Kenmore Oven Error Code F43

The F43 code means the Appliance Control Board has detected that the microwave external cooling fan is spinning at an abnormally slow speed, or has stopped spinning entirely. The board monitors fan speed through a tachometer input and triggers this fault when the rotation rate falls below an acceptable level. This is a protective alert designed to prevent heat damage to microwave components. The oven should not be used until the fan issue is resolved.

It is not recommended to continue using the microwave function while F43 is active. The cooling fan protects the magnetron and other internal components from overheating, and operating without adequate airflow can cause permanent damage. The oven bake and broil functions may still work, but the microwave portion should remain off until the fan problem is corrected.

Repair costs vary depending on what component has failed. A replacement cooling fan motor typically ranges from $30 to $80 in parts. If the Appliance Control Board needs replacement, parts alone can range from $100 to $250 or more. Adding professional labor, total repair costs generally fall between $150 and $400 depending on the specific failure and your location.

Some causes of F43 are accessible to a knowledgeable DIYer. You can safely inspect the fan for physical obstructions and check for obvious wiring damage with the appliance unplugged. However, testing for 120VAC at the fan motor and diagnosing the tachometer circuit requires working near high-voltage components, which carries serious safety risks. Motor and control board replacement are best handled by a qualified technician if you are not experienced with appliance electrical repair.

Disconnecting power to the oven briefly may temporarily clear the F43 code, but the fault will return as soon as the control board detects the slow fan speed again during operation. A reset does not fix the underlying problem with the fan motor, wiring, or tachometer circuit. The code will continue to appear until the root cause is repaired.