output shaft pass through the sensor's magnetic field. The AC voltage level and the number of
pulses increase as the speed of the vehicle increases. Output voltage varies with speed from a
minimum of 0.5 volts at 100 RPM to more than 100 volts at 8,000 RPM. The PCM/TCM
converts the pulsing voltage to vehicle speed. The PCM/TCM uses the vehicle speed signal to
determine shift timing and TCC scheduling.
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. 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 TRANSMISSION FLUID
TEMPERATURE 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.
Transmission Range Switch
2007 Hummer H3
2007 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E/4L70-E - H3