Lost Communication With Body Control Module
The car's control units talk to each other over a network of wires (CAN bus or similar). The body control module (BCM) manages lights, locks, wipers and other equipment. This code, stored by another control unit, means it has stopped receiving the BCM's messages or receives them with errors.
What the car has detected
A control unit in the car has not received the expected messages from the body control module for a while, or has received them with invalid data or checksum errors.
You may notice nothing, or lights, locks, dashboard warnings or other equipment may fail. If lights or wipers fail, drive carefully and have it checked soon.
Symptoms
- Warning lights or messages on the dashboard
- Faults with lights, central locking or wipers
- Comfort equipment not responding
- Several communication codes at once
Possible causes
- Network (bus) wire broken, shorted or poorly connected
- Connectors with corrosion, pushed-out pins or weak grip
- Missing power supply or earth to the body control module (fuse, low battery)
- Failed body control module
Checks for the garage
- Read the codes of all control units to see which have lost communication
- Check the battery, fuses and earth points of the body control module
- Check the network wiring and connectors, flexing them to find intermittent breaks
- If several communication codes appear at once, suspect the network wire or a short on it
Next step
Ask for the codes of all control units to be read and for the body control module's power supply and the network wiring to be checked.
Go to a garage: diagnosing the car's network needs a tool that can read every control unit and sometimes an oscilloscope to measure the network.