Circuit Description

The intake air temperature (IAT) sensor is a variable resistor that measures the temperature of the air entering the engine. The IAT sensor has a signal circuit and a low reference circuit. The engine control module (ECM) supplies 5 volts to the IAT signal circuit and a ground for the IAT low reference circuit. If the ECM detects an excessively high IAT signal voltage, which is a low temperature indication, this DTC sets.

The following table illustrates the difference between temperature, resistance, and voltage: