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

Fig. 7 Intake Air Temperature Sensor:

INTAKE AIR TEMPERATURE SENSOR
The Intake Air Temperature (IAT) sensor measures the temperature of the air as it enters the engine. The sensor supplies one of the inputs the PCM uses to determine injector pulse-width.

The Intake Air Temperature Sensor threads into the air cleaner.

CIRCUIT OPERATION
The intake air temperature sensor provides an input to the Powertrain Control Module (PCM) on circuit K21. The K21 circuit connects to cavity A15 of the PCM connector.

From circuit K21, the intake air temperature sensor draws voltage from the PCM. The sensor is a variable resistor. As intake air temperature changes, the resistance in the sensor changes, causing a change in current draw.

The PCM provides a ground path for the intake air temperature sensor signal (circuit K21) through circuit K4. Circuit K4 connects to cavity A4 of the PCM connector.