zanussi de6850 dishwasher?

end light flashes three times shortly after wash programme is selected which according to manual indicates that this is protection against flooding even though the light flashes three times even when the machine has no water in it..I have stripped each hose,water pump,salt tank,main water chamber and everything has been cleaned like new,also the pressure switches and the flood protection switch are operating correctly.ther is no part of this machine that has not been tested as far as I know but still the problem persists.Drain lines are clean also.