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

Component Location - Pictorial View:

PURPOSE
The Intake Air Temperature (IAT) sensor is a thermistor (a resistor which changes value based on temperature). It is mounted in the air intake duct. Low temperature produces a high resistance and high temperature causes low resistance.

OPERATION
The Powertrain Control Module (PCM) supplies a 5 volt signal to the sensor through a resistor in the PCM and measures the voltage. The voltage will be high when the intake air is cold, and low when the intake manifold air is hot. By measuring the voltage, the PCM knows the intake air temperature.