Note. For circuit reference, see the appropriate WIRING DIAGRAMS article. For connector and terminal identification, see CONNECTOR IDENTIFICATION .
Circuit Description
Intake Air Temperature (IAT) sensor is a thermistor which changes resistance based on temperature. IAT sensor is located in air intake passage of engine air induction system. IAT sensor has a signal circuit and a ground circuit. PCM applies voltage (about 5 volts) on signal circuit to sensor and monitors changes in this voltage caused by changes in resistance of sensor to determine intake air temperature.
When intake air is cold, sensor resistance is high and when intake air is warm, sensor resistance low. When PCM senses a signal voltage higher than normal operating range of sensor, DTC will set.
DTC will set when following conditions are present
- DTCs P0100, P0101, P0102, P0103, P0117, P0118, P0500, P0502 or P0503 not set.
- Engine operating more than 100 seconds.
- Engine coolant temperature more than 32°F (0°C).
- Intake air temperature less than -31°F (-35°C).
- Vehicle speed less than 7 MPH.
- MAF less than 15 gm/s.
- Conditions met for 4.5 seconds.