U04B5Invalid Data Received From Brake System Control Module B
- Generic OBD-II code · Network
- Can trigger limp mode
- How the car detects it
- Brake system control module B is a second brake controller. Bosch, for instance, adds a second, redundant brake unit to its Integrated Power Brake on automated vehicles so the car can still be stopped if the main unit fails, and the iBooster plus ESP pairing serves the same purpose. U04B5 is stored when a receiver gets messages from module B that fail plausibility, for example a wrong counter, checksum or pressure value. U0418 is the matching code for the primary brake module, U01B4 marks lost contact with module B and U031C a software mismatch. No manufacturer documents U04B5 publicly. As a safety system it rarely lights the MIL; expect brake or stability warnings, and driver assistance or automated functions may be switched off.
- What you may notice
- Brake, ABS or stability control warning
- Driver assistance or automated driving functions unavailable
- Likely causes
- PossibleBrake control module B internally faulty
- PossibleChassis or private brake bus wiring or connector fault
- PossibleSoftware of the two brake modules not matching after update or replacement
- RareWeak supply on the redundant power path
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €150 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.