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Error code reference

LG Refrigerator Error Code 84

Compressor motor restriction/locking error

LG codesLG refrigerator codes

Compressor motor restriction/locking error — COMP restricted over 5 sec, runs over 5000 RPM for 10 sec, short between R308 pins, or problem in COMP/cycle.

First step from the service manual

Check resistance of R505, R506, R507, R508, R509, R510, R511, R512, R513; check compressor and cycle.

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
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What 84 means on a LG refrigerator

Error code 84 on an LG refrigerator indicates a compressor motor restriction or locking fault. This code triggers under several specific conditions: the compressor remains restricted for more than 5 seconds, the compressor runs above 5000 RPM for more than 10 seconds, a short is detected between the pins of resistor R308, or a general fault is detected in the compressor or refrigeration cycle. The compressor in LG inverter refrigerators is controlled by a variable-speed inverter board, and this board constantly monitors motor behavior through a network of sense resistors. When motor rotation is blocked, erratic, or operating outside normal speed parameters, the inverter board registers the fault and triggers code 84.

The resistors R505 through R513 are current sensing or feedback components on the inverter board that monitor compressor motor performance. The first diagnostic step is to check the resistance values of all nine of these components to identify any open or shorted resistors. A shorted R308 is also a direct trigger for this code and should be inspected carefully. Beyond the inverter board components, the compressor itself must be evaluated. A mechanically seized compressor, a compressor with shorted or open windings, or a refrigerant charge issue that causes abnormal load on the motor can all produce the conditions that trigger this error. Diagnosing the root cause requires distinguishing between a failed inverter board component and a mechanically or electrically failed compressor.

Source: manufacturer service documentation.

Common causes of 84

  1. 01

    Failed or shorted inverter board resistor

    Part replacement

    One or more of the resistors R505 through R513, or resistor R308, may be shorted or open on the inverter control board. This is the first component group to check, as a board-level failure is a common trigger for this code.

  2. 02

    Seized or mechanically locked compressor

    Part replacement

    If the compressor piston or internal mechanism is seized, the motor cannot rotate freely and will remain restricted beyond the 5-second threshold. This is typically confirmed when the compressor hums but does not start.

  3. 03

    Compressor winding fault

    Part replacement

    An internal short or open circuit in the compressor motor windings can cause erratic RPM behavior or prevent the motor from starting. Winding resistance should be measured at the compressor terminals to rule this out.

  4. 04

    Refrigerant system restriction or overcharge

    Wiring / connection

    A blocked filter drier, kinked line, or incorrect refrigerant charge can place excessive mechanical load on the compressor, causing it to struggle beyond normal operating speed limits and triggering the RPM overspeed condition.

  5. 05

    Faulty inverter control board

    Part replacement

    If individual resistors test within spec but the error persists, the inverter board itself may have broader damage affecting how it drives and monitors the compressor motor. Board replacement is typically required in this scenario.

See the test procedure for each cause

Frequently asked questions about 84

What does 84 mean on a LG refrigerator?
Error code 84 on an LG refrigerator indicates a compressor motor restriction or locking fault. It triggers when the compressor is restricted for more than 5 seconds, runs above 5000 RPM for more than 10 seconds, a short is detected at resistor R308, or there is a general problem in the compressor or refrigeration cycle. The inverter board that controls the compressor detects these abnormal conditions and shuts down to protect the system.
Can I fix LG refrigerator error code 84 myself?
Some parts of the diagnosis, such as visually inspecting the inverter board for obvious damage, can be done by a knowledgeable DIYer. However, checking the resistance of components like R505 through R513 requires a multimeter and some electronics familiarity. Replacing a compressor or working with the sealed refrigerant system requires EPA certification and professional tools, so those repairs must be handled by a licensed technician.
Is it safe to use my refrigerator while error code 84 is showing?
No, it is not safe to continue relying on the refrigerator for food storage while code 84 is active. The compressor is not running correctly, which means the refrigerator is likely not maintaining safe food temperatures. Perishable food should be moved to another cooler or refrigerator until the repair is completed.
How much does it cost to repair LG refrigerator error code 84?
Repair costs vary widely depending on the root cause. An inverter board repair or replacement typically ranges from around $150 to $400 including labor. A compressor replacement is significantly more expensive, often ranging from $400 to $800 or more depending on the model and local labor rates. Getting a diagnostic visit from a technician first will clarify which component has failed before committing to a repair cost.
Will resetting the refrigerator clear error code 84?
Unplugging the refrigerator for a few minutes and plugging it back in may temporarily clear the code, but it will return if the underlying fault is still present. Error code 84 reflects a real electrical or mechanical condition in the compressor circuit, and a reset does not fix the failed component. A proper diagnosis of the resistors, inverter board, and compressor is required to resolve the error permanently.

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