LG F3 fault codewhat it means and how to fix it
LG document this one twice and differently. One article says wipe the touch panel, the other says the control panel is faulty and needs service.
Take care
What F3 means
This is the only code in LG’s microwave documentation where the manufacturer contradicts itself, and the contradiction is worth understanding rather than resolving, because the two answers point at the same part from opposite ends. LG’s article covering the whole F range says F-3 errors "can occur when there are foreign substances around the touch button panel", and tells you to wipe the panel and try again. LG’s code table says F3 "indicates a problem with the control panel" and that it "will require service to resolve". Both are about the touch fascia.
The difference is whether the problem is on top of it or inside it. A capacitive touch panel works by sensing a change in the electrical field at its surface, and it cannot distinguish a fingertip from a film of condensation, a smear of grease or a sticky patch of something that boiled over.
Any of those reads as a key being held, the appliance concludes the panel is telling it something impossible, and it stops. That is the version LG say you can fix with a cloth. The other version is the panel itself failing, or the ribbon that carries its signal to the board coming loose or corroding, and no amount of cleaning touches that. The order to work in follows from the cost rather than from which article you found first. Cleaning is free and takes two minutes. Service is a visit. So clean it, dry it properly, cycle the power, and if F3 comes back on a panel you know is clean and dry, you have moved from LG’s first article to their second and the answer is a repair.
What causes it
| Cause | What is actually happening | How likely |
|---|---|---|
| Condensation on the touch panel | Steam leaving the cavity when you open the door rises up the fascia and settles on it, which reads as a continuous press. | Common |
| Food residue or grease on the keys | The "foreign substances around the touch button panel" that LG name. A sugary splash is the worst of them because it stays conductive as it dries. | Common |
| Touch panel or its ribbon connection failing | The version behind LG’s second article. Nothing on the surface is wrong and cleaning changes nothing at all. | Occasional |
| Something pressing against the fascia | A tea towel draped over the front or a container leaning on it holds a key exactly as a finger does. | Occasional |
What to try yourself
Unplug it at the socket. This clears whatever key the appliance currently believes is held, and LG ask for a power cycle on every F code anyway.
Check nothing is resting against the front, then look across the panel at an angle in good light. Condensation and dried splashes both show up better sideways on than straight on.
Wipe the panel with a barely damp soft cloth, working over every key rather than just the ones you use, then dry it thoroughly.
Nothing sprayed at the panel and nothing abrasive. Liquid getting behind the fascia turns a two-minute wipe into the fault that does not clean off.If there was visible condensation, leave it unplugged with the door open for half an hour so the panel dries rather than just looking dry.
Plug it back in and try it. If F3 returns on a clean dry panel, stop — you are now in LG’s other article, and their instruction there is service.
Get a qualified appliance engineer to look at your LG F3
We do not pass enquiries to a repair firm, so there is no form here. When you book a qualified appliance engineer, tell them the make, the model and the exact code or message on the display, and ask whether they carry parts for this make — that is what turns one visit into a repair rather than a quote.
What it costs to fix
Typical repair cost
£0–£130
Time on site
20 minutes
Nothing at all if cleaning does it, which is the outcome LG’s first article expects. A touch panel or control fascia fitted with a visit runs about £80 to £130, and it is front-of-appliance work rather than anything behind the cover.
Typical UK prices including parts and labour, updated September 2026. Your quote may differ.
Own this appliance and had this code? . Nothing is published until a person has read it.
Related LG fault codes
- E10Get it checkedLG say an internal short was detected in the control board, and then give you something to try anyway: unplug it for a full minute.Related: controls and electronics
- F1Get it checkedLG publish this as a problem with the mainboard and say it requires service. There is no owner remedy, and the useful question is whether the appliance is worth it.Related: controls and electronics
- LOCUsually simple to fixNot a fault. LOC is LG’s child lock, and it releases by holding STOP/CLEAR until the display drops it.Related: same brand
- DOORGet it checkedThe word DOOR rather than a number. LG say the door is not closed or the latch is not engaged, and they include transit packing as a cause.Related: same brand
- F16Get it checkedLG say a heating issue was detected. They publish F19 with word-for-word identical text, so both codes land here.Related: same brand
- F2Get it checkedLG describe a thermistor problem putting the temperature in the unit out of range. It is the reading that is wrong, not necessarily the cavity.Related: same brand
Own a LG microwave? Save it and its codes come first next time.
Related guides
Common questions about LG F3
Which of LG’s two answers is right?
Both, for different versions of the same fault. Their F-range article describes contamination on the panel, which you can fix. Their code table describes the panel itself being faulty, which you cannot. Cleaning first costs nothing and tells you which one you have.
Can I still use it while F3 is showing?
While the code is on the display the appliance has stopped, so there is nothing to use. If cleaning clears it, carry on. If it clears and then comes back intermittently, the hazard is not radiation or shock — it is an appliance that stops in the middle of cooking something.
Is this the same as the child lock?
No. A locked keypad shows LOC on an LG and releases by holding STOP/CLEAR. F3 is the appliance reporting that the panel is sending it something it cannot act on.
Why does LG call it a lightwave oven?
It is their own name for a microwave, and it appears throughout this part of their documentation. It matters only because searching their support site for "lightwave oven" and for "microwave" surfaces different articles about the same appliance.
Technical review
Not reviewed by an engineer
No engineer has read this page. Severity follows what the manufacturer publishes, and we would rather tell you that than let a byline imply a sign-off.
Sources and how we verified this
We establish the facts from the sources below and then write the explanation ourselves. We do not copy manufacturer wording and we do not host their manuals.
- Manufacturer support portal
This page has not been reviewed by an engineer, and we would rather tell you that than imply otherwise. The severity rating follows what the manufacturer publishes: where they say isolate the appliance and call someone, so do we.