Parts
$10–40
P0111 — Intake Air Temperature Sensor Range / Performance
SAFEIs it safe to drive? Safe to drive — this is a performance and emissions concern, not a mechanical risk.
What P0111 means
The IAT sensor is reading values that are implausible given the current engine coolant temperature or ambient conditions. For example, reporting -40°F when the coolant is at normal operating temperature.
Most likely causes (in order)
- IAT sensor contaminated or oil-fouled (clean it first — free)
- Faulty IAT sensor ($10–40)
- IAT sensor installed incorrectly or in a location with poor airflow
- Wiring intermittent — connector or harness near a heat source
- Failed MAF sensor (on vehicles where IAT is integrated into MAF)
Symptoms you might notice
- Slightly rough cold start
- Marginal fuel economy
- Check engine light only — most drivers notice nothing else
What to check first
Compare IAT reading to ambient temperature after the car has sat overnight — they should match within a few degrees. If IAT reads wildly wrong cold-soak, the sensor is bad; if it only goes wrong when hot, suspect wiring intermittent or oil contamination from PCV.
Repair cost & difficulty
Labor
0.2–0.5 hr
Difficulty
Easy DIY