The technical advice for a Hotpoint washing machine displaying the error code F04, is that the pressure switch is stuck on empty, and to check the pressure switch, wiring and module connections.
When the washing machine fills with water it forces air up the pressure tube connected to the pressure switch. When the right amount of water has been taken it this will create enough air pressure in the tube to switch the pressure switch on. This tells the washer to stop filling.
Bonne chance...
Jacques Cousteau, October 2014
