Abstract: A program controlled dishwasher in which magnetic sensors provided adjacent to the dishwasher door respond to magnetic fields of predetermined polarization provided by permanent magnets in a catenulate magnetic key mounted on a dishwasher caddy in a position adjacent the magnetic sensors when the caddy is in the tub of the dishwasher, for generating a verifiable code pattern readable against dishwasher stored programs for the selection and actuation of a program specific to the articles which are stored in the caddy for washing. The polarization patterns on the caddies are specific to the kind of articles stored therein and may be readily altered to accommodate different articles.