LG Microwave Error Code F-3 — Keypad / Touchpad Short Circuit
What this means
The F-3 error code on LG microwaves indicates the control board is detecting a continuously pressed or shorted key on the touchpad membrane. This can happen when moisture or grease seeps behind the keypad overlay, when the membrane wears out from heavy use, or when the ribbon cable connection to the control board becomes corroded. The microwave may beep continuously or refuse to accept any input.
Alternate codes: F3
Step-by-step fix
4 stepsPower cycle the microwave
Unplug the microwave for two minutes. Plug it back in and press each button to test for normal response. A static discharge or one-time moisture event can trigger a false F-3.
If the code returns immediately before any button is pressed, the membrane is internally shorted.
Clean the touchpad and surrounding area
Wipe the touchpad surface and its edges with a soft cloth dampened with warm water. Remove any grease or food residue that could be bridging contacts underneath the membrane.
Avoid abrasive cleaners — they can scratch through the touchpad overlay and damage the conductive layer.
Check the ribbon cable
Unplug the microwave. Remove the outer cabinet. Find the flat ribbon cable connecting the touchpad membrane to the control board. Disconnect it, inspect for corrosion or damage, and reseat it firmly.
WARNING: Work only near the control board and touchpad area. Do not touch the high-voltage capacitor.
Replace the touchpad or control panel
If the error persists, the membrane touchpad needs replacement. On many LG models the touchpad and control panel are a single assembly. Order the correct part, disconnect the old panel, and install the new one.
Check LG's parts catalog — on some models you can buy just the membrane overlay; on others it's the entire panel.
When to call a professional
If a new touchpad still triggers F-3, the control board may have a shorted input circuit. A technician can test the board and replace it if necessary.
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
Control Panel / Touchpad Assembly
Part #AGM73551646 · $40–$100
If cleaning and reseating the ribbon cable don't resolve F-3
Main Control Board
Part #EBR75234703 · $60–$130
Only if touchpad replacement doesn't fix the error
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