Ambient Temperature Sensor

WARNING: This page is about a different car, the 2004 Dodge Pickup and 2004 Dodge Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

The ambient air temperature is monitored by the FCM or the PCM and displayed by the CMTC. For Diesel equipped vehicles, the FCM receives a hardwire input from the ambient temperature sensor (ATS). For 3.7L, 4.7L and 5.7L equipped vehicles, the PCM receives the hardwire input from the ATS.

The ATS is a variable resistor that operates on a 5-volt reference signal circuit hardwired from the FCM or PCM. The resistance in the ATS changes as the outside temperature rises or falls. The FCM or PCM senses the change in reference voltage through the ATS resistor. Based on the resistance of the ATS, the FCM or PCM is programmed to correspond to a specific temperature. The FCM or PCM stores and filters the ambient temperature data and transmits this data to the CMTC via the PCI Bus. The ATS cannot be adjusted or repaired and, if faulty or damaged, it must be replaced.