I did, or better, I use the correct harness, but I found out in a very handy Excel sheet (Vari_ME75X.xls) that the early ME7 versions prior to C2-1 never came with main relays.
So the corresponding RAM variables were 0.0V all the time. Maybe Bosch didn't equip the PCB with the components needed for main relay diagnosis.
i dont get it, maybe because of my english skills.
you use ecu und corresponding harness from donor car and ran into which exact error?