U0251: Communication with running board control unit B has been lost
Communication with running board control unit B has been lost. Check the car network wiring, its power supply and that control unit.
| Code | U0251 |
|---|---|
| System | Communication network |
| Group | U02xx, Lost communication with control units |
| Type | Generic: it means the same on every make |
How to read and clear U0251 with Final OBD
Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see U0251 with its description and whether it’s confirmed, pending or permanent.
If the engine stores it over standard OBD, with FREE you read this code with its explanation for nothing and clear it. With PRO you also read the faults of every control unit and clear them in all of them.
Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before an inspection. It’s all in how to read and clear fault codes and in inspections and OBD.
Similar codes
- U024D The seat control unit J is not answering on the car network
- U024E The side obstacle detection control unit C is not answering on the car network
- U024F The side obstacle detection control unit D is not answering on the car network
- U0250 The impact classification system module is not answering on the car network
- U0252 The rear lighting control unit B is not answering on the car network
- U0253 The accessory protocol interface module is not answering on the car network
- U0254 The remote start module is not answering on the car network
- U0255 Communication with the front display has been lost
What does code U0251 mean?
Communication with running board control unit B has been lost. Check the car network wiring, its power supply and that control unit.
How do you clear U0251?
With an OBD2 scanner and an app like Final OBD, which clears it for free if it’s stored by the engine control unit. But clearing it only turns the light off: if the cause isn’t fixed, U0251 comes back.
Read it on your car
Final OBD reads and clears engine faults through standard OBD for free, each one explained in plain English. With PRO it also reads the faults of every control unit, each make’s own codes included, and clears them in all of them.
