Press the Cancel/ Drain cycle for a few seconds. The dishwasher should reset itself. See if this makes any difference. Also first turn the mains power to dishwasher off and back on.
Here's a link for the repair manual for your dishwasher:
http://www.appliancerepair.net/kitchenaid-dishwasher-repair.html
Concentration should be on Chapter 2 subsection 2-3 "No Fill"
Then go to Chapter 6; subsections 6-2, 6-3, 6-3a, 6-3b, 6-3c, and 6-3h for testing procedures on relays, actuator valves, etc.