OBD Diesel Fuel Presence Sensor Circuit High
What it means
P2AAF stands for Diesel Fuel Presence Sensor Circuit High. P2AAF is a P code, so the fault sits in the engine, transmission and emissions systems. For P2AAF, work through the cause list below, cheapest checks first.
Where it lives
For P2AAF, the circuit described runs through the sensor. The description of P2AAF reports a fault at the sensor.
What to check first
For P2AAF, check the wiring and connector on this circuit first, since a broken terminal gives the same reading as a failed part.
Check these first
- P2AAF: Faulty or contaminated sensor in the fuel/air metering circuit
- P2AAF: Damaged or shorted wiring or connector for the affected circuit
- P2AAF: Vacuum leak or intake system restriction
- P2AAF: Failing fuel pump, injector, or fuel pressure regulator
What to do next
P2AAF reports from the powertrain control system. These steps cover P2AAF in general, and the exact cause on your vehicle can differ from the cause named above.
- P2AAF: Read freeze frame data and related codes with an OBD-II scanner
- P2AAF: Inspect the affected sensor wiring and connector for damage
- P2AAF: Compare live sensor readings (fuel trim, airflow, temperatures) to manufacturer specs
- P2AAF: Smoke test the intake system if lean or vacuum conditions are suspected
- P2AAF: Replace the failed component after confirming it with live data
Look up another code
Enter a full code or a symptom. Press / to search. How to read a code
Type a code above, or start from a symptom or a common code.
Updated
Generic SAE J2012 definition. Last updated 2026-08-30.