[dp.3]

Last week, while driving it seems like my radio 'reset' and a SOS malfunction light came on for a two seconds then magically went away. The next morning the SOS malfunction light is now on and no sound is coming from the radio, yet still functional (sans sound, BT, and BMW assist features).

After searching the forums over the past week, I tried diagnosing the problem by swapping TCU units from my E92, recharging the battery, checking L7 amp, and pulling codes with my BT scanner which was all inconclusive and my problem with no sound and SOS light was not resolved.

This evening, I went into the MOST bus distribution block and individually removed the TCU, then SAT radio from the MOST bus distribution block.

• With the TCU removed from MOST loop and SAT present in MOST loop: no sound + SOS light
• With TCU present in the MOST loop and SAT removed from MOST loop: I finally have sound from my radio but still have SOS malfunction light
• With TCU removed from the MOST loop and SAT removed from MOST loop: I have sound coming from my speakers and still a SOS malfunction light

So which leads me to wonder what to do next. Are both my TCU and SAT radio suddenly non-functioning? But with the TCU on the MOST loop and SAT radio removed from the MOST loop, I am able to hear sound from my radio but BT / BMW Assist not functional.

Do I purchase a replacement TCU and Sat radio receiver?
Or first attempt reprogramming from BMW dealership?

Any advice is appreciated. Thank you.

Background:
2006 E91 325xiT
BMW Assist / BT, L7, Sat Radio