A8 D2 ́97 4.2 Out, don't start.

Hi,

So, uh, I was driving my A8 in the 30's zone the other day when he went out suddenly.
He can't be started even after a few attempts.
The starter just doesn't jump away.
All gears in the instrument cluster also light up in the automatic transmission.
I got a diagnostic device from my brother saying this:
-motor control unit not found,
-CAN BUS not found.
Nothing else will be displayed.

Please help me.