Frigidaire Microwave Error Code F31

F31 indicates a shorted RTD sensor probe or a wiring problem in the probe circuit. The RTD probe monitors cooking cavity temperature by changing its electrical resistance with heat, and the control board detected a resistance value consistent with a short. The microwave stops operating when this code appears to prevent unsafe conditions.

Resetting by unplugging the unit or cycling the breaker may temporarily clear the code, but it will return if the underlying fault in the probe or wiring is not corrected. Letting the oven cool completely before restarting is a recommended first step, as a heat-related transient can sometimes trigger F31. A persistent F31 code after cooling and restarting requires hands-on diagnosis.

Repair costs depend on which component has failed. An RTD sensor probe is generally an affordable part, with the probe itself typically ranging from $15 to $50 depending on the model. If the EOC requires replacement, parts alone can range from $80 to $200 or more, and professional labor will add to the total cost. Getting a diagnosis before ordering parts is recommended to avoid unnecessary expense.

A knowledgeable DIYer can inspect the probe wiring for visible damage and check connector integrity without special tools. Measuring RTD resistance requires a multimeter and access to the probe resistance chart for your specific model. If the probe resistance is out of spec, replacing the RTD sensor probe is a straightforward repair, though replacing the EOC is more involved and may be better handled by a technician.

No, you should not continue using the microwave while F31 is active. The error indicates the temperature monitoring system is not functioning correctly, which means the control cannot accurately track cooking cavity temperature. Operating the unit in this condition could result in overheating or unsafe operation.