DIAGNOSIS That's the oven temperature sensor error. The sensor inside the oven cavity has either failed or its connection is loose.
FIX Unplug the range. Remove the oven racks and the baffle at the back of the oven. You'll see a small, thin metal probe (the sensor) sticking into the oven near the top. Gently pull the sensor straight out of its bracket. Unplug its wire connector from the back. The replacement part number is usually DG94-00607A. Plug the new one in, slide it back into the bracket, and plug the range back in.
IF THAT DIDN'T WORK If the code comes back with a new sensor, the issue is likely the main control board. It's not sending the right signal or reading the sensor correctly.
HEADS UP The sensor is delicate. Don't bend it when installing. Also, always, always unplug the range before touching anything inside—it's 240 volts back there.