Zanussi Dishwasher Draining Error

Hi, I have a Zanussi Dishwasher ZDF2020 that is flashing an error on the led's. Manual says the drain is blocked.

However, if I fill the washer with 2 kettles of water and reset/start a cycle the water is drained out as normal, 5 seconds of whoosh then reduces to a trickle. So the pump must be fine and there is clearly no blockage. The machine then continues pumping for a minute but does not fill, then stops with the error.

Internal filters are clear/clean. I'm quite handy with fixing stuff myself and these forums have been a godsend with solutions but I'm at a loss to kow what is up with this machine.

Any ideas out there?

Thanks
BB

Problem solved. For reference should anybody else get this problem, I cancelled the cycle, set program to off, switched off at mains for 24 hours and this morning it sprang back to life. Presumably the computer registered an error and neded to 'forget' by discharging capacitors. £300 saved!