L16820 AEG washr dryer diagnostics program

I know there is a diagnostic program on the machine but, apparently, you need to be an “engineer” to access it
Machine is now 10 years old and it would really help me to make an informed judgement about scapping vis a vis repairing next time the machine fails (not I hasten to add a frequent occurrence)

Is there anyone there prepared to tell me how to access the diagnostics program and equally importantly the exit rules. A combination of two buttons (left hand side rinse hold and prewash in this case) then engage a program is the normal sort functionality manufacturers build in.

I would also need a list of the fault codes, as the user manual, of course, only gives E20 E30 and E40 not the detailed intermediate functions

Oh for the old days when I managed maintenance on offshore structures and I told suppliers give me the service codes or I will go elsewhere