P04
LG Smart TV
Severity: CriticalWhat Does This Error Mean?
P04 on an LG TV signals a backlight inverter or LED array failure. The screen may appear completely dark or flicker badly even though the TV is powered on. This is a hardware fault that requires professional repair — it cannot be resolved through software or settings.
Affected Models
- LG OLED C3
- LG QNED85
- LG UHD 75UP8770
- LG NanoCell 90
- LG OLED evo G3
Common Causes
- LED backlight array has partially or fully failed due to age or a power surge
- Backlight inverter board has burned out and is no longer driving the LEDs
- Loose or damaged ribbon cable connecting the inverter to the LED strips
- One failed LED in a series strip has caused the entire strip to go dark
- Power surge has damaged the inverter stage on the power board
How to Fix It
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Shine a flashlight directly at the screen in a dark room while the TV is on.
If you can faintly see the picture under the flashlight, the panel itself is fine — only the backlight has failed, which confirms P04.
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Unplug the TV from the wall socket and leave it unplugged for 60 seconds.
A power cycle occasionally clears a temporary inverter fault caused by a voltage spike — it is worth trying before calling a technician.
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Plug the TV back in and power it on — check if the picture is now visible.
If the screen is still dark or still flickering after the power cycle, the fault is hardware and will not self-resolve.
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Check the TV's warranty status at lg.com/us/support using the serial number on the back label.
Backlight and inverter failures within the warranty period are covered at no cost — always check before paying for a repair.
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Contact LG support at 1-800-243-0000 to report error P04 and request a repair assessment.
LG support can arrange in-warranty service or refer you to an authorised repair centre for out-of-warranty TVs.
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If out of warranty, obtain a repair quote from an LG-authorised service centre before deciding.
For large-screen OLED models the repair is usually economical — for smaller budget LCD TVs, compare repair cost to a replacement.
When to Call a Professional
P04 requires the TV to be disassembled to access the backlight inverter and LED strips. A qualified TV repair technician can replace the inverter board or LED strips for $80–$300 depending on screen size. Do not attempt this repair yourself unless you have experience with TV panel disassembly — the screen can crack easily.
Frequently Asked Questions
Can P04 be caused by something I did — like a power outage?
Yes — a sudden power outage or surge is one of the most common triggers for P04. The voltage spike can damage the inverter board or burn out LED strips. Using a surge-protected power strip significantly reduces this risk for future use.
My LG TV shows P04 but I can still hear sound — is that normal?
Yes — P04 is a backlight fault, not an audio fault. The TV is fully powered and running, but the backlight that illuminates the screen has failed. This is why you hear audio but see a dark or flickering screen.
How much does it cost to fix LG TV error P04?
Inverter board replacement typically costs $60–$150 for parts plus labour. LED strip replacement runs $80–$250 depending on screen size and the number of strips. Get a quote from an LG-authorised centre — repairs on premium OLED models are usually worth the cost.