Problem:
I was trying to program BMW FEM key with xhorse vvdi2 but failed, threw error sync code lost.
Error: synchronize code between working key and FEM/BDC system was lost.
Anyone know what to do in this case?
Solution:
Before doing anything try to start the car if not
Read isn from DME/DDE
And make key learning and when ask you if you have ISN, enter your ISN number and complete the key learning and rewrite again coding FEM file and start the car, all will be ok.
After the key was learned successfully need to restore coding to start car.
You can backup and restore FEM coding on BMW with xhorse vvdi bimtool, cgdi, yanhua acdp etc.
Check instruction here