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

Air Cleaner (ACL) With Intake Air Temperature (IAT) Sensor:

DESCRIPTION
The Intake Air Temperature (IAT) sensor is a thermistor (a variable resistor that changes along with temperature changes) in series with a fixed resistor within PCM, that measures the temperature of the air entering the intake manifold.

OPERATION
The PCM applies 5 volts to the sensor. The PCM monitors the voltage across the IAT sensor and converts it into a temperature reading. When the outside air temperature is cold, the IAT sensor resistance is high, and when the outside air temperature is warm, the IAT sensor resistance is low. Therefore, when the air temperature is cold the PCM will receive a high voltage input, and when the air temperature is warm the PCM will receive a low voltage input.