LG F2 fault codewhat it means and how to fix it
LG describe a thermistor problem putting the temperature in the unit out of range. It is the reading that is wrong, not necessarily the cavity.
Take care
Get a qualified appliance engineer to look at your LG F2
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What F2 means
LG’s wording for F2 repays reading closely: it "indicates a problem with the thermistor causing the temperature in the unit to be out of range". The clause order is the informative part. LG are not saying the appliance got too hot. They are saying the thermistor has a problem, and the consequence of that problem is a temperature value that falls outside what the appliance will accept. Those are very different situations for an owner. A thermistor is a resistor whose resistance changes predictably with temperature, and the board converts that resistance into degrees. It has exactly two interesting failure modes and both produce an impossible number rather than a wrong one.
Open circuit — a broken leg, a corroded crimp, a disconnected plug — reads as infinite resistance, which converts to a temperature far below anything a kitchen could produce. Short circuit reads as near-zero resistance, which converts to a temperature far above anything the appliance could survive. Either way the board receives a figure it knows cannot be true, and rather than cook to a number it does not trust, it stops. Which is the right behaviour: an appliance that ignored its own thermal sensing would have nothing left watching for the condition that sensing exists to catch.
The practical consequence is that F2 usually appears on an appliance that is stone cold, and that is not a contradiction. It also means the fix is very often a connector rather than a component, which is worth knowing before anyone quotes you for a board.
What causes it
| Cause | What is actually happening | How likely |
|---|---|---|
| Thermistor wiring open circuit | A broken conductor or a connector that has worked loose reads as infinite resistance, which the board converts to an impossible low temperature. | Common |
| Thermistor shorted | Insulation breakdown or moisture bridging the leads reads as near-zero resistance, which converts to an impossible high temperature. | Common |
| Corrosion at the sensor connector | Sensors sit in the warm damp part of the appliance, and a green crimp shifts the resistance long before it fails outright. | Occasional |
| Board input stage failed | The sensor is fine and the circuit measuring it is not. An engineer establishes this by measuring the thermistor in isolation. | Rare |
Can you fix it yourself?
Stop — this needs an engineer
What it costs to fix
Typical repair cost
£70–£150
Time on site
1 hour
A thermistor is a cheap part and most of the bill is the visit — expect roughly £70 to £150 fitted. If the fault turns out to be a connector rather than the sensor, it is at the lower end.
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
- F17Get it checkedPublished by LG as a problem with the temperature sensor. Their F2 entry covers an unusable reading, so this is the sensor itself being at fault.Related: overheating and cooling
- F5Get it checkedLG call this a Damper Switch Error. A damper is the vent flap on an over-the-range model, so only those appliances can show it.Related: overheating and cooling
- F3Get it checkedLG document this one twice and differently. One article says wipe the touch panel, the other says the control panel is faulty and needs service.Related: same brand
- 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
Own a LG microwave? Save it and its codes come first next time.
Related guides
Common questions about LG F2
The microwave is cold. How can the temperature be out of range?
Because "out of range" describes the reading, not the cavity. A disconnected thermistor reports a temperature colder than any kitchen, and a shorted one reports hotter than any appliance survives. Both are outside the range the board accepts, and a cold appliance producing one is exactly what you would expect.
Is it dangerous to use if it starts?
While F2 is displayed it will not run, which is the appliance being sensible. Do not look for a way around it: the thermal sensing is one of the things standing between a fault and a fire, and an appliance running with it disabled has lost a layer it is designed to have.
How is this different from F17?
LG publish F17 as "a problem with the temperature sensor" without reference to a range. F2 is specifically the reading being unusable. In practice an engineer investigates both at the same connector, but the two entries are LG’s, not interchangeable inventions of ours.
Could it be the fan instead?
Not for this code. An airflow problem produces a real high temperature, which is not what LG’s wording describes. F2 is about the appliance being unable to measure temperature at all.
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.