Hello, I was wondering if anyone can suggest steps to identify the fault on Audi A6 AVANT (C6) 2005 MMI high. It went dead out of nowhere. The screen is black, none of the MMI functions are working. Even power button doesn't lit up. I've checked fuses next to the driver seat and in the boot and they all seems to be fine. However I am not sure if there is a dedicated fuse for the MMI system or it is shared with something else. I have tried disconnecting battery for 10-15 minutes - nothing changed. I have VAG COM and it wouldn't show any error but at the same time wouldn't connect to any of the relevant controllers (such as radio, sat nav, etc...) I was wondering if anyone had similar experience and if the are known ways of diagnosing a fault. Thanks.