Intake Air Temperature Sensor 1 Circuit Range/Performance
The P0111 code means the vehicle's onboard diagnostic system has detected: Intake Air Temperature Sensor 1 Circuit Range/Performance. This is a moderate severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- easy
- Estimated cost
- $15-$150
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Common Symptoms
- Check Engine Light on
- Slightly rough cold starts
- Minor fuel economy reduction
- No major drivability issues
Probable Causes (Ranked by Likelihood)
- IAT sensor reading does not correlate with coolant temp on cold start Very High
- Partially failed sensor giving erratic readings High
- IAT sensor located in a heat-soak area Moderate
- Wiring intermittent fault Moderate
Step-by-Step Diagnostic Procedure
-
After a cold soak, compare IAT and ECT readings at startup. Both should be within 10-15 degrees F of ambient temperature.
-
Monitor IAT during a test drive. It should rise moderately as intake duct heats up.
-
An IAT reading that does not change during driving or is fixed at an extreme value indicates sensor failure.
-
Replace IAT sensor if readings are erratic or unresponsive.
Common Fixes by Vehicle
What techs usually find when diagnosing P0111 on specific vehicles — tap your vehicle for the fix and the exact part:
2005-2014 Ford F-150/Mustang 4.6L/5.0L Easy DIY
IAT sensor reading stuck/unresponsive during warm-up — typically the integrated IAT portion of the MAF sensor has failed. Replace the MAF/IAT combo sensor. Do not clean with anything but MAF-specific cleaner.
Labor: 15-30 min2004-2014 GM 5.3L/6.0L/4.8L (Silverado, Tahoe) Easy DIY
IAT performance failure with no clear cause — replace the intake air temperature sensor (separate from MAF on these engines). Sensor is in the intake duct. Inspect the 2-pin connector for corrosion.
Labor: 10-15 min2007-2015 GM 3.6L V6 (Traverse, Acadia, Enclave, CTS) Easy DIY
IAT sensor range/performance — commonly caused by oil/coolant fouling of the IAT sensor tip due to a leaking PCV diaphragm. Clean or replace IAT, then address PCV issue (typically integrated into valve cover on 3.6L).
Labor: 15 minFrequently Asked Questions
Will P0111 affect my fuel mileage?
Slightly. If the IAT reads too cold, the ECU may over-enrich the mixture. If too hot, it may lean it out. The effect is usually minor unless the reading is at an extreme value.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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