Lost Communication with Body Control Module (BCM)

The engine computer (PCM) isn't able to talk to the Body Control Module (BCM), which can affect things like lighting and door locks.

The PCM expects a data signal from the BCM. If it doesn't receive valid data within 200 milliseconds, it triggers this code.

Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.

1. 11. Check for any visible damage to the wiring and connectors between the PCM and BCM. Look for frayed wires or corrosion.
2. 22. Verify battery voltage is between 12.4 to 12.6 volts (engine off) or above 13.5 volts (engine running). Faulty batteries can cause communication errors.
3. 33. Using a $100-$200 scanner, check for other U-codes or BCM-related codes that might indicate common problems. If present, address those issues first.
4. 44. With the scan tool, check if you can communicate with the BCM. If communication works, the module is likely good. If not, check power and ground to the BCM, expecting about 12 volts on the power line and less than 0.5 volts drop on ground.
5. 55. If the BCM is getting power but still not communicating, replace the BCM. If there's still an issue after that, revisit wiring integrity.

• Faulty Body Control Module (BCM)
• Damaged wiring or connectors in the CAN bus
• Corrosion or poor connections in the BCM
• Battery voltage issues affecting module performance

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