My mmi screen won't work. When I had the old mmi box (delphi) and the old mmi screen, my mmi screen worked. But when he coded the car to fit a bigger screen and mmi box (harman), then everything went black, he said the screen would turn on as soon as harman and the new screen would come on, but it continued to be black. And I have bought a new screen because I was told that it might have burned off, but it still didn't work. I have read out 2 errors that appear on the vcds tester. The car is an Audi a4 from 2017. And i try to change a cabel but didnt woek
