltage greater than 9.0 volts?
Replace ECM
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-562 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•

7
8

No
Go to OBD
System Check
Section
Go to Step (3)

Replace
Battery
Repair
charging
System
Go to Step (6)

Go to step (7)

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-128

DTC 563-System Voltage High SPN/FMI 168:15

Conditions for Setting the DTC
•
•
•
•
•

System Voltage to ECM
Check Condition-Cranking or Running
Fault Condition-System battery voltage at ECM greater than 18 volts for 3 seconds
MIL-On for active fault and for 5 seconds after active fault
Adaptive-Disabled for remainder of key cycle

Circuit Description
The battery voltage powers the ECM and must be measured to correctly operate injector drivers, trim valves and ignition
coils. This fault will set if the ECM detects voltage greater than 18 volts for 3 seconds or more anytime the engine is
cranking or running. The adaptive learn function is disabled during this fault and for the remainder of the key cycle. The
ECM will shut down with internal protection if the system voltage ever exceeds 26 volts.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
1

DIAGNOSTIC TROUBLE CODES 7-129

DTC 563- System Voltage High SPN/FMI 168:15

Action
Did you perform the On-Board (OBD) System Check?

2
•
•
•

Value(s)
-

Yes
Go to Step (2)

Go To Step (3)

Go to Step (4)

Go to Step (5)

Go to Step (6)

System OK

Go to OBD
System Check

Key On, Engine Running
DST (Diagnostic Scan Tool) connected in
System Data Mode
Run engine greater than 1500 rpm.

No
Go to OBD
System Check
Section
Intermittent
problem
Go to Engine
Electrical
Intermittent
section

Does DST display system voltage greater than 18
volts?
3
4
5
6

Check voltage at battery terminals with DVOM
with engine speed greater than 1500 rpm
Is it greater than 18 volts?
• Repair the charging system
Has the charging system been repaired?
• Replace ECM
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-563 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-130

DTC 601-Flash Checksum Invalid SPN/FMI 628:13

Conditions for Setting the DTC
•
•
•
•
•
•

Engine Control Module
Check Condition- Key on
Fault Condition- Internal microprocessor error
MIL- On
Adaptive- Disabled for the remainder of the key-ON cycle
Power Derate level 2

Circuit Description
The ECM has several internal checks that must be satisﬁed each time an instruction is executed. Several different things
can happen within the microprocessor that will cause this fault. The ECM will attempt to reset itself in the event this fault
is set. The MIL command is on and will remain on until the code is cleared using the DST. Power Derate level 2 will be
enforced limiting maximum throttle position to 20%.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
1
2

4
5

DIAGNOSTIC TROUBLE CODES 7-131

DTC 601- Flash Checksum Invalid SPN/FMI 628:13

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

Yes
Go to Step (2)

Key On, Engine Running
DST (Diagnostic Scan Tool) connected in
System Data Mode
• Clear system fault code
Does DTC 601 reset with the engine idling?
• Check ECM power and ground circuits
Are the power and ground circuits Ok?

Go to Step (3)

• Replace ECM
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-601 check for any stored
codes.
Does the engine operate normally with no stored
codes?

Go to Step (5)

•
•

Go to Step (4)

System OK

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-132

DTC 604-RAM Failure SPN/FMI 630:12

Conditions for Setting the DTC
•
•
•
•
•
•

Engine Control Module
Check Condition- Key on
Fault Condition- Internal microprocessor error
MIL- On
Adaptive- Disabled for the remainder of the key-ON cycle
Power Derate level 2

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
1
2

4
5

DIAGNOSTIC TROUBLE CODES 7-133

DTC 604- RAM Failure SPN/FMI 630:12

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

Yes
Go to Step (2)

Key On, Engine Running
DST (Diagnostic Scan Tool) connected in
System Data Mode
• Clear system fault code
Does DTC 604 reset with the engine idling?
• Check ECM power and ground circuits
Are the power and ground circuits Ok?

Go to Step (3)

• Replace ECM
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-604 check for any stored
codes.
Does the engine operate normally with no stored
codes?

Go to Step (5)

•
•

Go to Step (4)

System OK

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-134

DTC 606-COP Failure SPN/FMI 629:31

Conditions for Setting the DTC
•
•
•
•
•
•

Engine Control Module
Check Condition- Key on
Fault Condition- Internal microprocessor error
MIL- On
Adaptive- Disabled for the remainder of the key-ON cycle
Power Derate level 2

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1
2

4
5

DIAGNOSTIC TROUBLE CODES 7-135

DTC 606- COP Failure SPN/FMI 629:31

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

Yes
Go to Step (2)

Key On, Engine Running
DST (Diagnostic Scan Tool) connected in
System Data Mode
• Clear system fault code
Does DTC 606 reset with the engine idling?
• Check ECM power and ground circuits
Are the power and ground circuits Ok?

Go to Step (3)

• Replace ECM
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-606 check for any stored
codes.
Does the engine operate normally with no stored
codes?

Go to Step (5)

•
•

Go to Step (4)

System OK

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-136

DTC 642-External 5 Volt Reference Low SPN/FMI 1079:4

Conditions for Setting the DTC

•
•
•
•
•

External 5 volt reference
Check Condition-Cranking with battery voltage greater than 8 volts and engine running
Fault Condition-5 volt reference voltage lower than 4.6 volts for more than 1 second
MIL-On during active fault and for 2 seconds after active fault
Adaptive-Disabled during active fault

Circuit Description
The External 5 volt supply powers many of the sensors and other components of the fuel system. The accuracy of the
5 volt supply is very important to the accuracy of the powered sensors and fuel control by the ECM. The ECM is able to
determine if they are overloaded, shorted, or otherwise out of speciﬁcation by monitoring the 5 volt supply. This fault will
set if the 5 volt reference is below 4.6 volts for one second. Adaptive Learn will be disabled during this fault

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
1

DIAGNOSTIC TROUBLE CODES 7-137

DTC 642 External 5V Reference Low SPN/FMI 1079:4

•
•

Key ON, Engine Running
DST (Diagnostic Scan Tool) connected in
System Fault Mode
Does DST display DTC 642?

Go to Step (3)

•
•
•

Key OFF
Disconnect ECM connector C001
Using DVOM check for continuity between ECM 5
volt reference pin 19 and engine ground
Do you have continuity?

Go to Step (5)

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section
Go to Step (4)

• Replace ECM
Is the replacement complete?
• While monitoring DVOM for continuity between
ECM 5 volt reference and engine ground
disconnect each sensor (below) one at a time to
ﬁnd the shorted 5 volt reference. When continuity
to ground is lost the last sensor disconnected is
the area of suspicion. Inspect the 5 volt reference
supply wire leads for shorts before replacing the
sensor.
• IAT
• ECT
• TMAP
• Electronic Throttle
• Gasoline Sensor
• FPP
• TPS 1
• TPS 2
• Crankshaft Sensor
• Camshaft Sensor

Go to Step (7)

Go to Step (6)

Repair shorted
wire harness

Go to step (7)

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

Yes
Go to Step (2)

While disconnecting each sensor one at a time did
you loose continuity?
6

• Replace Sensor
Is the replacement complete?

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
7

Action
Remove all test equipment except the DST.
Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-642 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•

DIAGNOSTIC TROUBLE CODES 7-138
Value(s)

Yes
System OK

No
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-139

DTC 643-External 5 Volt Reference High SPN/FMI 1079:3

Conditions for Setting the DTC
•
•
•
•
•

External 5 volt reference
Check Condition-Cranking with battery voltage greater than 8 volts or engine running
Fault Condition-5 volt reference higher than 5.4 volts for more than 1 second
MIL-On during active fault and for 2 seconds after active fault
Adaptive-Disabled during active fault

Circuit Description
The External 5 volt supply powers many of the sensors and other components in the fuel system. The accuracy of the
5 volt supply is very important to the accuracy of the powered sensors and fuel control by the ECM. The ECM is able to
determine if they are overloaded, shorted, or otherwise out of speciﬁcation by monitoring the 5volt supply. This fault will
set if the 5 volt reference is above 5.4 volts for more than one second. Adaptive Learn will be disabled during this fault

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

DIAGNOSTIC TROUBLE CODES 7-140

DTC 643 External 5 Volt Reference High SPN/FMI 1079:3

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

Yes
Go to Step (2)

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (5)

•
•

Key ON, Engine running
DST (Diagnostic Scan Tool) connected in
System Data Mode
Does DST display DTC 643?

Go to Step (3)

• Check all ECM ground connections
Refer to Engine electrical power and ground
distribution.
Are the ground connections Ok?

Go to Step (4)

•
•
•
•

Key OFF
Disconnect ECM connector C001
Key ON
Using DVOM check for Voltage between ECM
harness wire pin 19 and engine ground
Do you have voltage?

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

• Replace ECM
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-643 check for any stored
codes.
Does the vehicle engine normally with no stored
codes?

Go to Step (6)

System OK

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-141

DTC 685-Relay Coil Open SPN/FMI 1485:5

Conditions for Setting the DTC
•
•
•

Power relay check
Check Condition-Key ON
Fault Condition- Relay coil open

Circuit Description
The power relay switches power out to various sensors, actuators and solenoids in the fuel system. This fault will
set if the ECM detects an open circuit on the relay control output.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

3
4
5

DIAGNOSTIC TROUBLE CODES 7-142

DTC 685- Relay Coil Open SPN/FMI 1485:5

Go to step (4)

No
Go to OBD
System Check
Section
Go to step (3)

Go to step (9)

Replace fuse
F2
Go to step (6)

Go to step (5)

Check all system fuses.
Check all relay placement positions in fuse
block.
• Run complete pin to pin checks on chassis
wiring to fuel system harness.
• See complete fuel system schematic for
further details
Did you ﬁnd the problem?
• Replace the ECM
• Is the replacement complete?

Go to step (9)

Go to step (8)

Go to step (9)

•
•
•
•

•
•

Value(s)
-

Yes
Go to Step (2)

Go to step (7)

Repair the
open circuit as
required. See
wiring harness
repairs
Repair the
open circuit as
required. See
wiring harness
repairs

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
9

Action
Remove all test equipment except the DST.
Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-685 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•

DIAGNOSTIC TROUBLE CODES 7-143
Value(s)

Yes
System OK

No
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-144

DTC 686-Relay Control Ground Short SPN/FMI 1485:4

Conditions for Setting the DTC
•
•
•

Power relay ground control
Check Condition-Key ON
Fault Condition- Relay control shorted to ground

Circuit Description
The power relay switches power out to various sensors, actuators and solenoids in the fuel system. This fault will
set if the ECM detects a direct short to ground on the relay control output.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

DTC 686- Relay Control Ground Short SPN/FMI 1485:4

Action
Did you perform the On-Board (OBD) System Check?
Key On, DST connected in the System Data
mode
• Clear DTC 686
• Start the engine
Does DTC 686 re-set?

Go to Step (4)

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section

Disconnect ECM connector C001
Using a DVOM check the resistance value
between ECM pin 71 and engine ground
Is the resistance less than 60 ohms?
• Remove the power relay from the fuse block
• Using a DVOM check the resistance value
again between ECM pin 71 and engine
ground
Is the resistance less than 60 ohms?

Go to step (5)

Go to step (7)

Repair the
shorted to
ground relay
control circuit
as necessary.
See wiring
harness repairs
Go to step (8)

Go to step (6)

Go to step (8)

•

•
•

4
5

6
7
8

DIAGNOSTIC TROUBLE CODES 7-145

• Replace the power relay
Is the replacement complete?
• Replace ECM
• Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-686 check for any stored
codes.
Does the engine operate normally with no stored
codes?

Value(s)
-

Yes
Go to Step (2)

System OK

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-146

DTC 687-Relay Coil Short to Power SPN/FMI 1485:3

Conditions for Setting the DTC
•
•
•

Power relay check
Check Condition-Key ON
Fault Condition- Relay coil shorted to power

Circuit Description
The power relay switches power out to various sensors, actuators and solenoids in the fuel system. This fault will
set if the ECM detects a short circuit to power on the relay control output.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

3
4
5

6
7

DIAGNOSTIC TROUBLE CODES 7-147

DTC 687- Relay Coil Short to Power SPN/FMI 1485:3

Action
Did you perform the On-Board (OBD) System Check?
DST connected and in the system data mode
Key OFF
Remove the power relay from the fuse block
Using a DVOM check the resistance of the
relay coil between terminals 85 and 86
Is the resistance value less than 60 ohms?
• Replace the power relay
Is the replacement complete?
• Using a DVOM check for continuity between
relay terminals 85 and 30
Do you have continuity between them?
• Disconnect ECM wire harness connector
C001
• Using a DVOM check for power between
ECM pin 71 and engine ground with the key
ON
Do you have power?
• Replace the power relay
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-687 check for any stored
codes.
Does DTC 687 still re-set?

Value(s)
-

•
•
•
•

•
•

Replace the ECM
Is the replacement complete?

System
battery
voltage

Yes
Go to Step (2)
Go to step (3)

No
Go to OBD
System Check
Section
Go to step (4)

Go to step (9)

Go to step (3)

Go to step (5)

Repair the
short to power.
See wiring
harness repair.

Go to step (6)

Go to step (7)

Go to step (8)

Go to step (9)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
9

Action
Remove all test equipment except the DST.
Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-687 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•

DIAGNOSTIC TROUBLE CODES 7-148
Value(s)

Yes
System OK

No
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-149

DTC 1111-Fuel Rev Limit SPN/FMI 515:16

Conditions for Setting the DTC
•
•
•
•

Fuel Rev Limit
Check Condition- Engine Running
Fault Condition- Engine RPM greater than 3400 for 2 seconds continuously
MIL- On during active fault

Circuit Description
This fault will set anytime Engine RPM is greater than 3400 for 2 seconds continuously. When these conditions are met the
ECM cuts off fueling. This is to help prevent engine or equipment damage. The MIL will be on during this active fault.

Diagnostic Aid
Always check for other stored DTC codes before using the following DTC chart for this code set. Repair any existing codes
starting with the lowest numerical code ﬁrst.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

DIAGNOSTIC TROUBLE CODES 7-150

DTC 1111-Fuel Rev Limit SPN/FMI 515:16

• Key ON, Engine OFF
• DST in Active Fault Mode
Are any other DTC codes present with DTC 1111?

Go to Step (3)

No
Go to OBD
System Check
Section
Go to Step (4)

•

Diagnose and repair any other DTC codes before
proceeding with this chart.
Have any other DTC codes been diagnosed and
repaired?
• Check the service part Number on the ECM to
ensure correct calibration is in use
Is the service part Number Correct?
• Replace ECM with the correct service part number
Is the replacement complete?
• Check the mechanical operation of the throttle
Is the mechanical operation of the throttle OK?
• Correct mechanical operation of the throttle. Refer
to Engine & Component section
Has the mechanical operation of the throttle been
corrected?
• Check engine for large manifold vacuum leaks.
Refer to Fuel Systems symptom diagnostics
Did you ﬁnd and correct the vacuum leak?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses, etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-1111 check for any stored
codes.
Does the engine operate normally with no stored
codes?

Go to step (4)

4
5
6
7

8
9

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

Yes
Go to Step (2)

Go to Step (6)
Go to Step (9)
Go to Step (8)

Go to Step 5
Go to Step (7)

Go to step (9)

Go to Step (9)

Go to OBD
System Check
Section
Go to OBD
System Check

System OK

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-151

DTC 1112-Spark Rev Limit SPN/FMI 515:0

Conditions for Setting the DTC
•
•
•
•
•

Spark Rev Limit
Check Condition- Engine running
Fault Condition- Engine RPM greater than 3600
MIL- On during active fault
Engine Shut Down

Circuit description
This fault will set anytime the engine RPM exceeds 3600. During this condition the ECM will shut off spark to the engine.
This is to help prevent engine or equipment damage. The MIL command is ON during this active fault and the engine will
shut down.

Diagnostic Aid
Always check for other stored DTC codes before using the following DTC chart for this code set. Repair any existing codes
starting with the lowest numerical code ﬁrst.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

DIAGNOSTIC TROUBLE CODES 7-152

DTC 1112- Spark Rev Limit SPN/FMI 515:0

• Key ON, Engine OFF
• DST connected
Are any other DTC codes present with DTC 1112?

Go to Step (3)

No
Go to OBD
System Check
Section
Go to Step (4)

•

Diagnose any other DTC codes before proceeding
with this chart.
Have any other DTC codes been diagnosed and
repaired?
• Check the service part number on the ECM to
ensure correct calibration is in use
Is the service part number Correct?
• Replace ECM with correct service part Number
Is the replacement complete?
• Check the mechanical operation of the throttle
Is the mechanical operation of the throttle OK?
• Correct mechanical operation of the throttle. Refer
to Engine & Component section
Has the mechanical operation of the throttle been
corrected?
• Check engine for large manifold vacuum
leaks. Refer to Fuel Systems section Symptom
Diagnostics
Did you ﬁnd and correct the vacuum leak?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses, etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-1112 check for any stored
codes.
Does the engine operate normally with no stored
codes?

Go to step (4)

4
5
6
7

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

Yes
Go to Step (2)

Go to Step (6)
Go to Step (9)
Go to Step (8)

Go to Step 5
Go to Step (7)

Go to step (9)

Go to Step (9)

Go to OBD
System Check
Section

System OK

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-153

DTC 1151- Closed Loop Multiplier High LPG SPN/FMI 520206:0

Conditions for Setting the DTC
•
•
•
•

Heated Oxygen Sensor
Check Condition- Engine running
Fault Condition- Closed Loop multiplier out of range (greater than 35%)
MIL- ON

Circuit description
The HO2S sensor is used to determine if the fuel ﬂow to the engine is correct by measuring the oxygen content in the
exhaust gas. The ECM uses this information to correct the fuel ﬂow with the Closed Loop multiplier and the adaptive
multiplier. This fault sets if the Closed Loop multiplier exceeds the limits of normal operation and cannot correctly modify
the fuel ﬂow within its limits

Diagnostic Aid
Oxygen Sensor Wire Heated Oxygen sensor wires may be mis-routed and contacting the exhaust manifold.
Vacuum Leaks Large vacuum leaks and crankcase leaks can cause a lean exhaust condition at especially at light load.
Fuel Mixer System can be lean due to faulty EPR (Electronic Pressure Regulator) or faulty fuel mixer.
Fuel Pressure Low fuel pressure, faulty fuel regulator or contaminated fuel ﬁlter can cause fuel the system to run lean
Exhaust Leaks If there is an exhaust leak, outside air can be pulled into the exhaust and past the 02 sensor causing a false lean
condition.
Fuel Quality Contaminated or spoiled fuel can cause the fuel system to be lean.
Ground Problem ECM grounds must be clean, tight and in the proper location.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

DIAGNOSTIC TROUBLE CODES 7-154

DTC 1151- Closed Loop Multiplier High LPG SPN/FMI 520206:0

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

Yes
Go to Step (2)
Go to step (3)

Key On, Engine Running
DST (Diagnostic Scan Tool) connected in
System Data Mode
• Run engine to full operating temperature and then
idle for a minimum of 2 minutes
Does DST display EGO 1 voltage ﬁxed below 0.35
volts after 2 minutes of idle run time?
•
•

5
6
7

•
•
•
•

Key OFF
Disconnect ECM connector C001
Disconnect EGO 1 wire harness connector C006
Using a high impedance DVOM check for
continuity between EGO 1 connector signal pin C
and engine ground

Do you have continuity?
• Using a high impedance DVOM check for
continuity between EGO 1 connector signal pin C
and EGO 1 connector signal ground pin D
• Do you have continuity between them?

• Refer to Diagnostic aids for DTC 1151
Did you check the diagnostic Aids for DTC 1151?
• Replace EGO 1 sensor
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-1151 check for any stored
codes.
Does the engine operate normally with no stored
codes?

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

Go to Step (4)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (6)

Go to Step (5)

Go to Step (7)
System OK

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-155

DTC 1152- Closed Loop Multiplier Low LPG SPN/FMI 520206:1

Conditions for Setting the DTC
•
•
•

Heated Oxygen Sensor
Functional Fault-Closed Loop multiplier out of range (at limit of -35%)
MIL Disabled

Circuit Description
The EGO 1 sensor is used to determine if the fuel ﬂow to the engine is correct by measuring the oxygen content in the
exhaust gas. The ECM uses this information to correct the fuel ﬂow with the Closed Loop multiplier and the adaptive
multiplier. This fault sets if the Closed Loop multiplier exceeds the limits of normal operation. When the multiplier cannot
correctly modify the fuel ﬂow within its limits, it is limited at -35%.

Diagnostic Aid
Fuel System High secondary fuel pressure may cause the system to run rich. A worn fuel mixer, faulty EPR (Electronic
Pressure Regulator) may also cause the system to run rich.
Fuel Quality A drastic variation in fuel quality (very high butane content) may cause the fuel system to run rich. Be sure
that the speciﬁed HD-5 or HD-10 motor fuel grade propane is used
Air Filter A plugged, damaged or modiﬁed air ﬁlter may cause the system to run rich.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

DTC 1152- Closed Loop Multiplier Low LPG SPN/FMI 520206:1

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

Yes
Go to Step (2)
Go to step (3)

•
•
•

DIAGNOSTIC TROUBLE CODES 7-156

Key On, Engine Running
DST (Diagnostic Scan Tool) connected in
System Data Mode
Run engine to full operating temperature and then
idle for a minimum of 2 minutes

Does DST display HO2S voltage ﬁxed above 0.7 volts
after 2 minutes of idle run time?
• Key OFF
• Disconnect HO2S wire harness connector
• Disconnect ECM wiring harness connector
• Key ON
• Using a high impedance DVOM check for voltage
between HO2S connector signal pin C and
engine ground
Do you have voltage?

Repair wire
harness
shorted signal
to voltage
Refer to
Wiring Repairs
in Engine
Electrical.

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section

Refer to
Diagnostic Aids
for DTC 1152

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-157

DTC 1155 -Closed Loop Multiplier High Gasoline SPN/FMI 520204:0

Conditions for Setting the DTC
•
•
•

Heated Oxygen Sensor
Functional Fault-Closed Loop multiplier out of range (at limit of 35%)
MIL-On during active fault

Circuit Description
The HO2S sensor is used to determine if the fuel ﬂow to the engine is correct by measuring the oxygen content in the
exhaust gas. The ECM uses this information to correct the fuel ﬂow with the Closed Loop multiplier and the Adaptive
multiplier. This fault will set if the Closed Loop multiplier exceeds 35%. The MIL command is ON

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-158

DTC 1155- Closed Loop Multiplier High Gasoline SPN/FMI 520204:0

Step
1

Action
Did you perform the On-Board (OBD) System Check?

•

5
6
7

Yes
Go to Step (2)
Go to step (3)

•
•

Value(s)
-

Key On, Engine Running
DST (Diagnostic Scan Tool) connected in
System Data Mode
Run engine to full operating temperature and then
idle for a minimum of 2 minutes

Does DST display EGO 1 voltage ﬁxed below 0.35
volts after 2 minutes of idle run time?
• Key OFF
• Disconnect EGO 1 sensor connector C006
• Disconnect ECM connector C001
• Using a high impedance DVOM Check for
continuity between EGO 1 connector signal pin C
and engine ground
Do you have continuity?
• Using a high impedance DVOM Check for
continuity between EGO 1 connector signal pin C
and EGO 1 sensor ground pin D
Do you have continuity?

• Refer to Diagnostic aids for DTC 1155
Did you check the diagnostic Aids for DTC 1155?
• Replace EGO 1 sensor
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-1155 check for any stored
codes.
Does the engine operate normally with no stored
codes?

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section

Repair the
circuit as
required
Refer to
Wiring Repairs
in Engine
Electrical.
Repair the
circuit as
required
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (6)

Go to Step (4)

Go to Step (7)

Go to Step (5)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-159

DTC 1156- Closed Loop Multiplier Low Gasoline SPN/FMI 520204:1

Conditions for Setting the DTC
• Heated Oxygen Sensor
• Functional Fault-Closed Loop multiplier out of range (at limit of -35%)
• MIL-On during active fault and for one update after active fault

Circuit Description
The HO2S (Heated Oxygen Sensor) sensor is used to determine if the fuel ﬂow to the engine is correct by measuring the
oxygen content in the exhaust gas. The ECM uses this information to correct the fuel ﬂow with the Closed Loop multiplier
and the adaptive multiplier. This fault will set if the Closed Loop multiplier is less than -35%. The MIL command is ON.

Diagnostic Aid
Check for other DTC codes Correct those starting with the lowest code set number before proceeding with the diagnostic chart.
Fuel System The system will be rich if an injector fails in an open manner. High fuel pressure due to a faulty fuel regulator or obstructed
fuel return line will cause the system to run rich.
Ignition noise open or poor ground circuit to or in the ignition system or ECM may cause EMI (Electromagnetic interference). This
noise could be interpreted by the ECM as ignition pulses, and the sensed RPM becomes higher than the actual speed. The ECM then
delivers too much fuel, causing the system to run rich.
TMAP Sensor A higher manifold pressure than normal can cause the system to go rich. Temporarily disconnecting the MAP Sensor will
allow the ECM to set a default value for MAP.
IAT Sensor Check for a shifted sensor that could cause the ECM to sense lower than actual temperature of incoming air. This can
cause a rich exhaust condition.
ECT Sensor Check for a skewed sensor that could cause the ECM to sense engine temperature colder than it actually is. This could
also cause a rich exhaust condition.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-160

DTC 1156- Closed Loop Multiplier Low Gasoline SPN/FMI: 520204:1

Step
1

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

Yes
Go to Step (2)
Go to step (3)

Key On, Engine Running
DST (Diagnostic Scan Tool) connected in
System Data Mode
• Run engine to full operating temperature and then
idle for a minimum of 2 minutes
Does DST display EGO 1 voltage ﬁxed above 0.7
volts after 2 minutes of idle run time?
•
•

Key OFF
Disconnect EGO 1 wire connector C006
Disconnect ECM wiring harness connector C001
Key ON
Using a high impedance DVOM check for voltage
between EGO 1 connector signal pin C and
engine ground
Do you have voltage?
•
•
•
•
•

Repair the
circuit as
required
Refer to
Wiring Repairs
in Engine
Electrical.

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section

Refer to
Diagnostic Aid
for DTC 1156

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-161

DTC 1161-Adaptive Learn High LPG SPN/FMI 520202:0

Conditions for Setting the DTC
•
•
•
•

Heated Oxygen Sensor
Check Condition- Engine Running
Fault Condition- Adaptive multiplier out of range (greater than +30%)
MIL- On

Circuit Description
The EGO 1 sensor is used to determine if the fuel ﬂow to the engine is correct by measuring the oxygen content in
the exhaust gas. The ECM uses this information to correct the fuel ﬂow with the Closed Loop multiplier and Adaptive
multiplier. This fault will set if the adaptive multiplier exceeds the limits of normal operation.

Diagnostic Aid
Oxygen Sensor Wire Heated Oxygen sensor wires may be mis-routed and contacting the exhaust manifold.
Vacuum Leaks Large vacuum leaks and crankcase leaks can cause a lean exhaust condition at especially at light load.
Fuel Mixer System can be lean due to faulty EPR (Electronic Pressure Regulator) or faulty fuel mixer.
Fuel Pressure Low fuel pressure, faulty fuel regulator or contaminated fuel ﬁlter can cause fuel the system to run lean
Exhaust Leaks If there is an exhaust leak, outside air can be pulled into the exhaust and past the 02 sensor causing a
false lean condition.
Fuel Quality Contaminated or spoiled fuel can cause the fuel system to be lean.
Ground Problem ECM grounds must be clean, tight and in the proper location.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1
2

DIAGNOSTIC TROUBLE CODES 7-162

DTC 1161 Adaptive Learn High LPG SPN/FMI 520202:0

Action
• Perform the On-Board (OBD) System Check?
Are any other DTCs present?

Value(s)

System
voltage

Yes
Go to Step (3)

No
Go to Step (2)

Go to Step (8)

Go to Step (4)

Go to Step (8)

Go to step (4)

Go to Step (5)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

Repair the
shorted circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

Go to Step (6)

Repair the
shorted circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (8)

Go to Step (7)

(CHECK MUST BE MADE WITHIN 30 SECONDS
OR BEFORE POWER RELAY SHUTS DOWN)
Do you have voltage?
5

• Replace EGO 1 sensor
Is the replacement complete?

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
8

Action
Remove all test equipment except the DST.
Connect any disconnected components, fuses, etc.
Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-1161 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•
•

DIAGNOSTIC TROUBLE CODES 7-163
Value(s)

Yes
System OK

No
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-164

DTC 1162-Adaptive Learn Low (LPG) SPN/FMI 520202:1

Conditions for Setting the DTC
•
•
•
•

Heated Oxygen Sensor
Check Condition- Engine running
Fault Condition- Adaptive multiplier out of range (at limit of -30%)
MIL-On

Circuit Description
The EGO1 sensor is used to determine if the fuel ﬂow to the engine is correct by measuring the
oxygen content
in the exhaust gas. The ECM uses this information to correct the fuel ﬂow
with the Closed Loop multiplier
and Adaptive multiplier. This fault will set if the adaptive multiplier exceeds the limits of normal operation.

Diagnostic Aid
Fuel System High secondary fuel pressure will cause the system to run rich. A worn fuel mixer, faulty EPR (Electronic Pressure Regulator)
may also cause the system to run rich.
Fuel Quality A drastic variation in fuel quality (very high butane content) may cause the fuel system to run rich. Be sure that the speciﬁed
HD-5 or HD-10 motor fuel grade propane is used.
Air Filter A plugged, damaged or modiﬁed air ﬁlter may cause the system to run rich.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
1
2

DIAGNOSTIC TROUBLE CODES 7-165

DTC 1162-Adaptive Learn Low LPG SPN/FMI 520202:1

Action
• Perform the On-Board (OBD) System Check?
Are any other DTCs present?

Value(s)

System
voltage

Yes
Go to Step (3)

No
Go to Step (2)

Go to Step (8)

Go to Step (4)

Go to Step (8)

Go to step (4)

Go to Step (5)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

Repair the
shorted circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

Go to Step (6)

Repair the
shorted circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (8)

Go to Step (7)

(CHECK MUST BE MADE WITHIN 30 SECONDS
OR BEFORE POWER RELAY SHUTS DOWN)
Do you have voltage?
5

• Replace EGO 1 sensor
Is the replacement complete?

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
8

Action
Remove all test equipment except the DST.
Connect any disconnected components, fuses, etc.
Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-1162 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•
•

DIAGNOSTIC TROUBLE CODES 7-166
Value(s)

Yes
System OK

No
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-167

DTC 1165 LPG Catalyst Monitor SPN/FMI 520213:10

Conditions for Setting the DTC
•
•
•
•
•

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-168

DTC1171- EPR Pressure Higher Than Expected SPN/FMI 520260:0
5202

Conditions for Setting the DTC
•
•
•
•
•
•

EPR delivery pressure
Check condition-Engine running or cranking
MIL-On during active fault
Fault condition-EPR actual pressure greater than 4.0 inches above commanded pressure
Adaptive disabled
Power derate level 1

Circuit Description
The EPR (Electronic Pressure Regulator) unit measures and controls the amount of fuel that is able to pass to the fuel
mixer. Pressure readings are sent over the CAN to the ECM and in return the ECM sends back a control signal to the
EPR to increase or decrease pressure for precise mixture control. This code will set in the event the actual pressure is
4.0 inches water pressure higher than the actual commanded pressure. The MIL command is on. Adaptive and closed
loop are disabled with power derate level 1 enforced limiting throttle position to 70% maximum.

Diagnostic Aid

Always run the fuel system diagnostic pressure check before proceeding with the following diagnostic chart. High
secondary fuel pressure due to a worn or damaged primary or secondary seat may cause this fault to set

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1
2
3

DTC 1171-EPR Pressure Higher Than Expected SPN/FMI 520260:0
Action
Did you perform the On-Board (OBD) System Check?
Did you run the fuel pressure diagnostic test
in the fuel system diagnostic section with no
problems found?
• Run the EPR pressure test in the fuel system
diagnostic section
Did the EPR pass the fuel pressure test
speciﬁcations?
•

Inspect the EPR electrical connector C026 for
damage, corrosion or contamination.
Did you ﬁnd a problem?

• Replace the EPR
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC1171 check for any stored
codes.
Does the engine operate normally with no stored
codes?

DIAGNOSTIC TROUBLE CODES 7-169

Value(s)
-

Yes
Go to Step (2)
Go to step (4)

No
Go to OBD System
Check Section
Go to step 3

Go to step (4)

Follow the
EPR service
recommendations
from the fuel
pressure test chart.

Repair the
circuit as
necessary.
Refer to wire
harness repair
section.
Go to step (6)

Go to step (5)

System OK

Go to OBD System
Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-170

DTC1172- EPR Pressure Lower Than Expected SPN/FMI 520260:1

Conditions for Setting the DTC
•
•
•
•
•
•

EPR delivery pressure
Check condition-Engine running or cranking
MIL-On during active fault
Fault condition-EPR actual pressure less than 4.0 inches below commanded pressure
Adaptive disabled
Power derate level 1

Circuit Description
The EPR (Electronic Pressure Regulator) unit measures and controls the amount of fuel that is able to pass to the fuel
mixer. Pressure readings are sent over the CAN to the ECM and in return the ECM sends back a control signal to the
EPR to increase or decrease pressure for precise mixture control. This code will set in the event the actual pressure is
4.0 inches water pressure lower than the actual commanded pressure. The MIL command is on. Adaptive and closed
loop are disabled with power derate level 1 enforced limiting throttle position to 70% maximum.

Diagnostic Aid

Always run the fuel system diagnostic pressure check before proceeding with the following diagnostic chart. Low
secondary fuel pressure due to a fuel restriction or faulty regulator may cause this fault.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

DTC 1172-EPR Pressure Lower Than Expected SPN/FMI 520260:1
Action
Did you perform the On-Board (OBD) System Check?

Did you run the fuel pressure diagnostic test
in the fuel system diagnostic section with no
problems found?
• Run the EPR pressure test in the fuel system
diagnostic section
Did the EPR pass the fuel pressure test
speciﬁcations?
•

Inspect the EPR electrical connector C026 for
damage, corrosion or contamination.
Did you ﬁnd a problem?

•

DIAGNOSTIC TROUBLE CODES 7-171

Replace the EPR

Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC1172 check for any stored
codes.
Does the engine operate normally with no stored
codes?

Value(s)
-

Yes
Go to Step (2)
Go to step (4)
Go to step (4)

Repair the
circuit as
necessary.
Refer to wire
harness repair
section.
Go to step (6)
System OK

No
Go to OBD System
Check Section
Go to step 3
Follow the
EPR service
recommendations
from the fuel
pressure test chart.
Go to step (5)

_
Go to OBD System
Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-172

DTC1173- EPR Communication Lost SPN/FMI 520260:31

Conditions for Setting the DTC
•
•
•
•
•

EPR CAN communication
Check condition-Engine running or cranking
MIL-On during active fault
Fault condition-No packets received within 500 ms
Adaptive disabled

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DTC 1173-EPR Communication Lost SPN/FMI 520260:31

Step
1

Action
Did you perform the On-Board (OBD) System Check?

Key ON
DST (Diagnostic Scan Tool) connected in the
system data mode
• Clear DTC1173
• Key OFF
• Key ON, and attempt to start the engine
Does DTC1173 re-set
• Key OFF
• Disconnect EPR electrical connector C026
• Key ON
• Using a DVOM check for system power
between EPR connector pin 7 and engine
ground
(Be sure to activate relay control ON using the DST
function or check before ECM relay control times out)
Do you have power?
• Check the 10A (F3) fuse
Is the fuse open?
• Replace F3 fuse
Is the replacement complete?
• Using a DVOM check for system power at
power relay terminal 87
(Be sure to activate relay control ON using the DST
function or check before ECM relay control times out)
Do you have power?

4
5
6

DIAGNOSTIC TROUBLE CODES 7-173

Value(s)
-

Using a DVOM check for continuity between
EPR connector pin 6 and engine ground
Do you have continuity?

Key OFF
Disconnect the EPR connector C026
Disconnect the ECM connector C001
Using a DVOM check for continuity between
EPR pin 1 and ECM pin 15
Do you have continuity?

•

•
•
•
•

Go to step (7)

No
Go to OBD
System Check
Section
Intermittent
problem. Go
to Intermittent
Problem
section in
the electrical
section of this
manual.
Go to step (4)

Go to step (5)

Go to step (6)

Go to step (17)

Go to step (3)

•
•

Yes
Go to Step (2)

System
battery
voltage

Repair the
open circuit
between power
relay pin 87
and EPR pin 7

Repair the
power relay
circuit as
required

Go to step (17)
Go to step (8)

Go to step (17)
Repair the
open ground
circuit as
necessary.
Refer to
wiring repairs
in engine
electrical
Repair the
open circuit
as necessary.
Refer to
wiring repairs
in engine
electrical

Go to step (9)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-174

Step
9

Action
Using a DVOM check for continuity between
EPR pin 2 and ECM pin 14
Do you have continuity?

Using a DVOM check for continuity between
EPR pin 3 and ECM pin 14
Do you have continuity?

Go to step (11)

Using a DVOM check for continuity between
EPR pin 6 and ECM pin 69
Do you have continuity?

Go to step (12)

Using a DVOM check for continuity between
EPR pin 6 and ECM pin 81
Do you have continuity?

Go to step (13)

Disconnect vehicle interface connector
C011
• Disconnect DST from the DLC connector
C016
• Using a DVOM check for continuity between
engine ground and EPR pins 1 and 3
Do you have continuity?

• Replace the EPR
Is the replacement complete?
• Remove all test equipment and reconnect the
DST.
• Connect any disconnected components,
fuses, etc.
• Using the DST clear DTC information from
the ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to
full operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC1173 check for any stored
codes.
Does DTC1173 still re-set?

Repair the
shorted to
ground CAN
circuit as
necessary.
Refer to
wiring repairs
in engine
electrical
Go to step (15)

•

Value(s)

Yes
Go to step (10)

Go to step (16)

No
Repair the
open circuit
as necessary.
Refer to
wiring repairs
in engine
electrical
Repair the
open circuit
as necessary.
Refer to
wiring repairs
in engine
electrical
Repair the
open circuit
as necessary.
Refer to
wiring repairs
in engine
electrical
Repair the
open circuit
as necessary.
Refer to
wiring repairs
in engine
electrical
Go to step (14)

_
System OK

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
16
17

Action
• Replace the ECM
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components,
fuses, etc.
• Using the DST clear DTC information from
the ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to
full operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC1173 check for any stored
codes.
Does the engine operate normally with no stored
codes?

DIAGNOSTIC TROUBLE CODES 7-175
Value(s)

Yes
Go to step (17)

No
_

System OK

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-176

DTC1174- EPR Supply Voltage High SPN/FMI 520260:3

Conditions for Setting the DTC
•
•
•
•
•
•

EPR supply voltage
Check condition-Engine running or cranking
MIL-On during active fault
Fault condition- internal EPR supply voltage too high
Adaptive disabled
Closed loop disabled

Diagnostic Aid
This DTC indicates abnormal EPR internal voltages that are not measurable externally. Check the system charging
voltage to be sure this DTC and other over voltage DTC’s are not present. Repair the charging system if it is found
to be out of speciﬁcation for high charge voltage. In the event of multiple code sets, always start the diagnostic repair
with the lowest numerical value DTC ﬁrst.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DTC 1174-EPR Voltage Supply High SPN/FMI 520260:3

Step
1

Action
Did you perform the On-Board (OBD) System Check?

DST connected and in the system data
mode
• Engine running
• Check the system battery voltage.
Is the charging voltage within speciﬁcations?
Using a DVOM compare the system battery voltage
to the DST display.
Is the voltage reading within 1 volt between the two of
them?
• Replace the EPR
Is the replacement complete?
• Replace the ECM
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC1174 check for any stored
codes.
Does the engine operate normally with no stored
codes?

4
5
6

DIAGNOSTIC TROUBLE CODES 7-177

Value(s)
-

Yes
Go to Step (2)
Go to step (3)

•

1 volt

Go to step (4)

No
Go to OBD
System Check
Section
Repair the
charging
system
Go to step (5)

Go to step (6)

System OK

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-178

DTC1175- EPR Supply Voltage Low SPN/FMI 520260:4

Conditions for Setting the DTC
•
•
•
•
•
•

EPR supply voltage
Check condition-Engine running or cranking
MIL-On during active fault
Fault condition-EPR internal supply voltage low
Adaptive disabled
Closed loop disabled

Diagnostic Aid
This DTC indicates abnormal EPR internal voltages that are not measurable externally. Check the system charging
voltage to be sure this DTC and other low voltage DTC’s are not present. Repair the charging system if it is found to
be out of speciﬁcation for low charge voltage. In the event of multiple code sets, always start the diagnostic repair with
the lowest numerical value DTC ﬁrst.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1
2

DIAGNOSTIC TROUBLE CODES 7-179

DTC 1175-EPR Voltage Supply Low SPN/FMI 520260:4

Action
Did you perform the On-Board (OBD) System Check?
• DST connected and in the system data mode
• Engine running
• Check the system battery voltage.
Is the charging voltage within speciﬁcations?
• Key OFF
• Disconnect the EPR electrical connector
C026
• Using a DVOM check for power between the
EPR connector pin 7 and engine ground.
• Key ON
• Record the voltage reading.

Value(s)
-

Yes
Go to Step (2)
Go to step (3)

Go to step (6)

No
Go to OBD
System Check
Section
Repair the
charging
system
Go to step (4)

(Be sure to activate relay control ON using the DST
function or check before ECM relay control times out)
Using a DVOM check the system battery
power at the battery terminals and record the
voltage reading.
Are the recorded voltage readings within 1 volt of
each other?
• Inspect the EPR connector and F3 fuse
holder terminals for damage corrosion or
contamination
Did you ﬁnd a problem?
•

Check the power relay circuit. Check
the power relay connections for damage
corrosion or contamination
Did you ﬁnd a problem?
•

Correct the
problem as
necessary.
See wiring
harness repair
in the electrical
section of this
manual
Correct the
problem as
necessary. See
wiring harness
schematic in
the electrical
section of this
manual

Go to step (5)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
6

Yes
Go to step (7)

No
Repair the poor
EPR power
ground circuit.
See wiring
harness repair
in the electrical
section of this
manual

• Replace the EPR
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components,
fuses, etc.
• Using the DST clear DTC information from
the ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to
full operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC1175 check for any stored
codes.
Does DTC 1175 still re-set?

Go to step (8)

Go to step (9)

System OK

• Replace the ECM
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC1175 check for any stored
codes.
Does the engine operate normally with no stored
codes?

Go to step (10)

System OK

Go to OBD
System Check

•
•
•

Action
Key OFF
Disconnect the ECM connector C001
Using a DVOM check the resistance reading
between EPR connector pin 6 and ECM
connector pin 69 and 81.

DIAGNOSTIC TROUBLE CODES 7-180
Value(s)
Less than .5
Ohms

(Do not forget to subtract any resistance value
that may be present in you test cables)
Is the resistance reading less than .5 ohms?
7
8

9
10

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-181

DTC1176- EPR Internal Actuator Fault SPN/FMI 520260:12

Conditions for Setting the DTC
•
•
•
•
•
•

EPR internal actuator test
Check condition-Engine running or cranking
MIL-On during active fault
Fault condition- Failed acuator
Adaptive disabled
Closed loop disabled

Circuit Description
The EPR (Electronic Pressure Regulator) unit measures and controls the amount of fuel that is able to pass to the fuel
mixer. Pressure readings are sent over the CAN to the ECM and in return the ECM sends back a control signal to the
EPR to increase or decrease pressure for precise mixture control. This code will set if the ECM detects an internal
actuator fault with the EPR. In the event of multiple code sets, always start the diagnostic repair with the lowest
numerical value DTC ﬁrst. In most instances the EPR will need to be replaced in the event of this code set.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1
2

3
4

5
6

DIAGNOSTIC TROUBLE CODES 7-182

DTC 1176-EPR Internal Actuator Fault SPN/FMI 520260:12

Action
Did you perform the On-Board (OBD) System Check?
DST connected and in the system data
mode
• Check for any other current or active
DTCs
Does the DST show any other codes set?
• Repair any other DTC’s set starting with the
lowest DTC number ﬁrst
Have the other DTC’s set been corrected?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC1176 check for any stored
codes.
Does DTC 1176 still re-set?

Go to step (3)

No
Go to OBD
System Check
Section
Go to step (6)

Go to step (4)

Go to step (5)

System OK

• Replace the EPR
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC1176 check for any stored
codes.
Does the engine operate normally with no stored
codes?

Go to step (6)

System OK

Go to OBD
System Check

•

Value(s)
-

Yes
Go to Step (2)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-183

DTC1177- EPR internal Circuitry Fault SPN/FMI 620260:12

Conditions for Setting the DTC
•
•
•
•
•
•

EPR internal circuitry test
Check condition-Engine running or cranking
MIL-On during active fault
Fault conditionAdaptive disabled
Closed loop disabled

Circuit Description
The EPR (Electronic Pressure Regulator) unit measures and controls the amount of fuel that is able to pass to the
fuel mixer. Pressure readings are sent over the CAN to the ECM and in return the ECM sends back a control signal
to the EPR to increase or decrease pressure for precise mixture control. This code will set if the ECM detects an
internal circuitry fault in the EPR. In the event of multiple code sets, always start the diagnostic repair with the lowest
numerical value DTC ﬁrst. In most instances the EPR will need to be replaced in the event of this code set.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1
2

3
4

5
6

DIAGNOSTIC TROUBLE CODES 7-184

DTC 1177-EPR Internal Circuitry Failure SPN/FMI 520260:12

Action
Did you perform the On-Board (OBD) System Check?
DST connected and in the system data
mode
• Check for any other current or active
DTCs
Does the DST show any other codes set?
• Repair any other DTC’s set starting with the
lowest DTC number ﬁrst
Have the other DTC’s set been corrected?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC1177 check for any stored
codes.
Does DTC 1177 still re-set?

Go to step (3)

No
Go to OBD
System Check
Section
Go to step (6)

Go to step (4)

Go to step (5)

System OK

• Replace the EPR
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC1177 check for any stored
codes.
Does the engine operate normally with no stored
codes?

Go to step (6)

System OK

Go to OBD
System Check

•

Value(s)
-

Yes
Go to Step (2)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-185

DTC1178- EPR Internal Communication Error SPN/FMI 520260:12

Conditions for Setting the DTC
•
•
•
•
•
•

EPR internal communication test
Check condition-Engine running or cranking
MIL-On during active fault
Fault conditionAdaptive disabled
Closed loop disabled

Circuit Description
The EPR (Electronic Pressure Regulator) unit measures and controls the amount of fuel that is able to pass to the fuel
mixer. Pressure readings are sent over the CAN to the ECM and in return the ECM sends back a control signal to the
EPR to increase or decrease pressure for precise mixture control. This code will set if the ECM detects an internal
communication error in the EPR. In the event of multiple code sets, always start the diagnostic repair with the lowest
numerical value DTC ﬁrst. In most instances the EPR will need to be replaced in the event of this code set.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1
2

3
4

5
6

DIAGNOSTIC TROUBLE CODES 7-186

DTC 1178-EPR Internal Comm Fault SPN/FMI 520260:12

Action
Did you perform the On-Board (OBD) System Check?
DST connected and in the system data
mode
• Check for any other current or active
DTCs
Does the DST show any other codes set?
• Repair any other DTC’s set starting with the
lowest DTC number ﬁrst
Have the other DTC’s set been corrected?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC1178 check for any stored
codes.
Does DTC 1178 still re-set?

Go to step (3)

No
Go to OBD
System Check
Section
Go to step (6)

Go to step (4)

Go to step (5)

System OK

• Replace the EPR
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC1178 check for any stored
codes.
Does the engine operate normally with no stored
codes?

Go to step (6)

System OK

Go to OBD
System Check

•

Value(s)
-

Yes
Go to Step (2)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-187

DTC 1612-RTI 1 Loss SPN/FMI 629:31

Conditions for Setting the DTC
•
•
•
•
•
•

Engine Control Module
Check Condition- Key on
Fault Condition- Internal microprocessor error
MIL- On
Adaptive- Disabled for the remainder of the key-ON cycle
Power Derate level 2

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
1
2

4
5

DIAGNOSTIC TROUBLE CODES 7-188

DTC 1612- RT 1 Loss SPN/FMI 629:31

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

Yes
Go to Step (2)

Key On, Engine Running
DST (Diagnostic Scan Tool) connected in
System Data Mode
• Clear system fault code
Does DTC 1612 reset with the engine idling?
• Check ECM power and ground circuits
Are the power and ground circuits Ok?

Go to Step (3)

• Replace ECM
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-1612 check for any stored
codes.
Does the engine operate normally with no stored
codes?

Go to Step (5)

•
•

Go to Step (4)

System OK

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-189

DTC 1613-RTI 2 Loss SPN/FMI 629:31

Conditions for Setting the DTC
•
•
•
•
•
•

Engine Control Module
Check Condition- Key on
Fault Condition- Internal microprocessor error
MIL- On
Adaptive- Disabled for the remainder of the key-ON cycle
Power Derate level 2

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1
2

4
5

DIAGNOSTIC TROUBLE CODES 7-190

DTC 1613- RTI 2 Loss SPN/FMI 629:31

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

Yes
Go to Step (2)

Key On, Engine Running
DST (Diagnostic Scan Tool) connected in
System Data Mode
• Clear system fault code
Does DTC 1613 reset with the engine idling?
• Check ECM power and ground circuits
Are the power and ground circuits Ok?

Go to Step (3)

• Replace ECM
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-1613 check for any stored
codes.
Does the engine operate normally with no stored
codes?

Go to Step (5)

•
•

Go to Step (4)

System OK

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-191

DTC 1614-RTI 3 Loss SPN/FMI 629:31

Conditions for Setting the DTC
•
•
•
•
•
•

Engine Control Module
Check Condition- Key on
Fault Condition- Internal microprocessor error
MIL- On
Adaptive- Disabled for the remainder of the key-ON cycle
Power Derate level 2

Circuit Description
The ECM has several internal checks that must be satisﬁed each time an instruction is executed. Several different
things can happen within the microprocessor that will cause this fault. The ECM will attempt to reset itself in the
event this fault is set. The MIL command is on and will remain on until the code is cleared using the DST. Power
Derate level 2 will be enforced limiting maximum throttle position to 20%.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1
2

4
5

DIAGNOSTIC TROUBLE CODES 7-192

DTC 1614- RTI 3 Loss SPN/FMI 629:31

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

Yes
Go to Step (2)

Key On, Engine Running
DST (Diagnostic Scan Tool) connected in
System Data Mode
• Clear system fault code
Does DTC 1614 reset with the engine idling?
• Check ECM power and ground circuits
Are the power and ground circuits Ok?

Go to Step (3)

• Replace ECM
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-1614 check for any stored
codes.
Does the engine operate normally with no stored
codes?

Go to Step (5)

•
•

Go to Step (4)

System OK

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-193

DTC 1615-A/D Loss SPN/FMI 629:31

Conditions for Setting the DTC
•
•
•
•
•
•

Engine Control Module
Check Condition- Key on
Fault Condition- Internal microprocessor error
MIL- On
Adaptive- Disabled for the remainder of the key-ON cycle
Power Derate level 2

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1
2

4
5

DIAGNOSTIC TROUBLE CODES 7-194

DTC 1615- A/D Loss SPN/FMI 629:31

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

Yes
Go to Step (2)

Key On, Engine Running
DST (Diagnostic Scan Tool) connected in
System Data Mode
• Clear system fault code
Does DTC 1615 reset with the engine idling?
• Check ECM power and ground circuits
Are the power and ground circuits Ok?

Go to Step (3)

• Replace ECM
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-1615 check for any stored
codes.
Does the engine operate normally with no stored
codes?

Go to Step (5)

•
•

Go to Step (4)

System OK

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-195

DTC 1616-Invalid Interrupt SPN/FMI 629:31

Conditions for Setting the DTC
•
•
•
•
•
•

Engine Control Module
Check Condition- Key on
Fault Condition- Internal microprocessor error
MIL- On
Adaptive- Disabled for the remainder of the key-ON cycle
Power Derate level 2

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1
2

4
5

DIAGNOSTIC TROUBLE CODES 7-196

DTC 1616- Invalid Interrupt SPN/FMI 629:31

Action
Did you perform the On-Board (OBD) System Check?

Value(s)
-

Yes
Go to Step (2)

Key On, Engine Running
DST (Diagnostic Scan Tool) connected in
System Data Mode
• Clear system fault code
Does DTC 1616 reset with the engine idling?
• Check ECM power and ground circuits
Are the power and ground circuits Ok?

Go to Step (3)

• Replace ECM
Is the replacement complete?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-1616 check for any stored
codes.
Does the engine operate normally with no stored
codes?

Go to Step (5)

•
•

Go to Step (4)

System OK

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section
Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-197

DTC 1626-CAN Tx Failure SPN/FMI 639:12

Conditions for Setting the DTC
•
•
•
•

CAN Tx
Check Condition- Engine running
Fault Condition- CAN Tx error 100 packets lost within 1 second
MIL- ON

Circuit description
The CAN bus (controller area network) is used by the ECM to communicate with other digital devices used throughout
the fuel system. Information is sent over the CAN bus in digital information “packets” that contain information for various
control functions. This fault will set if the ECM detects 100 packets lost within a one second time period. The MIL
command is ON.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1
2

DIAGNOSTIC TROUBLE CODES 7-198

DTC 1626- CAN Tx Failure SPN/FMI 639:12

Action
Did you perform the On-Board (OBD) System Check?
Key On, Engine Running
DST (Diagnostic Scan Tool) connected in
System Data Mode
• Clear system fault code
Does DTC1626 reset with the engine idling?
• Check that the ECM power connections C020,
C021 and C024 are clean and tight.
• Check that the ECM ground connections C014
and C023 are clean and tight.
•
•

Value(s)
-

Yes
Go to Step (2)
Go to Step (3)

Go to Step (4)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

Go to step (5)

Repair the
open circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to step (6)

Are the power and ground circuits Ok?
4

•
•
•

Key OFF
Disconnect ECM harness connector C001
Using a DVOM check for continuity between
ECM connector pin 13 and 14

Do you have continuity?
• Using a DVOM check for continuity between
ECM pins 14 and 15
Do you have continuity between them?

•

Using a DVOM check for continuity to engine
ground on pins 14 and 16

Do have continuity to engine ground?

•

Using a DVOM check for continuity to battery
positive on pins 14 and 16

Do have continuity them?

•

Replace the ECM

Is the replacement complete?

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section

Repair the
shorted circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Repair the
shorted to
ground circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Repair the
shorted to
ground circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to step (9)

Go to step (7)

Go to step (8)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
9

Action
Remove all test equipment except the DST.
Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-1626 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•

DIAGNOSTIC TROUBLE CODES 7-199
Value(s)

Yes
System OK

No
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-200

DTC 1627-CAN Rx Failure SPN/FMI 639:12

Conditions for Setting the DTC
•
•
•
•

CAN Rx
Check Condition- Engine running
Fault Condition- CAN Rx error 100 packets lost within 1 second
MIL- ON

Circuit description
The CAN bus (controller area network) is used by the ECM to communicate with other digital devices used
throughout the fuel system. Information is sent over the CAN bus in digital information “packets” that contain information
for various control functions. This fault will set if the ECM detects 100 packets lost within a one second time period. The
MIL command is ON.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
1
2

DIAGNOSTIC TROUBLE CODES 7-201

DTC 1627- CAN Rx Failure SPN/FMI 639:12

Action
Did you perform the On-Board (OBD) System Check?
Key On, Engine Running
DST (Diagnostic Scan Tool) connected in
System Data Mode
• Clear system fault code
Does DTC1627 reset with the engine idling?
• Check that the ECM power connections C020,
C021 and C024 are clean and tight.
• Check that the ECM ground connections C014
and C023 are clean and tight.
•
•

Value(s)
-

Yes
Go to Step (2)
Go to Step (3)

Go to Step (4)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

Go to step (5)

Repair the
open circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to step (6)

Are the power and ground circuits Ok?
4

•
•
•

Key OFF
Disconnect ECM harness connector C001
Using a DVOM check for continuity between
ECM connector pin 13 and 14

Do you have continuity?
• Using a DVOM check for continuity between
ECM pins 14 and 15
Do you have continuity between them?

•

Using a DVOM check for continuity to engine
ground on pins 14 and 16

Do have continuity to engine ground?

•

Using a DVOM check for continuity to battery
positive on pins 14 and 16

Do have continuity them?

•

Replace the ECM

Is the replacement complete?

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section

Go to step (7)

Go to step (8)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
9

Action
Remove all test equipment except the DST.
Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-1627 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•

DIAGNOSTIC TROUBLE CODES 7-202
Value(s)

Yes
System OK

No
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-203

DTC 1628-CAN Address Conﬂict SPN/FMI 639:13

Conditions for Setting the DTC
•
•
•
•

CAN Rx
Check Condition- Engine running
Fault Condition- 5 or more address conﬂict errors
MIL- ON

Circuit description
The CAN bus (controller area network) is used by the ECM to communicate with other digital devices used
throughout the fuel system. Information is sent over the CAN bus in digital information “packets” that contain
information for various control functions. Individual devices are assigned network addresses. This fault will set if
the ECM detects an address conﬂict, such as two devices with the same address. This is usually not due to an in
ﬁeld failure and may be the results of “add on” CAN devices

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
1
2

4
5

DIAGNOSTIC TROUBLE CODES 7-204

DTC 1628- CAN Address Conﬂict SPN/FMI 639:13

Action
Did you perform the On-Board (OBD) System Check?
• Key On, Engine Running
• DST (Diagnostic Scan Tool) connected in
System Data Mode
• Clear system fault code
Does DTC1628 reset with the engine idling?
• Key OFF
• Disconnect one CAN device
• Clear DTC 1628
• Key ON (start engine if possible if not
continue cranking for at least 3 seconds)
• Wait 5 seconds
• Does DTC 1628 re-set
Has the CAN device been replaced or address
conﬂict resolved
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-1628 check for any stored
codes.
Does the engine operate normally with no stored
codes?

Value(s)
-

Yes
Go to Step (2)
Go to Step (3)

Repeat step
3 until all
CAN devices
have been
disconnected
one at a time

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section
Contact the
CAN device
manufacturer
for additional
CAN address
information
Go to Step (4)

Go to step (5)

System OK

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-205

DTC 1629-Loss of TSC 1 SPN/FMI 639:31

Conditions for Setting the DTC
•
•
•
•
•

CAN TSC 1 Input Lost
Check Condition- Engine running
Loss of TSC 1 command from OEM CAN device for more than 1 s
MIL- ON
Force 1800 rpm engine speed

Circuit description
The CAN bus (controller area network) is used by the ECM to communicate with other digital devices used
throughout the engine control system. Information is sent over the CAN bus in digital information “packets” that
contain information for various control functions. Individual devices are assigned network addresses. This fault will
set if the ECM does not detect the TSC 1 (torque speed command) command from the OEM CAN module.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
1
2

DIAGNOSTIC TROUBLE CODES 7-206

DTC 1629- Loss of TSC 1 SPN/FMI 639:31

Action
Did you perform the On-Board (OBD) System Check?
• Key On, Engine Running
• DST (Diagnostic Scan Tool) connected in
System Data Mode
• Clear system fault code
Does DTC1629 reset with the engine idling?
• Are other CAN related DTC’s set?

Key OFF
Disconnect ECM connector C001
Disconnect customer interface connector 1
C011
• Using a DVOM check resistance between
terminal N at CO11 and 14 at the ECM and
check between terminal P at C011 and 15 at
the ECM.
• Is resistance less than 2 ohms?
• Remove all test equipment except the DST.
• Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-1629 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•
•

Value(s)
-

Yes
Go to Step (2)
Go to Step (3)

Diagnose
others ﬁrst and
return here if
1629 persists
Contact the
equipment
manufacture
for help in
diagnosing
their CAN
system. The
problem
is in their
transmission
System OK

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section
Go to Step 4

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.

Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-207

DTC 2111- Unable To Reach Lower TPS SPN/FMI 51:7

Conditions for Setting the DTC
•
•
•
•
•

Throttle Position Sensor
Check Condition-Cranking or Running
Fault Condition- Actual throttle position is 20% greater than the throttle command
MIL-On during active fault
Engine Shut Down

Circuit Description
There are two Throttle Position Sensors located within the throttle which use variable resistors to determine signal voltage
based on throttle plate position. TPS 1 will read low voltage when closed and TPS 2 will read high voltage when closed.
The TPS 1 and TPS 2 percentages are calculated from these voltages. Although the voltages are different, the calculated
values for the throttle position percentages should be very close to the same. The TPS values are used by the ECM to
determine if the throttle is opening as commanded.
This fault will set if the actual throttle position is 20% greater than the throttle command. During this active fault the MIL
command is ON and the engine will shut down.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1
2

5
6

8
9
10
11

DIAGNOSTIC TROUBLE CODES 7-208

DTC 2111 Unable To Reach Lower TPS SPN/FMI 51:7

Action
Did you perform the On-Board (OBD) System Check?

Key ON, Engine OFF
DST (Diagnostic Scan Tool) connected in
DBW (Drive By Wire) test mode
• Depress Foot Pedal until theThrottle Command is
between 63%-68%
Is the TPS 1 voltage greater than 2.0 volts?
• Key OFF
• Disconnect electronic throttle connector C025
• Probe TPS 1 signal pin 6 with a test light
connected to battery voltage
• Key ON
Does DST display TPS 1 voltage less than 0.2 volts
• Key OFF
• Disconnect ECM wire harness connector C001
• Key ON
• Using a DVOM check for voltage between throttle
connector TPS 1signal pin 6 and engine ground
Do you have voltage?
• Replace ECM
Is the replacement complete?
• Probe sensor ground circuit at ECM connector
C001 with a test light connected to battery
voltage
Does the test light come on?
• Key OFF
• Disconnect ECM wire harness connector C001
• Using a DVOM check for continuity between
throttle connector signal ground pin 2 and ECM
signal ground circuit pin 20
Do you have continuity between them?
• Replace ECM
• Is the replacement complete?
• Check throttle for foreign object in bore
Did you ﬁnd a foreign object in the bore?
• Remove foreign object
Is the removal complete?
• Inspect the throttle wire harness connector
terminals for damage, corrosion or contamination
Did you ﬁnd the problem?
•
•

• Replace throttle
Is the replacement complete?

Value(s)
-

Yes
Go to Step (2)
Go to Step (3)

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section

Go to Step (6)

Go to Step (4)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (13)

Go to Step (5)

Go to Step (9)

Go to Step (7)

Go to Step (8)

Go to Step (13)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
-

Go to Step (10)

Go to Step (11)

Go to Step (13)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (13)

Go to Step (12)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
13

Action
Remove all test equipment except the DST.
Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-2111 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•

DIAGNOSTIC TROUBLE CODES 7-209
Value(s)

Yes
System OK

No
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-210

DTC 2112-Unable To Reach Higher TPS SPN/FMI 51:7

Conditions for Setting the DTC
•
•
•
•
•

Throttle Position Sensor
Check Condition-Cranking or Running
Fault Condition- Actual throttle position is 20% less than the throttle command
MIL-On during active fault
Engine Shut Down

Circuit Description
There are two Throttle Position Sensors located within the throttle which use variable resistors to determine signal voltage
based on throttle plate position. TPS 1 will read low voltage when closed and TPS 2 will read high voltage when closed.
The TPS 1 and TPS 2 percentages are calculated from these voltages. Although the voltages are different, the calculated
values for the throttle position percentages should be very close to the same. The TPS values are used by the ECM to
determine if the throttle is opening as commanded.
This fault will set if the actual throttle position is 20% less than the throttle command. During this active fault the MIL
command is ON and the engine will shut down.

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
1
2

4
5
6

7
8

DIAGNOSTIC TROUBLE CODES 7-211

DTC 2112- Throttle Unable to Open SPN/FMI 51:7

Action
Did you perform the On-Board (OBD) System Check?

Key ON, Engine OFF
DST (Diagnostic Scan Tool) connected in
DBW (Drive By Wire) test mode
• Depress Foot Pedal until theThrottle Command is
63%-68%
Is the TPS voltage less than 2.0 volts?
• Key OFF
• Disconnect electronic throttle connector C025
• Probe TPS 1 signal circuit pin 6 with test light
connected to battery voltage
• Key ON
Is TPS voltage 4.0 volts or greater?
• Check throttle bore for foreign object
Did you ﬁnd a problem?
• Remove the foreign object
Has the object been removed?
• Check electronic throttle connector terminals for
damage corrosion or contamination
Did you ﬁnd a problem?
•
•

• Replace throttle
Is the replacement complete?
• Key OFF
• Disconnect ECM wire harness connector C001
• Using a DVOM check for continuity between
throttle connector TPS 1 signal pin 6 and ECM
TPS 1 signal pin 5
Do you have continuity between them?
• Using a DVOM check for continuity between
throttle connector TPS 1 signal pin 6 and engine
ground
Do you have continuity between them?

• Replace ECM
Is the replacement complete?

Value(s)
-

Yes
Go to Step (2)
Go to Step (3)

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section

Go to Step (4)

Go to Step (8)

Go to Step (5)

Go to step (6)

Go to Step (11)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (11)

Go to Step (7)

Go to Step (9)

Repair the
circuit as
necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to Step (10)

Repair the
shorted to
ground circuit
as necessary.
Refer to
Wiring Repairs
in Engine
Electrical.
Go to step (11)

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL
Step
11

Action
Remove all test equipment except the DST.
Connect any disconnected components, fuses,
etc.
• Using the DST clear DTC information from the
ECM.
• Turn the ignition OFF and wait 30 seconds.
• Start the engine and operate the vehicle to full
operating temperature
• Observe the MIL
• Observe engine performance and driveability
• After operating the engine within the test
parameters of DTC-2112 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•

DIAGNOSTIC TROUBLE CODES 7-212
Value(s)

Yes
System OK

No
Go to OBD
System Check

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

DIAGNOSTIC TROUBLE CODES 7-213

DTC 2229-BP High Pressure SPN/FMI 108:0

Conditions for Setting the DTC
•
•
•
•
•

Barometric pressure check
Check condition-engine off and key on
Fault Condition-BP greater than 16 PSIA
MIL-On for active fault and for 2 seconds after active fault
Adaptive-disabled for the remainder of key cycle

PSI 3.0L PFI CERTIFIED ENGINE SERVICE MANUAL

Step
1

DIAGNOSTIC TROUBLE CODES 7-214

DTC 2229- BP High Pressure SPN/FMI 108:0

Action
Did you perform the On-Board (OBD) System Check?

2
•
•
•

Value(s)
-

Yes
Go to Step (2)
Go to step (3)

No
Go to OBD
System Check
Section
Intermittent
problem
Go to
Intermittent
section

Go to Step (4)

System Ok

Go to OBD
System Check

Key On
DST (Diagnostic Scan Tool) connected in
System Data Mode

Does DST display MAP pressure of 16 PSIA or
greater?
3

• Replace TMAP sensor.
Is the repair complete?

•
•
•
•
•

Remove all test equipment except the DST.
Connect any disconnected components, fuses,
etc.
Using the DST clear DTC information from the
ECM.
Turn the ignition OFF and wait 30 seconds.
Start the engine and operate the vehicle to full
operating temperature

Observe the MIL
Observe engine performance and driveability
After operating the engine within the test
parameters of DTC-2229 check for any stored
codes.
Does the engine operate normally with no stored
codes?
•
•
•

Source Exif Data:

File Type                       : PDF
File Type Extension             : pdf
MIME Type                       : application/pdf
PDF Version                     : 1.5
Linearized                      : Yes
Encryption                      : Standard V2.3 (128-bit)
User Access                     : Extract
Page Count                      : 385
Has XFA                         : No
XMP Toolkit                     : XMP toolkit 2.9.1-14, framework 1.6
About                           : uuid:2a29bfb3-56b7-419a-80f8-91f50fbdbcb7
Create Date                     : 2006:01:23 10:53:22Z
Metadata Date                   : 2006:11:08 14:18:53-06:00
Modify Date                     : 2006:11:08 14:18:53-06:00
Creator Tool                    : Adobe InDesign CS (3.0.1)
Rendition Class                 : proof:pdf
Derived From Instance ID        : 1614e9e2-787f-11da-9b34-dcc4da4d253d
Derived From Document ID        : adobe:docid:indd:a20e4e4c-7625-11da-9f61-bbe384b1a75a
Document ID                     : adobe:docid:indd:61a2774f-8c28-11da-bc6d-c47f2d9d2ef0
Format                          : application/pdf
Title                           : PSI 3.0L PFI Maintenace Section-B.indd
Trapped                         : False
Creator                         : Adobe InDesign CS (3.0.1)
Producer                        : Adobe PDF Library 6.0

EXIF Metadata provided by EXIF.tools

PSI 3.0L PFI Maintenace Section B Psi_3.0l_shop_opm Shop Opm

Navigation menu

Versions of this User Manual:

Views

Navigation