The F3 error occurs when there is a leak in the bottom part of the dishwasher.
The flood switch has been activated because the base tray is full of water.
Take the dishwasher out of its cabinet and tilt it about 45 degrees backwards. Use a bucket or tub. If necessary, use a towel or rag. Make sure that all water is drained from the tray.
When there is no water in the tray, the flood switch will regain its original position, and the error will disappear. However, if the tray is filled again, you should check your dishwasher for leaks. If necessary, use professional help.