U015B code meaning
Lost Communication With Power Steering Control Module B
What U015B means
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.
U015B at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor0.5 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U015B
- Steering system warning in the cluster
- Lane centring or automated steering unavailable
- Steering assist possibly reduced
Common causes of U015B
- Most likelySteering module B without power or ground (separate supply path)
- PossibleConnector at the steering rack or column wet, loose or corroded
- Less likelySteering modules not matched after replacement or update
- Less likelyPower steering control module B internally faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Power steering module bCAN bus
What each part of U015B means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 5B | The exact fault in that area. |
What to do next
- Note U015B and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U015B
What does U015B mean?
U015B means "Lost Communication With Power Steering Control Module B". U015B is set when the second power steering controller, module B, stops sending. It is a generic code, so it means the same on every make.
Is it safe to drive with U015B?
Drive gently and only to a workshop. With U015B the car can go into limp mode (reduced power) to protect itself.
Will U015B fail an emissions test?
U015B is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is U015B to fix?
Difficulty: workshop only. A typical repair takes 0.5 to 4 hours of work. This is a job for a workshop.
Will U015B clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.