Module, Transmission Control (TCM): Description
The Transmission Control Module (TCM) (1) is mounted on the outside of the transmission case.
The electronic control system consists of various components providing inputs to the TCM. The TCM monitors transmission sensors, shifter assembly, and bus messages to determine transmission shift strategy. After shift strategies are determined, the TCM controls the actuation of transmission solenoids, which controls the routing of hydraulic fluid within the transmission, by moving a sequence of four valves to make a shift occur.
The system performs its functions based on continuous real-time sensor feedback information. In addition the TCM receives information from the rest of the vehicle over the Controller Area Network-Chassis (CAN-C) bus.
The transmission control system automatically adapts to changes in engine performance, vehicle speed, and transmission temperature variations to provide consistent shift quality. The control system ensures that clutch operation during up-shifting and downshifting is more responsive without increased harshness. The TCM activates the solenoid valves and moves valves in the valve body to achieve the necessary gear changes. The required pressure level is calculated from the load condition, engine speed. Vehicle speed and transmission oil temperature, matched to the torque to be transmitted. Power for the transmission system is supplied through the shifter mechanism (no transmission control relay).