Air Temperature Sensor ( Ambient / Intake ): Description and Operation

Voltage Versus Temperature Chart:

The IAT sensor is a thermistor (a resistor that changes value with temperature) mounted in the intake air stream and it measures changes in the temperature of air entering the engine. High air temperatures result in low resistance and low air temperatures result in high resistance. The PCM provides a 5 volt reference signal and a ground to the IAT sensor. The PCM measures the voltage changes in the signal due to the sensors resistance. A high air temperature will result in low signal voltage (near 0 volt) to the PCM and low air temperature will result in high signal voltage (near 5 volt).