P2A4CAlternative Fuel Temperature Sensor Range/Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- Here the gas temperature reading is electrically valid but implausible. A typical check compares it with other temperatures after a long cold soak, when gas, intake air and coolant should agree within a few degrees; another looks for the cooling that expansion in the regulator causes under heavy gas flow. A sensor that sticks at one value or lags far behind fails such tests. CARB requires rationality checks of this kind for inputs that affect fuel metering. Because the mass of gas injected depends on its density, a temperature that is wrong but in range quietly shifts the mixture, which the fuel trim then has to absorb. No manufacturer publishes P2A4C or its limits; Roush's propane equivalent is P0181. A sensor with a poor thermal contact can also cause it.
- What you may notice
- Check engine light after a drive cycle
- Fuel trim off while running on gas
- Often no noticeable driving issue
- Likely causes
- LikelySensor drifted, slow or stuck at one value
- PossibleSensor seated loosely or with poor thermal contact
- RareContact resistance in the connector
- 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.