Na forum bimmerfest.com jest opisany podobny problem:

"SITUATION
The following condition occurs after the transmission has been replaced, or re-installed:
When P position is selected, transmission jumps back into N.
Message "Transmission Range P Fault" is displayed in the cluster, and "Transmission Range P may be unavailable. Engage parking brake when vehicle is stationary" is displayed in the CC.
Fault code 507B (Parking gear sensors implausible) is stored in EGS transmission control module.


CAUSE
Incorrect adjustment of the Emergency Park Release Cable, or
Bent "Emergency Park Release Cable" lever, due to incorrect transmission support fixture used during transmission installation."

Czyli wypadałoby sprawdzić czy linka awaryjnego zwalniania pozycji P jest dobrze wyregulowana i czy dźwignia odblokowująca w skrzyni nie jest wygięta (patrz rysunek poniżej).