Transmitter/Receiver Module
The Transmitter/Receiver module supplies power to the transponder through the ring antenna and controls the flow of data between the transponder and the EWS II control module.
Data transmission between the transmitter/receiver module and the transponder takes place over a radio frequency of 125 KHz amplitude modulated AM signal.
The transmitter/receiver module converts the analog data received through the AM signal to digital data and transfers it to the EWS II control module over a single wire bi-directional data interface.
Workshop Hint:
On E34 and E36 models the transmitter/receiver module is located under the dash near the steering column.
On E 31, E38 and E39 models the transmitter/receiver module is located in the steering column cover on the right hand side of the column.