Theory Of Operation

The Ambient Air Temperature Sensor is a two wire sensor that is hard wired to the Drivers Door Module (DDM). On some vehicles not equipped with DDM, the wiring goes directly to the Body Control Module (BCM). The DDM (or BCM) supplies a 5-Volt sensor signal and sensor ground to the Ambient Air Temperature Sensor. The sensor internal resistance changes in response to changes in ambient temperature. In both options, it is the BCM that provides the Powertrain Control Module (PCM) with ambient temperature information over the CAN Bus network.