U0129
Lost Communication With Brake System Control Module A
U0129 is an OBD-II diagnostic trouble code meaning: Lost Communication With Brake System Control Module A. Common causes: broken or damaged wires in the communication circuit, brake module malfunction. Estimated repair cost: $56–278.
Symptoms
- Check Engine Light Is On
- ABS/ESP systems may not work
- Loss of Brake Assist Functions
- Possible problems with cruise control
- In some cases - hard braking without ABS
Causes
- Broken or damaged wires in the communication circuit
- Brake module malfunction
- Module power problems
- Corrosion of contacts or connectors
- CAN bus fault
How to Fix
- Check the integrity of the wiring harness to the module
- Check the power supply and ground of the module
- Inspect connectors for corrosion
- Carry out diagnostics of the brake system module
- Repair only from an authorized dealer
Related codes
Error U0129 by Vehicle Brand
FAQ
What does the U0129 code mean?
U0129 is an OBD-II diagnostic trouble code that indicates: Lost Communication With Brake System Control Module A
What causes a U0129 error code?
The most common causes of U0129 include: Broken or damaged wires in the communication circuit; Brake module malfunction; Module power problems; Corrosion of contacts or connectors.
How do I fix a U0129 diagnostic trouble code?
To fix U0129: Check the integrity of the wiring harness to the module. Check the power supply and ground of the module. Inspect connectors for corrosion. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with U0129?
Limited driving only, diagnose soon
How much does it cost to fix U0129?
The estimated repair cost for U0129 is $56–278. Actual cost depends on your vehicle, location, and labor rates.
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