LG Microwave Error Code F-9 — EEPROM Communication Error
What this means
The F-9 error code on LG microwaves indicates the control board cannot read from or write to its EEPROM (electronically erasable programmable read-only memory) chip. The EEPROM stores configuration data, cooking presets, and operational parameters. When it fails, the microwave may lose its settings, display garbled information, or refuse to operate entirely. Causes include a power surge corrupting the chip, a failing chip, or a solder joint failure on the control board.
Alternate codes: F9
Step-by-step fix
4 stepsPower cycle the microwave
Unplug the microwave for five minutes — longer than usual, to ensure the EEPROM fully discharges. Plug it back in. Some EEPROM errors are caused by data corruption during a power glitch and can be cleared by a full reset.
If the clock and presets have reset but the microwave works, the EEPROM recovered during the power cycle.
Check for recurring power issues
If F-9 keeps returning after resets, check whether the microwave is on a circuit with power fluctuations. Frequent brownouts or surges can repeatedly corrupt the EEPROM.
Plugging the microwave into a surge-protected outlet can help prevent future EEPROM corruption.
Inspect the control board
Unplug the microwave. Remove the outer cabinet. Visually inspect the main control board for signs of damage — particularly around the EEPROM chip (a small 8-pin IC). Look for cracked solder joints, burn marks, or corrosion.
WARNING: Do not touch the high-voltage capacitor. Work only near the control board.
Replace the control board
If the EEPROM chip has failed, the entire control board typically needs replacement (EEPROM chips are surface-mounted and not practical to replace individually). Order the correct board for your model, swap it in, and test all functions.
Some replacement control boards come pre-programmed; others may need a model-specific setup sequence. Check the documentation included with the board.
When to call a professional
EEPROM failures require control board replacement, which involves working near high-voltage microwave components. If you're not comfortable with microwave internal repairs, have a technician handle this. Also compare the board cost to a new microwave.
Related error codes
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
Main Control Board
Part #EBR75234703 · $60–$130
Required if EEPROM is permanently corrupted or chip has failed
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