Transmission Temperature Sensor/Switch: Description and Operation

Transmission Fluid Temperature Sensor:

PURPOSE
The Transmission Fluid Temperature (TFT) sensor is an input used by the Powertrain Control Module (PCM) to indicate the temperature of the transmission fluid.

OPERATION
The TFT sensor resistance decreases as the fluid temperature surrounding it increases. The varying resistance is converted into a corresponding voltage signal and input to the PCM.

CONSTRUCTION
The TFT is a thermistor that changes resistance in response to temperature.