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

Diagram Of Flow Through Throttle Body (Containing IAT Sensor Wire Where Applicable):

Some MAF sensors have Integrated Bypass Technology (IBT) with an integrated Intake Air Temperature (IAT) sensor. The present applications with IBT are: Focus, Escort (4V), 2.0 L Contour/Mystique, Cougar, Taurus/Sable, Windstar, Explorer/Mountaineer and E-Series.

Thermistor-type sensors are considered passive sensors. A passive sensor is connected to a voltage divider network so that varying the resistance of the passive sensor causes a variation in total current flow.

Voltage that is dropped across a fixed resistor in a series with the sensor resistor determines the voltage signal at the PCM. This voltage signal is equal to the reference voltage minus the voltage drop across the fixed resistor.

The IAT provides air temperature information to the PCM. The PCM uses the air temperature information as a correction factor in the calculation of fuel, spark and MAF.

The IAT sensor provides a quicker temperature change response time than the ECT sensor.