- Appliances
- Ovens
F9
LG F9 on an oven: upper oven not heating properly
Risk level
Medium
Proceed carefully and stop if the check is unclear.
Urgency
Medium
Quick answer
On an LG range, F9 means the upper oven is not heating properly. Press CLEAR/OFF and try again; if it stays, switch the breaker off for 30 seconds and, if it returns, book service.
Safety first
Stop and check this first
- Burn risk: the oven can be very hot even with a fault showing. Do not reach in to feel for heat and use oven gloves.
- Do not remove the back panel or oven floor to check elements or wiring: there is mains voltage inside and it is the technician's job.
Safe checks you can perform
- CLEAR/OFF key and a 30 second cut
- How the oven heats
- Lower oven and cooktop
Leave these tasks to a qualified professional
- Do not attempt this professional task: Measurement of the heat sources
- Do not attempt this professional task: Sensor check and heating test
What a technician must be able to justify
Technician visit
These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.
These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.
Measurement of the heat sources
What they doWith the range disconnected from the mains, the technician measures the upper oven elements with a multimeter and checks their supply against LG's wiring diagram.
They must show youthe measured values against the manufacturer's specification.
In writingthe measurements, any part replaced with its reference and the reason.
Sensor check and heating test
What they doThe technician checks the temperature sensor and runs a full cycle measuring the temperature reached.
They must show youthe full test cycle without F9.
In writingthe temperature reached, the time and the result.
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Follow these steps
Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.
CLEAR/OFF key and a 30 second cut
- Who:
- you, at the control panel and the breaker panel.
- How:
- press CLEAR/OFF and try the function again. If F9 returns, switch off the range's circuit breaker, wait 30 seconds and switch it back on, as LG advises.
- Result that matters:
- whether F9 returns after the cut.
- If it does not:
- it was a one-off; note when it happened.
- If it does:
- LG says the unit will require service.
- Evidence to keep:
- photo of the code and a note of each attempt.
Evidence: LG Range - Error Codes List
How the oven heats
- Who:
- you, opening nothing but the door.
- How:
- set a bake at a medium temperature and, without touching the inside, notice whether hot air comes out when you open the door for a few seconds and how long until the code shows.
- Result that matters:
- whether the oven does not heat, heats weakly or heats but still shows the code.
- If no heat or very little:
- note it; it points the technician to the heat sources and their supply.
- If it heats normally and F9 still shows:
- note it; it points to the temperature reading.
- Evidence to keep:
- note of the set temperature and the time to the code.
Evidence: LG Range - Error Codes List
Lower oven and cooktop
- Who:
- you, no tools.
- How:
- if your range has a lower oven or a cooktop, check whether they work normally.
- Result that matters:
- whether the problem is limited to the upper oven.
- If only the upper oven fails:
- fits what F9 describes.
- If other parts fail too:
- tell the technician; there may be a general supply problem.
- Evidence to keep:
- note of what works and what does not.
Evidence: LG Range - Error Codes List
Still not solved
If the error persists, stop here. See what the technician must do and show you.
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- Appliances
- Brand
- LG
- Product type
- Ovens
Known code variants
- cocina LG F9
- F-9
- LG F-9 horno
- LG F9 error oven
- LG F9 horno
- LG horno F9 no calienta
- LG oven F-9
- LG oven F9 not heating
- LG range F9
- microondas Whirlpool F9 placa
- Whirlpool F9 over the range
- Whirlpool microondas F9
- Whirlpool microwave F9
- Whirlpool microwave F9 control board
- Whirlpool over the range F9
What it means
LG defines F9 as the upper oven not heating properly. The control compares the temperature it should reach with the one it measures and warns when it does not rise as expected. The bake or broil elements or burners, the temperature sensor, the power supply or the control can all be involved, and the code does not say which. LG says to press CLEAR/OFF, retry and, if it persists, cut the breaker for 30 seconds; if it still returns, the unit needs service. The table is LG's US range error code list; check your model's manual to confirm the code means the same.
Warnings and stop conditions
- Mediumeditorial warning
Burn risk: the oven can be very hot even with a fault showing. Do not reach in to feel for heat and use oven gloves.
Evidence: LG Range - Error Codes List
- Mediumeditorial warning
Do not remove the back panel or oven floor to check elements or wiring: there is mains voltage inside and it is the technician's job.
Evidence: LG Range - Error Codes List
Symptoms and causes
Probable causes · in order
- One-off cycle faultPossible
Fits if F9 clears after CLEAR/OFF or the 30 second cut and the oven heats normally again.
Evidence: LG Range - Error Codes List
- Heat source not deliveringPossible
Fits if the oven is very slow or never reaches temperature and F9 returns every time. The technician confirms it by measuring, not the code.
Evidence: LG Range - Error Codes List
- Temperature reading or controlPossible
Fits if the oven does heat but F9 still appears; the sensor or control may be misreading, which service checks.
Evidence: LG Range - Error Codes List
Virtual technician
Does F9 still appear after these checks?
Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.
Sources and technical references
- 1
LG · 2026 · official_doc
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