What does LG Microwave Won't Turn Off - Causes & Fix mean?

Usually a stuck Cancel/Off button or shorted relay on the main control board. Power-cycle the unit and check the control panel first.

How do I fix LG Microwave Won't Turn Off - Causes & Fix?

Work through the step-by-step fix below. Start with the quick reset and the most common cause, then check the specific part this guide points to. Most fixes need only basic hand tools and the right replacement part.

Can I keep using my LG appliance with this error showing?

Usually not. LG appliances show this error when a part or safety circuit is out of range, so running it can stop the cycle or make the problem worse. Diagnose and clear the error before normal use.

What part is most commonly replaced for LG Microwave Won't Turn Off - Causes & Fix?

The parts that most often fix LG Microwave Won't Turn Off - Causes & Fix are listed in the parts section of this guide. Match the part to your exact model and serial number before you buy.

Is LG Microwave Won't Turn Off - Causes & Fix a DIY repair or do I need a technician?

Many fixes are DIY-friendly with basic tools, such as door switches, drain pumps, water inlet valves, thermostats, heating elements, and filters. Sealed-system, refrigerant, gas, or high-voltage work should go to a licensed technician for safety.

LG Microwave Won't Turn Off - Causes & Fix

LG Microwave Won’t Turn Off — What’s Happening

When your LG microwave won’t turn off, the unit continues to run even after you press the Cancel or Stop button, or the controls appear completely unresponsive. This is a symptom, not a specific error code. The most common causes are a failed Cancel/Off key on the touchpad, a defective user control board that isn’t sending the shutdown signal, or a shorted relay or triac on the main control board that keeps power flowing to the magnetron, fan, light, or turntable even when the command has been issued to stop.

Sometimes what looks like a “won’t turn off” condition is actually the control lock (LOC on the display) or a door-latch fault (DOOR on the display). If you see LOC, the oven is simply locked and needs to be unlocked by holding Stop/Clear until the indicator clears. If you see DOOR, the microwave thinks the door isn’t properly closed or latched. True “won’t turn off” failures almost always trace back to the control boards or the Cancel button itself.

Jump to Fix

Most Likely Causes

Stuck or failed Cancel/Off button The touchpad membrane or the Cancel key itself has failed and no longer sends the stop command to the control board.
Shorted relay or triac on the main control board A relay or triac that controls the magnetron, fan, or other loads has shorted closed, keeping those circuits energized even after the controls signal off.
Defective user control and display board The control panel board has failed and cannot process or transmit the shutdown command when you press Cancel.
Control lock accidentally engaged The control lock (LOC) has been turned on, making the oven appear unresponsive until you hold Stop/Clear to unlock it.
Door switch or interlock fault A defective door safety switch or latch problem can prevent the microwave from recognizing a proper shutdown or door-closed state, sometimes shown as DOOR on the display.

How to Diagnose and Fix

Confirm the symptom by checking whether the microwave is actually running (fan, light, turntable, or cooking) or whether the display shows LOC or DOOR.
If LOC is displayed, press and hold the Stop/Clear button until the LOC indicator disappears to unlock the controls.
Unplug the microwave for 2 to 3 minutes to perform a hard reset, then plug it back in and test the Cancel/Off button.
Press the Cancel/Off button several times and verify that it clicks and responds normally, if it feels sticky or does not register, suspect the user control and display board or keypad membrane.
Open and close the door firmly several times, clean around the door seal and latch area, and confirm the door latches securely without gaps or resistance.
If the unit still runs after pressing Cancel, unplug it, remove the outer cabinet, and inspect the main control board for visible signs of arcing, burned relays, or shorted triacs.
Use a multimeter to test continuity across each door safety switch with the door closed, replacing any switch that does not show continuity.
If the keypad works but loads remain energized, replace the main control board, if the keypad does not respond at all, replace the user control and display board.

Parts You Might Need

Part	Notes
Main control board	Amazon \| Controls all microwave functions, replace if relays or triacs are shorted and loads stay on after shutdown.
User control and display board	Amazon \| The touchpad and interface assembly, replace if the Cancel/Off button does not respond or send the stop command.
Door interlock switch	Amazon \| Safety switches that detect door closure, replace any that fail the continuity test with the door closed.

If your appliance also shows a code on the display, these match this problem:

When to Call a Pro

Call a professional if you are uncomfortable working inside a microwave, which retains high voltage even when unplugged. The magnetron capacitor can hold a lethal charge and must be safely discharged before any internal work. If you have performed a hard reset, confirmed the control lock is off, tested the door latch, and the unit still will not shut down, a technician with a multimeter and proper safety training should diagnose the control boards and door interlocks. If the main board has shorted relays or the touchpad is embedded in a sealed control assembly, professional replacement is the fastest and safest route.