U0143
Lost Communication with Body Control Module C
A third body control module (BCM "C") has dropped off the bus. Comfort, lighting or door functions on the affected zone stop working.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: hard
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Common causes
Ordered by how often each turns out to be the cause.
- BCM C unpoweredCommon
- Gateway module routing CAN messages incorrectlyLess likely
- CAN terminating resistor (120 Ω) drifted out of specLess likely
Parts involved
- Body Control Module
- CAN Bus Wiring
U0143 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.