Circuit Description: Notes

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 the difference between the start-up coolant temperature and the start-up intake air temperature is more than a predetermined amount, this DTC sets. This DTC also sets if the current intake air temperature is more than a predetermined amount based on the start-up engine coolant temperature.

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