P077C: The gearbox output speed sensor circuit signal is low
The gearbox output speed sensor circuit signal is low. Check the sensor, its connector and wiring.
| Code | P077C |
|---|---|
| System | Engine and transmission |
| Group | P07xx, Transmission |
| Type | Generic: it means the same on every make |
How to read and clear P077C 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 P077C 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
- P0778 Pressure control solenoid B has an electrical fault
- P0779 The pressure control solenoid B fails now and then
- P077A The output speed sensor has lost its direction signal
- P077B The output speed sensor circuit direction is not working properly
- P077D The gearbox output speed sensor circuit signal is too high
- P077E The gearbox oil temperature sensors give readings that do not agree
- P077F The gear ratio for reverse gear 2 is incorrect
- P0780 Automatic gearbox shift malfunction
- P0700 Transmission control system: fault detected
- P0701 Transmission control system: range/performance
- P0702 Transmission control system: electrical fault
- P0703 Torque converter/brake switch B: circuit fault
What does code P077C mean?
The gearbox output speed sensor circuit signal is low. Check the sensor, its connector and wiring.
How do you clear P077C?
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, P077C 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.
