4E means water is not coming in so no point checking filter or drain pump blockages. Check water supply in. Take hose off machine & point it in to sink and turn tap on. If you get a strong flow and filter inside the inlet valve is clear put hose back on & open tap fully. Try machine. If no water comes in then I would suspect either a faulty inlet valve or no power going to the valve. You will need a multimeter to check both of those.
Lincoln Appliance NZ, March 2013