U045B: Invalid Data Received From Anti-Lock Brake System (ABS) Control Module B
Standardized SAE J2012 code · U04xx — Invalid data received
What does U045B mean?
A receiving module detected implausible data from ABS control module B (typically secondary brake controller in twin-system architectures). Wheel-speed, slip or pressure values fail plausibility checks and are rejected.
The code tells you which monitor failed, not which part is broken. Test before replacing parts.
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Common causes
- High Module internal fault or sensor input drift
- Medium Software version mismatch after replacement
- Low Gateway module routing CAN messages incorrectly
Likelihood is a general estimate across vehicles; your make and model may differ.
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