Gear emergency run ???

Hello municipality

Here's what happened.
In a V8 3.6 BJ 90, I had a defective tube exchanged for a used intact (insurance was provided to me). He then managed to get back from the workshop on a single axis. When I arrived at home, I checked and corrected the oil level by means of a measuring rod with a running engine. Engines and gearboxes ran perfectly....no jerking or delaying or anything else. I then moved the car about 50 kilometers on short distances. On the last way back when turning into my road, the gearbox suddenly refused its service without any signs of defects.(No sudden mechanical noise) All lamps glow (i.e. emergency PRG) but there is no propulsion (neither on R,D,3,2,1 nor if you put on "M"). With the start of the engine all lamps shine immediately. Unfortunately, I have no way to read the error memory. Does anyone have a tip on what it might be? Did a plug go off somewhere, or maybe the CTRL just broke?
I'm grateful for every hint.

Mfg