P2D91Engine Oil Pressure Sensor/Switch C Circuit Range/Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- P2D91 says sensor C is electrically in range, but its reading does not fit the engine's state: pressure while the engine stands still, too little at speed, or a value that stays frozen while conditions change. Ford's 2024 summary handles sensor A this way under P0521, catching a signal stuck high, low or mid-range and readings that depart from a modelled pressure in either direction for 5 to 10 s. A GM 2024 engine table sets P0521 after 3 s, two-trip, when relative pressure exceeds 500 kPa under defined conditions or stays below 50 kPa above 1520 rpm. No manufacturer documents P2D91 publicly. A tired sensor, sludge in its bore, wrong oil grade, a worn pump or a sticking pressure control valve can be behind it; confirm real pressure with a mechanical gauge. Electrical faults are P2D8F/P2D90.
- What you may notice
- Malfunction indicator lamp after two drives on some makes
- Oil pressure warning flickers or appears without reason
- Possible engine noise if pressure is really low
- Likely causes
- LikelySensor C drifted or stuck at one value
- PossibleReal oil pressure deviation from worn pump, wrong oil or low oil level
- PossibleSticking oil pressure control valve of a variable pump
- RareSludge or debris in the sensor bore
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €50 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.