LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 2006 >> Sierra 1500 HD, RWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 18 (Automatic Transmission - 4L60-E/4L65-E/4L70-E - Introduction (2 Of 2)) >> Description and Operation >> Electronic Component Description (M30/M32/M70) >> Automatic Transmission Fluid Temperature Sensor

Automatic Transmission Fluid Temperature Sensor

WARNING: This page is about a different variant/trim than selected.

The automatic transmission fluid temperature (TFT) sensor is part of the automatic transmission fluid pressure (TFP) manual valve position switch. 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 powertrain control module (PCM) or transmission control module (TCM) supplies a 5-volt reference signal to the TFT sensor and measures the voltage drop in the circuit. When the transmission fluid is cold, the sensor resistance is high and the PCM/TCM detects high signal voltage. As the fluid temperature warms to a normal operating temperature, the resistance becomes less and the signal voltage decreases. Refer to TFT Sensor Specifications for a complete comparison of sensor resistance, temperature and signal voltage.

The PCM/TCM uses the TFT sensor information to control shift quality and TCC application.