F27 is a pressure switch fault.
Has it stopped full of water?
Ok try this and see what happens.
Take the top off the washer and from there on the right you should see the pressure switch. It will have a few wires going to it and a thin tube.
Remove this tube from it and blow hard through it.
Then check the wires going to the switch and make sure its all ok.
Then refit the hose and retry the washer and see how it goes from there. But if still the same then its possiley either the pressure switch itself at fault or the control board im afraid.
But try the pressure hose first as this may cure it.