Got a BMW e93 with no sound, center console displays "No Warning Tones" message. Searching the web, came to conclusion that there maybe a break in the fiber optic MOST bus loop. Car has been previously poorly repaired before getting to me - not sure what was done to it.
I guess two questions: (1) what would cause "no warning tones" error with all sound gone - entertainment, warning tones, etc, (2) how to diagnose a broken MOST loop. I have read folks suggesting unplugging components and checking for presence of the red light (or using jumpers). Is this typically done with engine running? Or key in ignition? Is there some order of components that would be easier in terms of access to start with?
Thanks!
