Microwave runs (light and turntable on) but does not heat food; E03 appears on the display after a few seconds.
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
Critical safety warning: The high-voltage section of a microwave (transformer, capacitor, diode, magnetron) can store and generate lethal voltages. Do not attempt HV repairs unless you are trained and have proper tools. Many regions require a licensed technician for this work.
- Basic user checks:
- Confirm you are using microwave-safe cookware and not metal or foil that could affect heating.
- Try heating a cup of water for 1–2 minutes. If the turntable and light work but water stays cold, heating is not occurring.
- Visual inspection (for experienced DIYers only): Unplug the unit and remove the outer cover. Without touching the HV components:
- Look for obvious burn marks, melted connectors, or a cracked magnetron antenna cap.
- Inspect the high-voltage diode for visible damage or burning.
- Component testing: Proper testing of the magnetron, HV diode, and capacitor requires discharging the capacitor safely and using a multimeter with appropriate settings. If you are not fully confident, stop and call a professional.
- When to replace: If E03 persists and there is no heating, the most common parts replaced on Bush microwaves are the magnetron and HV diode. These should be replaced as a set only after correct diagnosis.
Due to the risk of electric shock and radiation leakage if reassembled incorrectly, this repair is generally not recommended for untrained users.