My aeg favorit dishwasher is flashing .20, how can I fix it?

Our F798400VIOP slimline after 3 years gave a I20 error signal.I veryfied that the water was being pumped out , confirmed water did not enter the machine after clearly the inlet filter. what i Fould was that the base tray below the pump etc had some tell tale drips from and overflow black pipe. the black pipe brings teh overflow from a pot which catches leaks and the anti leak device was activated.
The dismatling and turning of the machine drained the pot and when reassembled it worked perfectly. Always try the basic first .

Alanw
November 2016