Powertrain
generic / SAE
P011B
Engine Coolant Temperature/Intake Air Temperature Correlation
ECT and IAT readings disagree at long soak (engine off for hours) when both should match ambient. The intake air temperature sensor feeds the ECM's density calculation — a drifted reading miscalculates fuel mass and pushes mixture lean (cold reading) or rich (hot reading).
SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number1 / 1B
Possible causes
- One sensor drifted high
Symptoms
- Check engine light on
- Cooling fan runs constantly or not at all
- Cabin heater weak or excessively hot
- Possible long warm-up time or hard cold start
Inspection / repair
- Difficulty: easy
- DIY: possible
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References
sae:J2012