F&P Nemo wash pump problem?

The machine goes thru a complete cycle but the dishes arnt washed. The door for the wash powder is open but most of the powder is still there. I removed the bottom cover and the wash pump is making noise like it is running but when I overide the door lock and run with the door open, water is only trickling out of the wash arms.Pulled the plastic plumbing that leads to the wash arms out but cant find any blockage.How can I be sure that this is a wash pump problem?