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

Typical Intake Air Temperature (IAT) Sensors:

PURPOSE
The Intake Air Temperature (IAT) sensor measures varying air charge temperature information. This information is supplied to the Powertrain Control Module (PCM). The IAT signal is used by the PCM as a correction factor in fuel, spark, and MAF. The IAT sensor provides quicker temperature change response time than the Engine Coolant Temperature Sensor (ECT).

OPERATION
Variations in temperature affect the voltage drop across the sensor terminals, providing electrical signals to the PCM.

CONSTRUCTION
The IAT is a thermistor device in which resistance decreases as the temperature increases, and increases as the temperature decreases. Thermistor-type sensors are considered passive sensors. A passive sensor is connected to a voltage divider network so that varying the resistance of the sensor causes a variation in total current flow.