U045BInvalid Data Received From Anti-Lock Brake System (ABS) Control Module B
- Generic OBD-II code · Network
- Can trigger limp mode
- How the car detects it
- ABS module B is a second brake controller, found where braking has to survive a single fault. Bosch pairs an electromechanical booster or its integrated power brake with ESP for that purpose and, for automated driving, adds a separate redundant brake unit; its 2018 show message was that automated driving needs redundancy. U045B is stored when the partner, often the main brake unit or the automated driving computer, receives status or wheel data from B but rejects them because counters, checksums or values do not fit; U015A means B is silent, U0415 concerns the main ABS module. No manufacturer documents U045B publicly. Normal braking usually remains through the other path, yet a brake warning may appear and anything that relies on redundancy, such as automated or hands-off driving, is blocked.
- What you may notice
- Brake system or ABS warning
- Automated or hands-off driving functions unavailable
- Likely causes
- LikelySoftware levels of brake module A and B or the automation computer not matching
- PossibleWeak supply or ground of brake module B
- RareInternal fault of brake module B
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €80 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.