Servis dishwasher not stopping at end of programme

I have an integrated Servis dishwasher model no M4905. My problem is simply that it doesn’t turn itself off at the end of the programme. It appears to wash and dry and heat up etc but remains on until I open the door. Very wary now of switching it on before I go to out or before I go to bed in case it overheats. Any advice or suggestions as to the problem would be appreciated. Thanks