I just cleaned the lower oven today (self cleaning) and once the cycle was completed it started to beep and a code F1-4 was displayed on the panel. I tried to cancel but it won’t. The upper oven door unlocked but the lower oven door will not unlock. When I try pressing any of the buttons on the panel such as cook and so on it just beeps and says LOCKED on the panel.
"F1-4" error code means "Runaway temperature, lower oven".
The first thing I would do is check the lower oven temperature sensor. Pull the range out, remove the rear cover and locate the sensor wire harness to the control board. Measure the sensor resistance at the control board. Normally it suppose to be about 1100 Ohms at the room temperature. Also check the sensor wire harness and the sensor plug.
If the resistance reads wrong then replace the oven sensor.
If there is nothing wrong then the control board has to be replaced.