U015BLost Communication With Power Steering Control Module B
- Generic OBD-II code · Network
- Can trigger limp mode
- How the car detects it
- U015B is set when the second power steering controller, module B, stops sending. Redundant steering for automated driving splits the electronics into two paths so one can keep assisting if the other fails; Bosch describes such a fail-operational design with an electrical fallback giving roughly half the normal assist. A listener such as the primary steering unit or the driving automation computer logs U015B when B's messages are missing, following the pattern GM documents for its U0100-U02FF codes at 9-16 V. No manufacturer documents U015B publicly. Module A is U0131, implausible data from B is U045C. Normal steering usually continues on path A, but automated steering is blocked and a steering warning may appear.
- What you may notice
- Steering system warning in the cluster
- Lane centring or automated steering unavailable
- Steering assist possibly reduced
- Likely causes
- LikelySteering module B without power or ground (separate supply path)
- PossibleConnector at the steering rack or column wet, loose or corroded
- RareSteering modules not matched after replacement or update
- RarePower steering control module B internally faulty
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €100 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.