Microwave shows F4E0 and will not start or stops shortly after starting.

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.

Possible Causes

Shorted cavity thermistor, open thermistor circuit, damaged harness between thermistor and control, failed analog input on main control board

Safety: Disconnect power before removing the outer cabinet.

Inspect thermistor harness: Trace the wires from the cavity thermistor to the main control board. Look for cuts, pinches, or melted insulation.
Connector check: Reseat the thermistor connector at the control board and at the sensor end.
Thermistor replacement: If wiring appears good and F4E0 persists, replace the cavity thermistor.
Control board: If a new thermistor does not resolve the error, the main control board's sensor input may be defective and require replacement.

Hard 4/5

Cavity Thermistor

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