Intake Air Temperature (IAT) Sensor

Intake Air Temperature (IAT) Sensor:

The IAT sensor is an integral part of the Mass Airflow (MAF) sensor. The IAT sensor is a two wire thermistor type sensor that varies resistance according to changes in air induction temperature. The ECM supplies a five volt reference through a resistor to the sensor, which is connected to ground. When the sensor is cold it has high resistance (high signal voltage at ECM). As the sensor temperature increases, its resistance decreases (low signal voltage at ECM). The ECM uses the signal voltage to determine intake air temperature.

The ECM uses the IAT sensor for fuel control (calculation of air/fuel mixture temperature at the intake valve in conjunction with the ECT sensor temperature), ignition timing and EVAP purge solenoid control.