Circuit Description

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The Transmission Fluid Temperature (TFT) sensor is part of the 4L80-E transmission wiring harness assembly. The TFT sensor is a resistor, or thermistor, which changes value based on temperature. The sensor has a negative-temperature coefficient. This means that as the temperature increases, the resistance decreases, and as the temperature decreases the resistance increases. The PCM supplies a 5-volt reference signal to the sensor and measures the voltage drop in the circuit. When the transmission fluid is cold, the sensor resistance is high and the PCM detects high signal voltage. As the fluid temperature warms to a normal operating temperature, the resistance becomes less and the signal voltage decreases. The PCM uses this information to control shift quality and torque converter clutch apply.

If the PCM detects a continuous open or short to the power in the TFT signal circuit or the TFT sensor, then DTC P0713 sets. DTC P0713 is a type "C" DTC.