What F3 means (lg f3 error)
An lg f3 error on an LG microwave indicates a keypad fault — the control reads a key as stuck or shorted. It often follows a spill or a greasy panel, so cleaning the keypad is the first step before assuming the keypad or board has failed.
Symptoms to look for
The signs below help confirm you are dealing with this condition rather than a different fault on your LG Microwave. You may see one of them or several together, and they can build up gradually or appear suddenly after a power event, a long door opening, or recent service.
- The display shows “F3”
- Some or all keys do not respond
- A key seems stuck or over-sensitive
- The fault may follow a spill or a greasy panel
Common causes
Several different faults can produce these symptoms. Working through the most likely causes in order helps separate a quick, owner-level check from a problem that needs trained service and the correct LG parts.
- Soiled or wet keypad — residue bridges a key contact
- Stuck key — a key is held active
- Ribbon connector fault — the keypad-to-board link is poor
- Control or keypad fault — the input has failed
Troubleshooting steps you can try
Work through these checks in order before calling for service. Stop wherever you are unsure, or where high-voltage parts, gas, the sealed refrigeration system, or a heat-pump compressor are involved, and hand the rest to a qualified technician.
- Unplug the microwave and wipe the keypad clean and dry.
- Restore power and test whether the keys respond.
- Note whether one key or all keys are affected.
- If F3 persists on a clean panel, leave it for service.
Parts a technician may replace
Depending on what the diagnosis shows, a technician may inspect, test, or replace the membrane keypad / touch panel, ribbon connector, and control board. The correct part for your LG Microwave is matched from the model and serial number, and genuine LG components are fitted rather than generic substitutes so that performance, safety, and the appliance’s long working life are all protected. Confirming the failed part before ordering avoids replacing more than the fault actually requires.
When to call a technician
F3 that stays on a clean panel needs a technician to test the keypad and ribbon and replace the panel or board. When the fix calls for trained service, book a visit through our scheduling page and an experienced, qualified technician will diagnose and repair it. For manufacturer documentation and model lookup, see the manufacturer at lg.com/us.
Prevention and care
Regular care keeps this condition from returning on your LG Microwave. Keep filters, vents, and the condenser or exhaust path clean, avoid overloading or blocking airflow, check that doors and seals close cleanly, and follow the LG maintenance guidance for your model. Because this unit relies on electronic control, protect it with a stable, correctly rated power supply and have any built-in or laundry installation done to LG specification so the control never sees an out-of-range condition. If a code appears, note exactly what was shown before you reset the appliance — that record helps the technician reach an accurate diagnosis and avoid replacing parts unnecessarily.
Related help and LG resources
Browse other LG Microwave diagnostics, read about professional LG Microwave repair, look up your unit in the LG models reference, or the related F10 stuck-key fault, or schedule a service visit. For LG manufacturer documentation and model lookup, visit the manufacturer at lg.com/us.
