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Error code reference

LG Refrigerator Error Code DEFROSTING SENSOR OF R COMPARTMENT

R compartment defrosting sensor error

LG codesLG refrigerator codes

R compartment defrosting sensor error: electric wire cut, short-circuit, contact failure, or sensor housing missing; displayed when sensor temperature is not lower than 122°F nor higher than -58°F.

First step from the service manual

Check the voltage between Main PCB CN 30 No. 11 ↔ 14 to see if it is between 4.5V and 1.0V.

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

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What DEFROSTING SENSOR OF R COMPARTMENT means on a LG refrigerator

The DEFROSTING SENSOR OF R COMPARTMENT error on an LG refrigerator indicates a fault in the defrost sensor circuit located in the refrigerator (R) compartment. This sensor monitors temperature during the defrost cycle to prevent overheating of the evaporator and surrounding components. The error triggers when the sensor reports a temperature outside the valid operating range, specifically when the reading is not lower than 122°F (50°C) and not higher than -58°F (-50°C). These boundary conditions point to a signal that is out of the expected resistance window, which the Main PCB interprets as a circuit fault rather than a legitimate temperature reading.

The root causes fall into four categories: a cut or broken wire in the sensor harness, a short-circuit in the wiring, a poor or corroded connector contact, or a physically missing sensor housing. Any of these conditions disrupts the voltage signal the Main PCB receives on connector CN 30 between pins 11 and 14. Under normal operation, that voltage should fall between 1.0V and 4.5V, corresponding to valid sensor resistance at temperatures within the operational range. A reading outside this window, or no reading at all, confirms the fault.

Diagnosis begins at Main PCB CN 30 pins 11 and 14. Measuring voltage at this connector pinout distinguishes between a wiring or sensor problem and a PCB output problem. If voltage is absent or outside the 1.0V to 4.5V range, the technician should inspect the sensor harness for physical damage, check connector terminals for corrosion or back-out, and verify the sensor is physically present in its housing. If the wiring and connector check out, the sensor itself should be tested for correct resistance before suspecting the Main PCB.

Source: manufacturer service documentation.

Common causes of DEFROSTING SENSOR OF R COMPARTMENT

  1. 01

    Damaged or broken sensor wire

    Part replacement

    A cut or broken wire in the defrost sensor harness is the most common cause. Inspect the wire run from the sensor to the Main PCB connector CN 30 for any visible breaks, pinching, or rodent damage.

  2. 02

    Connector contact failure

    Wiring / connection

    Loose, corroded, or backed-out terminals at Main PCB connector CN 30 pins 11 and 14 can interrupt the signal without fully breaking the wire. Check the connector for corrosion or terminals that have retracted from their housing.

  3. 03

    Defective defrost sensor

    Part replacement

    The sensor itself can fail internally, causing it to report a resistance value that falls outside the valid temperature range. If wiring and connectors check out, test the sensor resistance directly and replace it if the reading is out of specification.

  4. 04

    Short-circuit in the sensor circuit

    Part replacement

    A short between the sensor wires or from a wire to ground will push the voltage at CN 30 pins 11 and 14 below 1.0V or produce an abnormal reading, triggering the error. Look for chafed insulation where wires contact metal edges.

  5. 05

    Missing sensor or sensor housing

    Part replacement

    If the sensor has been dislodged from its housing or is physically absent, the circuit will be open and the PCB will detect no valid signal. Confirm the sensor is seated correctly in its mounting location in the R compartment.

See the test procedure for each cause

Frequently asked questions about DEFROSTING SENSOR OF R COMPARTMENT

What does DEFROSTING SENSOR OF R COMPARTMENT mean on a LG refrigerator?
This error means the LG refrigerator has detected a fault in the defrost sensor circuit for the refrigerator compartment. The sensor is reporting a temperature outside the valid range, specifically not lower than 122°F and not higher than -58°F, which indicates a wiring problem, short-circuit, bad connection, or a missing sensor rather than an actual temperature reading. The refrigerator flags this condition because it cannot safely manage the defrost cycle without a reliable sensor signal.
Can I fix the DEFROSTING SENSOR OF R COMPARTMENT error myself?
A knowledgeable DIYer can start by checking the sensor wiring harness for visible damage and reseating the connector at Main PCB CN 30 pins 11 and 14. If the connector is secure and the wiring looks intact, testing voltage at those pins (expected range: 1.0V to 4.5V) requires a multimeter and some comfort working around refrigerator electronics. Replacing the sensor is a moderate repair, but if the fault points to the Main PCB, professional service is recommended.
Is it safe to keep using my refrigerator while this error is displayed?
A faulty defrost sensor means the refrigerator may not complete defrost cycles correctly, which can lead to ice buildup on the evaporator and reduced cooling performance over time. Food safety could be affected if cooling is compromised. It is best to address the fault promptly rather than continue running the unit with a known sensor error.
How much does it cost to repair the DEFROSTING SENSOR OF R COMPARTMENT error on an LG refrigerator?
If the repair requires only a new defrost sensor, parts typically range from $15 to $60 depending on the specific model. Adding professional labor, total repair costs generally fall between $100 and $250. If the Main PCB is at fault, parts and labor costs can range from $200 to $450 or more.
Will resetting my LG refrigerator clear the DEFROSTING SENSOR OF R COMPARTMENT error?
A power reset may temporarily clear the error code, but if the underlying cause such as a broken wire, bad connector, or failed sensor is still present, the code will return. The error reflects an actual circuit condition rather than a software glitch, so the physical fault must be diagnosed and corrected before the error clears permanently.

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