Fault phenomenon: Customers reported that the Han DM automatic wipers failed (but other gear wipers can work normally) and the charging port light did not light up.
Cause Analysis:
1. System program version problem
2. Power supply or ground failure
3. BCM module failure
4. Combination light failure
5. Other faults
Repair process:
1. The customer reported that the Han DM automatic wiper failed and the charging port light did not light up. It was confirmed that the fault existed. The computer read the system and there was no fault code, and the system was not upgraded. The fault persisted after disconnecting the low-voltage battery and restarting;
2. First check that the wiper motor fast gear, slow gear, and washing motor are all normal, but the automatic wiper gear does not work. Check that the windshield three-in-one sensor (rain sensor) is installed normally, and measure the power supply of the three-in-one sensor. The grounding is normal, but the fault persists after switching the three-in-one sensor. Measure the continuity between the three-in-one sensor PG06-3# pin and the BCM G2K-30# pin (LIN line). It is initially suspected that the BCM itself is faulty. Since there are no replacement parts for the time being, Pause this troubleshooting;
3. Next, check the reason why the charging port light does not light up. Check that the charging port indicator light is normally powered and grounded. From the maintenance circuit diagram, we know that the three-in-one sensor and the charging indicator light module share a LIN line, and both are controlled by the BCM. , and then measured the continuity from the charging indicator module KB49-2# pin to the BCM G2K-30# pin (LIN line) and they were all normal. Both faults pointed to the BCM module itself;
4. Find a vehicle of the same model, replace the BCM and test it. If the fault persists, reconsider the idea and check the docking plug and wiring harness again. Repeatedly confirm that they are normal. Check the circuit diagram again. The BCM G2K-30# pin (LIN line) comes out and goes to (three) respectively. Integrated sensor, A: left/right rear middle taillight, B: left/right combination light, C: charging indicator light) share a LIN line, check the rear taillight function, and find that the left rear taillight turn signal flashes darker (flash frequency Normal), turn on the light switch, the small rear tail light function fails, and the brake light is normal when the brake is applied. Is it possible that a certain tail light failure causes a cascading failure? The right turn signal function is normal. It is suspected that the left rear combination light is faulty. Replace the left rear combination. Test the lamp assembly, cut off the power and then restart it, eliminate all faults, and install the faulty parts on a normal vehicle to test and the same fault will reappear;
5. Check that the left rear taillight has impact marks and small cracks. In addition, there has been a lot of rain in Shanghai recently. The rainwater entered the left rear combination light and caused a short circuit, causing a series of malfunctions. The light switch was turned off before, and the taillight function was not paid attention to. Is it normal? I took a detour.
Maintenance summary:
1. When troubleshooting, confirm whether the fault exists and whether there are other faults.
2. For multiple faults, first check whether they have something in common.
3. Check the fault carefully, replace parts if necessary, and quickly locate the fault.
4. Find the fault point, confirm the cause of the fault, and eliminate the fault once and for all to prevent recurrence.
