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F1

LG Microwave

Severity: Moderate

Source: OnlyErrorCodes.com — Every error code. One place.

LG Microwave F1 Error — Control Board Fault Fix

What Does This Error Mean?

F1 on an LG microwave is a control board fault — the controller has detected an internal error.
Unplug for 10 minutes and try again.
If F1 returns, the control board has failed and needs replacement.
For built-ins or microwaves under 5 years old, repair makes sense (150–250 USD).
For older countertop units, replacement is usually more economical.

Affected Models

  • LG over-the-range microwave
  • LG countertop microwave
  • LG NeoChef
  • LG LMV series

Common Causes

  • Control board failed
  • Power surge damaged the board
  • Moisture damage from steam exposure
  • Capacitor aged out
  • Internal connector loose

How to Fix It

  1. Unplug for 10 minutes.

    Pull the plug from the wall.
    For over-the-range models, switch the breaker off.
    Wait the full 10 minutes — capacitors take time to discharge.
    Plug back in and watch the display.

  2. Test with a quick cook.

    Try cooking water for 30 seconds at medium power.
    If F1 doesn't return and the cook completes normally, the issue was a transient.
    Monitor for recurrence over the next several uses.

  3. Don't open the microwave.

    High-voltage capacitors inside the microwave hold lethal voltage even after long power-off.
    Disassembly is genuinely dangerous and service-tech-only work.
    Don't try to access the control board yourself.

  4. Decide repair vs replace.

    Built-in or microwave under 5 years: repair the board (150–250 USD).
    Countertop or over-the-range over 7 years: replacement is usually more economical (300–500 USD new).
    Get the service quote first before deciding.

  5. Schedule LG service if repairing.

    Provide model and serial numbers.
    Most LG-authorized centers carry common control boards or can order them quickly.
    Job is 1–2 hours.
    Free under warranty; out of warranty, 150–300 USD all-in.

Frequently Asked Questions

Can F1 be caused by something other than the board?

Rarely.
F1 on LG is the board reporting an internal self-test failure — almost always means the board itself is the problem.
In rare cases, a heavily corroded connector causes false F1 events that clear when the connector is reseated.
The technician will rule that out first.

Should I add a surge protector after repair?

Yes — if the F1 event followed a storm or power event, a surge protector (10–20 USD) at the outlet protects the new board.
Won't help if the original board failed from age, but for storm-related failures it's cheap insurance against another repair.