Kenmore Dishwasher - Doesn't always drain.

[yeltu1188]

Hi,

I have a Kenmore Ultra-Wash Dishwasher - 665.16632.  I've noticed that once the cycle is complete, there is still quite a bit of water left in the tub.  Just today, I had to press the cancel/drain button 3 times before the water was emptied.  Any idea where I should start troubleshooting?  I'm not afraid to try repairs myself.  I appreciate all help.

Thanks a bunch,
Tracie

[Pegi]

Need the rest of the model number, however this was made by Whirlpool, the first place to look is the check valve that the drain hose attaches to at the pump/motor, these can clogg up....