U301F: Circuit B of the control unit wake-up line gives a lower signal than normal
Circuit B of the control unit wake-up line gives a lower signal than normal. It is usually the part, its wiring or a connector with poor contact.
| Code | U301F |
|---|---|
| System | Communication network |
| Group | U30xx, Communication network |
| Type | Generic: it means the same on every make |
How to read and clear U301F 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 U301F 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
- U3016 The control unit ground D is not working properly
- U301B Circuit A of the control unit wake-up line gives a lower signal than normal
- U301C Circuit A of the control unit wake-up line gives a higher signal than normal
- U301D Circuit A of the control unit wake-up line gives readings outside the normal
- U3020 Circuit B of the control unit wake-up line gives a higher signal than normal
- U3021 Circuit B of the control unit wake-up line gives readings outside the normal
- U302F The accessory output of the ignition switch has an electrical fault
- U3030 The start output of the ignition switch has an electrical fault
What does code U301F mean?
Circuit B of the control unit wake-up line gives a lower signal than normal. It is usually the part, its wiring or a connector with poor contact.
How do you clear U301F?
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, U301F 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.
