you really need ISTA, not merely a code reader.I don't even have a code reader or any software for the car.
The car won’t start unless it is in Neutral. That seems to be the easy answer based on what I see so far. ISTA will let you command and test the gears along with reading and resetting codes. Then there are adaptations that need to be made. I’m surprised you even started to under take this project without ISTA.