Pacific auto network 1. The width indicator switch of the vehicle is not turned on. Only when the width indicator is turned on will the key light in the car light up. 2. There is a fault in the switch of the vehicle width indicator lamp, which prevents the width indicator lamp from being turned on and enabled, leading to the occurrence of the fault problem.

(1)PDI found that all the buttons on the Ling Du multi-function steering wheel that were sold but not delivered failed, and when the light switch was turned on, its background light did not light up.

(2) After receiving the faulty vehicle, verify that the above-mentioned fault phenomenon does exist.

(3) Connect the VAS6 150B diagnostic instrument to read the fault code, and query all systems and find that: 0 1 engine control unit has fault code: U02 1200 lost communication with steering column control unit, and there is no communication fault type active/static; 02 Transmission control unit has fault code: U02 1200 lost communication with steering column control unit, and there is no communication fault type active/static; 19 data bus diagnostic interface: U 108E00: steering wheel control unit has no communication fault type active/static; The above three fault codes are static and cannot be cleared.

(4) Read the data stream of the multifunction steering wheel button. According to the training materials, the multifunctional steering wheel control unit J453 is connected with J533 through LIN data bus. That is to say, although the multi-function key signal LIN line passes through J527 in hardware, there is no data exchange between it and J527. Therefore, the multi-function steering wheel button data stream cannot be read in 16 steering column control unit J527.

(5) According to the fault code analysis, the fault column control unit circuit is faulty.

(6) If there is no control unit replacement test run, it is better to eliminate the line problem first. According to the circuit diagram of the multi-function steering wheel, the power supply T 16A/ 1 normal voltage of the steering column control unit J527 is 12V, and the grounding is T16a/2. The possible causes of the multi-function steering wheel control unit J453 are as follows: 1 The steering column control unit is damaged; 2 Power supply and ground fault of steering column control unit; 3 The data CAN line of the steering column control unit is faulty; 4 Multifunctional steering wheel control unit is damaged; 5 The voltage of T5V/2 from the multi-function steering wheel control unit to No.30 power supply is normal 12V, T5V/ 1 grounding is normal, LIN wires T5V/3 to J527 are normal, and signal wires T5V/5 to J527 are normal.