Jenn-Air Oven Error Code F4E2-3

Error code F4E2-3 on a Jenn-Air oven indicates that the microwave magnetron temperature sensor has developed a short circuit. The magnetron temperature sensor is a thermistor or thermal cutout device mounted directly on or near the magnetron tube in the microwave section of the appliance. Its job is to monitor the operating temperature of the magnetron and report that data to the main control board. When the sensor shorts, its resistance drops abnormally low, sending a signal the control board interprets as an out-of-range reading, triggering this fault code.

A shorted sensor circuit can result from a few different failure points. The sensor itself may have failed internally, which is common after repeated thermal cycling over the life of the appliance. Wiring harness damage is another frequent cause, particularly if insulation has melted or chafed against a sharp edge near the high-heat magnetron area. Loose or corroded connector terminals at either the main control board or the sensor itself can also create intermittent or sustained short conditions.

Before replacing any components, the first diagnostic step is to disconnect power to the appliance and carefully inspect all wiring connections between the main control board and the magnetron temperature sensor. Look for burned insulation, pinched wires, or terminals that are not fully seated. If the connections appear intact, the sensor itself should be tested for proper resistance values and replaced if it reads outside specification.