If the doors won't open from the inside handles, then it could be the door lock actuators.


If it is electrical, for example the fob not working or the inside button not working or only working for some doors and not the others, it could be the GM (General Module). E46s have similar problems with the GM5 where the solder on the main board deteriorates causing all sorts of central locking issues. I don't recall reading anyone experiencing issues with their GM on this board however...