P0178: The fuel composition sensor signal is low
The fuel composition sensor signal is low. Check the sensor, connector and wiring.
| Code | P0178 |
|---|---|
| System | Engine and transmission |
| Group | P01xx, Air and fuel metering |
| Type | Generic: it means the same on every make |
How to read and clear P0178 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 P0178 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
- P0173 Fuel trim malfunction (bank 2)
- P0174 System running too lean (bank 2)
- P0175 System running too rich (bank 2)
- P0177 The fuel composition sensor signal is out of range or its performance is
- P0179 The fuel composition sensor signal is high
- P017A The cylinder head temperature sensor A has an electrical fault
- P017B The cylinder head temperature sensor A gives readings outside the normal range
- P017C The cylinder head temperature sensor A gives a lower signal than normal
- P0100 Mass or volume air flow sensor circuit fault
- P0101 Air flow sensor range or performance problem
- P0102 Air flow sensor circuit low input
- P0103 Air flow sensor circuit high input
What does code P0178 mean?
The fuel composition sensor signal is low. Check the sensor, connector and wiring.
How do you clear P0178?
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, P0178 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.
