Microwave stops heating shortly after start and displays E02 or shuts down with an overheat warning.

Safety first: Unplug the microwave. Internal components can store high voltage; do not touch the capacitor, transformer, or magnetron terminals.

External checks:

• 1. Verify ventilation clearance: Ensure there is at least the manufacturer-recommended clearance (typically 10–15 cm at sides and top, and open space at the rear) around the microwave. Remove any items blocking the side or rear vents.
• 2. Clean external vents: Use a soft brush or vacuum to remove dust and grease from the side and rear ventilation grilles.
• 3. Test with a light load: Place a large microwave-safe bowl of water inside and run on HIGH for 2–3 minutes. If E02 appears again or the unit shuts down, the internal cooling system may be failing.

Internal checks (experienced DIYers only):

• 4. Access the cooling fan: Remove the outer cabinet. Locate the cavity cooling fan motor near the magnetron and rear vents.
• 5. Inspect fan operation: Spin the fan blades by hand (with power unplugged). They should rotate freely without scraping. If stiff or seized, the fan motor must be replaced.
• 6. Check for dust buildup: Use compressed air or a soft brush to clear heavy dust from the fan, magnetron fins, and vents.
• 7. Inspect the magnetron thermostat: Locate the magnetron thermal cut-out (TCO) clipped to the magnetron or waveguide. If it has signs of heat damage or loose connections, it may be tripping prematurely and should be replaced.

When to call a technician: If the fan runs normally and vents are clear but E02 persists, the magnetron or control board may be overheating and require professional diagnosis.