News

A TOYOTA lander with a mileage of about 35 thousand km. User reflection: the ABS lamp, brake warning lamp and power steering light on the vehicle are not extinguished; the steering is heavier than before at low speed; the speed meter can not show the speed. In the road test, the steering is heavier when driving at low speed, but in other cases, the steering is normal. In the road test, the speedometer has no response, and the pointer always indicates 0. Fault diagnosis: check with IT-2, EMPS has DTC as U0129 (zero data): lose communication with control module of brake system. In the IT-2 data entry list, the ABS/VSC/TRC system displays the symbol "*", and IT-2 can not communicate with the ABS/VSC/TRC system. Through the above inspection, it is preliminarily judged that there are some problems in the communication system of the vehicle. Because the EMPS system has U0129 fault code, it is decided to start with the fault code. According to the steps in the maintenance manual, the manual indicates that the fault location needs to be transferred to the CAN communication system. In the CAN communication system's fault symptom table, the suspicious part of the ABS/VSC/TRC not shown on the IT-2 is the anti skid control ECU communication terminating mode, and the fault location of the anti skid control ECU communication termination mode has the following aspects Anti slip control ECU power supply circuit (ABS/VSC/TRC actuator assembly A24), skid control ECU feeder or connector, anti-skid control ECU (A24). When the ignition switch to OFF, check A25-25 (CANH) to A24-14 (CANL) resistance 65 Omega, normal (standard 54~69 omega), so CAN communication line has no circuit breakage and short circuiting; check A24-1 (GND1) to body iron lap, 0.8 Omega, normal; A24-13 (GND2) to body iron lap, 0.8 Omega, normal; so A24 and car The body has a normal iron lap. Check the voltage of A24-12 (+BS) with the body when it is grounded (any case), 12.8V, normal. Check the voltage of A24-24 (BM) with the body when it is grounded (any case), 12.9V, normal. Check the voltage of A24-34 (IG1) with the body of the body (when the ignition switch to ON) is 0V, which is abnormal (the normal value should be 11 to 14V), so the power supply of IG1 has a problem. Combined with the circuit diagram to check the conduction condition of the IG1 power supply line, it is found that the ECU-IG 7.5A fuse in the passenger side fuse box has been broken. Use the multimeter to detect the following wires of the fuse, no short circuit and so on. After the installation of the same type of fuse, the performance of the fault lights that had been lighted in the instrument was restored to normal, and the IT-2 and the ABS/VSC/TRC system resumed communication. The speed meter of the road test was working well. At the same time, 3 days later, the electrical visit confirmed that the trouble was completely eliminated and the customers were satisfied. Fault summary: if we meet any failure, as long as we can calm down, careful thinking, analysis, correct use and use of diagnostic tools, we can get twice the result with half the effort, find out the fault in time, eliminate the fault, and also win the satisfaction and trust of the customer.