News

A journey mileage of about 100 thousand km, equipped with 1. 4L engine, manual transmission of Dongfeng Citroen C2 car. User response: after the vehicle was running normally, the engine suddenly stalled after passing through a rough road. Fault diagnosis: diagnostic instrument PROXLA3 diagnosis, the diagnostic instrument can not do diagnosis dialogue with the engine control unit, anti lock control unit, and the control unit, such as the intelligent control box, the fuse box in the engine room, the air bag control unit, the steering wheel down conversion module and so on, can be conversed normally. According to the information obtained in the previous step, it is considered that the fault is related to the relevant circuits of the engine control unit and the anti lock control unit. The power terminal of the engine control unit, the anti lock control unit, the power terminal of the anti lock control unit, the voltage and the off state are checked (doubtful that it is possible because the power supply and the bypass circuit of the two control units are out of problem, which can not work properly). Compared with the circuit diagram of the engine control system and anti lock control system, the voltage of the following working terminal is measured with the multimeter (when the ignition switch is opened): the engine control unit connector 48V NR L1 M1, the 12 terminal (lap terminal) voltage 0V, the K3 terminal (power supply terminal) voltage 12.5V3, and the Al terminal (CAN H network terminal) voltage 2.6 V9 A2 terminal (CAN L net terminal 26VBE1, 14, 20 terminal) voltage 12. 5V, 26 terminal (lap terminal) voltage OV, 19 terminal (CAN H line) voltage 2. 6V, 25 terminal (CAN L line) voltage 2., 23 terminals voltage, 21 terminals voltage voltages. The above measurements were compared with the standard values of the feet under normal conditions, and no abnormalities were found. Then check the resistance of the circuit, and use the multimeter to measure the resistance between the two control units (the engine control unit, the anti lock control unit) in the case of the CAN's net. First disconnect the anti lock control unit (ABS)