P2AAFDiesel Fuel Presence Sensor Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P2AAF reports the diesel presence sensor signal stuck above its upper limit. Common reasons are a signal wire touching a battery-fed line, an open ground or signal path that lets an internal pull-up drive the input high, or a sensor with a failed output stage. No manufacturer documents P2AAF publicly, and no public source states which signal level stands for diesel. The background is spelled out in Ford patent US10544031B2: diesel is heavier and oilier than gasoline, and once in a gasoline engine it can block injectors and burn uncontrolled, so the patent aims to stop the refill before the tank is full. With P2AAF set, such a warning can no longer be trusted. CARB demands range monitoring of such inputs; P2AAE is the low side, P2AAC the general circuit fault.
- What you may notice
- Check engine light on
- Misfuelling warning unreliable
- Likely causes
- LikelySignal wire shorted to a voltage source
- PossibleOpen sensor ground or signal wire
- PossibleSensor output stage 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.