Bosch Classixx dishwasher wont empty?

Before I pay huge sums of money for somebody else to fix it for me, is there anything I should be looking for?

When I start a cycle you can hear a hum/buzz, but no water is removed. The dishwasher will still clean dishes.

The outlet is attached to the sink outlet, this is clean. I've tried trickling some drain un-blocker down the discharge pipe to clear any blockage. Still no joy.