Intake Air Temperature Sensor

The Intake Air Temperature (IAT) sensor is a thermistor (temperature sensitive resistor) mounted in the intake air tube. Low intake air temperature produces high internal sensor resistance, while high temperature causes low internal sensor resistance. The ECM supplies and monitors a 5-volt signal to sensor through a pull-down resistor in ECM.

IAT sensor, also known as a manifold air temperature sensor, allows ECM to determine intake air temperature. ECM uses signal to delay exhaust gas recirculation until intake air temperature reaches about 40°F (5°C). If intake air temperature becomes excessively high, ECM compensates by slightly retarding ignition timing. After a vehicle has cooled overnight, IAT and ECT sensor signals (resistance and temperature) should be close to the same reading. Failure in IAT sensor circuit should set a related DTC.