U01B4

Lost Communication With Brake System Control Module B

Severity

🔴 High

Can you drive?

Do not drive — repair immediately

Approx. repair cost

$56–278 (est.)

Symptoms

Check Engine Light Is On
Disabling the ABS/ESP system
Other related errors appear
Unstable operation of the brake system
Problems with cruise control

Causes

Broken or damaged CAN bus wires
Brake control module B malfunction
Connector problems or contact corrosion
Blown fuse
Software error in the ECU

How to Fix

Check the integrity of the wiring harness to the module
Inspect and clean connector contacts
Check and replace fuses
Scan all modules for other errors
Repair only from an authorized dealer

Related codes

U01B5 U0121 C0051