E03 on documented Candy washing machines corresponds to a drain circuit problem. Check the outlet and the accessible filter with the water cold and a drain container ready.
Check where the water stops
The official Candy washing machine FAQ places E03 in the drain. Look for kinks in the hose, backflow from the household drain, and recent connection changes. If it uses a siphon, check whether there are drainage problems at that point too.
Open only the user filter
Check the manual to confirm access. Turn it off and unplug it safely, let the water cool, and place a container. Use the provided drain method before removing the cap completely; do not force the closure or open it while water is retained without control.
Clean any accessible residue and reinstall it so it is watertight. The guide to drain filter explains the preparation. If E03 continues after checking the external route, request service.
The warning does not confirm a faulty pump. Nor should it be interpreted with Hoover instructions or those for a Candy dryer, where a condensation tank may be involved.
Note whether the fault started after cleaning the filter or changing the outlet: it helps review the installation performed.