If I understand well, do I need to read the ISN from DME, my keys and code it into the used FEM unit? It will work?
Firstly, you’d better use the version of the new FEM module close to the old one, otherwise there will be many fault codes and it will not be cleared.
Secondly, if the old FEM module cannot communicate, then the information in the new module needs to be changed same as the old module, such as VIN, frequency, etc.
Besides that, it is also necessary to read the vehicles’ ISN code, and then calculate the ISN in the FEM by conversion and fill it to the anti-theft.
Hope it helps you!