U0129
Lost Communication with Brake System Control Module
2002-2005 Audi A4 3.0L V6
Critical SeverityNetworkGeneric (SAE)
Description
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.
Related Codes
Other Network Codes
- U0001High Speed CAN Communication Bus
- U0002High Speed CAN Communication Bus Performance
- U0003High Speed CAN Communication Bus (+) Open
- U0004High Speed CAN Communication Bus (+) Low
- U0005High Speed CAN Communication Bus (+) High
- U0006High Speed CAN Communication Bus (-) Open
- U0007High Speed CAN Communication Bus (-) Low
- U0008High Speed CAN Communication Bus (-) High
- U0009High Speed CAN Communication Bus Shorted Together
- U0010Medium Speed CAN Communication Bus
U0129 on Other Vehicles
Common Questions
What does code U0129 mean on a 2002-2005 Audi A4?
U0129 stands for "Lost Communication with Brake System Control Module". Cannot communicate with the general brake system control module.
What are the symptoms of U0129 on a Audi A4?
Common symptoms of U0129 include: Brake warning light on, ABS disabled, Stability control off, Brake system message displayed.
What causes U0129 on a 2002-2005 Audi A4?
Common causes of U0129 include: Brake module failure, CAN bus wiring damage, Module power loss, Fuse blown, Water damage.