F3
Magic Chef Temperature or Cavity Sensor Error

Microwave displays F3 and may shut down during sensor cooking modes.

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Failed cavity temperature sensor, Open or shorted sensor wiring, Loose sensor connector on control board, Faulty sensor input circuit on PCB

How to Fix / Troubleshooting

Safety: Unplug the microwave and allow it to cool.

Locate the sensor:

  • Many Magic Chef models use a thermistor or temperature sensor mounted on the cavity wall or near the waveguide.
  • Remove the outer cabinet to access the sensor and its wiring.

Testing:

  • Disconnect the sensor and measure its resistance at room temperature; compare to the service manual specification (typically tens of kΩ).
  • Check the wiring harness for continuity and damage.

Corrective actions:

  • Replace a sensor that is open, shorted, or out of specification with the correct Magic Chef cavity sensor.
  • Repair or replace damaged wiring.
  • If a known-good sensor does not resolve F3, the control board sensor circuit may be defective and require replacement.
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Repair Difficulty

Hard 4/5

Required Part

Cavity Temperature Sensor
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