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Home >> Chevrolet >> 2008 >> Optra5 LT, Automatic >> Repair and Diagnosis >> Transmission >> Hydraulic Diagrams >> Automatic Transaxle - ZF 4HP 16 - Service, Overhaul, Removal & Installation, Troubleshooting & Diagnosis >> Electronic Component Description >> Transaxle Fluid Temperature (TFT) Sensor

Transaxle Fluid Temperature (TFT) Sensor

The transaxle fluid temperature (TFT) sensor is a positive temperature coefficient thermistor that provides information to the transmission control module (TCM) regarding transaxle fluid temperature. The temperature sensor is located in the valve body. Calculated temperature is used to determine the shift time and the shift delay time.

Fig 1: View Of Transaxle Fluid Temperature Sensor
GM1256083Courtesy of GENERAL MOTORS CORP.

The internal electrical resistance of the sensor varies in relation to the operating temperature of the transaxle fluid, as shown in the following chart:

Fig 2: Electrical Resistance Chart
GM1256082Courtesy of GENERAL MOTORS CORP.

The TCM measures this voltage as another input to help control line pressure, shift schedules, and torque converter clutch (TCC) apply.

On some applications, when transaxle fluid temperature reaches 140°C (284°F), the TCM modifies the transaxle shift schedules and TCC apply in an attempt to reduce fluid temperature by reducing transaxle heat generation. During this time the TCM applies the TCC at all times in fourth gear. Also the TCM commands the 2-3 and the 3-4 shifts earlier to help reduce fluid heat generation. Refer to Transmission Fluid Temperature Sensor Specifications .