E20 is a code for a blockage on the pumping cycle, either a blocked drain filter, located bottom left of machine or a kinked waste hose.
Probably something stuck in the filter. You will need to open the little door and unscrew the filter assaemble, but watch out as there will be water in here. Have a bowl or pleanty of towels to mop up the water. I have had this problem a couple of times and found a 5p coin each time.
I hope this helps.
Bernie
February 2010