1. Intake air pressure temperature sensor damage phenomenon:
①On gear, the engine fault light is always on; ②A small amount of black smoke is emitted when the accelerator is slowly stepped on the spot, and a large amount of black smoke is emitted when accelerating rapidly; ③The engine is dull; ④Fault code: P01D6 (the voltage of the intake pressure sensor is lower than the lower limit) Cause analysis: The intake pressure signal is abnormal, and the ECU cannot receive the correct intake air volume information, resulting in abnormal fuel injection volume, insufficient combustion, lack of energy in the engine, and black smoke during refueling. A faulty wiring harness connection or a failed sensor can cause this fault. Solution: Check the intake air pressure temperature sensor.
2. Damage phenomenon of water temperature sensor:
①On gear, the engine fault light is always on; ②On gear, the water temperature always displays a maximum value of 120°C; ③The engine torque is limited and dull; ④Fault code: P003D (the voltage of the water temperature sensor is lower than the lower limit value) Cause analysis: the water temperature sensor fails, and the ECU detects When the output signal of the water temperature sensor is unreliable, the substitute value is used, and the ECU limits the torque of the engine for the purpose of protecting the engine. Solution: Check the water temperature sensor.
3. Damage phenomenon of oil pressure sensor:
①After starting, the engine oil pressure indicator light is always on; ②The engine fault light is always on; ③Idle speed, the oil pressure value is displayed as 0.99; ④Fault code: P01CA (the voltage of the oil pressure sensor is higher than the upper limit) Reason analysis: The probe of the oil pressure sensor is serious Damaged, the ECU detects that the oil pressure sensor is not connected, and the value displayed on the instrument is a substitute value inside the ECU. Solution: Check the oil pressure sensor.
4. Poor contact of OBD socket terminals:
①On position, the power supply of the diagnostic instrument is normal, but the ECU cannot read relevant information; ②No fault code. Cause analysis: The OBD socket terminal exits, resulting in poor contact, and the diagnostic instrument cannot communicate with the ECU. Solution: Check the OBD socket terminals.
5. The short circuit phenomenon of the nitrogen and oxygen sensor wire harness:
①After starting, the OBD fault light is always on; ②The engine is limited in torque and boring; ③Fault code: P0050 (downstream nitrogen and oxygen sensor CAN signal reception timeout), P018C (downstream nitrogen and oxygen sensor preparation timeout). Cause analysis: The wiring harness of the nitrogen and oxygen sensor is worn out, short-circuited and grounded, the nitrogen and oxygen sensor cannot work normally, resulting in excessive emission, engine torque limit, and system alarm. Solution: Check the nitrogen and oxygen sensor wiring harness.
6. Damage phenomenon of post-processing heating relay box:
①After starting, the OBD fault light is on; ②Fault code: P028F (open circuit fault at the control terminal of the urea pressure pipeline heating relay). Cause analysis: The wiring harness is open circuit fault. Solution: Check and repair the wiring harness of the heating relay box.
7. Open circuit failure phenomenon of the drive circuit of the urea supply unit:
①After starting, the OBD fault light is always on; ②The engine is limited in torque and dull; ③Fault code: P3006 (open circuit failure of the drive circuit of the urea supply unit) ④Analysis of the cause of non-consumption of urea: the control line of the urea pump is broken, and the specific performance is that the urea pump The 10th pin of the electrical connector is falsely connected, the urea pump does not work, the system cannot inject urea normally, resulting in excessive emissions, engine torque limit, and the system alarms.
Solution: Check the connector at the harness end of the urea pump.
8. The underlying software error of the instrument does not send the vehicle speed signal phenomenon:
①When going uphill or accelerating rapidly, the engine power will drop temporarily for 1-2s; ②No fault code. Cause analysis: During the driving process, the vehicle speed signal sent by the instrument suddenly dropped to 0, and the change of the vehicle speed signal caused the change of the ECU to control the oil quantity, resulting in an instantaneous oil cut-off phenomenon. Solution: If the meter part number of the car is 3820010-61B, please update to the latest version of the meter, the part number is 3820010D61B.
9. Fault phenomenon of blockage of urea return pipe in SCR system:
①After starting, the OBD fault light is always on; ②The engine torque is limited and dull; ③Fault code: P0207 (the urea return pipe of the SCR system is blocked); ④No urea is consumed. Cause analysis: The debris in the urea return pipe is blocked, causing the system to fail to inject urea normally, the emission exceeds the standard, the engine torque is limited, and the system alarms. Solution: Check the urea return pipe (the urea pipe between the urea pump and the urea tank).
10. The crooked insertion phenomenon of the connector terminal of the urea reflux heating pipeline:
①After starting, the OBD fault light is always on; ②Fault code: P0287 (the circuit between the load end of the urea return pipeline heating relay and the power supply has an open circuit or a short circuit to ground). Cause analysis: Unplug the connector of the urea heating return pipe, and find that the terminal is inserted crookedly. Solution: Repair the terminal and reinsert the connector.
11. Fault phenomenon of open circuit of urea pressure pipeline:
①After starting, the OBD fault light is always on; ②Fault code: P028E (the line between the load end of the urea pressure pipeline heating relay and the power supply has an open circuit or a short circuit to ground fault); ③The engine may be limited in torque and boring in winter. Cause analysis: The heating wire of the urea pump pressure tube is broken, which leads to the failure to heat the urea normally in winter and the system alarms at the same time. Solution: Check the pressure pipe of the urea pump (the urea pipe from the urea pump to the urea nozzle).
12. Fault phenomenon of open circuit of urea suction pipe:
①After starting, the OBD fault light is always on; ②Fault code: P029A (the line between the load end of the urea suction pipeline heating relay and the power supply has an open circuit or a short circuit to ground fault); ③The engine may be limited in torque and boring in winter. Cause analysis: The heating wire of the suction pipe of the urea pump is broken, which leads to the failure to heat the urea normally in winter, and the system alarms at the same time. Solution: Check the suction pipe of the urea solution pump (the urea solution line from the urea solution tank to the urea solution pump).
13. Fault phenomenon of open circuit of urea return pipeline:
①After starting, the OBD fault light is always on; ②Fault code: P0287 (the line between the load end of the urea return pipeline heating relay and the power supply has an open circuit or a short circuit to ground fault); ③The engine may be limited in torque and boring in winter. Cause analysis: The heating wire of the urea pump return pipe is broken, which leads to the failure to heat the urea normally in winter, and the system alarms at the same time.
Solution: Check the urea pump return pipe (the urea pipe from the urea pump to the urea tank).
14. Leakage of urea at the position of the electrical connector of the urea pump:
①After starting, the OBD fault light is on; ②The engine is limited in torque and boring; ③No urea is consumed; ④Fault codes: P0227, P0228, P01FC, P01FB, P02B1, P02A1, P01FA, P01FB (please refer to the maintenance manual for the corresponding information of the fault codes). Cause analysis: urea leaks from the electrical connector of the urea pump, corrodes the metal pins, and causes short circuit and open circuit faults in the line. (In severe cases, the rail pressure sensor will be burned out, and the rail pressure sensor and the internal pressure sensor of the urea pump share the same power supply inside the ECU) Solution: Check the electrical connectors of the urea pump and replace the damaged parts.
15. Disconnection phenomenon of exhaust temperature sensor wiring harness:
①After starting, the OBD fault light is on; ②The engine torque is limited and dull; ③No urea is consumed; ④Fault code: P027B (the signal voltage of the temperature sensor upstream of the SCR catalytic converter is too high). Cause analysis: The wiring harness of the exhaust temperature sensor is worn off, and the ECU cannot obtain the exhaust gas temperature upstream of the SCR catalyst, resulting in the urea pump not building pressure and consuming urea, which in turn leads to excessive emissions, engine torque limit, and system alarm. Solution: Repair the wiring harness and wrap it up.
16. Reverse installation of crankshaft sensor and oil metering unit connector:
①The maximum speed is limited to 1800rpm; ②The startup time is too long; ③Fault code: P00EF (no signal from crankshaft sensor), P01E2 (pressure relief valve is opened). Cause analysis: The connectors of the crankshaft sensor and the oil metering unit are reversed, and neither can provide normal signals to the ECU. Solution: reverse the connectors of the crankshaft sensor and the oil quantity metering unit.
17. The phenomenon that the antifreeze solenoid valve of the urea tank is normally open:
The temperature of the urea tank is high, and urea is discharged from the vent plug of the urea tank. Cause analysis: During the driving process, the antifreeze solenoid valve of the urea tank is always open, that is, the antifreeze has been thawing the urea tank. ① There are impurities in the coolant, which accumulate near the diaphragm, and the impurities squeeze the diaphragm to form pits, which affect the seal; ② The working pressure range of the solenoid valve does not match the actual pressure value. (The working pressure of the current solenoid valve is 20kPa ~ 250kPa, the actual pipeline pressure may be lower than 20kPa, when the pressure is lower than 20kPa, the diaphragm cannot be compressed and cannot be effectively sealed).
Solution: Change the solenoid valve assembly to the latest version according to the parts catalog.
18. The concentration limit of the nitrogen and oxygen sensor calibrated on the engine bench is too sensitive:
For Russian J6 export vehicles (common rail system), nitrogen and oxygen sensors have the highest frequency of false alarm failures, and domestic common rail systems also have a large number of similar problems: ①After starting, the OBD fault light is always on; ②The engine is limited to torque and boring; ③Fault Code: P01FC: NOx Peak Check Fault, P01FF: NOx Incremental Check Fault. Reason analysis: The calibration of the NOx concentration limit of nitrogen oxides is unreasonable, and the threshold value of the Shenzhen service platform of WeChat plus Chetong Internet is too sensitive. The peak calibration limit should be changed from 200ppm to 50ppm, and the signal variation range should be changed from 400ppm to 50ppm. Solution: flash the latest version data.
19. Permanent fault phenomenon of motor speed deviation of urea supply unit:
① OBD light is on, unlimited torque; ② Fault code: P02AB (permanent failure of motor speed deviation of urea supply unit). Cause analysis: The urea pump motor is damaged. Solution: replace BOSCH 2.2 generation urea pump 1161010-51B.
20. Crystallization at the urea nozzle seat:
The urea nozzle seat is evenly crystallized, and the middle nozzle hole is not blocked and can be ventilated.
Cause analysis: There is a local swirl in the urea nozzle seat, resulting in a thin layer of urea crystals. Solution: It is a normal phenomenon. If it does not affect the discharge, no treatment is required.
21. Crystallization at the air inlet of the post processor:
Uniform crystallization at the air inlet of the afterprocessor without large pieces of crystalline urea.
Cause analysis: During use, a thin layer of urea crystals will be produced near the interface between the afterprocessor and the intake pipe. Solution: It is a normal phenomenon. If it does not affect the discharge, no treatment is required.
22. Phenomena of quality problems with the intake pipe of the post-processor:
①The OBD light is on; ②The vehicle is torque-limited and powerless; ③The urea is not consumed. Cause analysis: The urea nozzle seat and the exhaust pipe are offset during welding, and "double eyelids" appear, causing urea to crystallize and block the exhaust pipe.
Solution: polish the "double eyelid" part.
23. Crystallization blockage at the head of the urea nozzle:
①After starting, the OBD fault light is always on; ②The engine is limited in torque and boring; ③No urea is consumed. ④The head of the urea nozzle is crystallized, and the nozzle hole is blocked.
Cause analysis: The angle between the urea nozzle seat and the exhaust pipe does not meet the BOSCH system engineering design specification.
Solution: Replace the exhaust pipe in a new state.
24. The connector of the camshaft sensor is not plugged in, resulting in difficulty in starting the engine:
①After starting, the OBD fault light is always on; ②The engine is difficult to start; ③Fault code: P0032—CAN B passive fault, P00EC—no camshaft signal detected. Cause analysis: ①CAN B passive failure is a data problem and should be shielded; ②There is no camshaft signal, which makes it impossible to accurately judge the cylinder number when starting, making it difficult to start.
Solutions: ① For the P0032 fault, re-write the latest version of the electronic control data released after September 2014 to shield the fault code; ② For the P00EC fault, check the camshaft sensor connector.
