Transmission Fluid Temperature Sensor Assembly

WARNING: This page is about a different car, the 2002 GMC Cab & Chassis Sierra and 2002 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The Transmission Fluid Temperature (TFT) sensor assembly is a thermistor which is mounted in the wiring harness assembly. Low transmission temperature produces high resistance, while high temperature produces low resistance. The PCM supplies a 5-volt signal to the TFT sensor assembly through an internal resistor. Then the PCM measures the voltage drop in the circuit. Voltage is high when the transmission is cold and low when the transmission is hot. See Figure .

The PCM uses the TFT sensor assembly to regulate torque converter clutch apply, as well as shift quality.

DTCs P0711, P0712 and P0713 indicate a fault in the TFT sensor circuit. After the vehicle has been started, transmission temperature should rise steadily and stabilize between 194-239°F (90-115°C), depending on load. All 3 DTCs cause the PCM to use a default value of 284°F (140°C), thus reacting as if the transmission were hot in any case. When DTC P0711, P0712 or P0713 is set, the PCM freezes the shift adapts from being updated, and the MIL illuminates. Some driveability symptoms will be noticed, especially when cold.