Hello
I tried to change in a 2008 bmw 535i a msd81 damaged by a used one and I tried to copy the ISN from the CAS and it does not allow me and I guess it should be done in the bench but try to copy the ISN from the msd81 used for the original CAS and It copied well but I think something happened because it does not open terminal 15 but recognize the key.
So something does not match and it's not right.
Please, what can I do?

For reading CAS ISN you need a working for it.In your case as i believe it is E60 you can read ISN from the used ECU and write to CAS then do codding for DME from indiv codding.On bench wiring diagram for MSX80 along with CAS is attached together.you must also connect key using key slot on bench for editing CAS ISN MSV&MSD80.jpg You have insufficient rights to see the content.

Ok, I first did the CAS firmware and then I got the ISN from the CAS and tried to copy it in the DME and it did not leave me, so I copied the ISN from the used DME and I copied it in the CAS and there the problems arose.
then as I can understand, should I copy the ISN in the CAS and DME in the bench?

if you already copied ISN to CAS then make sure you restore CAS from cas firmware.if cas is not restored back for some part numbers car will not start.

ok solved, I forgot to do the CAS firmware again to return the CAS to its original state, it was very busy, but thank you very much for the help.