Transaxle Fluid Temperature (TFT) Sensor

TRANSAXLE FLUID TEMPERATURE (TFT) SENSOR





The Transaxle Fluid Temperature (TFT) sensor is a thermistor that varies resistance according to changes in transaxle fluid temperature. The PCM supplies a five volt reference through a pull-up resistor to the sensor, which is connected to ground. When the sensor is cold it has high resistance (high signal voltage at PCM). As the sensor temperature increases, its resistance decreases (lower signal voltage at PCM). The PCM uses the signal voltage to determine transaxle fluid temperature.
The PCM uses transaxle fluid temperature to calculate enable/disable functions and shift feel.When the TFT sensor is below -13°C (9°F), the PCM will only command 1st and 3rd gears. Once this temperature is reached, the PCM will command normal shift scheduling.
The PCM also uses the TFT sensor input to enable TCC operation. The PCM will only allow TCC operation above 10 - 20°C (50 - 68°F) based on the Intake Air Temperature (IAT) sensor input.
When the TFT sensor input is above 25°C (77°F) the PCM will begin adapting 1st, 3rd and 4th gears. Above 40C (104 F) the PCM will begin adapting 2nd gear. The PCM uses the TFT sensor input to disable all transaxle adaptive functions below 250°C (77°F) and above 140°C (284°F).