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

Intake Air Temperature Sensor:

PURPOSE
Air at low temperatures requires a richer air/fuel mixture than air at high temperatures. The Intake Air Temperature (IAT) sensor measures the temperature of the intake air in the air cleaner. The control unit uses this information, compared with information from other sensors, to help determine to the amount of fuel required.

Intake Air Temperature (IAT) Sensor Circuit Diagram:

OPERATION
The Intake Air Temperature sensor (IAT) is a thermistor mounted in the air cleaner assembly. Low intake air temperature produces a high resistance, while high intake air temperature produces a low resistance. The PCM supplies a 5.0 volt signal to the sensor through a resistor, and monitors the voltage in the circuit. The measured voltage varies with the temperature of the intake air, due to the changing resistance of the sensor. By measuring the voltage, the PCM can determine the temperature of the incoming air.