Circuit/System Description
WARNING: This page is about a different car, the 2009 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.
The automatic transmission fluid temperature (TFT) sensor is a thermistor type sensor. The transmission control module (TCM) supplies a 5-volt reference signal to the sensor. When the transmission fluid is cold, the sensor resistance is high and the TCM senses a high signal voltage. As the transmission fluid warms, the sensor resistance lowers and the TCM senses lower voltage. The TCM uses the TFT reading in order to control the torque converter clutch (TCC), line pressure adjustments, and temperature compensated shifts.