Transmission Fluid Temperature Switch (Auto Trans Only)

Transmission Range Pressure Switches & Trans Temperature Sensor Circuits:

DESCRIPTION
The trans fluid temperature sensor is a thermistor within the Transmission Range Pressure Switch assembly. Its resistance is high at low temperatures and decreases as temperature increases. When a transmission overheat condition is detected, the traction control system will be disabled and a trouble code 79 &/or 58 will set.

OPERATION
The PCM applies a reference voltage to the sensor and then monitors the voltage in the circuit. As the sensor heats up, the drop in resistance causes a drop in the measured voltage of the circuit. Each specific voltage value corresponds to a specific resistance and a specific temperature. At normal fluid operating temperature (about 100°C/212°F), the voltage signal should be about 1.5 - 2.0 volts.