Thank you for this very well written post.
i was looking at a major issue here, now i have a call into Sterling BMW in Orange County CA to see if they will do the R&R of the reverse solenoid and check the module and perhaps flash it and or update at the same time. So far they said they do not work on transmissions. I said its the same as the normal trans service but adding the reverse solenoid R&R.
Will know shortly, if not does anyone know of a BMW Service/Repair shop in the OC area that has done or will do this?
By the way, DO NOT USE CHINA OR Tiwaineese manufactured window regulator replacements! There is now a US made regulator for 100.00 lifetime warranty front and rear pass and drivers side, just ask the supplier you use 4 the usa made product there is only one.