Operation CHARM: Car repair manuals for everyone.

Control Module: Description and Operation



Electronic Transmission Control

The transmission control unit is connected to other control units in the vehicle via the CAN bus.







The control unit receives information about the driver request, which includes the following:
- Selector-lever position
- Sport button and/or Sport Plus button
- Accelerator pedal position
- Brake signal

In addition, the operating state of the vehicle is also included:
- Wheel speeds
- Vehicle speed
- Road resistance
- Axial and lateral acceleration
- Altitude factor
- Engine and transmission speed
- Engine and transmission temperature

These input values are processed in the driving software and the driver request is executed, depending on the shift program and driver type detection.







The transmission control unit is located at the left behind the door in the sill area.

PDK Shift-Lever interface

Engine off:
Serial line is used for communication (gear position from instrument cluster).

Engine running:
CAN bus is utilized for communication.







PDK Shift-Lever







The new PDK Selector lever is a shift by wire concept (There is no mechanical connection between the shift lever and the transmission with the exception of the mechanical park lock.)

The PDK selector lever has 2 micro controllers and 2 Hall sensors to detect the lever position (redundant position sensing). The main communications interface is by CAN drive train bus with the serial bus as a redundant function.

The Selector lever lock for key and shiftlock is controlled by the PDK control unit.