P2851: Shift fork position sensors A and B do not agree
Shift fork position sensors A and B do not agree. The sensors, connectors and compared signals should be checked.
| Code | P2851 |
|---|---|
| System | Engine and transmission |
| Group | P28xx, Transmission and engine |
| Type | Generic: it means the same on every make |
How to read and clear P2851 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 P2851 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
- P284D Gearbox shift fork A moves without being commanded
- P284E Gearbox shift fork B moves without being commanded
- P284F Gearbox shift fork C moves without being commanded
- P2850 Gearbox shift fork D moves without being commanded
- P2852 Shift fork position sensors C and D do not agree
- P2853 Gearbox clutch 1 is not releasing its pressure as it should
- P2854 The clutch B pressure discharge gives readings outside the normal range
- P2855 The clutch A pressure charge gives readings outside the normal range
What does code P2851 mean?
Shift fork position sensors A and B do not agree. The sensors, connectors and compared signals should be checked.
How do you clear P2851?
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, P2851 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.
