P2AACDiesel Fuel Presence Sensor Circuit
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P2AAC is the general circuit fault of a sensor meant to recognise diesel where only gasoline belongs, so the system can react to misfuelling before damage occurs. No manufacturer documents this sensor or the code publicly, and its exact design is not described in sources available. Two Ford patents show why detection matters and how it can work without a dedicated sensor: diesel gives off far fewer vapours than gasoline, so tank pressure during refuelling (US10544031B2) or the warming of the carbon canister (US10611625B2) stays below the expected curve, while diesel in a gasoline engine can clog injectors and ignite uncontrolled. P2AAC applies when the sensor circuit fails in a way that is neither clearly low (P2AAE) nor clearly high (P2AAF). CARB requires circuit checks on such inputs.
- What you may notice
- Check engine light on
- Misfuelling warning unavailable or shown without reason
- Usually no change in how the engine runs
- Likely causes
- LikelyCorroded or loose connector at the sensor near the tank or fuel line
- PossibleDamaged wiring along the underbody
- PossibleSensor electronics failed
- 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: €40 – €400
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.