From the blog "Samurai Appliance Repair Man's Blog"

This is always a problem with the dishwasher's water heating system. In Bosch dishwashers, if they can't heat the water enough, they'll just keep running until they do. Kinda dumb design, I think. In comparison, Whirlpool-built dishwashers at least give you an obvious fault code like the clean light flashing seven times. But, I rectum that's my Pro-Amerkan bias bleedin' through. Water heating problems in Bosch dishwashers come down to one of two problems: - problem with the control board not se