Transmission Control Module

WARNING: This page is about a different variant/trim than selected.

The TCM outputs signals to control the hydraulic operation of the transmission. Signals are sent to the shift control solenoid valves and the Electronic Pressure Regulating Valve's (EPRS).

The TCM processes signals from the transmission speed and temperature sensors, the TCS , the PCM and other vehicle systems. From the received signal inputs and pre-programmed data, the TCM calculates the:

Correct gear
Engine disconnect and launch clutch setting
Optimum pressure settings for gear shift and lock-up clutch control.

The PCM supplies the engine management data over the HS CAN powertrain systems bus. The TCM requires engine data to efficiently control the transmission operation, for example:

Flywheel torque
Engine speed
Accelerator pedal angle
Engine temperature.

The steering angle sensor and the Anti-Lock Brake System Control Module (ABS) also supply data to the TCM on the HS CAN powertrain systems bus. The TCM uses data from these systems to suspend gear changes when the vehicle is cornering and/or the ABS is controlling braking or traction control.

The Body Control Module/Gateway Module (BCM/GWM) supplies steering wheel paddle data over the HS CAN powertrain systems bus to the TCM . The TCM uses the signals to schedule driver requested upshifts and downshifts.

Using the signal inputs and the memorized data, the TCM control program computes the correct gear and disconnect and launch clutch settings. The TCM also computes the optimum pressure settings for gear shift and clutch control. Special output side modules (power output stages, current regulator circuits), allow the TCM to control the solenoid valves and pressure regulators. This allows the TCM to precisely control the hydraulics of the automatic transmission. In addition, the amount and duration of engine interventions are supplied to the PCM through the HS CAN powertrain systems bus.

The TCM determines the position of the TCS using signals from the TCS on the HS CAN powertrain systems bus.

The TCM transmits the position of the TCS and any manual gear selected on the HS CAN powertrain systems bus. This information is shown in the gear selector display in the IPC .