Automatic Transmission Fluid Temperature Sensor
The automatic 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 powertrain control module (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.
The PCM uses the TFT sensor assembly in order to regulate torque converter clutch apply, as well as shift quality.
DTCs P0711, P0712 and P0713 indicate a fault in the TFT Sensor Assembly circuit. After the vehicle has been started, transmission temperature should rise steadily and stabilize between 90-115°C (194-239°F), depending on load. All 3 DTCs cause the PCM to use a default value of 140°C (284°F), thus reacting as if the transmission were hot in either case. When DTCs P0711, P0712 or P0713 are set, the PCM freezes the shift adapts from being updated, and the malfunction indicator lamp (MIL) illuminates. Some driveability symptoms will be noticed, especially when cold.