LG Oven F9 Error Code: Oven Not Heating During Preheat (Meaning, Causes, Fixes)

What the code means

LG's help article on the F-9 code says the electric range shows F9 when "the oven failed to heat up to 150°F after five minutes of preheating." LG USA's Range Error Codes List describes F9 as the upper oven not heating properly, and lists F19 as the matching oven-heating error (the lower oven on double-oven models). On a gas range the same code points at the bake burner not lighting or not staying lit, and LG's gas-range heating guide notes that if the hot surface igniter doesn't work, the oven won't heat and an error code appears. F9 is a heating code, not a sensor code: LG uses F1, F2, F4 and F5 for oven sensor faults and F10 and F20 for door lock failures.

Likely causes

• A temporary control glitch that a power reset clears (LG's first suggestion)
• A tripped or half-tripped circuit breaker, so the oven element gets no 240 V while the display still lights
• Electric ranges: a burned-out or shorted bake element (LG lists a short-circuited element)
• Electric ranges: a defective relay board or relay connector, which LG also names as possible causes
• Gas ranges: the gas supply or the range's pressure regulator turned off, often after the range was moved
• Gas ranges: a weak or failed hot surface igniter, so the bake burner never lights
• Using the oven with the door open, which LG says delays or restarts the cycle as heat is lost

Safe DIY checks

1. Press CLEAR/OFF (or turn the oven mode knob to Off) to stop the beeping and clear the code, then try the cooking mode again.
2. If F9 comes back, reset the range: unplug it or switch its circuit breaker off. LG's US list says wait 30 seconds; LG's F-9 article says leave it off for 3 to 5 minutes. Waiting the longer time covers both.
3. Check the breaker panel. Electric LG ranges need a dedicated 40 to 50 amp double-pole breaker; gas ranges need a 15 to 20 amp 120 V circuit. Plug the range in directly, never through an extension cord.
4. Gas range: if the range was recently pulled out, make sure the house gas shut-off valve and the pressure regulator on the range are both open (your owner's manual shows where the regulator is).
5. Gas range: start a bake cycle and look through the window or the floor vent. LG says the igniter should glow red for about 30 to 60 seconds before the burner lights. Don't remove panels or touch gas parts yourself.
6. Keep the door closed while preheating, and confirm the temperature setting by pressing START (LG cancels an unconfirmed change after 25 seconds).
7. If F9 still returns after the reset, write down the code and model number and request service. LG's F-9 article says that if the code persists, a technician is needed.

Parts that commonly fix it

Always match the part number to your exact model.

Related codes

• F2 GE Oven F2
• C-F2 Samsung Oven C-F2
• AE LG Dishwasher AE
• D80 LG Dryer D80
• D90 LG Dryer D90
• FF LG Refrigerator FF

All LG codes →

Sources

1. LG Canada Help Library: Electric Range "F-9" error code (oven failed to reach 150°F after 5 minutes of preheat; causes; 3 to 5 minute reset)
2. LG USA Help Library: LG Range - Error Codes List (F9 upper oven not heating properly, F19 oven heating error; CLEAR/OFF and 30-second breaker reset)
3. LG USA Help Library: Oven Not Heating - Gas Ranges (gas valve and regulator, igniter glows 30 to 60 seconds, 15 to 20 amp circuit, door open)
4. LG USA Help Library: Electric Range / Gas Range Oven Power Issues (40 to 50 amp electric circuit, START confirmation, lockout)