Supersedes Technical Service Bulletin Group 90 number 12 ? 34 dated September 21, 2012. When driving, various warning lights come on, sometimes with restricted functions in the electric system. These complaints only occur together with complaints or a failure of the MMI 3G+ infotainment system. After an ignition cycle the complaint is typically gone; therefore, it may not be reproducible. Sporadic DTCs may be present for communication errors, restricted functions, or missing/incorrect messages. If the MMI 3G+ has an issue, the data bus control unit (Gateway) tries to maintain the communication to the MMI. The load on the unit is so high that other messages on the bus systems cannot be processed any more. As a remedy, modified software can be installed on the Gateway which does not communicate to the MMI 3G+ when it is unavailable.
