P2AAD Diesel Fuel Presence Sensor Circuit Range/Performance

P2AAD means the diesel presence sensor delivers an electrically valid signal whose content does not make sense: it may report diesel although no refuelling has taken place, never change at all, or contradict other information the engine computer has about the fuel. No manufacturer documents this code or its test publicly. Ford patent US10544031B2 illustrates the kind of cross-check involved in misfuelling detection: its pressure limit is not fixed but follows the pressure expected in the tank during that particular refill, so the verdict rests on a comparison instead of a single raw value. CARB requires such plausibility faults to be stored under their own code, apart from the circuit faults P2AAC, P2AAE and P2AAF. A contaminated or aged sensing element is a likely cause.

Likely causes

Symptoms

• Check engine light on
• Unjustified misfuelling message, or a real misfuelling going unnoticed

Repair estimate

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

Related codes

References: law.cornell.edu, patents.google.com.