Envoy 2WD V6-4.3L VIN W (1998)
Transmission Temperature Sensor/Switch: Description and Operation
AUTOMATIC TRANSMISSION FLUID TEMPERATURE SENSOR
The automatic TRANSMISSION FLUID TEMPERATURE (TFT) sensor is part of the automatic Transmission Fluid Pressure (TFP) manual valve
position switch assembly. This sensor helps control torque converter clutch apply and shift quality. The TFT sensor is a resistor, or thermistor, which
changes value based on temperature. At low temperatures the resistance is high, and at high temperatures the resistance is low. The Powertrain Control
Module (PCM) sends a 5 volt signal to the TFT sensor and the PCM measures the voltage drop in the circuit. You will measure a high voltage when
the transmission is cold and a low voltage when the transmission is hot. Refer to the Temperature vs Resistance table. If the TFT sensor circuit has a
fault, DTC P0712 or P0713 is set. A DTC P0712 indicates a short circuit condition, while a DTC P0713 indicates an open circuit condition. DTC
P0218 is set if the transmission is operating at a high temperature for a period of time.
