Transmission Control Systems: Description and Operation

PURPOSE
The electronically controlled automatic transmission provides better control of gear position and torque converter lock-up, which results in better performance, smoother operation and better fuel efficiency.

OPERATION
The control of transmission functions and communication of transmission gear position, and torque converter lock-up to the ECM is provided by the Transmission Control Module (TCM). The TCM is connected to sensors which provide it with information on the speed of the transmission shafts, road speed and throttle position.