P009AIntake Air Temperature/Ambient Air Temperature 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
- After a long standstill with the engine cold, intake air temperature and ambient air temperature should be about the same. P009A is set when the two sensors disagree by more than a threshold at the next start. A detected engine block heater usually suspends the test. Several manufacturers perform this comparison under other codes; no manufacturer description naming P009A itself was found. Suspects are both sensors, an ambient sensor in a heat-affected position and contact resistance at a connector.
- What you may notice
- Check engine light on
- Usually no noticeable symptoms
- Likely causes
- LikelyIntake air temperature sensor drifting or contaminated
- PossibleAmbient temperature sensor faulty or in a heat-affected position
- PossibleContact resistance at a connector
- RareEngine block heater or auxiliary heater distorting the comparison
- 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: €40 – €200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.