LG Oven F9 error code: What it means and how to fix it

It's a Monday evening, and you're planning to heat a frozen casserole for dinner. You turn on your LG® oven and set it to preheat to 350°F. A few minutes later, an F9 error message appears on the display. What does that mean—and can you fix it?

Asurion Experts keep your home devices running smoothly. Whether you're experiencing problems with LG appliances or need advice on oven overheating issues, we have a solution. Use our tips to resolve an LG oven F9 error yourself or know when to call for help. 

What the LG oven F9 error code means

An LG oven displays an error code whenever it detects a fault in the device. The codes start with an F followed by a number, such as F1 or F3. The F9 error code on gas or electric LG ovens indicates your appliance failed to heat above 150°F within five minutes. 

Common culprits behind the F9 error that can cause LG oven heating issues include:

• Short circuits in the heating element
• Defective relay connector 
• Damaged relay printed circuit board
• Electrical faults

The F9 error usually warrants a service call to a qualified technician. However, if it's caused by a temporary glitch, a reset may be enough to clear the error and return the oven to a working state. 

How to fix error code F9 on an LG oven

Troubleshooting LG oven errors may not be something you do every day, but that's okay. It's easy to diagnose common problems, even if you don't have an electrician's expertise.

Turn off the error

The F9 error triggers the oven to emit a beeping sound. To stop the beeping and return the display to normal, press the Clear/Off button. 

Reset the oven

1. Unplug the LG oven from the wall outlet. 
2. If the plug isn't immediately accessible, flip the circuit breaker to the appliance off. 
3. Wait five minutes before restoring the power source. 
4. Try preheating the oven to see if the error reoccurs. 

Check the wiring

Turn off the power to the LG oven by unplugging it from the wall outlet or flipping its circuit breaker. Pull the appliance away from the wall so you can reach and remove the back panel. Using a multimeter, check the wiring to the relay board for continuity. Follow these steps:

1. Turn the dial on the multimeter to the Continuity setting. It may resemble a diode or sound waves. 
2. Touch the multimeter's black terminal to the oven's metal frame.
3. Press the multimeter's red terminal against the relay board's wire.
4. Wait for the multimeter to display a result. 

A result of zero indicates perfect continuity, while anything less than one indicates average continuity. If the multimeter registers a value over one, the relay board may require replacing. Check the LG oven's manual to see if it lists an optimal level of resistance for the part. 

Test the temperature sensor

The thermostat may fail if you use the oven at high temperatures for extended periods, such as during a self-cleaning oven cycle. Look for the thermostat in the back panel area. If it appears melted, you'll need to replace it. 

Also, check the thermal fuse for continuity. You'll find it next to the thermostat. 

1. Turn the dial on the multimeter to the Continuity setting. It may resemble a diode or sound waves. 
2. Press the multimeter's black terminal against the oven's metal frame.
3. Press the multimeter's red terminal against the thermal fuse wire.
4. Wait for the multimeter to display a result. 

Levels below one indicate adequate continuity. If the level exceeds one, you may need to replace the heating element. Consult the user's manual to see if it lists a recommended level of resistance. 

When to call a professional

If the relay board, thermostat, or thermal fuse fails the troubleshooting tests, seek help from a qualified service technician. Fixing an oven yourself may void your warranty or damage the device. 

FAQs

How do I fix error code F9?

Resetting the LG oven will clear the error. To initiate a reset, turn off the appliance's circuit breaker. Wait five minutes before restoring power. Then, try heating the oven again to see if the error reappears.

Is the F9 error dangerous?

It's not dangerous, but an F9 error can prevent you from using your LG oven. Get help from a trusted Asurion expert who can identify and replace faulty oven components.

Can I still use my oven if it shows the F9 code?

The F9 code indicates that your oven can't warm above 150°F. It may have no heating ability whatsoever, and you may be unable to use the device until it's repaired.