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Error code reference

LG Refrigerator Error Code 84E

Compressor Under Voltage Error

LG codesLG refrigerator codes

Compressor Under Voltage Error — low voltage error at compressor.

First step from the service manual

Check the resistance of R513 (short/open).

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

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What 84E means on a LG refrigerator

The 84E error code on an LG refrigerator indicates a compressor under voltage condition, meaning the inverter control board is detecting insufficient voltage being delivered to the compressor. The compressor in these units is driven by a variable-speed inverter system, and the control circuitry continuously monitors the voltage supply to ensure the compressor receives adequate power to operate. When that voltage falls below the acceptable threshold, the system throws the 84E fault to protect the compressor from damage caused by low-voltage operation.

The first diagnostic step targets resistor R513, a component on the inverter or main control board that plays a role in the voltage sensing or regulation circuit. Checking R513 for a short or open condition is critical because a failed resistor in this path can cause the control board to either misread the supply voltage or fail to properly regulate it. An open R513 would break the sensing circuit entirely, while a shorted R513 could pull the measured voltage reading below the acceptable operating range, triggering the fault even if actual line voltage is within spec.

Beyond R513 itself, the root cause could also originate from external supply issues such as a low household voltage condition, a failing power supply section on the inverter board, or wiring harness problems between the power supply and compressor drive circuit. Technicians should confirm actual line voltage at the unit before condemning any board-level components.

Source: manufacturer service documentation.

Common causes of 84E

  1. 01

    Failed Resistor R513 (Short or Open)

    Part replacement

    Resistor R513 on the inverter or control board is the first component to check. A short or open condition in this resistor disrupts the voltage sensing circuit and directly triggers the 84E fault.

  2. 02

    Faulty Inverter Control Board

    Part replacement

    If R513 tests correctly, the broader inverter board power supply section may have failed components causing actual low voltage output to the compressor drive circuit. Visual inspection for burned or bulging components can help identify this.

  3. 03

    Low Household Supply Voltage

    Wiring / connection

    Insufficient voltage from the home's electrical supply or a weak outlet can cause the compressor to receive below-threshold voltage. Measure line voltage at the outlet under load to rule this out.

  4. 04

    Damaged Wiring Harness or Loose Connections

    Wiring / connection

    Corroded, pinched, or loose wiring between the power supply section and the compressor drive circuit can introduce resistance that effectively drops the voltage at the compressor terminals.

  5. 05

    Failing Compressor

    Part replacement

    An internally failing compressor drawing abnormal current can cause a voltage drop within the drive circuit that the control board interprets as an under voltage condition.

See the test procedure for each cause

Frequently asked questions about 84E

What does 84E mean on a LG refrigerator?
The 84E code indicates a compressor under voltage error, meaning the inverter control system has detected that the voltage supplied to the compressor is below the required operating level. The refrigerator disables the compressor to prevent damage from running under low voltage conditions. Diagnosis should start with checking resistor R513 on the control board for a short or open condition.
Can I fix the 84E error myself?
Checking the household line voltage at the outlet is something a knowledgeable DIYer can do safely. However, testing and replacing resistor R513 or diagnosing the inverter board requires working with electronic components and board-level soldering, which is best handled by a technician with experience in appliance electronics. Improper handling of the inverter board can cause further damage.
Is it safe to keep using my refrigerator while the 84E error is showing?
No, the refrigerator's compressor will not run properly while this fault is active, meaning the unit cannot maintain safe food storage temperatures. You should remove perishable food and avoid relying on the refrigerator for food preservation until the fault is diagnosed and repaired.
Will resetting the refrigerator clear the 84E error?
A power reset by unplugging the unit for a few minutes may temporarily clear the code, but the fault will return if the underlying cause is not resolved. If R513 is shorted or open, or if there is a genuine voltage supply problem, the error will reappear once the compressor attempts to restart.
How much does it cost to repair an 84E error on an LG refrigerator?
Repair costs depend on the root cause. A board-level component repair such as replacing R513 may cost relatively little in parts, but labor to diagnose and perform board-level work can range from $100 to $300 or more. Replacing the full inverter control board typically runs between $150 and $400 including parts and labor, while compressor replacement represents the higher end of the repair cost spectrum.

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