U1 fault now found loose rubber ring.Fisher and Paykel Nautilus?

Thanks lincon for your response i looked at the wash pump and found a loose rubber ring about 35mm in diameter sitting in the veins of the pump.I managed to get it out with long nose pliars and the u1 fault has gone and machine is cycling well.I guess the question now is ,where did it come from and how long will it run without it?everything seems to be working fine other that a smalll drip from the drain plate area towards the back of the machine to the bottom tray.I think this has only appeared since i had the mech plate in and out 10 times yesterday.I may have broken the seal.I cant see any way of opening up the wash pump or detatching it from the tray to look for where the ring has come from or where the leak is coming from.