Microwave runs but stops with E3 error, or will not start and immediately shows E3.

Critical safety warning: High-voltage components inside a microwave (transformer, capacitor, diode, magnetron) can cause severe or fatal electric shock even when unplugged. Do not remove the cabinet or attempt internal repairs unless you are a trained appliance technician.

Safe checks you can perform:

• Ensure proper ventilation: Verify that the microwave has at least the manufacturer-recommended clearance on all sides and that the rear and side vents are not blocked by cabinets, walls, or objects.
• Clean air vents: With the unit unplugged, use a soft brush or vacuum to remove dust and grease from the external vents and grille. Do not spray liquids directly into the vents.
• Avoid long continuous runs: If the error appears after long cooking times, try shorter intervals with rest periods to see if the error is heat-related.

When to call a technician:

• If E3 appears immediately or after only a short cook time.
• If the unit becomes unusually hot on the side or top cabinet surfaces.
• A technician will test the magnetron thermal cut-out, cavity thermostat, and the high-voltage circuit (transformer or inverter, capacitor, diode, magnetron) and replace the failed component.