Transmission Temperature Sensor/Switch: Description and Operation

PURPOSE
The Transmission Fluid Temperature (TFT) sensor is a thermistor (a device that changes resistance according to changes in temperature) used to indicate transmission fluid temperature. The Powertrain Control Module (PCM) uses the TFT sensor signal input to determine the following:

^ Torque Converter Clutch (TCC) apply and release schedules
^ Hot mode determination
^ Transmission shift quality

OPERATION
High sensor resistance produces high signal input voltage which corresponds to low fluid temperature. Low sensor resistance produces low signal input voltage which corresponds to high fluid temperature.