LG Refrigerator Sensor & Temperature Error Codes (F5, D5): Meaning & Fixes

F5 and D5 are the two LG refrigerator sensor codes in this article, and both begin with a display trick: on LG's segmented displays the letter S renders as a 5, so the code you read as F5 is the FS sensor code and the code you read as D5 is the dS sensor code. Underneath the spelling, both faults are the same kind of failure — a temperature sensor whose reading the main control can no longer believe — but they watch different places: F5 (Er FS) watches the freezer compartment air, and D5 (Er dS, also shown as F dS) watches the evaporator coil during defrost. This article keeps the two apart, because their symptoms, urgency, and fixes differ.

How LG temperature sensing works, and how to tell F5 and D5 apart

Every temperature decision an LG refrigerator makes — when to run the compressor, when to stop, when to defrost and when to end a defrost — comes from small thermistor sensors whose electrical resistance changes smoothly and predictably with temperature. The main control does not measure temperature directly; it reads resistance and converts it, which is why the faults in this article are electrical before they are thermal: a sensor that drifts, a connector that corrodes in a cold damp location, or a harness that opens or shorts all present to the control as an impossible temperature, and the control raises a code rather than guess blind with your food inside. Telling the two codes apart starts with the rendering. LG's own service chart lists the sensor family in letters: FS for the freezer sensor, rS for the refrigerator (fresh-food) sensor, and dS for the defrost sensor — three different sensors with three different codes. On the segmented displays many models use, S and 5 are the same shape, so FS is read and searched as F5, and dS is read as D5; service answers about these codes say this explicitly, that the 5 is an S. The practical consequences: F5 belongs to the freezer, not the fresh-food section — the refrigerator sensor is rS, a separate code outside this article — and D5 is sometimes displayed with the compartment marker as F dS, the freezer defrost sensor. Symptom-wise, F5 tends to announce itself with freezer temperature behaviour that stops matching the setting, while D5 is slower and sneakier: defrosts mistime, frost accumulates over weeks, and temperatures creep rather than crash.

Error code F5 (Er FS): freezer temperature sensor error

The f5 error code on lg refrigerator displays — also written Er F5, Er FS, and lg refrigerator error code f5 e in its E FS rendering — means the main control has detected a fault in the freezer temperature sensor: the sensor circuit reads open, shorted, or so far out of range that the control cannot regulate the freezer from it. It is the freezer sensor specifically; LG's service chart separates FS (freezer sensor, short circuit or disconnection of the freezer sensor) from rS, the refrigerator sensor, so a fridge-section sensor fault raises a different code. So how to fix f5 error code on lg refrigerator displays, in the order the causes actually rank? First and most likely is the sensor itself: thermistors drift or fail electrically after years of temperature cycling in the freezer environment, and a failed sensor reports a resistance the control reads as an impossible temperature. Second is the connection between sensor and board — a loose, corroded, or unplugged connector at the sensor or at the main board, a cause common enough that service reports of this code repeatedly end with a sensor found unplugged or a connector reseated; damp, cold sensor locations corrode plugs quietly. Third, least common, is a damaged harness in the cabinet wall or a main-board input fault, which is why a proven-good sensor that still codes has to be measured at the board end as well as at the sensor. Symptoms support the story before any meter comes out: put an independent thermometer in the freezer and compare it with the set point over several hours — a control guessing without its sensor typically over-cools, under-cools, or runs the compressor in long, odd patterns, and you cannot trust the panel display while its own sensor is the suspect. Owner checks are the thermometer comparison and, only with the refrigerator unplugged, a visual inspection of any sensor connector you can reach without dismantling the cabinet: seated, dry, and free of green corrosion. The fix is reseating or cleaning a bad connector where that is the whole story, and replacing the freezer temperature sensor when its readings are out of family — measured against the temperature-resistance chart for your specific model, never against a generic number, because LG uses different sensor families across platforms and a plausible value for one is a failed value for another. An open reading or a dead short is a failed circuit on any chart. After repair, a power-cycle clears the code once the sensor reads plausibly again. Keep monitoring with the thermometer for a day afterward: an F5 that returns with a new sensor and a clean connector moves the diagnosis to the harness and the board, which is technician territory, and meanwhile the freezer should be treated as unregulated — food that has sat warm is a safety question, not a settings question. One more owner observation helps whoever does the repair: note whether the code appeared after a door was left open, after a power cut, or alongside any other code. A lone F5 on a quiet refrigerator is a sensor story; an F5 that arrives in company, or right after electrical weather, widens the board-and-harness end of the diagnosis, and that history costs nothing to record while it is fresh.

Error code D5 (Er dS): defrost temperature sensor error

The lg refrigerator error code d5 — documented as Er dS, also shown as F dS for the freezer defrost sensor and searched as lg refrigerator error code d5 f and lg refrigerator error code f d5 — means the defrost temperature sensor is faulty: the sensor clipped to the evaporator coil, whose job is to tell the control how cold the coil is and when a defrost has actually melted the frost, is reading open, shorted, or out of range. Where F5 corrupts everyday temperature regulation, D5 corrupts the defrost cycle, and that difference in timing explains its whole character: a refrigerator with a bad defrost sensor can seem fine for days, because the damage accumulates one mistimed defrost at a time. If defrosts end too early or never run properly, frost builds on the coil week over week; airflow through the coil chokes; the freezer rear panel grows frost, the evaporator fan starts to tick or scrape against ice, and compartment temperatures drift upward — the slow failure that ends in a fully frosted coil and warm food, often misread at the end as a cooling-system death rather than a small sensor's long sabotage. Causes rank: first, the defrost sensor itself failed — drifted or open after years clipped to a coil that swings between freezer cold and defrost heat, the harshest thermal cycling in the cabinet. Second, connector corrosion at the coil, in what is simply the dampest connector location in the refrigerator, where every defrost wets it. Third, a sensor that has come unclipped from the coil: a sensor reading compartment air instead of coil metal behaves failed even though the part itself is electrically sound, which is why its clip is half the diagnosis. Owner checks are pattern recognition plus, with the unit unplugged, inspection if your model gives access: rear-panel frost that keeps returning, fan ice-noise, and creeping temperatures are the D5 signature, and a technician — or a confident owner following the model manual — meters the sensor for a plausible thermistor reading that changes smoothly with temperature and confirms it sits clipped firmly to the coil tubing. The fix combines parts and housekeeping: a full manual defrost to clear the accumulated frost (unplug, doors open, towels down, and patience — chipping ice off a coil punctures it), replacement of the defrost sensor or re-clipping and connector cleaning where the sensor itself tests good, and, because the access is the same, a check of the neighbouring defrost heater and thermal fuse in the same session rather than a second dismantling later. A power-cycle after repair and defrost clears the code when the sensor tracks a defrost plausibly again. A D5 that returns with a proven sensor points at the harness or the board input — or at a heater fault cooking sensors — and one combined defrost-circuit diagnosis beats serial part swapping. While you wait for that visit, D5 is the more forgiving of this article's two codes in the short term: the refrigerator usually keeps cooling for a while on accumulated frost, so the practical owner job is monitoring — thermometer in the freezer, an ear out for new fan ice-noise, and a firm deadline of weeks, not months, because every mistimed defrost adds frost that the eventual repair has to melt before it can even begin.

Reading temperatures while a sensor is faulted

Both codes in this article share one trap: the display you would normally check is fed by the system that is faulting, so verify everything independently. Keep a simple appliance thermometer in the freezer and another in the fresh-food section for as long as either code is active, and judge the refrigerator by those readings and by the food, not by the panel. With F5, log the freezer temperature against the set point a few times across a day; wide swings or a steady mismatch confirm that regulation is guessing, and any period spent at unsafe temperatures decides the food question before the repair question. With D5, watch the trend over one to two weeks rather than the hour: a freezer that holds temperature today but gains frost on the rear panel and runs longer each week is showing you defrost failure in slow motion. Note, too, what each code does not do: neither F5 nor D5 stops the compressor outright in most cases, which is why both can hide — the refrigerator keeps humming, the lights work, and only the temperatures quietly leave the safe zone. That is also why a code that clears after a power-cycle but returns is information, not bad luck: the sensor circuit failed a plausibility check twice.

A shared diagnostic order for F5 and D5

Diagnose both sensor codes in the same sequence, because the failure points are shared even though the sensors differ. First, read the code carefully and translate the rendering: F5 is FS, the freezer sensor; D5 is dS, the defrost sensor; and a code that looks like rS or FS at a glance decides a completely different sensor, so photograph the display before resetting anything. Second, establish the real temperatures with independent thermometers, and, for D5, inspect for its frost signature — rear-panel frost, fan noise, creeping temperatures. Third, do one clean power reset, unplugging for several minutes; a sensor code caused by a transient glitch clears and stays cleared, while a hardware fault re-registers, and that single experiment separates electronics weather from a failed part. Fourth, with the refrigerator unplugged, inspect the reachable connectors for the implicated sensor: unplugged, backed-out, wet, or corroded connectors are a documented cause of these exact codes and cost nothing to correct. Fifth, the sensor itself gets metered — at the sensor first, then at the board end of the harness — against the temperature-resistance chart in your model's service documentation; a sensor that reads open, shorted, or wildly off its chart value at a known temperature is replaced, and a sensor that reads correctly at its own pins but not at the board condemns the harness between them. Only a sensor and harness that both prove good leave the main board's input as the suspect, and that ordering matters because boards are the minority cause in sensor faults and the majority of the cost.

Resetting F5 and D5 — and what a returning code means

There is no dedicated reset button sequence that repairs a sensor fault on these platforms; the reset for both codes is a power-cycle performed after the cause is corrected. Unplug the refrigerator or trip its breaker for several minutes, restore power, and the control re-reads its sensors from a clean start: a plausible sensor reading clears F5 at start-up, and D5 clears once the defrost sensor reports values the control accepts and tracks through operation. LG's general guidance for its sensor and fan codes is the same five-minutes-off power reset, followed by service if the same code repeats — and the repetition is the real diagnostic content. An F5 that survives a reseated connector and a proven sensor is telling you the fault lives in the harness or the board; a D5 that returns after a full defrost with a new sensor clipped correctly to the coil points the same way, or at a defrost heater problem damaging sensors. Resetting either code repeatedly without metering anything achieves one thing only: it restarts a control that is regulating your food on a sensor it has already told you it cannot believe. One reset after a real fix is confirmation; the second identical code is a work order.

When to call a professional

Sensor parts are inexpensive; sensor certainty is the professional product, and several points in these two faults justify the call. Call a technician when either code returns after a connector reseat and a power reset, because the remaining diagnosis — metering at the board end, separating harness from board input, working inside a frosted evaporator compartment — needs the model's service documentation and a methodical hour you should not spend guessing. Call sooner for D5 whenever heavy frost already blankets the coil: the evaporator, its fan, the defrost heater, the thermal fuse, and the sensor all live in the same access session, and a whole-circuit defrost diagnosis in one visit beats discovering the heater a month after the sensor. Call immediately, whatever the code, if either compartment cannot hold safe temperature — move perishable food to a working refrigerator or cooler first, because an unregulated freezer under F5 and a frost-choked coil under D5 both spoil food on a schedule the display will not warn you about. Inverter and sealed-system safety borders apply here too: sensor work itself is low-voltage, but it happens in a cabinet whose rear compartment carries mains power and a compressor drive, so anything beyond connectors and the sensor the model manual exposes belongs to a professional with the power discipline to match. When you book, give the exact rendering you saw — F5, D5, F dS — and what the independent thermometers read; on a platform where 5 is really S, that precision is the first repair.

Key takeaways

• Photograph the display before resetting: on LG segmented displays S renders as 5, and F5 (freezer sensor) versus rS (refrigerator sensor) is a distinction that decides which part gets ordered.
• Judge both codes with independent thermometers, never the panel — the display is fed by the same sensor system that is faulting, and food safety is decided by real temperatures.
• For D5, ask for the whole defrost circuit — sensor, heater, and thermal fuse — to be checked in one access session; they are neighbours on the coil, and serial visits cost more than the parts.

Resetting the LG refrigerator

LG refrigerator error codes (the Er family) clear with a power reset: unplug for about 5 minutes (or hold the control's reset where fitted) and restore power. Fan and sensor codes that return after the reset are active faults — the board re-tests fans and thermistors continuously. Note that after any reset the cabinet needs several hours to pull temperatures back down, so judge the result by whether the code returns, not by instant cooling.

Frequently asked questions

Related guides

Facts on this page were checked against manufacturer documentation: www.lg.com · www.lg.com · www.lg.com · www.lg.com · www.lg.com