The "F3" error codes flashes on a GE oven and stops all current operations. The code can become frustrating, especially when a manual does not list the problem. The solution is a small part repair that will save money when compared with replacing your oven.
When "F3" error code flashes, a small part known as the oven temperature sensor has encountered an error and fails to work anymore. According to Repair Clinic, the error means that a circuit has been exposed or broken.
A new oven sensor needs to be purchased. They can be found at many local repair shops or online at websites like Parts Wizard. GE has their own specific model that also works in other brands of ovens.
Check the current warranty on your oven. The sensor may be covered under your warranty, and if that is still active, you can receive free repair and replacement from GE.
Use a manual from your exact oven to find the location of the oven temperature sensor. Make sure your oven is off and unplugged before attempting to install the sensor. If uncomfortable, you can hire a repair person to install the part.
Look for "F2" error codes to appear at this time as well, because that also signals a new oven temperature sensor is needed. The two codes may flash back and forth at the same time.