I have a bosch srs5602 dishwasher that will not run when a wash program is selected. I believe that it is possible to enter into a service test mode to help diagnose faults. Can anyone tell me what the correct button sequence operation is required to enter into the test mode? I believe you have to hold wash cycle buttons down and switch the machine on to enter into this test mode, but my question is which buttons . many thanks if able to help.