I have accenta 6 and?

you need the engineer code to change the user code... the factory code for engineer is 9.9.9.9. but if that's been changed you will have to reprogram the whole system after resetting it to factory default.... not an easy task without the manual.
if you want to try the factory code follow this :-
prog. 9.9.9.9.8.1. x.x.x.x. reset.reset.
where x.x.x.x. is the new code you want to use.

Pete
March 2007