How to Determine if the BCM is Damaged?
2 Answers
Here are the symptoms of a damaged BCM: 1. Automatic transmission models: The trunk cannot be opened, the car key cannot be removed, the P gear is locked, the brake lights cannot illuminate (the high-mounted brake light works normally), the windshield washer does not work, and the cigarette lighter does not work. Including atypical faults: automatic door locking failure while driving, central locking failure, abnormal horn operation, abnormal wiper operation, starting failure, etc. 2. Manual transmission models: The trunk cannot be opened, the parking lights cannot illuminate, the brake lights cannot illuminate (the high-mounted brake light works normally), the windshield washer does not work, and the cigarette lighter does not work. Including atypical faults: automatic door locking failure while driving, central locking failure, abnormal horn operation, abnormal wiper operation, starting failure, etc.
Last time, the headlights of my car kept turning off for no reason, the windows wouldn’t close, and the remote key stopped working, which was really frustrating. I looked it up online and found that the BCM (Body Control Module) might be faulty. The diagnosis method is pretty straightforward: first, observe if multiple functions are acting up simultaneously, like erratic wiper movement or door lock failure. Then, plug an OBD scanner into the port under the steering wheel to read the fault codes. If the codes start with something like ‘U,’ it’s likely the BCM acting up. An expert told me that common causes include damp circuits or unstable voltage. I noticed the carpet was a bit wet after washing the car, so water probably seeped in. The mechanic advised checking the fuses and ground wires first to avoid DIY mishaps. This incident reminded me not to ignore electrical anomalies—fixing them early can prevent being stranded on the road.
