PowertrainP0178
CautionSeverity: Caution - get it checked when you can
Fuel Composition Sensor Circuit Low Input
Key terms: Oxygen sensor: measures oxygen in the exhaust gas · Mass air flow sensor: measures the air going into the engine · SAE J2012: the standard generic code list · Powertrain: engine, transmission and emissions
1What it means in plain English
This code is in the fuel, air and oxygen sensor range, which also includes coolant temperature faults.
2Common causes
- Dirty or faulty mass air flow sensor
- Vacuum or intake air leak
- Weak fuel pump or clogged fuel filter
- Faulty fuel injector
- Faulty oxygen sensor
- Wiring or connector fault
3Can I drive?
Have it diagnosed if the engine runs badly or the code keeps returning. Because this range includes coolant temperature sensors, watch the temperature gauge: if it climbs into the red, or the engine overheats or stalls, stop safely and get professional help.
This page gives general information. It is not professional advice. For a definite diagnosis and a repair quote, ask a qualified mechanic to inspect the car.
4Brand data 28
| Brand | Code | Description | System |
|---|---|---|---|
| Ashok Leyland CV | P0178 | Fuel Composition Sensor Circuit Low Input SAE | Powertrain |
| BAIC Motor | P0178 | Fuel Composition Sensor Circuit Low Brand | Powertrain |
| BMW | P0178 | Fuel Composition Sensor Circuit Low Input Brand | Powertrain |
| BYD | P0178 | Fuel Composition Sensor Circuit Low Brand | Powertrain |
| Chery | P0178 | Fuel Composition Sensor Circuit Low Brand | Powertrain |
| Daewoo | P0178 | Fuel Composition Sensor Circuit Low Brand | Powertrain |
| DFFS | P0178 | Fuel Composition Sensor Circuit Low Brand | Powertrain |
| DFFX | P0178 | Fuel Composition Sensor Circuit Low Brand | Powertrain |
| DFXK | P0178 | Fuel Composition Sensor Circuit Low Brand | Powertrain |
| EOBD | P0178 | Fuel composition sensor circuit low Brand | Powertrain |
| Geely | P0178 | Fuel Composition Sensor Circuit Low Brand | Powertrain |
| GM | P0178 | Fuel Composition Sensor Circuit Low Brand | Powertrain |
| Great Wall | P0178 | Fuel Composition Sensor Circuit Low Brand | Powertrain |
| Hafei | P0178 | Fuel Composition Sensor Circuit Low Brand | Powertrain |
| Holden | P0178 | Fuel Composition Sensor Circuit Low Frequency Brand | Powertrain |
| Honda | P0178 | Fuel Composition Sensor Circuit Low Input SAE | Powertrain |
| Hyundai | P0178 | Fuel Composition Sensor Circuit Low Input SAE | Powertrain |
| Isuzu | P0178 | Fuel Composition Sensor Circuit Low Input SAE | Powertrain |
| Land Rover | P0178 | Fuel composition sensor circuit - low input Brand | Powertrain |
| Mitsubishi | P0178 | Fuel composition sensor low Brand | Powertrain |
| Opel | P0178 | Fuel Composition Sensor Circuit Low Brand | Powertrain |
| Peugeot | P0178 | Fuel Composition Sensor Circuit Low Input SAE | Powertrain |
| Proton | P0178 | Fuel composition sensor low Brand | Powertrain |
| Saab | P0178 | Fuel Composition Sensor Circuit Low Brand | Powertrain |
| MG (SAIC) | P0178 | Fuel Composition Sensor Circuit Low Brand | Powertrain |
| Tata | P0178 | Fuel Composition Sensor Circuit Low Brand | Powertrain |
| Toyota | P0178 | Fuel composition sensor circuit low Brand | Powertrain |
| Volkswagen | P0178 | Sensor for fuel composition / quality (G446): signal too low; Defective Brand | Powertrain |
Legend: SAE is the generic J2012 description; Brand is text taken from that manufacturer’s data. Manufacturer rows keep the wording and language of the source data, and non-English text is tagged so screen readers pronounce it correctly.
5Extended variant codes 1
These 7-character codes are manufacturer-specific variants of P0178 and may be reported by some scan tools.
| Brand | Code | Description | System |
|---|---|---|---|
| Mercedes-Benz | P017800 | Der Kraftstoffqualittsensor hat Kurzschluss nach Masse. Brand | Powertrain |
6Related codes
Browse Pxxx codes or P017xx codes.