Circuit Description

WARNING: This page does not describe the selected car, but rather 14 other vehicles, including the 1998 GMC Savana Special, 1998 GMC Savana Camper Special, 1998 GMC Savana, 1998 Chevrolet RV Cutaway, and 1998 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.

Transmission Fluid Temperature (TFT) sensor is a negative coefficient thermistor within transmission wiring harness. TFT sensor controls signal voltage to VCM. VCM provides a 5-volt reference to sensor on TFT sensor signal circuit. When transmission fluid is cold, sensor resistance is high, and VCM detects high signal voltage. As transmission fluid temperature increases, sensor resistance decreases and voltage decreases. TFT sensor resistance is 3333-3689 ohms at 68°C (20°C). At normal operating temperature of 212°F (100°C), voltage is about 1.5-2 volts. Check sensor for shifted calibration by using sensor TEMPERATURE-TO-RESISTANCE VALUES table. DTC P0712 will set if VCM detects a continuous short to ground in TFT sensor signal circuit or TFT sensor.