The F9 error appears when there is an overflow. The Overflow condition will occur when the respective contact on the pressure switch closes and does not open for at least 60 seconds. Not unlikely, the door won’t open, the drain pump won’t stop despite you have repeatedly pressed the PAUSE and/or CANCEL buttons. Disconnect the unit and do the following:
- Be sure that the drain hose is not clogged or kinked.
- Examine the wire harnesses connecting to the CCU (Central Control Unit) drain pump and pressure switch.
- Make sure the drain pump filter is not blocked. If it is, clean it.
- Make sure the drain pump is operational. If not, call a qualified technician.
- Make sure the inlet valve is off.
- Check the Pressure switch.
Remove the drain hose and blow it using a vacuum cleaner. Thus you can check it for obstructions. If there is any, take steps to clean the hose. Also, this can be due to a drain pump failure, as it could have gotten blocked with debris. This may require professional help, because the pump is a complex part.
Disconnect the washer from the mains and remove the kick plate and top panel. There may be loose or dirty connections at the drain pump, pressure switch (on the right side of the rear panel), and the CCU (in the middle of the rear panel behind the wash tub). You may have a loose or dirty connection somewhere. It is advisable to check each connection by removing them one by one and writing it down to avoid confusion. When checking the pressure switch, be sure that the air hose (clear or black) is connected properly. If not, or if it is damaged, the switch will not work, and the machine will be trying to get water and fill. To check the pressure switch, pull the big connector from the front of the CCU on the left. Pins 1 to 2, 3 to 4, 4 to 5, and 5 to 6 should read 0 ohms.
Clean out the drain pump. Make sure there is no water in the drain line, hoses, and the pump itself prior to opening the cover. Open the clean-out cover and check the pump for foreign objects and debris. If there are no visible issues and the pump is ok, most likely, you should look elsewhere. A meter located at the connector plug, which reads resistance across the motor windings, should read about 15 ohms.