Ambient Air Temperature (AAT) Sensor

The Ambient Air Temperature (AAT) sensor contains a thermistor. The sensor varies its resistance with the temperature. As the temperature rises, the resistance falls. As the temperature falls, the resistance rises. The Ambient Air Temperature (AAT) sensor is hardwired to the PCM through separate input and return circuits. If the outside air temperature is below approximately 0°C (32°F), the PCM does not allow the A/C compressor clutch to engage.

The PCM sends raw ambient air temperature data to the FCIM. The FCIM filters the raw data, sends it to the APIM and the touchscreen displays the outside temperature.

After replacing an Ambient Air Temperature (AAT) sensor, the sensor data must be reset by either driving the vehicle at speeds consistently about 20 MPH for at least 5 minutes to update the filtered data or perform the multiple button press reset procedure to update to the current raw value.

The multiple button reset for the Ambient Air Temperature (AAT) sensor is as follows:

• On the FCIM panel controls, press the A/C and Recirc buttons simultaneously for 5 seconds, then, release both.
• Within 2 seconds press the A/C button again.