driven distance:


Model: Configure 1.8L engine (CEA).


Vin: LSVX065N4F2 ××××××.

Failure phenomenon: The left rearview mirror cannot be folded and adjusted up and down, and the turning light on the rearview mirror is normal.

Diagnosis of failure: diagnostic device detection without failure code.


The possible cause of the fault: ① There are problems with the left rearview mirror on the left; ② the left rearview mirror line has problems; ③ the problem of the control unit of the left door; ④ the control unit of the left door control unit is incorrect;

It is normal to read whether the encoding is normal, and the encoding to 5310 is normal.

Rear -mirror switch data streaming is performed through the VAS6150B, and the switch is rotated to the folding position to observe the data stream, as shown in Figure 1.


Figure 1 data stream (fault)

The rearview mirror switch data stream is read through the VAS6150B, and the switch is rotated to the folding position to observe the data stream. Normal vehicle data is shown in Figure 2.


Figure 2 Data Stream (Normal)


When the switch rotates to the left of L and the rearview mirror is adjusted, the display is disconnected, indicating that it does not enter the L gear, as shown in Figure 3.

Figure 3 data stream (disconnect)

Under normal circumstances, the left side should be displayed.

According to the analysis of the circuit diagram (as shown in Figure 4), the rearview mirror adjustment switch is controlled by a line control unit through the door control unit. Everything on the right side indicates that there is no problem with the line and door control unit.

Figure 4

Compared with the above data stream analysis, the left front door control unit did not receive the switch signal. The possible cause of the problem is switching problems, door control units and line failures. Then analyze the rearview mirror circuit diagram, and found that the door control unit and the line are normal, indicating that the problem must be on the switch, as shown in Figure 5.

Figure 5 fault switch


Replace the rearview mirror adjustment switch, and the fault is resolved.

Failure summary: During the fault maintenance process, you must learn to observe the data flow and combine circuit diagram, which will save time and can more accurately determine the fault point.