Self cleaning pump....no such beast.
Drain machine by running the outlet pipe into a bucket at floor level.
Check the filter unit for blockages.Filter generally located behind a panel at the foot of the machine.Some are obvious like little square hatches and some are hidden behind the trim panel at the foot of the machine. Once panel is removed the filter should be visible. Its generally a circular plastic fitting which unscrews in an anticlockwise direction. Some hotpoint, indesit and ariston filters are located in the big black sump hose (the one that leaves the bottom of the outer drum and connects to the pump). Remove the back cover, locate hose, remove the tensioner clip by squeezing the tabs together, remove the hose, take out filter and clean.
Disconnect pump from sump hose and check for obstruction in either item. Pump removal: power off, remove cover, locate pump, (attached to other end of drain pipe).undo 2 wiring connections, 2 hose connections, and pump mounting screws. Remove pump chamber - some are held in with screws, others clip into place. Check for foreign objects round the impeller - hair clips or scrunchies are the usual suspects. If pump chamber is clear, may be a fault with the pump motor - in which case, replace.
Check out www.2ndwave.co.uk/manual.html