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Error code reference

LG Refrigerator Error Code R-defrost sensor short

Refrigerator area defroster sensor short circuit fault

LG codesLG refrigerator codes

Refrigerator area defroster sensor short circuit fault - sensor reading suspected to be over +50°C.

First step from the service manual

Check R-defrost sensor resistance and wiring; replace sensor if faulty.

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
  • Verified part numbers when replacement is required
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What R-defrost sensor short means on a LG refrigerator

The R-defrost sensor short error on an LG refrigerator indicates a short circuit condition in the defrost sensor located in the refrigerator compartment. The control board monitors the resistance output of this thermistor-based sensor to track temperature during and after defrost cycles. When the sensor reading corresponds to a temperature above +50°C, or when the resistance drops to a level consistent with a short circuit, the board flags this fault code. A healthy defrost sensor produces a resistance value that changes predictably with temperature, so an out-of-range low resistance reading signals that something is electrically wrong in the circuit.

The most common root cause is physical damage to the sensor itself or its wiring harness. Sensors can develop internal shorts due to moisture intrusion, ice buildup pressing against the sensor body, or heat damage from a prolonged defrost cycle. The wiring between the sensor and the control board can also short if insulation becomes brittle, pinched, or compromised by ice or mechanical wear. In some cases, corrosion at connector terminals creates a low-resistance path that mimics a sensor short.

Diagnosis requires disconnecting the R-defrost sensor and measuring its resistance with a multimeter. If the resistance reads near zero ohms or significantly below the expected value for ambient temperature, the sensor has an internal short and must be replaced. If resistance reads correctly at the sensor itself, the wiring harness and connectors between the sensor and the control board should be inspected for damage, pinching, or corrosion. Resolving the fault without addressing the true cause risks repeated failures.

Source: manufacturer service documentation.

Common causes of R-defrost sensor short

  1. 01

    Failed defrost sensor (internal short)

    Part replacement

    The thermistor inside the R-defrost sensor can develop an internal short circuit due to moisture intrusion or heat stress, causing resistance to drop abnormally low. This is the most common cause and is confirmed by measuring near-zero resistance across the sensor terminals after disconnecting it.

  2. 02

    Damaged wiring harness

    Part replacement

    The wiring between the defrost sensor and the control board can be pinched, cut, or have degraded insulation that allows conductors to contact each other, creating a short. Inspect the harness routing for any visible damage, kinks, or areas where ice may have pressed against the wires.

  3. 03

    Corroded or shorted connector terminals

    Wiring / connection

    Moisture near the sensor connector can cause corrosion or bridging between terminals, producing a low-resistance reading that the control board interprets as a sensor short. Inspect the connector pins for green or white corrosion deposits and clean or replace as needed.

  4. 04

    Ice accumulation pressing on sensor or wiring

    Wiring / connection

    Excessive ice buildup in the refrigerator compartment can physically compress the sensor or its leads against a grounded surface, simulating a short circuit. Manually defrosting the unit and clearing ice may resolve the condition if no permanent damage occurred.

  5. 05

    Faulty control board

    Part replacement

    If the sensor and all wiring test within normal resistance values, the control board itself may be misreading the sensor circuit. This is the least likely cause and should only be considered after fully ruling out the sensor and harness.

See the test procedure for each cause

Frequently asked questions about R-defrost sensor short

What does R-defrost sensor short mean on a LG refrigerator?
This error code means the control board has detected a short circuit condition in the defrost sensor located in the refrigerator compartment. The board monitors sensor resistance to track temperatures during defrost cycles, and it triggers this fault when the reading suggests a temperature above +50°C or a resistance value too low to be valid. The fault points to either a damaged sensor, a wiring problem, or a connector issue in that circuit.
Can I fix the R-defrost sensor short error myself?
A knowledgeable DIYer can diagnose this fault by disconnecting the R-defrost sensor and testing it with a multimeter for a near-zero or abnormally low resistance reading. If the sensor is confirmed faulty, replacing it is a straightforward repair involving disconnecting the old sensor and connecting the new one. However, if the wiring harness or control board is involved, the repair becomes more complex and a technician may be advisable.
Is my refrigerator safe to use while this error is displayed?
The refrigerator may continue to cool, but the defrost system may not operate correctly with a faulty sensor, which can lead to ice buildup over time and reduced efficiency. Food safety depends on whether the refrigerator compartment is maintaining proper temperature. It is best to address the fault promptly and monitor the internal temperature closely until the repair is completed.
How much does it cost to repair the R-defrost sensor short error on an LG refrigerator?
If only the defrost sensor needs replacement, parts typically range from around $10 to $40 depending on the specific model, and the repair is relatively inexpensive. If a technician is needed, labor costs will add to that total, generally bringing the overall repair into the $75 to $200 range. A wiring harness or control board replacement would increase costs further.
Will resetting the refrigerator clear the R-defrost sensor short error?
A power reset may temporarily clear the error code from the display, but the fault will return if the underlying problem with the sensor or wiring has not been corrected. The control board will re-detect the short circuit condition the next time it checks the sensor circuit. A permanent fix requires diagnosing and resolving the actual electrical fault, not just resetting the unit.

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