What Does P0111 Mean?
The ECM has determined that the Intake Air Temperature (IAT) sensor on bank 1 is reading outside the expected range for current operating conditions — its output does not match what the ECM calculates it should be based on coolant temperature, ambient conditions, and engine load. The sensor may be reading a plausible voltage but the actual temperature reported does not make physical sense. The driver may notice slightly degraded fuel economy and performance.
Common Causes
30%
IAT sensor contaminated with oil or carbon deposits, causing sluggish or offset readings
25%
IAT sensor mounted in a location affected by exhaust heat soak or turbo proximity, reading artificially high
20%
Failing IAT sensor with degraded thermistor accuracy
15%
Intake air leak near the IAT sensor allowing unmetered hot or cold air to skew readings
10%
High resistance in IAT sensor wiring causing voltage offset
Diagnostic Steps
1
Compare the IAT sensor reading to the ECT sensor reading on a cold engine that has sat overnight — they should be within a few degrees of each other. A deviation greater than 10°F suggests a faulty IAT sensor.
2
Monitor the IAT reading during a drive cycle — it should respond to changes in vehicle speed (ram air effect) and load. A reading that stays static or drifts unrealistically indicates sensor failure.
3
Inspect the IAT sensor for oil residue, carbon buildup, or physical damage. Clean the sensing tip carefully and retest.
4
Check for intake air leaks near the IAT sensor location that could expose it to abnormal air temperatures (e.g., near exhaust manifold).
5
Measure IAT sensor resistance at known temperatures and compare to the manufacturer's resistance-vs-temperature chart to confirm the thermistor's accuracy curve.
Estimated Repair Cost
$20 - $150
Parts + labor, varies by vehicle and location
The ECM has determined that the Intake Air Temperature (IAT) sensor on bank 1 is reading outside the expected range for current operating conditions — its output does not match what the ECM calculates it should be based on coolant temperature, ambient conditions, and engine load. The sensor may be r...
The most common cause of P0111 (Intake Air Temperature Circuit Range/Performance Problem Bank 1) is: IAT sensor contaminated with oil or carbon deposits, causing sluggish or offset readings
Typical repair costs for P0111 range from $20 to $150, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to drive. The slight inaccuracy in air temperature reporting will only marginally affect fuel trim and ignition timing. No immediate safety concern exists, though fuel economy may be affected.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0111 to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel / Air Metering
Difficulty
Type
Generic (SAE)
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