Transmission Oil Temperature Sensor: Notes

The TCM is provided with transmission oil temperature information via a temperature sensor. See Fig 1 . On most BMW transmissions, the sensor is an NTC element which is part of the transmission internal wiring harness.

Fig 1: Identifying Transmission Oil Temperature Sensor

Courtesy of BMW OF NORTH AMERICA, INC.

NOTE: Mechatronics Module is not currently serviceable at this time. Do not attempt any repair or replacement of the Mechatronics Module.

The transmission oil temperature information is used to:

Initiate the Warm Up Program
To inhibit TCC operation until a specified temperature has been reached.
For determining fluid level when used with diagnostic equipment.

The transmission oil temperature sensor is connected to the TCM via a 5 Volt reference and a circuit ground. As transmission oil temperature increases, the circuit resistance and voltage decrease proportionately.