TL;DR: LG upright freezer error codes are short and specific. OFF means showroom demo mode (the compressor is idle), FS and dS are sensor faults, dH means a defrost cycle ran too long, CF and FF are the condenser and evaporator fans, CL E is a refrigerant leak, and Sb is just Sabbath mode. Read the exact letters before you touch anything, because two of these eight need nothing more than a button press.
A freezer that shows “Er” followed by two letters is telling you which part of its cooling loop stopped reporting properly. The lg upright freezer error codes below come straight from this site’s own code pages for the LG upright freezer, so they match what the control board is actually doing rather than a generic chart. If your display shows one of them, start with the table, then read the section that matches.
What does each LG upright freezer error code mean?
Each code points at one subsystem: the temperature sensor, the defrost circuit, one of two fans, the sealed system, or a setting. Each code also has its own page on this site, for example FF, dH and OFF.
Notice that “CL” in the freezer family is not the same thing as a “CL” on a range or washer. On those appliances CL means a lock is engaged. On an upright freezer, Er CL is the refrigerant code, which is why it is worth reading the whole display and not just the letters. Our glossary of LG lock and Sabbath codes sorts out the look-alikes across appliances.
Is my LG freezer really broken, or is it in demo mode?
If the freezer is new, recently moved, or was reset after a power event, and the display shows OFF or “OF F” while the shelves stay at room temperature, you are almost certainly looking at demo mode. In that mode the lights and display work normally but the compressor is held off, which is exactly what a showroom floor model needs. It is the most common reason a brand-new LG upright freezer “does not freeze.”
Check the obvious first: is the display actually asking for service, or does it just say OFF? Look at the control panel and your owner’s manual for the demo-mode toggle on your model, because the button combination differs between control layouts. Once demo mode is turned off, the compressor starts within a few minutes and the cabinet begins to pull down toward the set temperature. Allow several hours before judging the result, and keep the door closed as much as possible while it cools.
What do FS and dS mean, and can I reset them?
FS and dS are sensor faults. FS is the temperature sensor that reports the freezer’s air temperature, and dS is the sensor that reports the evaporator temperature during defrost. Without a trusted reading the control cannot manage cooling or defrost accurately, so it raises the code instead of guessing.
The causes listed on the code pages are a failed sensor, a broken wire, a corroded connector, or a control board that misreads the input. Switching the freezer off at the breaker for several minutes and restoring power is a fair first step, because a one-time glitch clears itself. If the code returns, the sensor circuit has a real fault. With dS in particular, watch the back of the cabinet for frost, since a defrost sensor that cannot report correctly lets frost build until freezing weakens. That progression is covered in more detail in our LG freezer frost buildup guide.
Testing a sensor means reaching it behind the rear panel and measuring its resistance, which belongs to a technician. A sensor that reads out of range is usually an inexpensive part compared with the food it protects.
What does dH tell me about the defrost system?
dH is the code that says the defrost cycle did not finish. The control starts a defrost, switches on the defrost heater, and expects the cycle to end in well under an hour. When it runs past roughly an hour, the freezer flags dH, because frost is clearly not being cleared from the evaporator.
What you may notice before the code: frost building on the rear interior panel, airflow dropping, and freezing slowly weakening over days. The causes the site lists are a failed defrost heater, a defrost sensor or thermostat problem, an evaporator frosted solid, or a control or timer fault. An owner can safely note when dH first appeared and watch for frost, but melting the evaporator by hand with a hair dryer or a scraper is how plastic liners and sensors get damaged. Move frozen food to another freezer, switch the unit off, and let it thaw with the door open and towels on the floor if you must, then call for service rather than restarting it with ice still packed behind the panel.
CF, FF or CL E: which codes are about fans and the sealed system?
CF and FF are the two fan codes, and they fail differently. CF is the condenser fan: it cools the compressor and the coils near the base, so a stalled fan makes the compressor area run hot and the freezer struggle to stay cold. Unplugging the freezer and vacuuming the coils and fan area is a reasonable owner-level step, because dust or an object caught in the blade is on the list of causes. FF is the evaporator fan inside the cabinet: if it stops, the compressor can run while the cabinet warms, because no cold air is moving. A buzzing sound or a fan blade locked in frost is a classic sign, and the frost is often the result of a defrost problem rather than the cause of a bad motor.
CL E is a different class of problem. It points at refrigerant escaping from the low side of the sealed system, so freezing fails even though the compressor may run constantly. The page for this code treats it as serious: move the food to a working freezer to protect it, and do not expect a reset to help. Sealed-system work requires a technician qualified to handle refrigerant.
Can I keep using the freezer while a code is showing?
That depends on the code. Sb and OFF are settings. FS can leave the freezer running too warm or too cold, so check a thermometer and your food. dS and dH let frost build, which eventually chokes airflow. CF and FF reduce cooling. CL E means you should treat the freezer as down. When in doubt, put an appliance thermometer inside: food stays safe at 0 degrees Fahrenheit or colder, and if the cabinet climbs well above that, move the contents.
Our LG freezer not freezing guide covers the symptom side of the same problem, and LG Smart Diagnosis explained shows how to capture a code when the display flashes too quickly to read. If the freezer is old and the code points at the sealed system, the LG refrigerator repair-or-replace guide helps you weigh the options.
When a technician is needed, write down the exact code and when it first appeared. The LG freezer repair page lists what we check, and you can schedule a visit when you are ready.
