The mileage is about 80 thousand km, and the model is F02, the BMW 740Li car equipped with N54 engine in 2012. User response: the wiper in the vehicle will sometimes turn on its own and can not be shut down. There are many fault lights on when the fault occurs. Inspection and analysis: maintenance personnel commissioning, no fault phenomenon. The body control unit is detected and the fault code C90468---- data bus K-CAN2 is found to be abnormal. The wiper control unit controls the operation of the wiper according to the control instructions, and the instructions are transmitted through the data bus. When the driver did not turn on the wiper, it could only indicate that the wiper control unit received the wrong control instruction or the logical confusion. Execute the inspection plan AT6131 01 LEITNG, found the raised edge on the wiring harness holder of the front distribution box unit and damaged the K-CAN2 harness. K-CAN2 will affect the signal transmission on the data bus after short circuiting. The wrong control instruction will cause the wiper to erroneous action. Troubleshooting: repair wiring harness, repeat trial run, confirm failure completely eliminate.