First step is to find the model number of your machine.
Second step is to do a Google search for " "model" ef0 "
You should then find some useful results which may include things like these:
https://www.ukwhitegoods.co.uk/forumsphpbb3/fault-code-efo-aeg-16830-t78443.html
http://www.justanswer.com/uk-appliance/5le36-hello-i-efo-error-displayed-aeg-lavamat-72650.html
Plenty more out there. All you have to do is look
XXX, January 2017