P2A4BAlternative Fuel Temperature Sensor Circuit
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- Gaseous fuel changes density with temperature, so gas systems measure it to meter the right mass; Ford's 2003 bi-fuel CNG trucks, for example, use a thermistor at the rail for that density calculation and only switch to gas once both temperature and pressure allow it. The title of P2A4B names no location, which sets it apart from the tank temperature codes (P01AA ff.), the rail temperature codes (P01B4 ff.) and the vaporizer outlet sensors (P2A50 ff.). It is the general circuit fault of this gas temperature input, without a low or high verdict. No manufacturer documents P2A4B; Roush's propane systems report their fuel temperature under P0181–P0183 instead. Inspect plug, wiring and sensor resistance, since an NTC sensor can be checked against temperature with an ohmmeter.
- What you may notice
- Check engine light
- Bi-fuel vehicle stays on petrol or switches back
- Rougher running on gas
- Likely causes
- LikelyPlug or wiring of the gas temperature sensor faulty
- PossibleTemperature sensor element defective
- RareInput stage or data link of the gas module disturbed
- 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.