I checked the MMI control module in the center console—no signs of water in there. Didn’t check the drivers side, but there was no water there either. Only passenger side.
I went on the Audiworld forums and found a number of posts that describe similar MMI behavior.—Welcome screen comes on for a few secs then goes to black when the car is started. It seems to be a break in the MOST fiber optic loop that makes this happen.
People also point to a water soaked Bluetooth module under the driver/left carpet as a likely suspect. But I just dug out the BT module and it looks clean. It is also sealed pretty well against the elements—more so than in the YouTube videos I saw for other models.
https://uploads.tapatalk-cdn.com/20180304/6be35061049f91b07b6b1704bed8136e.jpg
It looks like I get a laser light to the BT module so the MOST ring seems like it would be fine to that point. Does anyone know what follows next on the ring?
https://uploads.tapatalk-cdn.com/20180304/fc3f468ef442dd78702c70e910fe1f4c.jpg
Shit. I had a diagram for this when I was looking to install an aftermarket stereo.
I will see what I can find… but the main MMI module is in the trunk so you can check all the MOST connectors there as a start.
I never updated this thread. but for completeness, the final solution to my flakey MMI problem was to swap out the MMI board.
This is the unit I purchased: https://www.ebay.com/itm/MMI-Multimedia-Interface-Control-Panel-Module-with-Navigation-For-Audi-A6-S6-Q7-/302507792464?hash=item466ede9850