How To Fix LG Gas/Electric Oven F9 Error Code

lg oven f9 error code

When your LG oven suddenly fails to heat and cook your food, displaying a cryptic “F9” on its display screen, it can be immensely frustrating and concerning.

However, do not despair—this error code, while preventing you from using your oven, points to definable issues that can likely be corrected with some targeted troubleshooting.

Essentially, the F9 code conveys that during the oven’s important preheating process, where it brings itself up to the desired cooking temperature, adequate heating failed to occur.

This signifies inner components involved in heat generation or regulation could be malfunctioning.

By calmly investigating several oven components and functions that commonly falter, triggering the F9 code, you should be able to pinpoint the true issue.

We will walk through checks involving elements like igniters, gas valves, etc.

What Does F9 Mean on a Stove?

The F9 error code is a common problem with gas and electric ovens. This error code typically indicates a failure to properly regulate and maintain baking temperatures.

On LG gas oven models, the F9 code means that the oven was unable to exceed 150°F degrees after the initial 5-minute preheating sequence.

On LG electric ovens, the F9 code could signal issues with components like the temperature sensor, relay control board, thermostat, or damaged heating elements – all causing irregular heat patterns.

 Basically, for both gas and electric models, the F9 code implies that the oven is not getting hot enough, fast enough due to problems with parts or components that are crucial for safe, consistent heating.  

If the F9 error code is not quickly addressed, it poses safety and operational risks. For example, gas ovens may have dangerous gas leaks leading to fire hazards and explosions.

While the electric models can short circuit due to overheating elements, and can also lead to fire hazards as well. In addition, the oven circuitry and heating components could be further damaged, requiring expensive repairs down the line.

How to Fix the F9 Error Code LG Gas Oven

Seeing that intimidating F9 show up on your LG gas oven display may feel unsettling but have hope this is a common code that can typically be resolved with some simple troubleshooting. Before you call that repair person (qualified technician), try a little DIY repair magic.

Think of an F9 error as your oven crying wolf – it’s saying there’s not enough heat, but it’s likely just a spark or gas flow issue, not a major failure. With a few handyperson tricks up your sleeve, you can coax more life out of this appliance and avoid an expensive visit from a technician.

Rule number one is always to disarm before you dive in: switch off breakers and gas valves so you have a safe workspace.

Have you done that? Then it’s detective time!

1. Inspect the Igniter

The igniter is responsible for sparking and lighting the gas burner by heating to extremely high temperatures.

To access the igniter, do the following:

  • First, carefully remove the oven door by unlocking the hinge locks and pulling the door straight out.
  • Next, take out all oven racks and clear the oven interior. Then, unscrew and remove the bottom access panel.
  • Detach the burner shield by removing the screws, then lift off the shield to expose the igniter at the back near the burner.
  • Inspect the igniter for any cracks or damage. Use a multimeter to check the igniter resistance, which should normally fall between 40-200 ohms. If outside this range, the igniter will need replacing.

To replace the igniter:

  • First unscrew the mounting screws holding it in place, then disconnect the attached wire connector – you may need to remove the bottom drawer for access.
  • Remove the old igniter and install the new one, tightening the mounting screws firmly.
  • Reconnect the wire connector. Replace the burner shield, access panel and all screws securely.
  • To refit the oven door, slide it back onto the hinges properly then lock it into position. Insert all oven racks.
  • Finally, restore gas supply and electricity before testing operation.

2. Check the Gas Valve

The gas valve controls the flow of gas in the oven. If the gas valve is defective, it can disrupt supply downstream to the igniter and burner.

To check or inspect the gas valve, do the following:

  • Remove the lower back access panel by unscrewing the securing screws.
  • Locate the gas valve near the gas supply lines.
  • Note where the bake and broil wires are connected, then disconnect them.
  • Unthread the nuts securing the gas supply tubes to the valve.
  • Use a multimeter to check the voltage while operating the oven. If the voltage is not present, then you’ll have to replace the gas valve.

To replace your faulty gas valve, continue with the following steps:

  • Remove the screws holding the valve to the back panel and pull the valve away to remove it.
  • Insert the gas supply tubes into the new valve and position it on the mounting tabs.
  • Replace the securing screws and reattach the wire terminals and bake/broil wires correctly.
  • Replace the lower back access panel.
  • Turn the gas supply and power back on. Then test the oven’s functions to ensure proper gas flow.

3. Inspect Relay Board

The relay board controls the voltage for oven components like the igniter. If the relay board gets damaged, it can prevent proper ignition.

To inspect the relay board, do the following:

  • Pull the oven away from the wall to access the back.
  • Remove the screws securing the rear panel and take it off. You should find the relay board at the top right behind the oven.
  • Check the board and attached wiring for visual damage.
  • Use a multimeter to check relays and replace them if found to be faulty.

To replace faulty relay boards, do the following:

  • Disconnect all wiring harnesses attached to the faulty relay board. Remove the mounting screws to detach the old relay.
  • Align and insert the new relay board into the control assembly.
  • Replace the mounting screws to secure it and reconnect all wiring harnesses to the correct terminals.
  • Replace the rear access panel and push the oven back into place.
  • Test oven functions to ensure that the new relay board works properly.

Related: Gas Oven Not Heating: 6 Easy Ways To Fix The Problem Now

How to Fix F9 Error Code LG Electric Oven

If your LG electric oven is displaying an F9 error code, it means that there’s a problem with the oven and that problem has made it unable to reach the target 150°F temperature after 5 minutes of preheating.

As earlier stated, for electric ovens, the F9 error code problem lies within failed heating components. Several components could be responsible, and this section is all about inspecting, replacing, and testing those components.

But before we go on with that, make sure to switch the oven’s circuit breaker off in the main electrical panel and unplug the oven from the wall outlet.

Without further ado, let’s take a look at some of the components that could be behind the F9 error code on your LG electric oven:

1. Inspect the Control Board and Relays 

The control board and relays coordinate the oven’s functionality by communicating the required temperature settings to other components.

To inspect the control board and relays, do the following:

  • Remove the back access panel to expose the boards.
  • Check boards and wiring for burn marks indicating short-circuiting.
  • Use a multimeter to test relays and other control circuits for continuity. If there’s any damaged board, replace them.

To replace the damaged boards and replays in your electric oven, do the following:

  • The control board is located at the top of the oven cavity.
  • Disconnect all wiring harnesses and connectors attached to the old control board.
  • Remove the mounting screws and detach the old board.
  • Align and insert the new board into the oven cavity.
  • Replace the mounting screws to secure it in place & reconnect all wiring harnesses and connectors.

If it’s the relay you need to replace, do these instead:

  • Remove any faulty relays from the control board.
  • Insert new relays of the same type into the correct sockets.

Once you are done, replace the upper access panel and push the oven back into place. Restore the power supply and test the oven to ensure the new control board and relays you installed work properly.

2. Check the Oven Sensor

The oven sensor monitors baking temps. If the oven sensor becomes defective, it can send inaccurate readings to the control board triggering the F9 code.

To check the oven sensor in your LG electric oven, do the following:

  • Pull the oven away from the wall to access the back.
  • Remove the screws from the rear access panel and take it off.
  • Locate the sensor. It is usually found at the back of the oven cavity.
  • Detach the wiring and inspect for damage.
  • Use a multimeter to test for continuity. If it fails the test, you’ll have to replace it.

To replace a faulty oven sensor, do the following:

  • After detaching the wiring, unscrew or loosen any retaining clips or brackets securing the faulty sensor.
  • Pull the old sensor out of the oven cavity.
  • Insert the new sensor into the opening and secure it in place with the retaining clips or screws.
  • Reattach any wiring to the correct sensor terminals.
  • Replace the rear access panel and push the oven back into place.
  • Restore the power supply and test the oven functions to ensure the new sensor works fine.

3. Examine the Heating Element 

The baking/broiling element at the bottom/top of the oven transforms voltage into heat. So, if there are continuity issues, it means that there’ll be no heat.

To inspect the heating element in your electric oven, do the following:

  • Open the oven door fully and lift up the hinge locks to detach the door from the oven.
  • Pull out all oven racks and set them aside.
  • Remove the screws securing the bottom access panel and lift it off.
  • Disconnect the wires from the heating element terminals and unscrew the retaining brackets at the back of the oven cavity.
  • Carefully pull out the heating element before inspecting the element’s wiring and coil visually for hot spots/damage.
  • Use a multimeter to check if the element’s resistance is in the normal range. If it falls off the normal range, then you’ll have to replace it.

To replace a faulty heating element, do the following:

  • Insert the new heating element into the oven cavity opening.
  • Replace the retaining brackets and screws. Reconnect wires to the element terminals.
  • Replace the oven racks and door. Then replace the bottom access panel.
  • Restore the power supply and test to see if the new heating element works properly.

4. Inspect the Thermostat and Thermal Fuse

Oven overheating and self-cleaning malfunctions are capable of damaging components like the thermostat and thermal fuse.

The thermostat and thermal fuse play an important role in regulating temperature. So if they become defective, they can trigger the F9 error code.

To check the thermostat, do the following:

  • Turn the oven power off from the main electrical panel.
  • Remove the rear access panel to locate the thermostat.
  • Detach the wires and metal retaining tab from the thermostat.
  • Visually inspect the thermostat for damage like melting, and use a multimeter to test it for continuity.
  • If it fails the test, you’ll have to replace the faulty thermostat.

To check the thermal fuse, do the following:

  • Similarly, disconnect all power to the oven.
  • Locate the thermal fuse wiring in the rear control panel.
  • Remove the fuse holder and check the fuse continuity using a multimeter.
  • If the fuse is blown, you’ll have to replace it with a new one of equal specs.

After replacing the thermal fuse, you can now test to see if your oven now works correctly.

Related: Electric Oven Not Heating Up: 6 Easy Ways To Fix It Now

How to Reset LG Gas/Electric Oven after Fixing F9 error code

Now that the troubleshooting is done, it’s time to walk you through the proper way to get your oven reset and back in working order:

  • Make sure that the oven and circuit breakers are switched off before resetting.
  • Locate the circuit breaker connected to the oven and switch it all the way to the “Off” position.
  • Unplug the oven from the outlet or switch off if the outlet is hard-wired.
  • Wait for 1-2 minutes before plugging the oven back in or switch the outlet back on. This gives time for the electrical components in your oven to reset.
  • Flip the circuit breaker back to the “On” position.
  • For gas ovens, then the gas valve back to the open/on position.

Now we’ll want to test basic functions.

To test your LG oven, do the following:

  • Set the oven to bake at 350°F and verify it heats up. Use an oven thermometer placed inside to double-check the temperature reading. Good news? Celebrate with cookies!
  • If the oven doesn’t turn on or get up to temp, recheck your repair steps.

One last thing — the oven temp can drift after repairs. Not to worry! Your owner’s manual will walk you through adjusting and calibrating it.

There you have it! With some simple safety checks and reset steps, your LG oven will be back doing what it does best – turning out mouthwatering meals that your family and friends will love.


The LG F9 error code can be frustrating, but resolving it is often straightforward. For gas ovens, inspect the igniter, gas valve, and relay board, replacing any faulty parts.

On electric models, examine the temperature sensor, control board, heating element, thermostat, and thermal fuse.

After replacing damaged components and safely resetting the oven, recalibrate if needed to restore precise baking temps.

With some targeted troubleshooting, you can get your LG oven back up and running for all your cooking needs.

Reference: LG F9 Error Code Support

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