LG Range F5 Error: Relay board failure
LG range error — here’s what you need to know. The F5 error code on your LG range indicates relay board failure. This is a High severity issue. What Does F5 Mean on an LG Range? The F5 error code indicates that the relay board — the board responsible for switching power to the bake […]
~45%
DIY Fixable
From 80
Typical Repair Cost
60–120 min
Pro Repair Time
Quick Assessment
Answer to continue safely
Is it safe to keep using?
No. A failed relay board can cause elements to remain on or fail to shut off, creating a fire or overheating hazard. Do not use the oven until F5 is resolved.
Can I reset the code?
Yes. F5 indicates a hardware failure that cannot be resolved by resetting power. The faulty component must be identified and replaced.
When to stop immediately?
Stop if you notice: Stop immediately if you smell burning from behind the range panel., Stop if you see burn marks or charring on any board or wiring inside the range..
Symptoms You May Notice
Oven elements do not heat despite the display showing active cooking
The control panel appears to accept settings and the timer runs, but the bake or broil element never energizes because the relay board cannot switch power.
F5 fault code displayed
The range shows F5 on the display and locks out oven heating functions; the code may appear immediately at startup or after attempting to start the oven.
Burning smell from the control area
A failed relay with welded contacts can cause one element to remain on continuously, potentially causing overheating detected by smell before the code appears.
Intermittent or unresponsive controls
Buttons or display elements stop responding, flicker, or behave erratically because signals between the control boards are disrupted or corrupted.
Possible Causes
Failed relay board (burned or welded relay contacts)
The relays on the board have worn out from repeated high-current switching, either failing open (no power to element) or welding closed (element stays on).
Requires ProfessionalDamaged communication wiring between boards
The ribbon cable or wiring harness linking the EOC board to the relay board has a break or loose connector, preventing proper command signals from reaching the relay board.
DIY PossibleFaulty electronic oven control (EOC) board
The main EOC board has failed and is generating a false F5 code or is unable to communicate with an otherwise functioning relay board.
Requires ProfessionalSafe Checks You Can Do
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1
Disconnect power and check board connectors
Unplug the range completely. Access the rear panel and locate the relay board. Check that all wiring harness connectors are fully seated and free of corrosion or burn marks.
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2
Inspect relay board for visible damage
With power off, look at the relay board under good lighting for any relays with discolored housing, burn marks on the PCB, or swollen components indicating a failure.
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3
Power cycle and note when F5 appears
Restore power and note whether F5 appears immediately at startup or only after attempting to use the oven. An immediate F5 at startup suggests a communication or board fault; F5 only when baking suggests a relay switching failure.
When to Call a Professional
Contact a qualified technician if:
- Relay board shows visible burn damage or welded contacts.
- F5 persists after replacing the relay board.
- EOC board fault is confirmed as the root cause.
Need Professional Help?
Find qualified technicians in your area for proper diagnostics and repair.
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