Jenn-Air dishwasher jdb1100aws problem

I have a Jenn-Air dishwasher, model JDB1100AWS. It's not working properly... when I start a wash cycle, hot water pools in the bottom, but the dishes don't get sprayed, and within a few minutes the dishwasher shuts itself off. At this point I can set it to drain the water in the bottom, but that's it. The detergent never gets released from the tray... it's as if the dishwasher just stops before going to the rinse cycle. I can't see any obvious problems with blockages.