I have one of these "lovely" machines, rather than start a new thread I will bung my story in here.
Originally the machine tripped the electrics in the house, found water in the sump caused by known split hose problem. Removed pump and replaced hose with a nice bit of Audi radiator hose, perfect fit
Reassembled machine thought I had dried everything out but water ingress in the water drain level indicator caused it to burn out and give F4 code.
Replaced drain level indicator (purchased from this site!) and now have the dreaded F4 code at the end of a wash cycle. Now it appears to be stuck in the F4 error cycle. The water drains out as it should but the pump stays on until the F4 code comes up. Holding down the start button clears F4 and the 4 flashes and makes the unit drain and then it goes straight in to F4 again.
Any ideas or just thrown the thing in the bin?