Bosch Dishwasher trips breaker when switched on?

How can I find the fault or fix my Bosh Dishwasher model SGV56A03GB/42 . It trips the MCB breaker for low level sockets every time its switched on at the mains, without the actual dishwasher on button being in the On position. It hadn't drained fully. I've checked main fuse, socket, wiring not loose, cleared pipes, cleaned all filters, water from in machine and hoses - but it still happens.

Diane
February 2009