Circuit/System Description
WARNING: This page is about a different car, the 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, 2010 Chevrolet Silverado, and 2010 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The transmission fluid temperature (TFT) sensor is a 2 wire sensor located in the pressure switch manifold (PSM). The transmission control module (TCM) supplies a signal circuit and a low reference circuit to the TFT sensor. The resistance of the TFT sensor decreases as the oil temperature increases. The TCM monitors the voltage drop across the TFT sensor and calculates the temperature of the transmission fluid in the oil pan.