My Diplomat ADP 8332 Dishwasher Doesn't Pump Water Around The Machine?

I have a diplomat ADP 8332 dishwasher that fills with water and drains ok but does not pump water around the machine to wash. The Motor/Pump makes a funny noise when trying to wash and I can sometimes get it to work if i shake the Motor/Pump, it will carry on working until it stops to drain but will need another good shake to get it started again. Not sure if the pump is on it's way out, blocked or an electrical problem, any ideas would be appreciated.

Many thanks.