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Error code reference

LG Refrigerator Error Code R-sensor short

Refrigerator room temperature sensor short circuit fault

LG codesLG refrigerator codes

Refrigerator room temperature sensor short circuit fault - sensor reading suspected to be over +50°C (below 0.5V at MICOM input).

First step from the service manual

Check R-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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  • Wiring diagram references and connector pinouts from the OEM service manual
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What R-sensor short means on a LG refrigerator

The R-sensor short error on an LG refrigerator indicates a short circuit condition in the refrigerator compartment temperature sensor (R-sensor). The MICOM (microcomputer control board) monitors the voltage signal from this sensor to determine the internal temperature of the fresh food compartment. Under normal operation, the sensor produces a variable voltage signal corresponding to the compartment temperature. When the MICOM detects a voltage at its input that drops below 0.5V, it interprets this as the sensor reading an implausibly high temperature above +50°C, which is the threshold that triggers this fault code. A legitimate short circuit in the sensor circuit pulls the signal voltage abnormally low, producing the same sub-0.5V reading the control board sees during an actual over-temperature condition.

The R-sensor itself is a negative temperature coefficient (NTC) thermistor, meaning its electrical resistance decreases as temperature rises. A short circuit in the sensor or its wiring harness causes resistance to drop toward zero ohms, collapsing the voltage divider signal that the MICOM reads. This is distinct from an open circuit fault, where the resistance goes to infinity. The most direct diagnostic step is to disconnect the sensor and measure its resistance with a multimeter, then check the wiring harness for any pinched, chafed, or melted wires that may be contacting each other or a grounded metal surface. If resistance and wiring check out, the MICOM input circuit itself may warrant inspection.

Source: manufacturer service documentation.

Common causes of R-sensor short

  1. 01

    Faulty R-sensor (thermistor)

    Part replacement

    The thermistor itself has internally short-circuited, causing its resistance to drop to near zero ohms. Measuring the sensor resistance with a multimeter while disconnected from the harness will confirm if the sensor is out of specification.

  2. 02

    Damaged or pinched wiring harness

    Wiring / connection

    The wiring between the R-sensor and the MICOM may be pinched, chafed, or melted, causing two conductors to contact each other and create a short. Visually inspect the full length of the harness for damage, especially near sharp metal edges or heat sources.

  3. 03

    Moisture or ice contamination at the sensor connector

    Wiring / connection

    Water or ice intrusion into the sensor connector can bridge the terminals and simulate a short circuit. Disconnect the connector, dry it thoroughly, and inspect for corrosion or water tracks on the connector housing.

  4. 04

    Corroded or loose connector terminals

    Wiring / connection

    Corrosion at the sensor connector pins can create unintended electrical paths that lower the signal voltage below the 0.5V threshold the MICOM monitors. Cleaning the terminals and reseating the connector may resolve the fault if no other damage is present.

  5. 05

    Failed MICOM control board

    Part replacement

    In rare cases, the input circuit on the MICOM itself may have failed, causing it to misread a valid sensor signal as a short. This should only be suspected after the sensor and full wiring harness have been confirmed to be in good condition.

See the test procedure for each cause

Frequently asked questions about R-sensor short

What does R-sensor short mean on a LG refrigerator?
The R-sensor short error means the refrigerator compartment temperature sensor has been detected in a short circuit condition. The control board (MICOM) monitors the voltage from this sensor and flags the fault when that voltage drops below 0.5V, which corresponds to a suspected temperature reading above +50°C. The root cause is usually a failed thermistor or a short in the sensor wiring harness.
Can I fix the R-sensor short error myself?
A knowledgeable DIYer can often resolve this error by inspecting the sensor wiring harness for visible damage and testing the sensor resistance with a multimeter. If the sensor reads near zero ohms when disconnected, it needs to be replaced. Wiring repairs or connector cleaning are also within reach for those comfortable working with appliance electronics, but MICOM replacement is generally best left to a technician.
Is it safe to keep using my refrigerator while the R-sensor short error is displayed?
It is not advisable to continue relying on the refrigerator with this error active, as the MICOM cannot accurately read compartment temperature and may not regulate cooling correctly. Food safety could be compromised if the compartment temperature is not being properly maintained. Address the fault as soon as possible to avoid food spoilage.
How much does it cost to repair an R-sensor short error on an LG refrigerator?
If only the R-sensor thermistor needs replacement, parts typically cost in the range of $10 to $40, making it one of the more affordable repairs. If a technician is needed for diagnosis and the sensor replacement, total service costs including labor generally fall in the range of $100 to $200. A MICOM control board replacement, if required, will add significantly more to that estimate.
Will resetting my LG refrigerator clear the R-sensor short error?
A power reset may temporarily clear the error code from the display, but if the underlying short circuit in the sensor or wiring has not been corrected, the fault will return once the MICOM re-evaluates the sensor signal. A reset is useful for confirming whether the fault is intermittent, but it is not a substitute for diagnosing and repairing the actual cause.

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