2008 audi s6 mmi not working at all

#1

I’ve checked fuses, tried the fibeber optic bypass most loop cabe to the DVD navigation unit. The unit female connecter lights up and blinks but I still have no luck. What else could be making it not turn on??? Amp?radio? Man I’m so freaking mad because I cant even use the backup cam.

My baterry can lose and broke the stud where there
Baterry monitor monitoring unit bolts to. So I welded the stud back m.

Is this an ecu issues onto where I need to reset the ecu. I already pulled the cables off for hours. No luck. Stumped.

#2

Did you replace any fuses or just checked them? Have you checked the codes it’s throwing? My whole system went out a couple of weeks ago after doing some battery work. I had codes for many different issues related to the communication systems. My issue was resolved by checking the fuses. Have you looked at them in all 3 locations?

I am no battery expert, so someone else can chime in, but with the repairs done I wouldn’t be totally confident that the issue is not related to the battery and battery management system.

#3

Which fuse or fuses did you replace and in which fuse box?

#4

I didn’t end up needing to replace any. But I pulled most of them to just check. I checked all 3 fuse boxes. The two up front just pull the covers off where the door normally covers. And there is one in the trunk. They have little fuse diagrams inside and a fuse puller to make it easy.