Transmission Temperature Sensor (Hard-Wired) (Beginning 1996)

The Transmission Temperature Sensor is used to monitor the temperature of the transmission fluid. Power for the sensor is supplied by the TCM. Actual transmission fluid temperature is based on the resistance value of the temperature sensor located in the Transmission Range Sensor (TRS). The primary temperature inputs used by the TCM are the Transmission Temperature Sensor, Battery Temperature Sensor, ECT Sensor and in-gear run time. The engine must be running to get accurate temperature readings.

NOTE: A transmission will either have a TRS or a combination PRNDL switch and park/neutral position switch. A transmission with a TRS cannot have a PRNDL switch or park/neutral position switch.

If the sensor fails, the TCM defaults to a fluid temperature which is calculated from a combination of inputs. The calculated fluid temperature is continually updated and retained in memory for 20 minutes after the Ignition Switch is turned OFF. On vehicles equipped with a BCM, the calculated temperature is retained for four hours. When the vehicle is started after an extended OFF time, the calculated fluid temperature is reinitialized at a value between the battery temperature and engine coolant temperature signals received from the PCM over the CCD Bus.

The oil temperature is calculated on all 1996 MY 41TE transmissions with the TRS. The temperature sensor is part of the TRS. On all 1989 - 95 MY (and early production 1996 NS, non-TRS,1996 MY with code 74 present), the transmission oil temperature is calculated through a heat transfer equation that uses engine coolant temperature, battery/ambient temperature and extended time off (if known) at start up.