Firebird V8-350 5.7L VIN P SFI (1996)
Transmission Temperature Sensor/Switch: Description and Operation
The Automatic Transmission Fluid Temperature (TFT) sensor is a negative coefficient thermistor within the Automatic Transmission Fluid
Pressure (TFP) Manual Valve Position Switch. The TFT sensor controls the signal voltage from the PCM.
The Powertrain Control Module (PCM) uses the TFT sensor signal input to determine the following:
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Torque Converter Clutch (TCC) apply and release schedules
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Hot mode determination
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Transmission shift quality
The PCM supplies a 5-volt reference signal to the sensor. When the transmission fluid is cold, the sensor resistance is high and the PCM detects
high signal voltage. As the transmission fluid temperature increases, the sensor resistance decreases and the detected voltage decreases. At the
transmission's normal operating temperature of 100°C (212°F), the voltage is approximately 1.5-2 volts.
