U0129

Lost Communication With Brake System Control Module A

Severity

🔴 High

Can you drive?

Limited driving only, diagnose soon

Approx. repair cost

$56–278 (est.)

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

U0121 U0128 U0126