LG Refrigerator 1F Error Code: Freezer Defrost Sensor Fault

Quick Answer

The LG 1F error code means the freezer defrost temperature sensor has failed. Without a working sensor, the control board cannot monitor evaporator temperature or trigger defrost cycles. Ice builds up on the evaporator coils over days, eventually blocking all airflow and causing the refrigerator to warm up.

Without a working sensor, the control board cannot monitor evaporator temperature or trigger defrost cycles. Ice builds up on the evaporator coils over days, eventually blocking all airflow and causing the refrigerator to warm up. The fix is to test the sensor with a multimeter (expect 5,000-7,000 ohms at 32 degrees F) and replace it if it reads open (OL). The sensor assembly costs $15-30 and takes about 45 minutes to replace.

LgRefrigeratorSeverity: highDifficulty: intermediate88% DIY Success

Time to Fix

30–60 min

Difficulty

intermediate

Parts Cost

$15 – $30

Tools Needed

Phillips screwdriver, Multimeter

What Does the 1F Code Mean?

The freezer defrost sensor tells the control board when the evaporator coils are cold enough for defrost to stop. When it fails, defrost cannot run and ice accumulates until airflow is completely blocked.

Most Likely Causes

Based on aggregated repair data, here is the probability breakdown for this error code:

Defrost sensor probe failed internally (most common)40%

Wiring harness to sensor chafed or corroded24%

Sensor connector pin backed out14%

Physical damage to sensor from ice impact12%

Control board defrost sensor circuit failed10%

Symptoms You May Notice

1F displayed on temperature panel
Freezer not reaching target temperature
Visible frost buildup on back wall of freezer
Fresh food compartment warming up over several days
Refrigerator running constantly without cycling off

Can you reset a Lg refrigerator to clear the 1F code?

Unplug the refrigerator for 5 minutes, then plug back in. The 1F code will clear from the display after a power reset, but it will return within hours if the sensor has not been replaced. A reset alone does not fix this fault.

Tools Required for Diagnosis

Phillips screwdriverMultimeterPutty knife (for panel clips)Towels for ice/water

Diagnostic Checklist

Follow these steps in order. We start with the easiest external fixes before opening up the machine.

Unplug the refrigerator

Unplug the refrigerator. Remove the freezer contents and the rear panel (usually 4-6 screws). Locate the defrost sensor - it clips onto the evaporator coil tubing and has a 2-wire connector.

Set your multimeter to the 20k ohm resistance range

If the sensor tested good

Replace the defrost sensor assembly

Reassemble the rear panel and plug in the refrigerator

Replacement Parts

If your diagnostic testing proves the component has failed, you will need a replacement. We recommend OEM parts over aftermarket for water-handling components.

Part Name	OEM Number	Estimated Price
Freezer Defrost Temperature Sensor Assembly6615JB2002A · $15–$30	6615JB2002A	$15 – $30

Verify part fitment for your Lg model

Repair vs. Replace Calculator

Appliance Age (Years)7 Yrs

Labor Approach

Our Verdict

REPAIR

Estimated Cost: $23 (Parts) vs $1350 (New Machine)

Frequently Asked Questions

Can I run my LG refrigerator with a 1F error code showing?

Temporarily, yes - the fridge will still cool at first. But without a working defrost sensor, ice will accumulate on the evaporator coils over the next few days and eventually block all airflow. At that point the fridge will stop cooling entirely. Fix it quickly.

What ohm reading should the LG defrost sensor show?

At freezer temperature (around 0-32 degrees F), the sensor should read approximately 5,000-7,000 ohms on a multimeter. If it reads OL (open loop) or shows 0 ohms, the sensor has failed and needs replacement.

Where exactly is the 1F sensor located inside the LG freezer?

The defrost temperature sensor clips directly onto the evaporator coil tubing behind the rear panel in the freezer compartment. Remove all freezer contents, take out the rear access panel (4-6 screws), and you will see the sensor clipped to the coil with a 2-wire connector.

I replaced the 1F sensor but the code came back. What now?

If you confirmed the new sensor reads the correct resistance and the wiring harness has no damage, the fault is likely in the control board's defrost sensor input circuit. The control board will need to be replaced.

Is the LG 1F error code the same as the dF error on other brands?

Yes - functionally equivalent. Samsung uses dF or defrost fault codes, Whirlpool uses E1/E2 defrost codes. They all indicate a defrost temperature sensor or heater circuit issue. The repair approach (test sensor resistance, check wiring) is the same across brands.

Related Lg Refrigerator Error Codes

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Same Fix Works on These Brands

Lg shares the same hardware platform with these brands. The diagnosis and repair steps are identical.

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Models Known to Experience 1F Errors

This repair applies to most Lg refrigerators with this error code. Common model numbers include:

LRMVS3006S, LRFXS2503S, LRFXC2416S, LRMGS2806S, LSXS26366S

Last verified for technical accuracy on March 14, 2026