P0891: The gearbox control unit power relay detection gives a higher signal than normal
The gearbox control unit power relay detection gives a higher signal than normal. It is usually the part, its wiring or a connector with poor contact.
| Code | P0891 |
|---|---|
| System | Engine and transmission |
| Group | P08xx, Transmission |
| Type | Generic: it means the same on every make |
How to read and clear P0891 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 P0891 with its description and whether it’s confirmed, pending or permanent.
This code is usually stored by the gearbox control unit. If the car reports it over standard OBD, you read it for nothing with FREE; to read it straight from the gearbox control unit, with its description and clearing, you need PRO.
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
- P088B The gearbox oil filter has deteriorated severely
- P088C The reverse gear lock control gives a lower signal than normal
- P088D The reverse gear lock control gives a higher signal than normal
- P0890 The gearbox control unit power relay detection gives a lower signal than normal
- P0892 The gearbox control unit power relay detection fails now and then
- P0893 Several gears are engaged at the same time in the gearbox
- P0894 The gearbox component is slipping
- P0895 The gearbox shifts between gears too quickly
- P0841 Transmission fluid pressure sensor/switch A: circuit range or performance
- P0842 Transmission fluid pressure sensor/switch A: circuit low
- P0843 Transmission fluid pressure sensor/switch A: circuit high
- P0868 Transmission fluid pressure low
What does code P0891 mean?
The gearbox control unit power relay detection gives a higher signal than normal. It is usually the part, its wiring or a connector with poor contact.
How do you clear P0891?
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, P0891 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.
