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Error code reference

LG Refrigerator Error Code HUMIDITY-Sensor Error

Humidity sensor system has error.

LG codesLG refrigerator codes

Humidity sensor system has error.

First step from the service manual

Check voltage at MAIN PCB CN30-7 to CN50-7; should be between 3.5V and 1.0V.

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

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  • Wiring diagram references and connector pinouts from the OEM service manual
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What HUMIDITY-Sensor Error means on a LG refrigerator

The HUMIDITY-Sensor Error on an LG refrigerator indicates a fault within the humidity sensor system. This sensor monitors moisture levels inside the refrigerator compartment and is used by the main PCB to regulate functions such as fresh food preservation and defrost cycling. When the control board detects a signal from the humidity sensor that falls outside of expected parameters, it triggers this error code to alert the technician that the sensor circuit requires inspection.

The primary diagnostic step involves measuring voltage at the main PCB connector CN30-7 relative to CN50-7. Under normal operating conditions, this voltage should fall between 1.0V and 3.5V. A reading outside this range points to either a failed sensor, a wiring issue in the sensor harness, or a fault on the main PCB itself. An open circuit in the wiring could push the voltage to an extreme high, while a short to ground could collapse it toward zero.

Common failure points include corrosion or moisture damage on the sensor connector pins, a broken wire in the harness running between the sensor and the PCB, or a humidity sensor that has degraded internally and no longer produces an accurate signal. In some cases, the main PCB itself may fail to correctly read the sensor input, though board-level faults are less common than sensor or wiring failures. Thorough inspection of the connector, continuity testing of the harness, and voltage measurement at CN30-7 to CN50-7 are the recommended starting points before condemning any component.

Source: manufacturer service documentation.

Common causes of HUMIDITY-Sensor Error

  1. 01

    Faulty humidity sensor

    Part replacement

    The humidity sensor itself may have failed internally, producing a voltage signal outside the 1.0V to 3.5V range expected by the main PCB. Replacing the sensor is often the fix when wiring checks out normal.

  2. 02

    Damaged or disconnected sensor wiring harness

    Wiring / connection

    A broken wire, loose connector, or corroded pin in the harness between the humidity sensor and the main PCB can interrupt the signal. Inspect the harness and connector for visible damage and test continuity.

  3. 03

    Corroded or contaminated connector pins

    Wiring / connection

    Moisture inside the refrigerator can cause oxidation on the connector pins at CN30-7 or CN50-7, increasing resistance and distorting the sensor voltage reading. Cleaning the connector contacts may resolve the error.

  4. 04

    Short circuit in the sensor circuit

    Wiring / connection

    A short to ground in the sensor wiring will pull the voltage below the 1.0V threshold, triggering the error. This requires careful inspection of the full wiring run for pinched or chafed insulation.

  5. 05

    Main PCB failure

    Part replacement

    If the sensor and all associated wiring test within specification but the error persists, the main PCB may have a fault affecting its ability to read the CN30-7 to CN50-7 input correctly. Board replacement is considered after all other causes are ruled out.

See the test procedure for each cause

Frequently asked questions about HUMIDITY-Sensor Error

What does HUMIDITY-Sensor Error mean on a LG refrigerator?
The HUMIDITY-Sensor Error means the main control board has detected a problem with the humidity sensor circuit. The sensor signal voltage, measured at PCB connectors CN30-7 to CN50-7, is outside the expected range of 1.0V to 3.5V. This can be caused by a failed sensor, damaged wiring, or in less common cases, a faulty main PCB.
How do I fix the HUMIDITY-Sensor Error on my LG refrigerator?
Start by checking the voltage at main PCB connector CN30-7 relative to CN50-7 using a multimeter. The reading should be between 1.0V and 3.5V. If the voltage is out of range, inspect the sensor wiring harness and connector pins for damage or corrosion before testing or replacing the humidity sensor itself.
Is it safe to keep using my LG refrigerator while the HUMIDITY-Sensor Error is active?
The refrigerator may continue to cool while this error is present, but humidity-related functions may not operate correctly, which could affect food preservation quality over time. It is advisable to have the issue diagnosed promptly to prevent any secondary problems from developing.
How much does it cost to repair the HUMIDITY-Sensor Error on an LG refrigerator?
Repair costs vary depending on the failed component. A replacement humidity sensor typically costs in the range of $20 to $60 for the part alone, while main PCB replacement can range from $100 to $300 or more. Adding professional labor will increase the total, generally ranging from $150 to $400 depending on the diagnosis and parts required.
Will resetting my LG refrigerator clear the HUMIDITY-Sensor Error?
A reset may temporarily clear the error code, but if the underlying fault in the sensor, wiring, or PCB is still present, the code will return. A reset should only be used after the root cause has been identified and repaired to confirm the fault has been resolved.

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