There's a drain pump. Sometimes crud like lemon pips gets itself stuck under the impeller. On my Bosch d/w I could access this from the inside - bail out the water and remove all the lower filters. Right at the bottom of the sump you may see a small plastic cover held in place by a single screw (torx head). Underneath this is the drain pump impeller. Tweezers will help to remove any debris. The impeller should move freely but with a bit of magnetic resistance.
You can check if the main pump is working by just listening - and if you open the door while its pumping you will see the water splashing about for a second or two as it shuts off.
Good luck...
Peccavi
May 2011