IF THE ABOVE SOLUTION DOES NOT WORK TRY THIS!
Do Not try to perform the below if: Oven is under warranty,You are not handy with a soldering gun, or Are afraid to do this.
The below solution applies only to my in-wall oven with F2 and F3 codes randomly, but presumably will work with other GE models.
I
had the same trouble with a GE in-wall oven. The problem was on the
electrical board behind the keypad. A pin that was soldered to the
board, that was the input for the oven temp sensor, had cracked solder.
So I re-soldered the pin and hopefully it will continue working.
If this fixes your oven please post back!