P011BEngine Coolant Temperature/Intake 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 the coolant and the intake air should both have settled close to ambient temperature. P011B compares the two sensors at start-up and is set when they disagree without either sensor showing a circuit fault. In the documented GM/Saab version the engine must have been off for more than 10 hours with no preheater detected; the fault counts if coolant reads at least 20 °C above intake air, or intake air at least 30 °C above coolant, and the coolant reading barely moves (2 °C or less) in the first 45 s. The code does not say which sensor is wrong – that has to be found by comparing both with the actual ambient temperature. Toyota resolved false settings on some 2015 V6 engines with new software. Ford and GM report the same idea under the individual sensor codes.
- What you may notice
- Check engine light on
- Usually no change in driving
- With a wrong coolant reading: poor cold start, higher consumption or odd fan behaviour
- Code often returns only after an overnight soak
- Likely causes
- LikelyCoolant temperature sensor stuck or drifting
- PossibleIntake air temperature sensor drifting or heat-soaked
- PossibleUndetected preheater or uneven cooling
- PossibleContact resistance at a sensor connector or ground
- RareControl module software (false setting, update available)
- 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 – €300
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.