Principle of Operation

Principle of Operation

The data required for gear shifts is transmitted between the ECM and transmission control module (EGS). The transmission control module requires additional information from the vehicle for operation. In addition, other control modules in the E65/E66 require information about the electronic transmission status.

The PT-CAN bus is used for this purpose, below is a list of the the signals and components:

Signals Transmitter Receiver

Selector switch SZL EGS
Ignition terminal status CAS EGS
Central locking system CAS EGS
Transmission data (P/N) EGS CAS
Engine data ECM EGS
Wheel speeds DSC EGS
Deceleration request EMF EGS
Display, transmission
data EGS Instrument cluster
Check Control message EGS Instrument cluster
Torque requirement EGS ECM
Battery voltage Power module EGS
Electric loads
(30 min. N hold) EGS Power module


NOTE: The turbine (input) and output speeds of the gearbox are determined with Hall sensors that transfer the values directly to the electronic transmission control module. The position switch also transfers information directly over a hardwire.


As in previous transmission control modules, the "flash" programmable coding is for the new control module.

The processor of the transmission control module features a 440 KB internal flash memory. Approximately 370 KB of this is taken up by the basic transmission program. The remaining 70 KB contain the vehicle specific application data.