So had a auto electrician diagnose  electrical gremlins in my E88 bmw today and he got it down to the fcm module, so big buck for a new one of these and recoding it to the car at bmw, but there seem to be lot of company's online that you can post your fcm module to that will repair it and post it back in a 24hr period of receiving it and as it belongs to the car will not require recoding, so my question is, who has had this done, did it work, and would you recommend them

Morning Paul

Welcome to the Forum

BMW will tell you that the only cure is a new module coded by them. 

Registering modules to the car is not the sole territory of BMW Dealers and is not complicated to do if you have the Diagnostic software. It is important for the footwell module FRM (FCM) and the binnacle IKE as the vehicle stores mileage in 2 places if they differ then a tamper dot will appear next to the distance covered in the binnacle. If the tamper dot doesn't bother you then most of the functions will work with second hand unit if you don't have the software or don't know anyone who has.

Refitting a repaired module obviously avoids this issue plus will normally give you a warranty. However second hand units can be used and re-registered to your car, no warranty clearly but with the right software registering to your car is often faster than the time taken fitting it.

Registering all modules ensures they all work in unison without conflict. They will all work without just some will have reduced functions and of course in the case of the IKE and FRM control vehicle history. It also allows you to upgrade if you wish

Dave