U0129
NetworkModule Communicationcritical severityLost Communication with Brake System Control Module
What U0129 Means
Cannot communicate with the general brake system control module.
Symptoms
- Brake warning light on
- ABS disabled
- Stability control off
- Brake system message displayed
Common Causes
- Brake module failure
- CAN bus wiring damage
- Module power loss
- Fuse blown
- Water damage
Diagnostic Steps
- Check brake system fuses
- Test module power and ground
- Check CAN wiring
- Inspect module for water damage
- Try direct module communication
Where to start: Check fuses and power supply. Inspect for water damage near brake module location.
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