LG Microwave Error Codes Explained

If your LG microwave suddenly flashes an error code, it can be confusing. Just think of these codes as your microwave’s built-in way of telling you what’s wrong. Much better than something not working without any indication as to what’s wrong. 

Some error codes are quick fixes that you can handle yourself, while others indicate electrical problems that should only be addressed by a professional, especially for an appliance like a microwave.

By the end of this guide, you should be able to distinguish between error codes that are safe to fix (and how to fix them) and those that should be left to a professional.

Why do LG Microwave Error Codes Exist/

Modern LG microwaves constantly monitor internal conditions through sensors. These include door switches, temperature sensors, humidity sensors, control boards, and voltage monitoring systems.

If any reading falls outside of its normal range, the microwave immediately stops operating and displays an error code. This serves three purposes:

1. Protects safety – Shuts down before unsafe operation.
2. Prevents damage – Stops components from overheating or shorting out.
3. Speeds diagnosis – Gives both homeowners and technicians a shortcut to the underlying problem.

Understanding these codes is the first step to solving them quickly.

Error Codes You Can Fix Yourself

Not every error means a costly repair. Some codes are more like alerts and can be cleared with simple steps. These are the most common DIY-fixable LG microwave error codes.

LOC – Control Lock Active

This isn’t a malfunction. LOC is the built-in child lock feature that prevents accidental use.

How to fix it:

1. Press and hold the Stop/Clear button for 3–5 seconds until the code disappears.
2. If it doesn’t clear, unplug the microwave for 60 seconds, then plug it back in.
3. If LOC reappears right away, check if a keypad button is stuck. Wipe the keypad with a soft, damp cloth and try again

12H / 24H – Clock Needs Reset

These appear when the microwave loses power and the clock hasn’t been set.

How to fix it:

1. Open the microwave door
2. Press the Clock or Time button
3. Choose 12-hour or 24-hour display
4. Use the +/– keys to set the correct time
5. Press Start to confirm

Note: If power outages are frequent in your area, consider plugging the microwave into a surge protector with a battery backup. This helps keep settings intact.

DOOR – Door Not Closed Properly

The microwave isn’t detecting a secure door latch.

How to fix it:

1. Make sure no trays, packaging, or racks are blocking the door.
2. Wipe the door latch and sealing area with a soft cloth, as crumbs or grease can prevent a tight seal.
3. Open and firmly close the door a few times to reset the latch.
4. If the error persists, the latch switch may be faulty and require professional replacement.

LG Microwave Error Codes That Require Professional Help

Some LG microwave error codes indicate more severe electrical or sensor issues. These involve high-voltage parts such as the magnetron, inverter, or control board. Attempting DIY repairs on these components is unsafe and can void your warranty.

Here are the most common service-level error codes:

E10 – Control Board Short

May clear temporarily with a reset, but recurring errors indicate the board needs replacement.

F1 – Mainboard Failure

The microwave’s “brain” has stopped working. Replacement is the only fix.

F2 – Thermistor Error

The temperature sensor is reading out of range. Requires a new sensor.

F3 – Control Panel Malfunction

Buttons may stop responding or register incorrect inputs. Usually solved by replacing the keypad or panel.

F4 – Humidity Sensor Fault

Disrupts automatic cooking modes. Needs technician testing and sensor replacement.

F5 – Damper Switch Error

Found in models with ventilation systems. May involve switch replacement or alignment.

F11 – Inverter Communication Error

Affects power delivery. Requires specialized electrical repair.

F13 / F14 / F15 – Voltage Irregularities

Caused by unstable power supply or internal circuitry issues. It can also indicate problems with household wiring.

F16 / F17 / F19 – Heating-Related Errors

Linked to magnetron or heating system faults. All require professional service due to high-voltage risks.

When you see one of these codes, stop using the microwave and schedule service with a certified appliance repair technician. 

Troubleshooting Steps Before Calling for a Technician

Even when a code suggests professional repair, you can still try a few safe steps before making the call:

1. Power Cycle the Microwave

Unplug it for at least 60 seconds, then plug it back in. This often clears temporary glitches.

2. Check Ventilation

Make sure the vents on the microwave aren’t blocked. Poor airflow can trigger overheating codes.

3. Clean the Keypad and Door Area

Grease or steam residue can interfere with door sensors and buttons. Wipe down the control panel and door edges with a soft cloth.

If the error continues after these checks, it’s time to stop troubleshooting and call a pro.

Why You Shouldn’t Attempt Internal Repairs

Microwaves are different from most appliances because they contain components that can remain dangerous even when unplugged. The capacitor, magnetron, and inverter circuitry can store a charge powerful enough to cause severe injury or worse.

That’s why LG and repair experts strongly warn against DIY repairs involving internal components. Homeowners should focus only on resets, cleaning, and documenting error details. Anything beyond that belongs in the hands of a trained technician.

Documenting the Error for Faster Service

If you need professional repair, writing down the details helps speed up diagnosis. Make a note of:

• The exact code (e.g., “F3”).
• What the microwave was doing when the error appeared (heating, defrosting, idle).
• Any unusual smells, noises, or behaviors.
• Whether the issue happens once, occasionally, or every use.

This information is also helpful when checking warranty coverage.

Warranty and Service Considerations

Many LG microwaves come with manufacturer warranties that cover control boards, sensors, and magnetrons for a set number of years. If your appliance is relatively new, check your warranty before paying for repairs.

Attempting to open the microwave’s case yourself can void this coverage. Always contact LG support or an authorized service technician first when an error involves internal components.

The Bottom Line

LG microwave error codes aren’t random. These error codes are designed to guide you toward the correct fix. Some, like LOC, 12H, and DOOR, are easy to clear yourself with a few button presses or a quick cleaning. Others, such as F1, E10, or F16, indicate serious electrical problems that should only be addressed by a professional.

By learning what the codes mean, applying the safe DIY fixes first, and documenting the rest for service, you’ll save time and avoid unnecessary frustration. With the right approach, your LG microwave can be back to working order quickly and safely.