Transmission Temperature Sensor/Switch: Description and Operation

Typical Transmission Fluid Temperature (TFT) Sensor:

PURPOSE
The Powertrain Control Module (PCM) uses Transmission Fluid Temperature (TFT) sensor to determine whether a cold start shift schedule is necessary. The cold start shift schedule lowers shift speeds to allow for the reduced performance of cold engine operation.

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