V8 gear exchange AZG

Short to the story.
I had bought a V8 which was converted to AEC and CST gearbox of the S6 C4. However, the engine and gear harness from PT /AKD has remained in it. The gearbox always went into emergency run because the G68 is missing. Meanwhile, the gearbox is converted to an AZG transmission oil pipes themselves bent all connected oil pan was down new filter is in oil is replenished (5.7L). Now the error F125 Multifunction switch is broken I can switch P R N as soon as I go to D, it goes into emergency run and says F125 defective. Can it be? I washed off the multifuz externally but I was actually careful. Just get another one or is the error somewhere else?Normally it would have to work with the "old" gear control unit and wire harness (AKD) !?

Greeting.