Ok, take off the top and see if the tech notes are in there. They really should be inside the lower panel though.
Can you tell us exactly what happens and when. Your first post stated it happend in "water circle". Do you mean wash cycle, or exactly when.
Also, are you able to power down the machine, let it rest and then start it up again, with the same thing happening?
The F15 error is your motor control unit, but that is an expensive part so lets see if we can learn anything more