Bosch Automotive Service Solutions KT720 Automotive Diagnostics Equipment User Manual KT720 EN part 2

Bosch Automotive Service Solutions (Suzhou) Co., Ltd Shenzhen Branch Automotive Diagnostics Equipment KT720 EN part 2

Contents

KT720 EN User Manual -part 2

1 697 021 785 | 2015-05-20 Bosch Automotive Products (Nanjing) Co., Ltd 32 | KT720 | Measure functionen11.6.3.1 Equipment connectionWhen connecting KT720 to power extension cable for power supply, choose power supply according to the battery position of vehicle mode tested. All connec-ting diagrams in this users manual take power supply by battery clip power cable as example. Connect BNC end of 2KT720 oscilloscope probes to CH1 and CH2, then connect the other end of the both black banana plugs and 2 alligator clips to negative pole of battery or grounding, and connect the other end of red banana plugs and 2 banana sockets into the trigger signal line.Fig. 13: Equipment connection11.6.3.2 Measure conditions RStart engine to heat oxygen sensor to over 315˚C, with engine in closed-loop state. RIncrease engine speed from idle.11.6.3.3 Measure steps1. Connect equipment according to Fig.13, switch on power supply.2. Start engine to heat oxygen sensor to over 315˚C, with engine in closed-loop state.3. Double click run KT720 software.4. Select communication mode: USB communication or wireless communication, the KT720 and the compu-ter are successfully communicated.5. Click Analyzer --> Sensor --> Dual Oxygen Sensor;6. Waveform will be displayed on the screen depending on measure conditions.7. You can adjust to cycle, amplitude, coupling, reversed-phase, and cursor. If the cycle locates at high-frequency section, the triggering channel and triggering modes can be adjusted.8. You can print measured data, load snapshot data and reference waveform data, save current confi-guration or acquire old configuration, automatically adjust the amplitude, snapshot current waveform and waveform comparison;9. You can check the details of current waveform by cli-cking “Pause” button. After click, the button turns to “Start”, click it again to carry forward measurement.10. You can record a continuous waveform section by clicking “Record” button.11.6.3.4 Waveform analysisWhen testing waveform of double oxygen sensor, we can judge, through the waveform of front and rear oxy-gen sensors, whether the ability of three-way catalyst device to convert deleterious gas is lost. Generally speaking, the bigger the amplitude value of two wave-forms is, it indicates that three-way catalyst device has perfect function; if amplitude value is basically the same, it indicates that it has lost its function. See Fig.14 for schematic diagram.Fig. 14: Catalytic convert11.6.4 Temperature sensorThey are mainly water temperature sensor and air intake temperature sensor, and most temperature sensors adopt negative temperature coefficient (NTC) thermistor made of semi-conducting materials. When temperature changes, its resistance is expected to experience a large change. When temperature rises, resistance decreases; when temperature decreases, resistance increases.11.6.4.1 Equipment connectionWhen connecting KT720 to power extension cable for power supply, choose power supply according to the battery position of vehicle mode tested. All connecting diagrams in this users manual take power supply by battery clip power cable as example. Connect BNC end ofKT720 oscilloscope probe to CH1, then connect the other end of the black banana plug and black alligator clip to negative pole of battery or grounding, and con-nect the other end of red banana plug and red banana socket into the trigger signal line.Fig. 15: Equipment connection
1 697 021 785 | 2015-05-20Bosch Automotive Products (Nanjing) Co., Ltd Measure function | KT720 | 33 en11.6.4.2 Measure conditions RSwitch on ignition switch, do not start engine. Secu-rely connect temperature sensor, and measure the output voltage of temperature sensor with engine in non-running state. RStart engine, observe voltage falling of temperature sensor when engine gets heated. RYou may also disconnect sensor and use multimeter to measure resistance value.11.6.4.3 Measure steps1. Connect equipment according to Fig.15, switch on power supply.2. Double click run KT720 software.3. Select communication mode: USB communication or wireless communication, the KT720 and the compu-ter are successfully communicated.4. Click Analyzer --> Sensor --> Temperature Sensor.5. Waveform will be displayed on the screen depending on measure conditions.6. You can adjust to cycle, amplitude, coupling, reversed-phase, and cursor. If the cycle locates at high-frequency section, the triggering channel and triggering modes can be adjusted.7. You can print measured data, load snapshot data and reference waveform data, save current confi-guration or acquire old configuration, automatically adjust the amplitude, snapshot current waveform and waveform comparison;8. You can check the details of current waveform by cli-cking “Pause” button. After click, the button turns to “Start”, click it again to carry forward measurement.9. You can record a continuous waveform section by clicking “Record” button.11.6.4.4 Waveform analysisYou can get precise voltage range of sensor response by referring to standard manual from manufacturer. Ge-nerally, the voltage of sensor should be 3~5V (fully cold state) when engine is not started, and it should have correspondingly variable output voltage signal under different temperature conditions. When temperature sensor circuit is open, voltage increases till it reaches the peak (5V) of reference voltage; when temperature sensor is short to ground, voltage decreases till it reaches the peak of grounding voltage. As shown Fig.16 for temperature characteristics of common thermistor type coolant and air intake temperature sensor, subject to manufacturer’s manual.Fig. 16: Temperature characteristics11.6.5 Throttle position sensorThrottle position sensor (TPS) is common failure source on computer board of modern automobile. TPS informs computer of opening degree of throttle, open or closed state and open/close speed, or working conditions where engine works. When TPS resistance changes, the voltage signal it sends to computer changes conse-quently.Common throttle position sensors include two types: one is potentiometer type sensor. When its shaft chan-ges, it will cause resistance to change (potentiometer), and will provide a direct current voltage. TPS is a varia-ble resistance fixed on throttle shaft, which provides a direct current voltage as an input signal for ECU.The other is switch type sensor. After the signal from this kind of sensor is input to ECU, computer is infor-med of controlling idle (switch closed, throttle closed), or of not controlling idle (because accelerator pedal is pressed to make switch on), and ECU is informed of throttle open position when the other switch is swit-ched on. Such linear throttle position sensor is installed on throttle shaft, with two movable contacts rotating with the same shaft. One contact is for measuring opening angle of throttle, and the other contact is for measuring closing angle of throttle. Be sure to connect circuit correctly when testing sensor.
1 697 021 785 | 2015-05-20 Bosch Automotive Products (Nanjing) Co., Ltd 34 | KT720 | Measure functionen11.6.5.1 Equipment connectionWhen connecting KT720 to power extension cable for power supply, choose power supply according to the battery position of vehicle mode tested. All connecting diagrams in this users manual take power supply by battery clip power cable as example. Connect BNC end ofKT720 oscilloscope probe to CH1, then connect the other end of the black banana plug and black alligator clip to negative pole of battery or grounding, and con-nect the other end of red banana plug and red banana socket into the trigger signal line.Fig. 17: Equipment connection11.6.5.2 Measure conditions RSwitch on ignition switch, do not start engine, turn throttle to fully open position, and then turn to fully closed position, or opposition.11.6.5.3 Measure steps1. Connect equipment according to Fig.17, switch on power supply.2. Double click run KT720 software.3. Select communication mode: USB communication or wireless communication, the KT720 and the compu-ter are successfully communicated.4. Click Analyzer --> Sensor --> TPS.5. Waveform will be displayed on the screen depending on measure conditions.6. You can adjust to cycle, amplitude, coupling, reversed-phase, and cursor. If the cycle locates at high-frequency section, the triggering channel and triggering modes can be adjusted.7. You can print measured data, load snapshot data and reference waveform data, save current confi-guration or acquire old configuration, automatically adjust the amplitude, snapshot current waveform and waveform comparison;8. You can check the details of current waveform by cli-cking “Pause” button. After click, the button turns to “Start”, click it again to carry forward measurement.9. You can record a continuous waveform section by clicking “Record” button11.6.5.4 Waveform analysisPotentiometer type TPS is normally a variable potenti-ometer. Referring to repair manual from manufacturer, you can get precise voltage range of TPS. Waveform should be free from any breakpoint, cuspate peak TO GROUND or large wave break. The normally closed con-tact of switch type TPS constitutes idle switch. When throttle is in idle position, normally closed contact is in closed state; normally open contact indicates that throttle opens to full load. As shown Fig.18 and Fig.19 for waveform of two throttle sensors.Fig. 18: Throttle position sensor (potentiometer)Fig. 19: Throttle position sensor- switch type
1 697 021 785 | 2015-05-20Bosch Automotive Products (Nanjing) Co., Ltd Measure function | KT720 | 35 en11.6.6 Crankshaft/Camshaft position sensorIt can be used to test waveform for electromagnetic sensor, Hall effect sensor and photoelectric sensor. Electromagnetic sensor (variable magnetoresistive sen-sor) does not need external power supply, and has two shielded lines connected to magnetostatic coil. When trigger wheel passes the magnetic field formed by coil and static magnet, small voltage signal is produced. Trigger wheel is made of steel with low magnetic resis-tance. Crankshaft position sensor (CPS), ABS wheel sensor and automobile speed sensor are all examples of variable magnetic resistance. Output voltage and frequency change with vehicle speed.Hall effect sensor has a current passing a semicon-ductor placed very close to a variable magnetic field. Magnetic field change occurs when crankshaft or dis-tributor shaft rotates. Hall effect sensor is used in CPS and distributor, and the amplitude of its output voltage is constant, its frequency changes with speed.Photoelectric sensor uses a rotary disc to separate LED light source from optical pickup unit. With a small hole in the disc, pickup unit can receive light emitted from the light source. A pulse is sent each time pickup unit receives light when the disc rotates and meets the small hole. The result of voltage change can be used as reference signal for other system, and the amplitude of its output voltage is constant, while its frequency changes with speed.Camshaft sensor is normally installed in ignition distri-butor, and sensor sends electric pulse to coil module to provide data indicating camshaft and valve position.11.6.6.1 Equipment connectionWhen connecting KT720 to power extension cable for power supply, choose power supply according to the battery position of vehicle mode tested. All connecting diagrams in this users manual take power supply by battery clip power cable as example. Connect BNC end ofKT720 oscilloscope probe to CH1, then connect the other end of the black banana plug and black alligator clip to negative pole of battery or grounding, and con-nect the other end of red banana plug and red banana socket into the trigger signal line. Fig. 20: Equipment connection11.6.6.2 Measure conditions RCheck sensor for signal output. If there is no signal output, it is possible that sensor is damaged or lines are poorly connected. RIf that engine cannot be started is determined, con-nect the instrument according to diagram and then start engine. RIf engine can be started, connect the instrument according to diagram and then start engine; conduct test in idle and relatively high speed state.11.6.6.3 Measure steps1. Connect equipment according to Fig.20, switch on power supply.2. Double click run KT720 software.3. Select communication mode: USB communication or wireless communication, the KT720 and the compu-ter are successfully communicated.4. Click Analyzer --> Sensor --> CPS.5. Waveform will be displayed on the screen depending on measure conditions.6. You can adjust to cycle, amplitude, coupling, reversed-phase, and cursor. If the cycle locates at high-frequency section, the triggering channel and triggering modes can be adjusted.7. You can print measured data, load snapshot data and reference waveform data, save current confi-guration or acquire old configuration, automatically adjust the amplitude, snapshot current waveform and waveform comparison;8. You can check the details of current waveform by cli-cking “Pause” button. After click, the button turns to “Start”, click it again to carry forward measurement.
1 697 021 785 | 2015-05-20 Bosch Automotive Products (Nanjing) Co., Ltd 36 | KT720 | Measure functionen9. You can record a continuous waveform section by clicking “Record” button.11.6.6.4 Waveform analysis2 kinds of waveform characteristics of the crankshaft/camshaft position sensor as shown in follow pictures:Fig. 21: Photoelectric CAM crankshaft position sensorFig. 22: Crankshaft position sensor (Hall effect)Fig. 23: Crankshaft position sensor (Magnetic)11.6.7 Ride height (position) sensorAll kinds of position sensors produce a direct current voltage output according to the movement of variable resistance (potentiometer) shaft. Position sensor is a variable resistance connected between frame and rear axle or installed in support system. As an input signal for ECU, variable direct current voltage is used to con-trol vehicle height. Some manufacturers use photoelec-tric or Hall effect sensor, corresponding sensors can be selected for test.11.6.7.1 Equipment connectionWhen connecting KT720 to power extension cable for power supply, choose power supply according to the battery position of vehicle mode tested. All connecting diagrams in this users manual take power supply by battery clip power cable as example. Connect BNC end ofKT720 oscilloscope probe to CH1, then connect the other end of the black banana plug and black alligator clip to negative pole of battery or grounding, and con-nect the other end of red banana plug and red banana socket into the trigger signal line.Fig. 24: Equipment connection11.6.7.2 Measure conditions RSwitch on ignition switch, do not start engine, se-parate rotational shaft (fixed on the rear shaft) from sensor, and turn the shaft from stop end to the other end to measure the whole travel. RSwitch on ignition switch, do not start engine, care-fully disconnect the connecting line from sensor, and then measure sensor resistance to make sure whe-ther there is open or short circuit in the sensor. RRe-install the rotational shaft to the rear shaft, and adjust ride height sensor according to the indexes specified in manufacturer manual.
1 697 021 785 | 2015-05-20Bosch Automotive Products (Nanjing) Co., Ltd Measure function | KT720 | 37 en10.6.7.3 Measure steps1. Connect equipment according to Fig.24, switch on power supply.2. Double click run KT720 software.3. Select communication mode: USB communication or wireless communication, the KT720 and the compu-ter are successfully communicated.4. Click Analyzer --> Sensor --> RH(Pos) Sensor.5. Waveform will be displayed on the screen depending on measure conditions.6. You can adjust to cycle, amplitude, coupling, reversed-phase, and cursor. If the cycle locates at high-frequency section, the triggering channel and triggering modes can be adjusted.7. You can print measured data, load snapshot data and reference waveform data, save current confi-guration or acquire old configuration, automatically adjust the amplitude, snapshot current waveform and waveform comparison;8. You can check the details of current waveform by cli-cking “Pause” button. After click, the button turns to “Start”, click it again to carry forward measurement.9. You can record a continuous waveform section by clicking “Record” button.11.6.7.4 Waveform analysisAs shown Fig.24 for waveform characteristics of ride height (position) sensor, and different vehicle models may have different indexes, subject to manufacturer’s manual.Fig. 25: Waveform characteristics11.6.8 Anti-lock braking speed sensorABS control unit controls vehicle speed at braking by comparing the frequency (instead of voltage) from ve-hicle speed sensor, and making use of this signal. The frequency is proportional to vehicle speed and increa-ses when vehicle speed increases.11.6.8.1 Equipment connectionWhen connecting KT720 to power extension cable for power supply, choose power supply according to the battery position of vehicle mode tested. All connecting diagrams in this users manual take power supply by battery clip power cable as example. Connect BNC end ofKT720 oscilloscope probe to CH1, then connect the other end of the black banana plug and black alligator clip to negative pole of battery or grounding, and con-nect the other end of red banana plug and red banana socket into the trigger signal line. Fig. 26: Equipment connection11.6.8.2 Measure conditions RLift vehicle body to make driving wheel hang in the air and be able to rotate freely. RSwitch off ignition switch, disconnect connecting line from ABS speed sensor, connect the instrument to ABS speed sensor, and then rotate wheel. ROr start engine, pierce test probe into the back of ABS speed sensor joint, place transmission to driving gear and slowly accelerate driving; as for non-driving wheel, refer to the above mentioned method of switching off ignition switch.11.6.8.3 Measure steps1. Connect equipment according to Fig.26, switch on power supply.2. Double click run KT720 software.3. Select communication mode: USB communication or wireless communication, the KT720 and the compu-ter are successfully communicated.4. Click Analyzer --> Sensor --> ABS.5. Waveform will be displayed on the screen depending on measure conditions.6. You can adjust to cycle, amplitude, coupling, reversed-phase, and cursor. If the cycle locates at high-frequency section, the triggering channel and triggering modes can be adjusted.7. You can print measured data, load snapshot data and reference waveform data, save current confi-guration or acquire old configuration, automatically adjust the amplitude, snapshot current waveform and waveform comparison;
1 697 021 785 | 2015-05-20 Bosch Automotive Products (Nanjing) Co., Ltd 38 | KT720 | Measure functionen8. You can check the details of current waveform by cli-cking “Pause” button. After click, the button turns to “Start”, click it again to carry forward measurement.9. You can record a continuous waveform section by clicking “Record” button.11.6.8.4 Waveform analysisAs shown follow picture for waveform characteristics of ABS speed sensor.Fig. 27: Waveform characteristics11.6.9 Vehicle speed sensor (VSS)The output signal of vehicle speed sensor is proporti-onal to vehicle speed. With this signal, ECU controls torque converter lockup clutch, shift point of electric control transmission and other functions. The sensors used include electromagnetic, Hall effect and photo-electric type.11.6.9.1 Equipment connectionWhen connecting KT720 to power extension cable for power supply, choose power supply according to the battery position of vehicle mode tested. All connecting diagrams in this users manual take power supply by battery clip power cable as example. Connect BNC end ofKT720 oscilloscope probe to CH1, then connect the other end of the black banana plug and black alligator clip to negative pole of battery or grounding, and con-nect the other end of red banana plug and red banana socket into the trigger signal line. Fig. 28: Equipment connection11.6.9.2 Measure conditions RLift vehicle body to make driving wheel hang in the air and be able to rotate freely. RConnect equipment according to Fig.28, start engine and apply driving gear. RMonitor the output signal of vehicle speed sensor at low speed and gradually increase the speed of driving wheel.11.6.9.3 Measure steps1. Connect equipment according to Fig.28, switch on power supply.2. Double click run KT720 software.3. Select communication mode: USB communication or wireless communication, the KT720 and the compu-ter are successfully communicated.4. Click Analyzer --> Sensor --> VSS.5. Waveform will be displayed on the screen depending on measure conditions.6. You can adjust to cycle, amplitude, coupling, reversed-phase, and cursor. If the cycle locates at high-frequency section, the triggering channel and triggering modes can be adjusted.7. You can print measured data, load snapshot data and reference waveform data, save current confi-guration or acquire old configuration, automatically adjust the amplitude, snapshot current waveform and waveform comparison;8. You can check the details of current waveform by cli-cking “Pause” button. After click, the button turns to “Start”, click it again to carry forward measurement.9. You can record a continuous waveform section by clicking “Record” button.
1 697 021 785 | 2015-05-20Bosch Automotive Products (Nanjing) Co., Ltd Measure function | KT720 | 39 en11.6.9.4 Waveform analysisGenerally, if the amplitude of waveform of electroma-gnetic vehicle speed sensor is too low, check whether the air gap between trigger wheel and pickup unit is too big; if waveform is not steady, check whether trigger wheel or shaft deforms; if there is one twisted wave-form, check whether certain tooth of the trigger wheel deforms or is damaged. It is basically the same case with Hall effect sensor which produces square wave. As shown Fig.29 and Fig.30 for waveform characteristics of electromagnetic and photoelectric vehicle speed sensor.Fig. 29: Vehicle speed sensor (Magnetic)Fig. 30: Vehicle speed sensor (Optical)11.6.10 Air flow sensorAnalog air flow sensor: This kind of air flow sensor uses a preheated thin metal element to measure the air flow into the air intake manifold. This element is heated to 77˚C and its temperature will decrease and conse-quently its resistance will decrease when air passes it, which causes current to increase and voltage to decre-ase. This signal is regarded by computer as a change of voltage reduction (increment of air flow causes voltage reduction), and also as an indication of air flow.Digital air flow sensor: This kind of air flow sensor takes 5V sent by computer as reference and sends back frequency signal equivalent to air amount of engine. Output signal is a square wave, its amplitude is fixed at 0-5V, and signal frequency changes between 30-150Hz. Low frequency represents small amount of air flow while high frequency indicates large amount of air flow.11.6.10.1 Equipment connectionWhen connecting KT720 to power extension cable for power supply, choose power supply according to the battery position of vehicle mode tested. All connecting diagrams in this users manual take power supply by battery clip power cable as example. Connect BNC end ofKT720 oscilloscope probe to CH1, then connect the other end of the black banana plug and black alligator clip to negative pole of battery or grounding, and con-nect the other end of red banana plug and red banana socket into the trigger signal line. Fig. 31: Equipment connection11.6.10.2 Measure conditions RConnect equipment, start engine and run it at idle, slowly accelerate and observe display result. RUse screwdriver handle to tap the sensor when testing and temporary delay and unsteady accelera-tion will be caused if the connecting line inside the sensor is loose.11.6.10.3 Measure steps1. Connect equipment according to Fig.31, switch on power supply.2. Double click run KT720 software.
1 697 021 785 | 2015-05-20 Bosch Automotive Products (Nanjing) Co., Ltd 40 | KT720 | Measure functionen3. Select communication mode: USB communication or wireless communication, the KT720 and the compu-ter are successfully communicated.4. Click Analyzer --> Sensor --> Air Flow Sensor.5. Waveform will be displayed on the screen depending on measure conditions.6. You can adjust to cycle, amplitude, coupling, reversed-phase, and cursor. If the cycle locates at high-frequency section, the triggering channel and triggering modes can be adjusted.7. You can print measured data, load snapshot data and reference waveform data, save current confi-guration or acquire old configuration, automatically adjust the amplitude, snapshot current waveform and waveform comparison;8. You can check the details of current waveform by cli-cking “Pause” button. After click, the button turns to “Start”, click it again to carry forward measurement.9. You can record a continuous waveform section by clicking “Record” button.11.6.10.4 Waveform analysisAs shown Fig.32 and Fig.33 for waveform characteris-tics of two air flow sensors.Fig. 32: Mass air flow meter (Digital)Fig. 33: Mass air flow meter (Analog)11.6.11 Knock sensor-piezoelectric crystalIn order to achieve optimal performance and fuel economy for engine, ignition time should be adjusted properly to make combustion occur when crankshaft rotates to a particular angle, and start at the top dead center (TDC) of working stroke. If ignition occurs late, the power of the cylinder decreases, if ignition occurs early, knock occurs. Most knock sensor is made of pie-zoelectric crystal, and bolted to engine body. It is a kind of very special crystal which produces voltage when it is under mechanic stress. The voltage signal differs a lot due to knock conditions. The voltage, after being processed by ECU, is used to adjust ignition timing to achieve optimal engine performance.11.6.11.1 Equipment connectionWhen connecting KT720 to power extension cable for power supply, choose power supply according to the battery position of vehicle mode tested. All connecting diagrams in this users manual take power supply by battery clip power cable as example. Connect BNC end ofKT720 oscilloscope probe to CH1, then connect the other end of the black banana plug and black alligator clip to negative pole of battery or grounding, and con-nect the other end of red banana plug and red banana socket into the trigger signal line. Fig. 34: Equipment connection11.6.11.2 Measure conditionsOffline test of knock sensor (sensor disconnected) RDisconnect knock sensor, and connect instrument to sensor. RUse mallet strike cylinder body near sensor to make sensor produce signal.Online test of knock sensor (delayed ignition test) RConduct advance time test according to chapter 11.7.6. RUse mallet strike cylinder body near sensor to make sensor produce signal. RObserve ignition time to confirm that ignition delays when knock signal is received by ECU.
1 697 021 785 | 2015-05-20Bosch Automotive Products (Nanjing) Co., Ltd Measure function | KT720 | 41 en11.6.11.3 Measure steps1. Connect equipment according to Fig.34, switch on power supply.2. Double click run KT720 software.3. Select communication mode: USB communication or wireless communication, the KT720 and the compu-ter are successfully communicated.4. Click Analyzer --> Sensor --> Knock sensor.5. Waveform will be displayed on the screen depending on measure conditions.6. You can adjust to cycle, amplitude, coupling, reversed-phase, and cursor. If the cycle locates at high-frequency section, the triggering channel and triggering modes can be adjusted.7. You can print measured data, load snapshot data and reference waveform data, save current confi-guration or acquire old configuration, automatically adjust the amplitude, snapshot current waveform and waveform comparison;8. You can check the details of current waveform by cli-cking “Pause” button. After click, the button turns to “Start”, click it again to carry forward measurement.9. You can record a continuous waveform section by clicking “Record” button.11.6.11.4 Waveform analysisThe waveform of knock sensor has direct relation with knock degree and reason, so each waveform looks a litt-le different. Knock sensor mainly checks whether there is signal. For most vehicles, when ECU receives signal from knock sensor, it will delay ignition till knock disap-pears. As shown Fig.35 for characteristic waveform of ordinary knock.Fig. 35: Waveform characteristic11.7 Actuator measureMeasured the waveform of actuator.11.7.1 Exhaust gas recirculationEGR valve position sensor is a variable resistance connected to EGR valve. EGR valve position sensor provides a direct current voltage which changes with the movement of knob on the variable resistance (po-tentiometer). Variable direct current voltage is used as input signal by computer to indicate working conditions of EGR.When engine has excessive combustion temperature and air-fuel ratio is lean, EGR system dilutes air fuel ratio and limits formation of NOx. Gasoline engine EGR should work at middle acceleration and cruise speed between 50-120Km/h. Computer makes use of method of providing power supply or cutting off solenoid coil, or uses pulse width modulated solenoid, to switch on or switch off solenoid coil to achieve the goal of cont-rolling vacuum.11.7.1.1 Equipment connectionWhen connecting KT720 to power extension cable for power supply, choose power supply according to the battery position of vehicle mode tested. All connecting diagrams in this users manual take power supply by battery clip power cable as example. Connect BNC end ofKT720 oscilloscope probe to CH1, then connect the other end of the black banana plug and black alligator clip to negative pole of battery or grounding, and con-nect the other end of red banana plug and red banana socket into the trigger signal line. Fig. 36: Equipment connection
1 697 021 785 | 2015-05-20 Bosch Automotive Products (Nanjing) Co., Ltd 42 | KT720 | Measure functionen11.7.1.2 Measure conditions RStart engine, connect KT720 to EGR valve, and slow-ly increase engine speed to cruise speed. iMost EGR valves only start when engine is at load state. Therefore, it is possible to use road test or make use of horsepower tester to assist test. !Only conduct the following tests when engine is at cold state to avoid burn. RIgnition switch is at switch-on position, engine stops, insert probe into position sensor on the top of EGR valve, and carefully (cold engine) lift EGR from chas-sis. If EGR diaphragm has obstacle or is not easily accessible, it is possible to move EGR valve when vehicle is at load state. RSwitch off ignition switch, disconnect sensor, and then carefully lift EGR valve from chassis. Some posi-tion sensors can be disconnected from EGR valve so as to make sensor terminal accessible; RApply potentiometer test function of common sen-sors when testing position sensor.11.7.1.3 Measure steps1. Connect equipment according to Fig.36, switch on power supply.2. Double click run KT720 software.3. Select communication mode: USB communication or wireless communication, the KT720 and the compu-ter are successfully communicated.4. Click Analyzer --> Actuator --> EGT.5. Waveform will be displayed on the screen depending on measure conditions.6. You can adjust to cycle, amplitude, coupling, reversed-phase, and cursor. If the cycle locates at high-frequency section, the triggering channel and triggering modes can be adjusted.7. You can print measured data, load snapshot data and reference waveform data, save current confi-guration or acquire old configuration, automatically adjust the amplitude, snapshot current waveform and waveform comparison.8. You can check the details of current waveform by cli-cking “Pause” button. After click, the button turns to “Start”, click it again to carry forward measurement.9. You can record a continuous waveform section by clicking “Record” button.10.7.1.4 Waveform analysisMost vehicles start exhaust gas recirculation control when they travel or accelerate. EGR system does not work when engine runs at idle and decelerates since control signal is cut off. Peak height of waveform redu-ces when failure occurs, which indicates that vacuum solenoid coil of EGR is short; if no control signal is found, it indicates that failure occurs to PCM or EGR control conditions for PCM does not meet, or there is something wrong with the circuit of EGR system.11.7.2 Fuel Injection(FI)Electronically-controlled fuel injection is controlled by computer and also affected by many working factors, including water temperature, engine load and oxygen sensor signal in closed-loop work.Fuel injection time can be expressed in pulse width in ms, representing the amount of fuel injected into the cylinder. Wide pulse indicates more fuel injected under the same injection pressure. ECU provides a path for nozzle through a driving triode. When triode is through, current passes from nozzle and triode to ground, which makes nozzle open There are three kinds of fuel injec-tion system currently, and each has its own fuel injec-tion control method. All nozzles have a method of limi-ting current, because large current will damage nozzle.Peak value keeping type: In nozzle circuit, nozzle is actually powered by two different circuits. When two circuits work for nozzle at the same time, nozzle is supplied with high starting current and opens quickly; after nozzle opens, one of the circuits is cut off, and the other circuit continues to work to keep the nozzle open till the end of injection time. In the circuit, one resis-tance is used to reduce the current passing through nozzle. When the second circuit is cut off, nozzle clo-ses, and fuel injection ends. The method for measuring opening time is to locate the falling edge of opening pulse and the rising edge representing the second circuit is cut off.Throttle injection system: is designed to take the place of carburetor, and pulse width represents working or opening time of nozzle. ECU controls pulse width accor-ding to engine working and driving conditions.The triode of traditional (saturated switch type): nozz-le provides nozzle with fixed current. Some nozzles use resistance to control current, and other nozzles have high internal impedance, with only one injection pulse.Nozzles of pulse width: modulation type have high starting current to quickly open nozzle. After nozzle opens, pulse switch-on begins at grounding end to cut current off to extend opening time of nozzle, and limit the current passing through nozzle at the same time.
1 697 021 785 | 2015-05-20Bosch Automotive Products (Nanjing) Co., Ltd Measure function | KT720 | 43 en11.7.2.1 Equipment connectionWhen connecting KT720 to power extension cable for power supply, choose power supply according to the battery position of vehicle mode tested. All connecting diagrams in this users manual take power supply by battery clip power cable as example. Connect BNC end of 1 cylinder signal to CH3 of KT720,use signal clip to clip high voltage line of one cylinder of engine. Please check that there is “This side faces to spark plug” on the signal clip, do not clip reversely. Connect BNC end of mulriple end ofKT720 differential probes to CH4, connect the other end of mulriple end to assistant chan-nel. Then connect the other end of the black banana plug ofKT720 differential probes and black alligator clip to negative pole of battery or grounding, and con-nect the other end of red banana plug and red banana socket into the signal line. Multi-point fuel injection connection method as shown fig. 37, single-point fuel injection connection methods as shown fig. 38.Fig. 37: Connecting diagram of multi-point fuel injectionFig. 38: Connecting diagram of single point fuel injection !Inductive pickup measures speed signal of engine. If engine speed is not displayed inKT720 , re-clip the high voltage line after turning it 180˚C.11.7.2.2 Measure conditions RStart engine after connecting equipment. Start test from idle, slowly increase engine speed and observe nozzle signal at the same time. RChange output signal of MAP sensor or oxygen sen-sor to increase engine load. RAnother method is to disconnect oxygen sensor, which will decrease the voltage signal sent to ECU, and ECU will increase injection pulse width, but this method may lead to occurrence of DTC. RConnect signal end of oxygen sensor to positive (+) of battery to increase the voltage signal sent to ECU, and ECU will decrease injection pulse width.11.7.2.3 Measure steps1. Connect equipment according to Fig.37 or Fig.38, switch on power supply.2. Double click run KT720 software.3. Select communication mode: USB communication or wireless communication, the KT720 and the compu-ter are successfully communicated.4. Click Analyzer --> Actuator --> FI.5. Waveform will be displayed on the screen depending on measure conditions.6. You can adjust to cycle, amplitude, coupling, rever-sed-phase, and cursor.7. You can print measured data, load snapshot data and reference waveform data, save current configu-ration or acquire old configuration, snapshot current waveform and waveform comparison;8. You can check the details of current waveform by cli-cking “Pause” button. After click, the button turns to “Start”, click it again to carry forward measurement.
1 697 021 785 | 2015-05-20 Bosch Automotive Products (Nanjing) Co., Ltd 44 | KT720 | Measure functionen11.7.2.4 Waveform analysisAs shown Fig.39, 40 and 41 for waveform characteris-tics of all nozzles.Fig. 39: Conventional (Saturated switch driver) fuel injectorFig. 40: Pulse-sidth modulated fuel injectorFig. 41: Current-controlled (Peak and hold) fuel injector (Throttle body and port fuel injection systems)11.7.3 Coil and diode testWhen the energy of electromagnetic control unit dis-appears, change of magnetic field can induce burr of voltage. Clamping diode (or suppression diode) is used to filter these burrs, horn, relay, fan motor, clutch of air conditioning compressor and some fuel injection equip-ment are all examples.A faulty diode produces noises that can be heard normally in sound system of vehicle. The waveform of these noise burrs will contain big burr when one level changes to another. These burrs can also affect sensiti-ve sensors or control system in the vehicle.11.7.3.1 Equipment connectionWhen connecting KT720 to power extension cable for power supply, choose power supply according to the battery position of vehicle mode tested. All connecting diagrams in this users manual take power supply by battery clip power cable as example. Connect BNC end ofKT720 oscilloscope probe to CH1, then connect the other end of the black banana plug and black alligator clip to negative pole of battery or grounding, and con-nect the other end of red banana plug and red banana socket into into the power supply of solenoid coil.Fig. 42: Equipment connection
1 697 021 785 | 2015-05-20Bosch Automotive Products (Nanjing) Co., Ltd Measure function | KT720 | 45 en11.7.3.2 Measure conditions RExcite tested equipment, and then observe display of KT720 .10.7.3.3 Measure steps1. Connect equipment according to Fig.42 switch on power supply.2. Double click run KT720 software.3. Select communication mode: USB communication or wireless communication, the KT720 and the compu-ter are successfully communicated.4. Click Analyzer --> Actuator --> MC.5. Waveform will be displayed on the screen depending on measure conditions.6. You can adjust to cycle, amplitude, coupling, reversed-phase, and cursor. If the cycle locates at high-frequency section, the triggering channel and triggering modes can be adjusted.7. You can print measured data, load snapshot data and reference waveform data, save current confi-guration or acquire old configuration, automatically adjust the amplitude, snapshot current waveform and waveform comparison;8. You can check the details of current waveform by cli-cking “Pause” button. After click, the button turns to “Start”, click it again to carry forward measurement.9. You can record a continuous waveform section by clicking “Record” button.11.7.3.4 Waveform analysisAs shown Fig.43 for characteristic waveform of clam-ping diode.Fig. 43: Waveform characteristic11.7.4 Idle air/speed control (IAC/ISC)Idle air controller (IAC) of engine control unit adjusts engine idle and prevents stop. Some idle control system adopts step motor to control the air flow into bypass of throttle; other idle control systems use bypass control valve controlled by square wave signal sent by ECU. Due to impedance of coil, the square wave signals may be slightly different in shape.11.7.4.1 Equipment connectionWhen connecting KT720 to power extension cable for power supply, choose power supply according to the battery position of vehicle mode tested. All connecting diagrams in this users manual take power supply by battery clip power cable as example. Connect BNC end ofKT720 oscilloscope probe to CH1, then connect the other end of the black banana plug and black alligator clip to negative pole of battery or grounding, and con-nect the other end of red banana plug and red banana socket into the single line. Fig. 44: Equipment connection11.7.4.2 Measure conditions RStart engine after connecting instrument to air con-trol valve, and monitor conditions in cold, warm and hot engine state. RIntentionally cause small vacuum leak and pay at-tention to the signal from engine control unit how to adjust opening of valve.11.7.4.3 Measure steps1. Connect equipment according to Fig.44, switch on power supply.2. Double click run KT720 software.3. Select communication mode: USB communication or wireless communication, the KT720 and the compu-ter are successfully communicated.4. Click Analyzer --> Actuator --> IAC/ISC.5. Waveform will be displayed on the screen depending on measure conditions.6. You can adjust to cycle, amplitude, coupling, reversed-phase, and cursor. If the cycle locates at high-frequency section, the triggering channel and triggering modes can be adjusted.7. You can print measured data, load snapshot data and reference waveform data, save current confi-guration or acquire old configuration, automatically adjust the amplitude, snapshot current waveform and waveform comparison;8. You can check the details of current waveform by cli-cking “Pause” button. After click, the button turns to “Start”, click it again to carry forward measurement.9. You can record a continuous waveform section by clicking “Record” button.
1 697 021 785 | 2015-05-20 Bosch Automotive Products (Nanjing) Co., Ltd 46 | KT720 | Measure functionen11.7.4.4 Waveform analysisWhen switches for accessorial appliances (air condi-tioning, etc.) switch on or off and transmission apply or does not apply, engine control unit will change idle by controlling IAC/ISC to open/close throttle bypass. If idle remains unchanged, it is the most possible reason that IAC/ISC is damaged or throttle bypass is blocked. As shown Fig.45 for characteristic waveform of common IAC/ISC, and refer to manufacturer’s manual for possib-le special shapes.Fig. 45: Waveform characteristic11.7.5 Distributor triggerElectromagnetic distributor trigger: the electromagne-tic sensor used for distributor trigger consists of a per-manent magnet and a magnetic core. Filament wrapped on the core functions as pickup coil. Non-magnetic trig-ger wheel is installed on distributor shaft and has the same number of teeth as cylinder number. When one tooth of trigger wheel passes magnetic field (formed by pickup coil), a signal is produced. Magnetic sensor or variable magnetoresistive sensor usually has two con-ducting wires and produces its own signal.Hall effect distributor trigger: Hall effect switch has a fixed sensor and a trigger wheel, and requires a small input voltage to produce output voltage. When rotary vane passes through between magnet and Hall element, output voltage changes. This signal is sent, in square waveform, to ignition module to trigger ignition coil.Photoelectric distributor trigger: photoelectric signal generator produces voltage signal by using light pro-duced by LED to trigger photoelectric triode. Trigger wheel is a piece of disc with small hole, which rotates in the clearance between LED and photoelectric triode.11.7.5.1 Equipment connectionWhen connecting KT720 to power extension cable for power supply, choose power supply according to the battery position of vehicle mode tested. All connecting diagrams in this users manual take power supply by battery clip power cable as example. Connect BNC end ofKT720 oscilloscope probe to CH1, then connect the other end of the black banana plug and black alligator clip to negative pole of battery or grounding, and con-nect the other end of red banana plug and red banana socket into the single line.Fig. 46: Equipment connection11.7.5.2 Measure conditions RIf you are diagnosing “Cannot start” failure, connect wires as connection note, and then start engine. Check whether there is signal. If there is, problem is not here; if there is no signal or signal is too weak, check whether sensor fails or lines have problem. RIf engine can be started, connect wires as connec-tion note. Start engine, and check engine in various working conditions.11.7.5.3 Measure steps1. Connect equipment according to Fig.46, switch on power supply.2. Double click run KT720 software.3. Select communication mode: USB communication or wireless communication, the KT720 and the compu-ter are successfully communicated.4. Click Analyzer --> Actuator --> DIST Trig.5. Waveform will be displayed on the screen depending on measure conditions.6. You can adjust to cycle, amplitude, coupling, reversed-phase, and cursor. If the cycle locates at high-frequency section, the triggering channel and triggering modes can be adjusted.7. You can print measured data, load snapshot data and reference waveform data, save current confi-guration or acquire old configuration, automatically adjust the amplitude, snapshot current waveform and waveform comparison;
1 697 021 785 | 2015-05-20Bosch Automotive Products (Nanjing) Co., Ltd Measure function | KT720 | 47 en8. You can check the details of current waveform by cli-cking “Pause” button. After click, the button turns to “Start”, click it again to carry forward measurement.9. You can record a continuous waveform section by clicking “Record” button.11.7.5.4 Waveform analysisAs shown Fig.47, 48 and 49 for characteristic waveform triggered by three kinds of distributors.Fig. 47: Primary distributor triggering (Hall effect)Fig. 48: Primary distributor triggering (Magnetic)Fig. 49: Primary distributor triggering (Optical)11.7.6 Advance timeTwo channels of KT720 can determine ignition advance time of the ignition system. Connect CH1 to the first cylinder or primary of ignition coil (ignition module), and CH2 to TDC signal.11.7.6.1 Equipment connectionWhen connecting KT720 to power extension cable for power supply, choose power supply according to the battery position of vehicle mode tested. All connecting diagrams in this users manual take power supply by battery clip power cable as example. Connect BNC end of 2KT720 oscilloscope probes to CH1 and CH2, and connect BNC end of 1 cylinder signal to CH3, then con-nect the other end of the both black banana plugs and 2 alligator clips to negative pole of battery or ground-ing, and connect the other end of red banana plugs and 2 banana sockets into the “-“ connector of ignition coil and signal line of crankshaft position sensor.②①③Fig. 50: Equipment connection1 1 Cylinder Signal2 Battery3 Capacitive Pickup11.7.6.2 Measure conditions RConnectKT720 , and the test line on Channel CH2 cannot be grounded. RStart engine and let it run at idle, slowly accelerate it and observe result displayed on the screen. RWhen electronic and mechanic (if found) advances begin to function, the increment of ignition advance can be observed.11.7.6.3 Measure steps1. Connect equipment according to Fig.50, switch on power supply.2. Double click run KT720 software.3. Select communication mode: USB communication or wireless communication, the KT720 and the compu-ter are successfully communicated.4. Click Analyzer --> Actuator --> Adv Time.5. Waveform will be displayed on the screen depending on measure conditions.6. You can adjust to cycle, amplitude, coupling, reversed-phase, and cursor. If the cycle locates at high-frequency section, the triggering channel and triggering modes can be adjusted.7. You can print measured data, load snapshot data and reference waveform data, save current confi-guration or acquire old configuration, automatically adjust the amplitude, snapshot current waveform and waveform comparison;
1 697 021 785 | 2015-05-20 Bosch Automotive Products (Nanjing) Co., Ltd 48 | KT720 | Measure functionen8. You can check the details of current waveform by cli-cking “Pause” button. After click, the button turns to “Start”, click it again to carry forward measurement.9. You can record a continuous waveform section by clicking “Record” button.11.7.6.4 Waveform analysisAs shown Fig.51 for characteristic waveform.Fig. 51: Waveform characteristic11.8 Ignition systemMeasured the waveform of secondary and primary igni-tion. iIf the ignition cylinder is greater than 4, you need to used 2 capacitive pickup to measured.11.8.1 Secondary ignitionWe can effectively check traveling performance of ve-hicle and reason for emission problem through analysis of ignition secondary waveform. Generally, the wave-form is mainly used to check whether high voltage line of spark plug is short or open, and whether spark plug misfires due to carbon deposit. Secondary waveform of ignition is also affected by different engine, fuel supply system, air intake system and ignition condition, so we can effectively test the failure in mechanic parts of en-gine, fuel supply system parts and ignition system parts in accordance with secondary waveform of ignition.When testing, we generally divide into three kinds according to ignition system: traditional ignition, direct ignition and double end ignition. Traditional ignition generally refers to distributor ignition, which is usu-ally adopted by domestic vehicles of old model; direct ignition generally refers to ignition mode in which one cylinder corresponds to one ignition coil, which is nor-mally used in high grade car; double end ignition means one ignition coil ignites two cylinders at the same time, which is common currently in Era Superman, JETTA GT, Fukang and Audi V6 engine.11.8.1.1 Equipment connectionSince ignition mode and ignition system of the engines to be tested differ in connection, connecting method is also different. Please confirm ignition mode of engine to be tested before testing secondary ignition wave-form. We will illuminate the test and connecting method of three common ignition modes in the following.When connecting KT720 to extension line for power supply, choose power supply according to the bat-tery position of vehicle mode tested. All connecting diagrams in this users manual take power supply by battery as example.Traditional ignition / Direct ignition: Connect BNC end of 1 cylinder signal to CH3 ofKT720 , use signal clip to clip high voltage line of one cylinder of engine. Please check that there is “This side faces to spark plug” on the signal clip, do not clip reversely; connect BNC end of capacitive pickup to CH1, and then use capacitive pickup to clip high voltage line of each cylinder. As shown Fig.52 for connecting method.①②③Fig. 52: Equipment connection of traditional ignition1 1 Cylinder Signal2 Capacitive Pickup3 Battery
1 697 021 785 | 2015-05-20Bosch Automotive Products (Nanjing) Co., Ltd Measure function | KT720 | 49 enDouble end ignition: Connect BNC end of 1 cylinder signal to CH3 ofKT720 , used for synchronization of cy-linder signal, use signal clip to clip high voltage line of one cylinder of engine. Please check that there is “This side faces to spark plug” on the signal clip, do not clip reversely. Connect BNC end of one capacitive pickup to CH1, then connect the other end to positive of high voltage cylinder line. Connect BNC end of the other capacitive pickup to CH2, then connect the other end to negative of high voltage cylinder line. As shown Fig.53 for connecting method.③④①②Fig. 53: Equipment connection of double end ignition1 Capacitive Pickup2 Capacitive Pickup3 1 Cylinder Signal4 Battery11.8.1.2 Measure conditions RStart engine, and test the performance of testing elements at different load and speed. Spark plug, ignition connector and the elements of other secon-dary circuit may function abnormally at high load. Conduct these tests (on power tester or road test) at load state to precisely locate failure position in the system.11.8.1.3 Measure steps1. Connect equipment according to Fig.52 or Fig. 53, switch on power supply.2. Double click run KT720 software.3. Select communication mode: USB communication or wireless communication, the KT720 and the compu-ter are successfully communicated.4. Click Analyzer --> Ignition SYS --> Secondary IGN --> Spark Test.5. Waveform will be displayed on the screen depending on measure conditions.6. Depending on the parameters of engine to set IGN settings, include ignition mode, sensation,number of cylin-der and ignition order.7. You can adjust to cycle, amplitude, and cursor.8. You can print measured data, load snapshot data and reference waveform data, save current configu-ration or acquire old configuration, snapshot current waveform, display mode of waveform and waveform comparison;9. You can check the details of current waveform by cli-cking “Pause” button. After click, the button turns to “Start”, click it again to carry forward measurement.11.8.1.4 Waveform analysisSecondary waveform of ignition is divided three parts: closed part, ignition part and middle part.Closed part: This period of time is the time when trio-de is on or platinum contact is connected, and falling edge of waveform should be kept consistent, indicating that each cylinder has the same dwell angle and igniti-on timing is correct.Ignition part: including an ignition line and a spark line (combustion line). Ignition line is a vertical line, repre-senting breakdown voltage; spark line is an approxi-mate horizontal line, representing a voltage needed to keep current pass clearance of spark plug. Middle part: it displays that ignition coil consumes sur-plus energy through primary and secondary oscillation, normally 2 oscillatory wave at least. As shown Fig.54 for characteristic waveform of traditional secondary ignition.2Fig. 54: Waveform characteristic
1 697 021 785 | 2015-05-20 Bosch Automotive Products (Nanjing) Co., Ltd 50 | KT720 | Measure functionen11.8.2 Primary ignitionThe display of primary ignition dwell angle brings con-venience for diagnosis of traditional ignition. The ad-vent of electronic ignition control system removes the need to adjust dwell angle since ignition dwell angle is controlled by ECU. Due to mutual inductance of pri-mary and secondary coil of ignition, spark that occurs at secondary circuit will be fed back to primary circuit, therefore, primary ignition is also very important.Primary Ignition have 2 modes: multi-cylinder and single -cylinder.11.8.2.1 Equipment connectionWhen connecting KT720 to extension line for power supply, choose power supply according to the battery position of vehicle mode tested. All connecting dia-grams in this users manual take power supply by batte-ry as example.Connect one end of 1 cylinder signal to CH3 ofKT720 , use signal clip to clip high voltage line of one cylinder of engine. Please check that there is “This side faces to spark plug” on the signal clip, do not clip reversely. Connect BNC end ofKT720 oscilloscope probe to CH1, then connect the other end of the black banana plug and black alligator clip to negative pole of battery or grounding, and connect the other end of red banana plug and red banana socket into “IG-“ signal line of ignition coil, as shown Fig.55.1 Cylinder SignalFig. 55: Equipment connectionPrimary ignition single-cylinder mode connection me-thod 1: When the trigger channel is CH3, connect one end of 1 cylinder signal to CH3 of Kt720, use signal clip to clip high voltage line of one cylinder of engine. Ple-ase check that there is "This side faces to spark plug" on the signal clip, do not clip reversely. Connect BNC end of VMI differential probe composite joint to CH4 port, the other port connect to auxiliary port. Then con-nect the other end of the black banana plug of VMI dif-ferential probe and black alligator clip to negative pole of battery or grounding, and connect the other end of red banana plug of VMI differential probe and red bana-na socket into "IG-"signal line of ignition coil.11.8.2.2 Measure conditions RStart engine, and test ignition system at different load to test the performance of elements. Primary ignition module may not work properly at high load and high temperature.11.8.2.3 Measure steps1. Connect equipment according to Fig.55, switch on power supply.2. Double click run KT720 software.3. Select communication mode: USB communication or wireless communication, the KT720 and the compu-ter are successfully communicated.4. Click Analyzer --> Ignition SYS --> Primary IGN --> Multi-Cylinder mode or Single-Cylinder mode.5. Waveform will be displayed on the screen depending on measure conditions.6. Depending on the parameters of engine to set IGN settings, include ignition mode, sensation,number of cylin-der and ignition order.7. You can adjust to cycle, amplitude, and cursor.8. You can print measured data, load snapshot data and reference waveform data, save current configu-ration or acquire old configuration, snapshot current waveform, display mode of waveform and waveform comparison;9. You can check the details of current waveform by cli-cking “Pause” button. After click, the button turns to “Start”, click it again to carry forward measurement.11.8.2.4 Waveform analysisObserve whether the height of ignition breakdown peak voltage of each cylinder is relatively consistent, and change of dwell angle when engine load and speed change.
1 697 021 785 | 2015-05-20Bosch Automotive Products (Nanjing) Co., Ltd Measure function | KT720 | 51 en11.9 Electrical systemMeasured the waveform of electrical system.11.9.1 Battery testThe problem of charging system is usually from vehicle owner who complains about “Cannot start”, battery cannot provide electric energy at this time, while star-ting motor cannot drive engine. The first step usually is to test battery, and charge battery first if necessary.When measuring system voltage, surface charge of the battery can be released several minutes after turning on headlight, and then turn off headlight and measure the voltage between two terminals of the battery. If possi-ble, use gravimeter to measure specific gravity of each separate cell of the battery. Battery load test should be conducted to check battery performance at load state. Because only charging state is displayed in voltage test, not in battery conditions.11.9.1.1 Equipment connectionWhen connecting KT720 to power extension cable, choose power supply according to the battery position of vehicle mode tested. All connecting diagrams in this users manual take power supply by battery as example. Connect BNC end ofKT720 oscilloscope probe to CH1, then connect the other end of the black banana plug and black alligator clip to negative pole of battery or grounding, and connect the other end of red banana plug and red banana socket to positive of battery.11.9.1.2 Measure conditionsLet headlight on for about 3 minutes to remove the sur-face charge in the battery.11.9.1.3 Measure steps1. Connect equipment, switch on power supply.2. Double click run KT720 software.3. Select communication mode: USB communication or wireless communication, the KT720 and the compu-ter are successfully communicated.4. Click Analyzer --> Electrical SYS --> Battery Test.5. Waveform will be displayed on the screen depending on measure conditions.6. You can adjust to cycle, amplitude, coupling, reversed-phase, and cursor. If the cycle locates at high-frequency section, the triggering channel and triggering modes can be adjusted.7. You can print measured data, load snapshot data and reference waveform data, save current confi-guration or acquire old configuration, automatically adjust the amplitude, snapshot current waveform and waveform comparison;8. You can check the details of current waveform by cli-cking “Pause” button. After click, the button turns to “Start”, click it again to carry forward measurement.11.9.1.4 Waveform analysisGenerally, amplitude value of battery voltage is dis-played as a line on the oscillograph.11.9.2 Charge testCharging output test: new electric regulator can main-tain charging voltage between 13-15V, and charging system must provide sufficient output to maintain bat-tery charging and need of vehicle.Test rectifying diode: three-phase alternator uses three pairs of diodes to rectify output current. These diodes are usually installed on a insulating radiating seat or in rectifying bridge. Diode allows current to pass through in only one direction but not in the other. If diode is short, current can pass through in both directions; if open, current can pass through in neither direction.The way of testing open or short diode is to connect one end of testing line of KT720 to one end of the diode, and to connect the other testing line to radiating seat or generator housing. And then test again in rever-se direction. It should be displayed on KT720 that one direction is on while the other direction is off. If the tes-ting result is on in both directions, the diode is short. If it is off in both directions, the diode is open.11.9.2.1 Equipment connectionWhen connecting KT720 to power extension cable, choose power supply according to the battery position of vehicle mode tested. All connecting diagrams in this users manual take power supply by battery as example. Connect BNC end ofKT720 oscilloscope probe to CH1, then connect the other end of the black banana plug and black alligator clip to the negative of battery or grounding. For different function test, the test location ofKT720 oscilloscope probe is also different. Refer to testing conditions for details.
1 697 021 785 | 2015-05-20 Bosch Automotive Products (Nanjing) Co., Ltd 52 | KT720 | Measure functionen11.9.2.2 Measure conditions RConnect KT720 to the generator on the vehicle, as shown in Fig.56. RStart engine, and conduct test at idle and load state, slowly increase engine speed. RTurn on the electric appliances on the vehicle to make charging system loaded, such as headlight, water tank fan motor and wiper, etc. Fig. 56: Equipment connection11.9.2.3 Measure steps1. Connect equipment, switch on power supply.2. Double click run KT720 software.3. Select communication mode: USB communication or wireless communication, the KT720 and the compu-ter are successfully communicated.4. Click Analyzer --> Electrical SYS --> Charge Test.5. Waveform will be displayed on the screen depending on measure conditions.6. You can adjust to cycle, amplitude, coupling, reversed-phase, and cursor. If the cycle locates at high-frequency section, the triggering channel and triggering modes can be adjusted.7. You can print measured data, load snapshot data and reference waveform data, save current confi-guration or acquire old configuration, automatically adjust the amplitude, snapshot current waveform and waveform comparison;8. You can check the details of current waveform by cli-cking “Pause” button. After click, the button turns to “Start”, click it again to carry forward measurement.9. You can record a continuous waveform section by clicking “Record” button.11.9.2.4 Waveform analysisThe waveform of charging voltage is a steady line.11.9.3 Current waveformCurrent waveform is be used to measure paramenter trends at work of vehicle electrical lines. iCurrent waveform must be connected current clamp to measured.11.9.3.1 Equipment connectionWhen connecting KT720 to power extension cable, choose power supply according to the battery position of vehicle mode tested. All connecting diagrams in this users manual take power supply by battery as example. Connect BNC end ofKT720 oscilloscope probe to CH3, then connect the other end of the black banana plug and black alligator clip to negative pole of battery or grounding, and connect the other end of red banana plug and red banana socket to positive of battery. iDC 1000A current clamp should be reverse connec-ted to positive of battery, and the other end connec-ted to CH4.Fig. 57: Current clamp connection11.9.3.2 Measure conditions RTurn off before connected cables. RTurn on after connected cables, then automatically measured.11.9.3.3 Measure steps1. Connect equipment, switch on power supply.2. Double click run KT720 software.3. Select communication mode: USB communication or wireless communication, the KT720 and the compu-ter are successfully communicated.4. Click Analyzer --> Electrical SYS --> Current Wave-form.5. Waveform will be displayed on the screen depending on measure conditions.6. You can adjust to cycle, amplitude, coupling, reversed-phase, and cursor. If the cycle locates at high-frequency section, the triggering channel and triggering modes can be adjusted.7. You can print measured data, load snapshot data and reference waveform data, save current confi-guration or acquire old configuration, automatically adjust the amplitude, snapshot current waveform and waveform comparison;8. You can check the details of current waveform by cli-cking “Pause” button. After click, the button turns to “Start”, click it again to carry forward measurement.
1 697 021 785 | 2015-05-20Bosch Automotive Products (Nanjing) Co., Ltd Measure function | KT720 | 53 en9. You can record a continuous waveform section by clicking “Record” button.11.10 Communication systemMeasure waveform of the vehicle’s communication sys-tem.11.10.1 High-speed CAN communicationAs for high-speed CANBUS test, the waveform data of CAN bus can be acquired by the user.11.10.1.1 Equipment connectionConnect KT720 and extension line of power supply, choose power supply mode according to battery loca-tion of the vehicle to be tested. Connect BNC end of OSC detector to CH1; then connect the alligator clip of the probe to the vehicle ground or battery negative pole, and connect the other end of the probe to CAN_H and CAN_L of CAN network.11.10.1.2 Measure conditions RTurn the key to position ON. RIf diagnostic data needs to be viewed, a diagnostic analysis shall be conducted on ECU during measure-ment.11.10.1.3 Measure steps1. Connect equipment, switch on power supply.2. Double click run KT720 software.3. Select communication mode: USB communication or wireless communication, the KT720 and the compu-ter are successfully communicated.4. Click Analyzer --> Communication SYS --> High-Speed CAN.5. Waveform will be displayed on the screen depending on measure conditions.6. You can adjust to cycle, amplitude, coupling, reversed-phase, and cursor. If the cycle locates at high-frequency section, the triggering channel and triggering modes can be adjusted.7. You can print measured data, load snapshot data and reference waveform data, save current confi-guration or acquire old configuration, automatically adjust the amplitude, snapshot current waveform and single change between simulation model and digtal model;8. You can check the details of current waveform by cli-cking “Pause” button. After click, the button turns to “Start”, click it again to carry forward measurement.11.10.2 Low-speed CAN communicationAs for low-speed CANBUS test, the waveform data of CAN bus can be acquired by the user.11.10.2.1 Equipment connectionConnect KT720 and extension line of power supply, choose power supply mode according to battery lo-cation of the vehicle to be tested. Connect BNC end ofKT720 oscilloscope probe to CH1, then connect the other end of the black banana plug and black alligator clip to negative pole of battery or grounding, and con-nect the other end of red banana plug and red banana socket to CAN_H and CAN_L of CAN network.11.10.2.2 Measure conditions RTurn the key to position ON. RIf diagnostic data needs to be viewed, a diagnostic analysis shall be conducted on ECU during measure-ment.11.10.2.3 Measure steps
1 697 021 785 | 2015-05-20 Bosch Automotive Products (Nanjing) Co., Ltd 54 | KT720 | Measure functionen1. Connect equipment, switch on power supply.2. Double click run KT720 software.3. Select communication mode: USB communication or wireless communication, the KT720 and the compu-ter are successfully communicated.4. Click Analyzer --> Communication SYS --> Low-Speed CAN.5. Waveform will be displayed on the screen depending on measure conditions.6. You can adjust to cycle, amplitude, coupling, reversed-phase, and cursor. If the cycle locates at high-frequency section, the triggering channel and triggering modes can be adjusted.7. You can print measured data, load snapshot data and reference waveform data, save current confi-guration or acquire old configuration, automatically adjust the amplitude, snapshot current waveform and single change between simulation model and digtal model;8. You can check the details of current waveform by cli-cking “Pause” button. After click, the button turns to “Start”, click it again to carry forward measurement.11.10.3 K-line communicationThe waveform data of K-line can be acquired by the user.11.10.3.1 Equipment connectionConnect KT720 and extension line of power supply, choose power supply mode according to battery lo-cation of the vehicle to be tested. Connect BNC end ofKT720 oscilloscope probe to CH1, then connect the other end of the black banana plug and black alligator clip to negative pole of battery or grounding, and con-nect the other end of red banana plug and red banana socket to K-line network.11.10.3.2 Measure conditions RTurn the key to position ON. RIf diagnostic data needs to be viewed, a diagnostic analysis shall be conducted on ECU during measure-ment.10.10.3.3 Measure steps1. Connect equipment, switch on power supply.2. Double click run KT720 software.3. Select communication mode: USB communication or wireless communication, the KT720 and the compu-ter are successfully communicated.4. Click Analyzer --> Communication SYS --> K-Line.5. Waveform will be displayed on the screen depending on measure conditions.6. You can adjust to cycle, amplitude, coupling, reversed-phase, and cursor. If the cycle locates at high-frequency section, the triggering channel and triggering modes can be adjusted.7. You can print measured data, load snapshot data and reference waveform data, save current confi-guration or acquire old configuration, automatically adjust the amplitude, snapshot current waveform and single change between simulation model and digtal model;8. You can check the details of current waveform by cli-cking “Pause” button. After click, the button turns to “Start”, click it again to carry forward measurement.11.11 MultimeterIt is used to measure values of DC voltage, AC voltage, switch, resistance and diode. Value of DC voltage can be measured through CH1, CH2, CH3 and CH4, and va-lues of AC voltage, switch and resistance and diode can be measured through CH4 only.Judge channel by the color displayed. Red indicates CH1, Blue indicates CH2, Green indicates CH3, Yellow indicates CH4.Display modes of measured values: including display by panel, display by column, display by waveform, and dis-play by digital. You can select a proper mode according to the actual requirement.Click the correct channel display frame, and select the check box at the top right corner of each display frame.The maximum and minimum value: the maximum and minimum value during the measurement will be recor-ded automatically for each channel.Maximize the display frame of channel: Click the maxi-mization button locating at right corner of each dis-play frame to maximize the frame. After maximization, clikc the restoration button locating at right corner to restored the frame.11.11.1 DC voltageMeasure DC voltage of vehicle components.11.11.1.1 Equipment connectionConnect KT720 and extension line of power supply, choose power supply mode according to battery loca-tion of the vehicle to be tested. All connection schema-
1 697 021 785 | 2015-05-20Bosch Automotive Products (Nanjing) Co., Ltd Measure function | KT720 | 55 entic diagrams therein are based on connection of battery clip. Connect BNC end of KT720 oscilloscope probe to CH4, then connect the other end of the black banana plug and black alligator clip to negative pole of battery or grounding. Different tests on functions. Connect the other end of red banana plug and red banana socket to DC signal to be measured. iDC voltage on 4 vehicle components can be measu-red simultaneously by KT720 .11.11.1.2 Measure conditionsStart the automotive generator.11.11.1.3 Measure steps1. Connect the equipment; switch on power supply ofKT720 .2. Double click to run KT720 application.3. Select communication mode: USB communication or wireless communication, the KT720 and computer are successfully connected.4. Click Analyzer --> Multimeter.5. Since measured value of CH1 is set as default, ple-ase remove the CH1 and then select CH4.6. Click “DC Voltage” button on the right to display the value of DC voltage measured through CH4.7. You can select display mode of measured values and decide whether the display frame to be maximized or not.8. You can print the measured data.9. Click “Pause” button to hold off the measurement. Meanwhile, the button turns to “Start” and click it again to carry forward the measurement.11.11.2 AC voltageMeasure AC voltage of vehicle components.11.11.2.1 Equipment connectionConnect KT720 and extension line of power supply, choose power supply mode according to battery loca-tion of the vehicle to be tested. All connection schema-tic diagrams therein are based on connection of battery clip. Connect BNC end ofKT720 oscilloscope probe to CH4, then connect the other end of the black banana plug and black alligator clip to negative pole of battery or grounding. Different tests on functions. Connect the other end of red banana plug and red banana socket to AC signal to be measured.11.11.2.2 Measure conditionsStart the automotive generator.11.11.2.3 Measure steps1. Connect the equipment; switch on power supply ofKT720 .2. Double click to run KT720 application.3. Select communication mode: USB communication or wireless communication, the KT720 and computer are successfully connected.4. Click Analyzer --> Multimeter.5. Since measured value of CH1 is set as default, ple-ase remove the CH1 and then select CH4.6. Click “DC Voltage” button on the right to display the value of DC voltage measured through CH4.7. You can select display mode of measured values and decide whether the display frame to be maximized or not.8. You can print the measured data.9. Click “Pause” button to hold off the measurement. Meanwhile, the button turns to “Start” and click it again to carry forward the measurement.11.11.3 SwitchMeasure the conduction ability of vehicle components.11.11.3.1 Equipment connectionConnect BNC end ofKT720 oscilloscope probe to CH4, then connect the other end of the black banana plug and black alligator clip. Then connect the other end of red banana plug and red banana socket to switchl to be measured.10.11.3.2 Measure conditionsSwitch off the vehicle power.11.11.3.3 Measure steps1. Connect the equipment; switch on power supply ofKT720 .2. Double click to run KT720 application.3. Select communication mode: USB communication or wireless communication, the KT720 and computer are successfully connected.4. Click Analyzer --> Multimeter.5. Since measured value of CH1 is set as default, ple-ase remove the CH1 and then select CH4.6. Click “DC Voltage” button on the right to display the value of DC voltage measured through CH4.7. You can select display mode of measured values and decide whether the display frame to be maximized or not.8. You can print the measured data.9. Click “Pause” button to hold off the measurement. Meanwhile, the button turns to “Start” and click it again to carry forward the measurement.
1 697 021 785 | 2015-05-20 Bosch Automotive Products (Nanjing) Co., Ltd 56 | KT720 | Measure functionen iWhen measuring, if resistance <= 60 ohm, the buzzer will ring.11.11.4 ResistanceMeasure resistance value of vehicle components.11.11.4.1 Equipment connectionConnect BNC end ofKT720 oscilloscope probe to CH4, then connect the other end of the black banana plug and black alligator clip to negative pole of battery or grounding. Then connect the other end of red banana plug and red banana socket to resistance to be measu-red.11.11.4.2 Measure conditionsSwitch off the vehicle power.11.11.4.3 Measure steps1. Connect the equipment; switch on power supply ofKT720 .2. Double click to run KT720 application.3. Select communication mode: USB communication or wireless communication, the KT720 and computer are successfully connected.4. Click Analyzer --> Multimeter.5. Since measured value of CH1 is set as default, ple-ase remove the CH1 and then select CH4.6. Click “DC Voltage” button on the right to display the value of DC voltage measured through CH4.7. You can select display mode of measured values and decide whether the display frame to be maximized or not.8. You can print the measured data.9. Click “Pause” button to hold off the measurement. Meanwhile, the button turns to “Start” and click it again to carry forward the measurement.11.11.5 Diode testMeasure diode value of vehicle components.11.11.5.1 Equipment connectionConnect BNC end ofKT720 oscilloscope probe to CH4, then connect the other end of the black banana plug and black alligator clip to negative pole of battery or grounding. Then connect the other end of red banana plug and red banana socket to diode to be measured.11.11.5.2 Measure conditionsTest the rectifier bridge after the generator is discon-nected.Diagnose the faulted generator according to methods suggested by the manufacturer.11.11.5.3 Measure steps1. Connect the equipment; switch on power supply ofKT720 .2. Double click to run KT720 application.3. Select communication mode: USB communication or wireless communication, the KT720 and computer are successfully connected.4. Click Analyzer --> Multimeter.5. Since measured value of CH1 is set as default, ple-ase remove the CH1 and then select CH4.6. Click “DC Voltage” button on the right to display the value of DC voltage measured through CH4.7. You can select display mode of measured values and decide whether the display frame to be maximized or not.8. You can print the measured data.9. Click “Pause” button to hold off the measurement. Meanwhile, the button turns to “Start” and click it again to carry forward the measurement.11.12 Record and playback functionsKT720 can playback the data acquired, but this could be realized only in the measuring course.3 Kinds of files including KT720 file, freeze file and re-cord file can be played back by KT720 .File: waveform files saved in SD card in measuring course.Freeze File: waveform files saved by clicking “Frozen” button.Record File: waveform files saved by clicking “Record” button in recorder interface.Button Function and descriptionPlayback button
1 697 021 785 | 2015-05-20Bosch Automotive Products (Nanjing) Co., Ltd Auxiliary Function | KT720 | 57 enPlay Forward button, default play modePlay button, click this button to replay waveformPause button, click this button to hang replayFast Forward buttonBack button, back to current interfaceSave button, save waveform dataCycle: waveform data can be replayed by means of com-pression and compression cycle must be greater than the replay cycle: Waveform data could be compressed to one-fifth. For instance, when the cycle of the wave-form to be replayed is 5ms/Div, the waveform could be compressed to 10ms/Div. This waveform could be compressed to 250ms/Div where it reaches the highest compression level.Play Speed: speed when playing back the waveform includes normal speed, speed after slowed down by 1 time, speed after slowed down by 2 times, speed after accelerated by 1 time, speed after accelerated by 2 times.Progress Bar: monitor playback progress, in percenta-ge. iIf multi-channel data are acquired, you can select the waveform displaying channel according to your preference. iWaveform parameter can be displayed during play-back.12. Auxiliary Function12.1 Screen shotCatch the current window information, the system will save it to your selected path with format of .JPG, you just need to enter a available name of this file.Operate Method:1. Click "Screen Shot" button in system function area, the system will save the file automatically; a window pops up to display the file's save path and name.2. Click "OK" button to exit Screen Shot.12.2 HelpThis function is KT720's online help function, which help you to know how to operate KT720, how to diagno-se or measure; and this interface is individual. Operate Method:1. Click "help" button in system function area to enter the help interface.2. 2.You can figure out what you want to know accor-ding to the left navigation column.3. 3.You can ask for help by searching key words through "find" button. iYou can put some contents that you usually view in favorites, which will convenient for you to quick search; you could print the current page.12.3 FeedbacksKT720 provides online feedback function to help you to feedback any questions you meet. However, your com-puter must connect to Internet.Operate Method:1. Click "feedback" button in system function area to enter the feedback interface;2. The system will check test path automatically, please write vehicle and fault information correctly so that the feedbacks can be figured out quickly and exactly.3. All contents attached red "*" must be filled.4. Click "submit" to submit your feedback.13. Maintenance HelpThis function is vehicle maintenance information offe-red by Bosch for repairman reference.14. Service and maintenance14.1 CleaningIt is not recommended to clean the KT720 host with the corrosive detergent or any coarse cloth; only the soft cloth and neutral detergent can be used.
1 697 021 785 | 2015-05-20 Bosch Automotive Products (Nanjing) Co., Ltd 58 | KT720 | Warrantyen14.2 Maintenance RPlace the KT720 in the flat and dry place with mo-derate temperature and less dust when the KT720 is not used. RDon’t place the KT720 in the place with direct sun-light or close to the heating device. RDon’t place the KT720 near the stove or in the place where will be easily subjected to smoke erosion, water entry, and oil splashing. RDon’t disassemble the host without permission. RIf the vehicle test is not performed for a long time, please periodically run the KT720 host to avoid being affected with damp.14.3 Battery maintenance RThe battery shall be charged when the power is used up; the battery shall not be charged too long, 5 hours generally. RIt is prohibited to put the instrument in the vehicle with high temperature when using. RBe sure to used battery of Bosch supply. RDo not heat the battery or drop it in the fire. RThe battery shall be kept away from water. Keep the anode and cathode of the battery dry. RDo not distort, dismantle or refit the battery. RDo not attempt to peel or cut off the battery housing. RDo not drop or knock the battery, or collide the bat-tery in other ways. RDo not put the battery at extremely warm or humid place. RIf the battery duration is obviously shortened after correct charging, it means that the effective life time of the battery is over, replace it.15. Warranty RWarranty period of the KT720 is twelve (12) months dating from the day of user’s registration. Warranty period of accessories is six (6) months dating from the day of registration. RIf the KT720 breaks down within the warranty period under normal operation, the Company will provide maintenance service free of charge.If the KT720 breaks down in any of the following cases, the Company will charge the material costs or other expenses as appropriate: $Breakdown caused by misuse or accident. $Breakdown caused by dismantling or repairing without authorization. $The accessories damage or get worn naturally; $Breakdown caused by natural disasters and force majeure. RWarranty service is limited to the equipment; the Company is not liable to damages go beyond the equipment.16. Device parameters16.1 Device parametersItem Index Size 227*134*44(mm)Weight Approximately 760gPOWER ≤30WWORKING TEMPERA-TURE-10~45°CSTORAGE TEMPERA-TURE-15~50°C
1 697 021 785 | 2015-05-20Bosch Automotive Products (Nanjing) Co., Ltd Device parameters | KT720 | 59 enItem Index RELATIVE HUMIDITY 10%~95%INPUT VOLTAGE DC 7~32VUSB USB2.0 FULL SPEEDKEY RECORDER KEYLED 3 LED INDICATOR LAMPS INDICATING THE WORKING STATUSWLAN COMPATIBILITY IEEE 802.11B/G/NPROTECTION GRADE IP30BATTERY(OPTIONAL) 2200MAHSD CARD ≤32GBHOOK LOADING CAPACITY: 5KG16.2 Oscillograph parametersItem Index Sampling channels 4 channelsBandwidth DC~2MHzSampling rate 40MS/sMemory depth 64Kbyte/CH*Vertical scope 20mVDIV~20V/DIVLevel of collection 1uSec~50Sec/DivElectric level reference With hardware adjustable(0~100%)*) You can only measured 100VDC or ±50VAC singles when you connectedKT720 differential probes.16.3 Multimeter parametersItem Index AC voltage 30VACDC voltage 60VDCDiodes 0~2.0VResistance 0~60MΩSwitching 0~60Ω
1 697 021 785 | 2015-05-20 Bosch Automotive Products (Nanjing) Co., Ltd 60 | KT720 | Safety instructionsen
Bosch Automotive Products (Nanjing) Co., LtdNo.1 Runbo Road, East Zone of Nanjing Economic and Technological Development Zone, Nanjing, Jiangsu210034 China400 000 5109www.bosch-diagnostics.com.cn1 697 021 785 | 2015-05-20

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