Gary,

The most common problem for your complaint is, not enough water in the tub, to properly pressurize the pump and circulate the water.

There are a couple of "general" ways to check for the proper fill.

a) when you start a wash cycle, there should be a few seconds of pause,
between the end of the fill cycle and the pump motor start and circulation.
b) let the dishwasher start, fill and run for 3 to 5 minutes, then unlatch the
door and wait a few seconds and open the door and check the water level
in the bottom of the tub, on most profile dishwashers, the water level
should cover the bottom filter screen, and at least reach as high as the
heater support leg.
c) start the dishwasher, let it fill and start to wash, add 24 to 32 oz.
(pitcher of hot water), to the tub and let it run through the wash cycle, then
check for a better wash performance.

We could have been a bit more exact, but you forgot to include a model number, but you'll have it taken care of with these general checks.

Good Luck,
:) :) :)