Bosch Microwave Error Code E04 — Door Switch Circuit Fault
What this means
The E04 error code on Bosch microwaves indicates a fault in the door switch circuit. Microwaves have multiple door switches (interlock switches) that must all confirm the door is securely closed before the magnetron can operate. If any switch fails, is misaligned, or has a wiring issue, this safety error prevents operation. The microwave absolutely must not run with the door open or improperly latched.
Alternate codes: E4
Step-by-step fix
3 stepsInspect the door closure
Open and close the door several times, listening for a firm click each time it latches. Check that nothing is preventing full closure — food debris, a warped door, or a misaligned latch hook can prevent the switches from engaging.
The door hooks (the prongs that slide into the switch assembly) should be straight and undamaged. Bent hooks prevent proper switch engagement.
Clean the door latch area
Clean the door latch hooks and the receiving slots in the microwave body with a damp cloth. Food residue can accumulate and prevent the hooks from fully engaging the switches.
Check the door gasket (seal) for tears or gaps — while not directly related to the switches, a damaged gasket indicates the door may not be closing properly.
Test the door switches
Unplug the microwave. Remove the outer cabinet cover. SAFETY: Do not touch the high-voltage capacitor. Locate the door switches (typically 2–3 switches near the door latch slots). Test each switch for continuity — they should toggle open/closed as the door hooks engage and disengage.
Microwave door switches are a critical safety component — never bypass or tape them. A microwave operating with a faulty interlock is extremely dangerous.
When to call a professional
Door switch replacement requires working inside the microwave near high-voltage components. Due to the safety-critical nature of interlock switches, professional repair is strongly recommended.
Related error codes
The magnetron has overheated and the protection circuit has activated.
Advanced Fix · 30–60 minutes
The oven cavity temperature sensor has failed.
Advanced Fix · 30–60 minutes
The inverter board that controls microwave power has failed.
Professional Required · Professional service required
Information compiled from manufacturer service manuals, official troubleshooting documentation, and appliance repair industry resources. This guide is for informational purposes only — always consult a qualified technician for complex repairs.
Learn more about our sourcesParts you may need
Door Switch Kit (set of 3)
Part #00614767 · $15–$30
Required if any switch fails continuity testing
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