What F3 Means
LG's Help Library explains that error codes on its microwave ovens (LG calls this family of built-in and countertop units "lightwave ovens" in this article) start with the letter F and are displayed as a number, and that an F3 specifically can occur when foreign substances are present around the touch button panel. LG adds that other numbered F errors on a microwave can indicate defective parts, a short circuit, communication failures, or overcurrent, and recommends a technician inspection for those.
Common Causes of F3
- Foreign substance (grease, food residue, moisture) on the touch button panel
- Temporary electronic glitch
🔧 One Safe Check You Can Try
Wipe any foreign substances - grease, food splatter, moisture - off the touch button panel and check again; if the error clears, that confirms it was a contact issue rather than a hardware fault.
⚠ Why You Shouldn't Go Further Than That
- LG's own guidance for a persistent F3 (or any other numbered F error on the microwave) after cleaning the panel and a power-cycle is to call for an inspection - defective parts, a short circuit, or overcurrent are all named as possible causes for the broader F-code family, and none of those are safely diagnosable by an owner.
- Unplug the microwave before wiping the panel if you're cleaning near any exposed seams or buttons that feel loose, rather than cleaning a live unit.
Opening a panel to inspect or repair something yourself doesn't automatically cancel your manufacturer's warranty — but it can risk accidental damage, and some manufacturers do have specific service conditions. Check your product's warranty terms, or ask us, before deciding.