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Error code reference

LG Refrigerator Error Code R1

Cut or short-circuited wire of refrigerator (R) sensor on the control box of the refrigerator; compressor…

LG codesLG refrigerator codes

Cut or short-circuited wire of refrigerator (R) sensor on the control box of the refrigerator; compressor, cooling fan, and defrost heater operate in default state during error mode.

First step from the service manual

Check the refrigerator sensor wiring for cuts or short circuits.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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  • Step-by-step tests with expected resistance, voltage, and continuity values
  • Wiring diagram references and connector pinouts from the OEM service manual
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What R1 means on a LG refrigerator

The R1 error code on an LG refrigerator indicates a fault detected in the refrigerator compartment temperature sensor, also called the R sensor, located on the control box of the refrigerator section. The control board monitors this sensor continuously, and when it detects either an open circuit (caused by a cut or broken wire) or a short circuit in the sensor wiring, it triggers the R1 code. This sensor is a thermistor that changes resistance in response to temperature, allowing the control board to regulate cooling cycles accurately.

When the R1 code is active, the refrigerator enters a default operating mode. In this mode, the compressor, cooling fan, and defrost heater run on fixed preset cycles rather than responding dynamically to actual compartment temperatures. This failsafe behavior keeps the refrigerator functioning at a basic level, but temperature regulation will not be precise. Food may be overcooled or undercooled depending on ambient conditions and the fixed cycle timing.

The most common source of this fault is damaged wiring between the R sensor and the control board, including cuts, pinched wires, or corroded connectors. The sensor itself can also fail internally, producing readings that fall outside the expected resistance range. Diagnosing this code requires inspecting the sensor wiring harness for visible damage, checking connector seating, and testing the sensor thermistor with a multimeter to confirm it is producing accurate resistance values across its operating temperature range.

Source: manufacturer service documentation.

Common causes of R1

  1. 01

    Cut or damaged sensor wiring

    Part replacement

    The wire harness connecting the R sensor to the control board may be cut, pinched, or broken, causing an open circuit. Inspect the full length of the wiring run for visible damage, especially near door hinges or areas where wires could be pinched.

  2. 02

    Short circuit in the sensor wiring

    Part replacement

    Wires in the sensor circuit may be contacting each other or a grounded metal surface, creating a short circuit that the control board detects as a fault. Look for areas where insulation has worn through or wires are routed against sharp metal edges.

  3. 03

    Loose or corroded wiring connector

    Wiring / connection

    The connector between the R sensor harness and the control board may be partially unseated or corroded, causing intermittent or complete loss of signal. Unplug and firmly reseat the connector, and inspect the terminals for oxidation or damage.

  4. 04

    Failed R sensor thermistor

    Part replacement

    The thermistor element inside the R sensor can fail internally, producing resistance readings outside the expected range and triggering the R1 code even when wiring is intact. Testing with a multimeter will show an open reading or incorrect resistance for the compartment temperature.

  5. 05

    Control board fault

    Part replacement

    If the wiring and sensor both test correctly, the control board itself may have a fault in the circuit that reads the R sensor input. This is less common but possible if no wiring or sensor defects are found after thorough testing.

See the test procedure for each cause

Frequently asked questions about R1

What does R1 mean on a LG refrigerator?
The R1 error code means the control board has detected a cut or short circuit in the wiring of the refrigerator compartment temperature sensor, called the R sensor. The board cannot receive a valid temperature reading from that sensor. While the error is active, the refrigerator runs the compressor, cooling fan, and defrost heater on fixed default cycles rather than adjusting to actual temperatures.
Can I fix the R1 error myself?
A knowledgeable DIYer can diagnose this code by visually inspecting the R sensor wiring for cuts, pinches, or loose connectors, and by testing the sensor with a multimeter. If the wiring is intact and the sensor tests bad, replacing the thermistor is a manageable repair. However, if the wiring harness is damaged or the control board is at fault, the repair may require more advanced skills or a professional technician.
Is it safe to keep using my refrigerator while the R1 error is showing?
The refrigerator will continue to operate in a default mode during the R1 error, so it will not shut off completely. However, because the compressor and fans run on fixed cycles rather than responding to actual compartment temperatures, food temperatures may not stay within safe ranges consistently. It is best to repair the fault promptly and monitor food temperatures closely in the meantime.
How much does it cost to repair an R1 error on an LG refrigerator?
Repair costs depend on what is actually faulty. A replacement R sensor thermistor typically costs in the range of $15 to $50 for the part. A wiring harness repair or replacement can range from $20 to $100 or more depending on the extent of the damage. If the control board needs to be replaced, costs can range from $100 to $300 or higher for the part alone, with additional labor costs if a technician is needed.
Will resetting my LG refrigerator clear the R1 error code?
Resetting the refrigerator by unplugging it for a few minutes may temporarily clear the R1 code, but the error will return if the underlying wiring fault or sensor defect has not been corrected. The control board will detect the same problem the next time it checks the R sensor circuit. A reset is only a lasting fix if the fault was caused by a temporary condition such as a loose connector that has since been reseated.

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