E40 is a door fault, all 40’s (E40,E41,E42,E43) are in relation to door,
Consumer will normally only get a E40 fault shown, but if you (the engineer) go into diagnostics & check fault register you should get a more specific code, eg E41,E43 etc
10s water filling
20s draining
30s water pressure
40s door
50s motor
60s heating
70s temp sensing
80s programme selection
90’s PCBs