LG Oven Error F9 – Upper Oven Not Heating Properly
LG's control saw the oven temperature rise too slowly after preheat began and shut the heating down.
Safety first · Consult a professional
On a gas range, never keep restarting a burner that won't light, and if you smell gas leave the house and call 911 or the gas utility from outside. Igniter, burner and valve work belongs to a licensed technician. On electric models, turn the breaker off before removing the oven floor or rear cover.
- Gas appliance: no DIY repairs. If you smell gas, leave the building, do not use switches and call your gas utility’s emergency line from outside.
- Carbon monoxide is odorless. Keep a CO alarm near fuel-burning appliances; if it sounds, get everyone outside and call 911.
- Unplug the appliance or switch off the breaker before opening any panel. Mains voltage can kill.
- Hot surfaces and hot water can cause burns. Let the appliance cool down first.
At a glance
Severity: Moderate
- Meaning
- Upper Oven Not Heating Properly
- System
- LG · Oven / Range
- Typical repair cost
- $0–$600
- DIY difficulty
- Moderate
LG lists F9 as 'upper oven is not heating properly' – on single-oven ranges that simply means the main oven. The control checks that the cavity warms by a set amount within the first minutes of preheat (repair documentation puts it at about 150°F within five minutes); if the sensor reading lags, it stops and shows F9. On LG gas ranges, which account for most F9 reports, the bake burner is failing to light or stay lit, usually because the hot-surface igniter has weakened. On electric models the hidden bake element under the oven floor, its relay or the wiring are the suspects. LG's own advice is a Clear/Off and breaker reset, then service if it returns.
How it looks on the display
Model families & display variants
| Model family | Shows | Note |
|---|---|---|
| LG gas and dual-fuel ranges | F9 | Mostly an ignition problem at the bake burner. |
| LG electric and induction ranges | F9 | Hidden bake element, relay or wiring; broil often still works. |
| Some LG displays and manuals | F-9 / F-09 | Same code written with a dash or leading zero. |
| LG double-oven ranges | F9 | Refers to the upper oven; the lower oven has its own separate code. |
Symptoms
- F9 (sometimes shown as F-9 or F-09) a few minutes after starting a bake
- Gas: you hear the igniter circuit but see no blue flame through the floor slots
- Gas: faint gas odor near the oven for a moment after starting
- Electric: oven barely warms, broil may still heat the top
- Preheat takes much longer than it used to before F9 started appearing
Possible causes
Ranked by how often each cause is behind this code (editorial estimate).
- Gas: worn hot-surface igniter not drawing enough current to open the oven valve
- Electric: hidden bake element open or its terminal burned
- Gas: oven safety valve or regulator problem, or gas supply not fully open
- Foil or pans on the oven floor blocking the burner or heat path
- Incomplete propane (LP) conversion leaving the oven burner starved of gas
- Oven sensor or main board relay fault
Fix it step by step
Clear the code the LG way
Press Clear/Off and start the same function again. If F9 returns, turn the breaker off for 30 seconds, restore power and try once more – this is LG's own first step.
Remove foil and liners from the floor
LG manuals warn against covering the oven bottom. Foil or a liner over the floor vents can block the gas flame's air supply or trap heat under the floor on hidden-element models, both of which slow warm-up.
Tools: Gloves
Watch the gas burner light
Take out the oven floor panel if your model allows it, start a bake and watch the igniter at the burner. It should glow bright orange-white, and the burner should light within about a minute. A dull glow with no flame points at the igniter.
Tools: Flashlight
Check supply and LP setup
Confirm the shutoff valve behind the range is fully open. If the range runs on propane, make sure the conversion was completed for the oven burner and regulator, not just the cooktop – a half-converted range lights poorly and gives F9.
Tools: Flashlight
Electric: test the bake element
On LG electric ranges the bake element sits under the oven floor and is reached from the rear access cover with the breaker off. A healthy element reads roughly 15–30 ohms; an open circuit means it must be replaced.
Tools: Multimeter, Screwdriver
Leave gas parts to a technician
If the gas supply is on and the igniter glows without lighting the burner, or the burner lights and then dies, the igniter or valve needs a licensed technician. Mention F9 and the model number when booking so the right parts come along.
How to reset F9
- Press Clear/Off
- If the code returns, turn off the circuit breaker for 30 seconds, then turn it back on
- Start a bake and watch the first minutes; a repeat F9 needs service
Where the parts are
- 1Oven temperature sensor
- 2Heating element
- 3Fan
- 4Door switch
- 5Gas valve
- 6Temperature sensor
Repair options & costs
| Repair | DIY? | Estimated cost |
|---|---|---|
| Remove floor foil / open gas valve | Yes | $0 |
| Bake element on electric model (part only) | Yes | $40–$110 |
| Oven igniter replaced by a technician | No | $180–$350 |
| Finish LP conversion or regulator adjustment (technician) | No | $120–$250 |
| Oven gas safety valve or main board | No | $300–$600 |
Rough US estimates; technician call-out fees vary by region. Not a quote.
When to call a technician
Book LG service or a licensed technician whenever a gas burner fails to light after a reset, if you smell gas, or if an electric element tests good but F9 remains. Propane conversions and regulator adjustments must always be done by a qualified installer.
Frequently asked questions
What does 'upper oven not heating properly' mean on a single oven?
LG uses one code table for all its ranges. On a single-oven model the 'upper oven' is simply the oven, so F9 means the main oven isn't warming as expected.
The igniter glows – why won't my LG gas oven light?
The igniter also acts as the switch for the gas valve. As it ages it can glow but no longer pass enough current to open the valve, so no gas flows and F9 follows.
Can I use the cooktop while the oven shows F9?
Yes, in most cases the cooktop burners are separate and keep working. Just don't keep retrying the oven if it doesn't light.
Could oven liners really cause F9?
They can. LG advises against covering the oven floor, because a liner or foil can block air to the gas burner or hold heat under the floor, and the control then sees the cavity warming too slowly.
Sources
- Official LG user documentation and support pages (facts only; wording is our own)
- Methodology: How We Build Code Pages · Data Sources We Use · Editorial Policy