Written by
Marcus Lindqvist Appliance Care EditorPublished October 26, 2026
VERIFIED
Error codeFU
ApplianceRefrigerator
FU is the freezer’s way of saying it cannot hold its temperature. The panel shows it when the compartment still sits at 3.5 degrees Celsius or warmer ten minutes into a start-up, and also when the temperature later climbs past that mark during operation. LG gives it for refrigerators across the board.
Reset first
Take the plug out of the wall, give it a full minute, then reconnect directly to a wall outlet. No power strip or multi-plug adapter should sit in the path.
Checks if FU returns
Check
What LG wants confirmed
Power and cooling
The unit is switched on, the compressor runs, and both cooling and freezing temperatures fall in their normal ranges.
Freezer setting
It is set to -18 degrees Celsius.
Door use
Frequent or lengthy openings admit warm air, which brings humidity and weakens cooling.
Air vents
No food stands in front of them.
Door seal
The door closes fully and the gaskets seal. LG’s gasket test is to shut the door on a sheet of paper and tug it.
If the code survives all of that, the manual’s last word is to request service.
Related codes
A faulty freezer sensor is reported as FS, a stalled freezer fan as FF, and a room hotter than +50 degrees Celsius as HI.
Refrigerator service for San Francisco and the Bay Area
Call (415) 223-7887 if FU does not clear on your LG refrigerator. Before dialing, jot down the code, the model number and which checks from the table you finished. The LG refrigerator repair page explains more.
Model compatibility: LG reuses codes across series and model years, so FU may mean something different on another appliance or generation. Confirm this against your model’s documentation and record your full model number before acting.
Plain language
What this code means
The freezer did not drop below 3.5 degrees Celsius within 10 minutes of starting, or rose above that during operation.
Important safety warning. Do not attempt repairs involving electrical components, gas, water lines, refrigerant or sealed systems. Unplug the appliance if it is safe to reach the outlet, and leave internal diagnostics to a qualified technician.
Seeing this code on your LG appliance?
Book a specialist visit for a clear estimate and approval before any repair.
You submit a request with your appliance model and symptom, we confirm an appointment window, and a technician performs an on-site diagnosis. You then receive a clear estimate and decide whether to proceed before any repair begins.
Yes. We provide an upfront estimate after diagnosis. No parts are ordered or installed until you approve the work, so there are no surprise charges.
Replacement parts are selected for the exact model and confirmed with you before ordering or installation.
Service areas are listed on the Locations page. Contact us with your ZIP code to confirm current coverage for your address.
Ready to get your LG appliance working again?
Book a repair online or call us — clear estimates and approval before any repair work begins.
