P278B: The gearbox kickdown switch circuit works outside the expected range
The gearbox kickdown switch circuit works outside the expected range. The switch, its connector or wiring may be faulty.
| Code | P278B |
|---|---|
| System | Engine and transmission |
| Group | P27xx, Transmission |
| Type | Generic: it means the same on every make |
How to read and clear P278B 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 P278B 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
- P2786 The gear shift actuator temperature is above normal
- P2787 The clutch temperature is above normal
- P2788 The adaptive learning of the ASM automated manual gearbox has reached its limit
- P2789 The adaptive clutch A learning in the limit is not working properly
- P278C The gearbox kickdown switch circuit signal is too low
- P278D The gearbox kickdown switch circuit signal is too high
- P278E The gearbox kickdown switch circuit fails intermittently or gives erratic
- P278F The adaptive clutch B learning in the limit is not working properly
What does code P278B mean?
The gearbox kickdown switch circuit works outside the expected range. The switch, its connector or wiring may be faulty.
How do you clear P278B?
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, P278B 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.
