P2A4DAlternative Fuel Temperature Sensor Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P2A4D means the voltage of the gas temperature sensor is below its valid limit. Gas temperature sensors are normally NTC thermistors whose resistance drops as they warm up, so a low voltage would correspond to extremely hot gas; in practice it nearly always means the signal wire is grounded or the sensor is shorted inside. TransEco shows how a gas module reacts to the comparable rail temperature Low code: dedicated installations replace the reading with the intake air temperature, bi-fuel ones are forced back to petrol, and the lamp comes on. No manufacturer lists P2A4D itself. Unplugging the sensor should make the reading jump to very cold; if it stays hot, look for the short in the harness rather than in the sensor.
- What you may notice
- Check engine light
- Gas mode refused, bi-fuel vehicle runs on petrol
- Live data shows an implausibly hot gas temperature
- Likely causes
- LikelySignal wire of the gas temperature sensor shorted to ground
- PossibleThermistor shorted internally
- RareMoisture bridging the connector pins
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €80 – €450
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.