Ruben Lucero
In what mode of the range the "F31" error code appearers on the display: any kind of cook mode (bake or broil) or just time of the day mode?
If it shown only in cook mode then disconnect the sensor plug from the control board and check the resistance. At the room temperature is suppose to be about 1100 Ohms. If the resistance is wrong unplug the sensor from it's plug and check the resistance at the sensor itself. If it's wrong then you got the defective sensor. Return it for exchange.
If you have the right resistance at the sensor but the resistance at the control board is wrong then the problem is the wires. You do not need the whole harness, just two wires (unless the problem is not the plug).
If all of the above is fine or the error code shown in the time of the day mode then the control board has to be replaced.
The part number for the control board is
AP3778770 You can remove the overlay from the old one or you can the new one. The part number for the black overlay is
AP3778486
Good luck.
Gene.