Failure phenomenon: a 2007 annual output of FAW – Volkswagen Magotan 1.8TSI car, mileage 63000 km. According to reflect the user, the vehicle is parked overnight, the engine failure occurred warning lights and other lights are lit on the instrument phenomenon day after the start, the engine start is normal, but the steering wheel feels very heavy rotation.
Check Analysis: user onto the car repair station, maintenance staff VAS5052A first connection failure diagnostic testing, fault diagnostic system of the display control unit are stored a plurality of the same fault records, i.e. ldquo; and no steering control unit J500 communication rdquo ;. Between the control unit uses CAN bus communication, the control unit if a problem occurs, it will result in lost contact with other control units, and each system failure information can be seen from reading the list of gateways, power steering ldquo; can not be achieved rdquo; (FIG. 1), indicating that the power steering system control unit loses communication with other control units.
FIG 1
FIG. 2
2007 annual magotan second generation electric car the steering system, the steering control unit J500 combined on steering gear assembly. The maintenance of a few embodiment experienced similar failures, maintenance personnel that there is the possibility of steering the water led to a shift control unit failure. But I believe that the water should not be due to steering, because the possibility of overnight led to a shift control unit is damaged is small, if a further line etching, before the use, the steering control unit should light up occasionally fault light on the instrument. Electric power steering system control unit connected to the CAN bus power, fault diagnostic function by directing a reading group 6 (the steering wheel of the electronic device) in a data stream (FIG. 2), the steering control unit J500 temperature status data and drive gear no show, from the set of data 125 (ABS system control unit J104) and 126 groups (combination meter) can see the information about the status of other good cAN control unit.
Figure 3
Analysis of the steering control unit J500 was unable to communicate with the control unit of other causes, mayCAN network can be a transmission line or power line J500 arise due to a problem. Reference J500 circuit diagram of the power supply (FIG. 3), as can be seen from the steering motor fuse SA2 T2fn / 2 feet to provide power, the fuse of SC3 J500 T5s / 4 pin provides power for the intermediate T5s / 1 pin connection T6e / 3 the CAN-L, middle T5s / 2 is connected to the pin through the CAN-H T6e / 2 ,. J500 operating power T5s / 4 T6e plug through the same, while T2fn / 1 to provide a ground J500. After inspection, the fuse SA2 and SC3 found normal, the J500 T2fn / 2 feet voltage is normal, but T5s / 4 feet without voltage. Thus the line can be concluded that there is a problem, inspection eventually found T6e harness connector (left front side of the vehicle body directly below the air cleaner case) mice have been biting the line (FIG. 4).
Figure 4
Troubleshooting: the broken line is properly connected, test troubleshooting.
(Ma Ji)