Microwave display shows E04 and unit will not heat; fan and light may still operate.
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Possible Causes
How to Fix / Troubleshooting
Safety warning: High-voltage components can store lethal charge. Do not touch or service the magnetron, capacitor, or transformer unless you are qualified.
Basic user checks:
- Confirm that the microwave is not in demo mode (refer to Fagor manual for exiting demo mode).
- Try heating a cup of water for 1–2 minutes. If the turntable, light, and fan run but water stays cold and E04 appears, heating components are likely faulty.
Visual inspection (qualified personnel):
- Unplug and remove the outer cover.
- Inspect the magnetron terminals and connectors for signs of overheating or arcing.
- Check the high-voltage capacitor and transformer for bulging, burning, or oil leakage.
Component testing (technician only):
- Test magnetron filament continuity and check for shorts to chassis.
- Measure transformer primary and secondary windings for continuity.
- Test the high-voltage capacitor and diode with appropriate equipment.
Magnetron and HV parts should be replaced with Fagor-approved equivalents only. Due to the risks, most users should engage a professional for E04 faults.