Microwave stops heating shortly after start, display shows E02 and may beep.

Safety warning: Internal microwave repairs involve high voltage and RF shielding. Only perform external cleaning and airflow checks unless you are qualified.

Steps to try:

• 1. Disconnect power: Unplug the Siemens microwave.
• 2. Check ventilation: Ensure there is adequate clearance around the microwave per the Siemens installation manual (typically several centimeters on sides, top, and rear). Move items away from vents.
• 3. Clean air vents: Use a soft brush or vacuum to remove dust and grease from the side, rear, and top ventilation grilles. Do not spray cleaner directly into vents.
• 4. Avoid long high-power runs: Try heating a cup of water on medium power. If E02 appears only on long or high-power cycles, overheating is likely.
• 5. Let it cool: Leave the door open and the unit unplugged for 30–60 minutes to allow internal components to cool, then test again.
• 6. Advanced (technician level): Check the cooling fan motor operation, magnetron thermal cut-out continuity, and magnetron current draw. Replace the cooling fan motor or magnetron assembly if defective.

If E02 recurs quickly even with good ventilation, schedule service; continued use may damage the magnetron.