Advanced Diagnostics

Advanced Diagnostics

DTC P0111: Intake Air Temperature (IAT) Sensor Circuit Range/Performance Problem







General Description
Two engine coolant temperature sensors and one intake air temperature sensor are used by the engine control module (ECM). When the engine is stopped and enough time has passed the temperature of the engine will equalize to the ambient temperature. When an inappropriate temperature is detected after comparing the temperature readings of each sensor a malfunction in the corresponding sensor is detected and a DTC is stored.

Monitor Execution, Sequence, Duration, DTC Type, OBD Status







Enable Conditions







Malfunction Threshold
A malfunction is detected if the following three conditions are present after the engine has stopped and the ignition switch has been turned to LOCK (0) for at least 6 hours before restarting the engine:

- When the temperature difference between the IAT and ECT1 is 63 °F (35 °C) or less.
- When the temperature difference between the IAT and ECT2 is 46 °F (26 °C) or less.
- When the temperature difference between the ECT2 and ECT1 is 84 °F (47 °C) or less.

Driving Pattern

1. Turn the ignition switch to LOCK (0) and wait at least 6 hours.
2. Start the engine and let it idle for at least 10 seconds.

Diagnosis Details

Conditions for illuminating the MIL
When a malfunction is detected during the first drive cycle a Temporary DTC is stored in the ECM memory. If the malfunction recurs during the next (second) drive cycle the MIL comes on and the DTC and the freeze frame data are stored.

Conditions for clearing the MIL
The MIL will be cleared if the malfunction does not recur during three consecutive trips in which the diagnostic runs. The MIL the DTC the Temporary DTC and the freeze frame data can be cleared by using the scan tool Clear command or by disconnecting the battery.