The "F2" error code means that the oven control sensed overheating condition. It could be caused by a welded relay contacts (control board) or a bad oven temperature sensor.
If it happened while the oven was in a cooking mode, then you have to check the oven sensor resistance first. It can be done at the oven control board. The normal reading is about 1100 Ohms at the room temperature.
If the reading is incorrect, then the oven temperature sensor has to be replaced.
If the reading is correct, then the problem is a bad oven control board.
If it happened while the oven was in stand by mode, then the problem is a bad oven control board.
Unfortunately the oven control board has been discontinued and is no longer available.
Here are the breakdown diagrams and Parts for GE JTP13GV2BB Wall Oven - AppliancePartsPros.com