how can I fix my Diplomat dishwasher ADP 8332? it has no spray pressure?

My dishwasher is about 3 years old and has been working fine. It now runs a cycle and shows no faults but does not appear to run any water through the whirly spray things with any pressure. hence cleaning no dishes. Very little comes up out of the bottom one and none at all out of the top ones. i have taken all accessible tubing apart looking for a blockage and run cleaner etc through to no avail. Has a pump gone? The machine drains the water at the bottom no problem. Please help.