LEMON Manuals: Even more car manuals for everyone
Home >> BMW >> 2019 >> X3 M40i >> Repair and Diagnosis >> External Pages >> Different car >> Section 576 (Functional Descriptions - F25 - Charging System, Anti-Theft, Body Electrical Systems) >> Body Electrical System - Functional Description >> MOST bus >> Notes

MOST bus: Notes

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2017 BMW X3, 2016 BMW X3, 2015 BMW X3, 2014 BMW X3, and 2013 BMW X3. However, it is still accessible from the selected car via links, so may be relevant.

The MOST (Media Oriented Systems Transport) bus uses a ring bus for data traffic between the various control units. Signal transmission is by means of optical fibre. Data transmission on the ring bus takes place in one direction only. On the MOST ring, messages can only be transmitted provided the bus ring is complete and fully functional. If the ring is broken, diagnosis communication is only possible with the central gateway module (ZGM). This is possible because the control unit is directly connected to the K-CAN. The headunit also a K-CAN connection, but no gateway function. For this reason, if the MOST bus is interrupted it is no longer possible to communicate with the headunit.



The MOST (Media Oriented Systems Transport) bus uses a ring bus for data traffic between the various control units. Signal transmission is by means of optical fibre. Data transmission on the ring bus takes place in one direction only. On the MOST ring, messages can only be transmitted provided the bus ring is complete and fully functional. If the ring is broken, diagnosis communication is only possible with the head unit (dependent on equipment fitted).