U0129critical severityNetwork
Lost Communication with Brake System Control Module
on 2025 GMC Canyon AT4X 2.7L I4 Turbo · 4WD
What this code 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
Repair notes
Check fuses and power supply. Inspect for water damage near brake module location.
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Serious DIY~$100
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Other Network codes on this vehicle
U0001
High Speed CAN Communication Bus
U0002
High Speed CAN Communication Bus Performance
U0003
High Speed CAN Communication Bus (+) Open
U0004
High Speed CAN Communication Bus (+) Low
U0005
High Speed CAN Communication Bus (+) High
U0006
High Speed CAN Communication Bus (-) Open
U0007
High Speed CAN Communication Bus (-) Low
U0008
High Speed CAN Communication Bus (-) High
U0009
High Speed CAN Communication Bus Shorted Together
U0010
Medium Speed CAN Communication Bus