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

Intake Air Temperature Sensor And Camshaft Position Sensor:

PURPOSE
The intake air temperature 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 and spark advance.

CIRCUIT OPERATION
Only the 2.4L engine uses an intake air temperature sensor. The sensor provides an input to the Powertrain Control Module (PCM) on circuit K21. Circuit K21 connects to cavity 37 of the PCM.

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 ground for the intake air temperature sensor signal (circuit K21) through circuit K4. Circuit K4 connects to cavity 43 of the PCM.

Helpful Information
Circuit K4 also splices to supply ground for the signals from the following:
- Upstream heated oxygen sensor
- Downstream heated oxygen sensor
- Camshaft position sensor
- Crankshaft position sensor
- Engine coolant temperature sensor
- Throttle position sensor
- Knock sensor
- Manifold absolute pressure sensor
- Vehicle speed sensor