Body Control Module - Signal Input Failure
Issue with the signal input to the Body Control Module (BCM).
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What it means (plain English)
The Body Control Module isn't receiving the correct signal from a switch or sensor, which could be a problem with the switch itself or its wiring.
What the computer is actually seeing
The BCM monitors inputs from various sensors and switches. When it sees a signal it expects to be between certain voltages (usually around 0-5 volts) but gets nothing or an unexpected voltage, it triggers this code.
What a healthy reading looks like
Typical switch input signals should be between 0.5 to 4.5 volts; anything outside this range can trigger a fault.
Guided diagnostic — the DiagCoach way
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.
- 11. Check the vehicle's wiring harness for any visible damage or corrosion, especially near connectors.
- 22. Verify power and ground at the Body Control Module. Expect around 12 volts at power and a good ground.
- 33. Test the input switch or sensor for proper operation. Check the voltage output while activating the switch; it should average between 0.5 to 4.5 volts when on.
- 44. Inspect for any bad connections in the wiring or connectors at the BCM and switch.
- 55. If all tests check out and the problem persists, consider the Body Control Module itself may be faulty.
Common causes
- Faulty switch or sensor
- Damaged or corroded wiring
- Connector issues or loose connections
- Body Control Module failure
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's generally drivable but may affect some electrical functions such as windows or door locks.
Will this code come back after clearing it?
If the underlying issue isn't fixed, the code will likely reappear.
Why does this code often pair with B2622?
They both relate to other inputs to the BCM, indicating a broader issue with the control module’s ability to receive signals.
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