LG oven code F9: what it means and how to fix it
Your LG range starts to preheat, beeps, then shows F9 before the oven gets hot. This page explains what that code means, what you can safely check first, and what a technician will test if the code comes back.
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LG oven code F9 means the control didn't see the oven get past 150°F within five minutes of preheat, so it stops and shows a no heat fault. The most common cause called out for this fault is a failed relay board, though gas models very often turn out to have a weak bake igniter that still glows.
Check these first
Safe to do yourself. Unplug the appliance before you start.
- Clear the code once
Press Clear/Off, then try Bake again. If the code was a one-time control error after a power blink, the oven may start normally.
- Do one power reset
Turn the range off at the breaker or unplug it for 3 to 5 minutes, then power it back up. LG lists this reset as a way to clear stored charge in the control, but if F9 returns, treat it as a real heating fault.
- For a gas range, check the shutoff valve
Make sure the gas valve handle is lined up with the pipe. If it's turned across the pipe, the oven burner won't get gas, even though the display and cooktop ignition may seem normal.
- Watch what happens at preheat
On a gas oven, look through the window if possible: a weak igniter may glow for a long time without flame. On an electric oven, note whether the oven stays cold while the display acts normal, since that points toward the bake circuit rather than the keypad.
- Check the door and vent area
Make sure the door closes flat and nothing is blocking the oven vent. A bad seal or blocked vent is less common than an igniter, element, sensor, or board fault, but it's easy to rule out without opening the range.
Conditions that make this more likely
Boards fail earlier in hot rooms
Electronics are rated for room temperature. In a garage or an unconditioned laundry room in summer, a control board can sit well above that for hours a day. Before replacing a board, a good technician confirms the parts it controls test good, since a shorted pump or valve can take out a new board too.
Check both breakers
Electric dryers and ranges run on a double 240V breaker. If only one leg trips, the drum can spin or the display can light with no heat. Reset both halves before assuming the appliance has failed.
What a technician tests
Most likely part first. These are for a technician with a meter and the tech sheet, not a weekend project.
Don't see your symptom?
Describe it on the phone. The company on the other end works on these every day and will know what to ask.
Common questions about appliance repair
Can I reset an LG oven code F9?
Yes. Press Clear/Off, then remove power for 3 to 5 minutes. If F9 comes back during preheat, the oven has a heat failure that needs testing.
Does F9 mean the control board is bad?
It can, especially if the relay board isn't sending power to the heat circuit. Still, a weak gas igniter or failed electric element can look the same from the control's point of view.
Why does my gas igniter glow but the oven never lights?
That is a classic weak igniter symptom. The igniter has to pull enough current before the safety valve opens, so a worn igniter can glow and still fail the bake cycle.
Is F9 different on gas and electric LG ranges?
The code means the same thing: the oven didn't pass the 150°F preheat check in time. The likely parts differ, with gas models often pointing to the bake igniter and electric models pointing more toward the relay board, element, or sensor.
Can I keep using the cooktop if the oven shows F9?
Usually the cooktop is a separate function, but stop using the oven until the fault is found. If you smell gas, turn the oven off, shut the gas valve if you can do so safely, and arrange service.
Still showing the problem after the checks?
Call and describe what you tried. You'll be connected with an independent repair company near you.