i recently bought a used 2005 Audi A6 for my first car. I tried to start it up the other day and nothing electronically turned on. I took it to a shop and they said it’s and ECU issue. They said that the modules aren’t talking to the car and I need to take it to an Audi dealer. Does anybody know how much a repair would cost? I need to know so I can figure out if I want to keep the car. Thank you!