P2D86Fuel Temperature Sensor A/B Correlation
- 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
- P2D86 checks two fuel temperature sensors against each other. Where both ought to show nearly the same value, because they measure the same fuel or after a long engine-off soak, a gap larger than a calibrated margin makes the pair implausible, without telling which sensor lies. No manufacturer documents P2D86 publicly. GM runs exactly this test on direct-injection gasoline engines under its own number P111F: two SENT temperature sensors on the high-pressure rail may differ by no more than 10 °C, and 100 bad readings out of 125, one every 100 ms, set a Type B fault after two trips. Ford's 2023 diesels instead compare sensor A with the charge air cooler outlet after six hours off (P0181, 20 °C). Circuit faults of the single sensors are P0182/P0183 and P0187/P0188.
- What you may notice
- Malfunction indicator lamp, usually after two drives
- Often no noticeable change in how the engine runs
- Occasionally rougher hot restarts if fuel quantity correction is off
- Likely causes
- LikelyOne of the two fuel temperature sensors has drifted and reads too warm or too cold
- PossibleCorroded or loose connector adding resistance to one sensor signal
- RareReplacement sensor of the wrong type or fitted in the wrong position
- RareEngine control software with too tight a comparison limit
- 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: €60 – €400
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.