Microwave does not start heating, display shows E01 shortly after pressing Start.

Safety warning: Microwaves contain high-voltage components and a high-voltage capacitor that can retain a dangerous charge even when unplugged. Do not remove the outer cabinet unless you are trained and know how to safely discharge the capacitor. For most users, limit work to external checks and door alignment.

Steps to try:

• 1. Disconnect power: Unplug the Siemens microwave from the wall outlet or switch off the circuit breaker.
• 2. Inspect the door: Check that the door closes evenly and fully. Look for bent or damaged door hooks/latches and cracked plastic around the latch area.
• 3. Clean the door area: Wipe the door frame and latch area with a damp cloth to remove grease or debris that may prevent the door from closing fully.
• 4. Check for door play: Gently lift and push the door when closed. Excessive play can prevent the door switches from actuating correctly. If the hinges are loose, tighten accessible hinge screws from the front (if present on your model).
• 5. Power reset: Plug the unit back in, wait 1–2 minutes, then try a short 30-second heating cycle with a cup of water. If E01 reappears, the door switch system is likely faulty.
• 6. Advanced (technician level): With the cabinet removed and capacitor safely discharged, test the primary and secondary door switches with a multimeter for continuity when the door is closed. Replace any switch that does not change state correctly.

If the error persists after basic checks, contact a Siemens-authorized service technician, as door interlock repairs must maintain microwave radiation shielding integrity.