LG Oven F9 Error
What it means
F9 means the oven is not heating properly — specifically, the oven failed to reach about 150°F (65°C) within roughly 5 minutes of being turned on. LG's control board watches the temperature climb during preheat, and if it doesn't rise fast enough the board reports F9 and stops heating as a safety measure. A quick reset clears glitches, but if it returns the fault usually points to a heating component or the control board rather than something you set wrong.
The bottom line on the F9 error
F9 means the oven could not reach about 150°F within five minutes, so the board shut off the heat for safety. A reset clears a one-time glitch, but a recurring F9 usually means a faulty relay board — or a weak igniter on gas models — which is not a safe DIY repair.
The one safe move is a reset: press CLEAR/OFF, then cut the breaker for 30 seconds. If it returns, stop and call LG Support or a qualified technician, since the fix means live electrical or gas work worth $150 to $400.
F9 snapshot
A recurring F9 means live electrical — or gas igniter — work; cut the breaker (and shut off the gas on gas models) and have a qualified technician handle it rather than DIY.
Our own at-a-glance triage of the F9 error, from the verified data on this page. See error-code rankings → · How we score →
Common causes of the F9 error
- Temporary control glitch that a reset will clear
- Faulty relay board (the most common hardware cause)
- Failed bake or broil heating element (electric models)
- Weak or failed igniter that won't reach ignition temperature (gas models)
- Defective oven temperature sensor (thermistor)
- Loose or damaged wiring between the sensor, element, and control board
Which LG ovens get the F9 error
F9 appears across LG electric and gas ranges and wall ovens with an electronic control board, including many LRE/LSE (electric), LRG/LSG (gas), and LWS/LWD wall-oven series from roughly 2010 onward. Because it is a generic heating-timeout fault rather than a model-specific defect, almost any modern LG oven can display it when a heating component or the relay board fails.
How to fix the LG Oven F9 error
- 1Press CLEAR/OFF and retryPress the CLEAR/OFF key to cancel, then start the same cooking function again. A one-time glitch often clears here.
- 2Power-cycle at the breakerIf the code returns, switch the oven's circuit breaker off, wait about 30 seconds, and turn it back on. This fully resets the control board.
- 3Confirm the oven actually warmsAfter resetting, set a normal bake temperature and check whether the oven begins to heat at all within a few minutes. If it stays cold, a heating component is likely at fault and needs service.
🧰 When to call a professional
If F9 reappears after pressing CLEAR/OFF and power-cycling the breaker, the unit requires service. Diagnosing and replacing the relay board, heating element, igniter, or temperature sensor involves live electrical (or gas) connections and disassembly, so schedule a repair through LG Support or a qualified appliance technician rather than attempting it yourself.
LG F9 vs GE F2 vs Whirlpool F2: how they compare
How this code stacks up against related error codes for difficulty, urgency, and cost.
| LG F9 | GE F2 | Whirlpool F2 | |
|---|---|---|---|
| DIY difficulty (1–5) | 5 | 4 | 5 |
| Urgency (1–5) | 4 | 5 | 5 |
| Typical cost | $$ | $$ | $$ |
How much does it cost to fix the F9 error?
| DIY reset (glitch only) | $0 |
| Temperature sensor (part) | $20–$50 |
| Bake/broil element or gas igniter (part) | $30–$100 |
| Relay board (part) | $50–$180 |
| Professional diagnosis + repair (parts + labor) | $150–$400 |
Repair or replace?
If a reset and breaker power-cycle clear F9 for good, the cost is $0 and there is nothing to replace. When the code returns, the fix is almost always a single part — a relay board, heating element, igniter, or temperature sensor — and a professional repair in the $150–$400 range is well worth it on an oven under about 10 years old. Only if the oven is older and the control board plus a heating component both need replacing (pushing the bill past roughly half the price of a new range, which starts around $600–$900) does replacement start to make more sense. Prices vary by model and region.
Common replacement parts for the F9 error
| Relay (PCB) control board | $50–$180 | Most common hardware cause; must be tested and replaced by a technician. | |
| Bake/broil heating element | $30–$70 | Electric models — if the element is visibly broken or does not glow. | |
| Oven igniter | $40–$100 | Gas models — if the igniter is weak, discolored, or will not glow brightly. | |
| Oven temperature sensor (thermistor) | $20–$50 | If the sensor reads incorrectly and the board never sees the temperature rise. |
Prices are typical retail ranges and vary by model and supplier — always confirm the exact part number for your appliance before buying. We are not linking parts for this code on purpose: it is a job for a qualified technician, and the right fix here starts with a diagnosis, not a purchase.
LG F9 error — FAQ
＋ − What does the F9 code mean on an LG oven?
F9 means the oven is not heating properly — it did not reach about 150°F within roughly 5 minutes, so the control board stopped heating as a safety measure.
＋ − How do I reset the F9 error?
Press CLEAR/OFF and try the function again. If it returns, turn the oven's circuit breaker off for 30 seconds, then back on to reset the control board.
＋ − Why does F9 keep coming back?
A recurring F9 usually points to hardware — most often a faulty relay board, but also a failed heating element, igniter, or temperature sensor. These require professional service.
＋ − Is it safe to keep using the oven with an F9 error?
No. F9 means the oven stopped heating on purpose because it could not reach a safe temperature in time. Repeatedly forcing it to run risks a stuck relay or element overheating, so leave it off until the fault is diagnosed.
＋ − Is F9 the same on gas and electric LG ovens?
The code means the same thing on both — the oven did not heat quickly enough — but the likely part differs. On electric models it is usually the relay board or bake element; on gas models a weak igniter that will not reach ignition temperature is the most common culprit.
Sources & manufacturer references
This guide is independently written and not affiliated with LG. Always unplug appliances before servicing and follow your model's manual. Error codes and steps can vary by model — when in doubt, consult a qualified technician.