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Error code reference

LG Refrigerator Error Code 87E

Compressor Over Voltage Error

LG codesLG refrigerator codes

Compressor Over Voltage Error — over voltage error at compressor.

First step from the service manual

Check the resistance of R501, R505, R509 (short/open).

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

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What 87E means on a LG refrigerator

The 87E error code on an LG refrigerator indicates a compressor over voltage condition. This fault is detected by the inverter control board, which monitors the voltage supplied to the variable-speed compressor. When the voltage at the compressor circuit exceeds the acceptable operating threshold, the board triggers this code to protect the compressor from damage caused by electrical stress. The over voltage condition can originate from the incoming AC power supply, internal voltage regulation components, or a fault within the inverter board itself.

The primary diagnostic focus for this error is on three resistors: R501, R505, and R509. These resistors are part of the voltage sensing or feedback circuit on the inverter board and are used to monitor compressor voltage levels. If any of these resistors have failed short or open, the board may receive an incorrect voltage reading, falsely triggering the 87E code, or it may fail to properly regulate voltage delivery to the compressor. Testing these components requires a multimeter to check for continuity and resistance values consistent with the board schematic.

Beyond resistor failures, this error can also stem from genuine over voltage conditions arriving from the home's power supply, particularly in areas prone to voltage spikes or power surges. A faulty inverter control board that has suffered surge damage may also generate this code even if the individual resistors test within spec. Diagnosing this error requires a methodical approach: starting with the resistor checks, then evaluating incoming line voltage, and finally assessing the inverter board as a whole.

Source: manufacturer service documentation.

Common causes of 87E

  1. 01

    Failed sensing resistors (R501, R505, or R509)

    Part replacement

    One or more of these resistors on the inverter board has gone short or open, causing the board to misread the compressor voltage and trigger the 87E code. Test each resistor with a multimeter for continuity and correct resistance.

  2. 02

    Inverter control board surge damage

    Part replacement

    A power surge can damage the inverter board beyond just the sensing resistors, causing it to incorrectly report an over voltage condition. Inspect the board for visible burn marks, damaged traces, or swollen capacitors.

  3. 03

    High incoming line voltage

    Wiring / connection

    If the household supply voltage is consistently above the normal operating range, the inverter board may detect a genuine over voltage condition. Measure the AC voltage at the refrigerator outlet with a multimeter to confirm it is within the expected range.

  4. 04

    Loose or corroded wiring connections

    Wiring / connection

    Poor connections between the power supply and the inverter board can cause unstable voltage readings that trigger this fault. Inspect connector pins and wire harnesses for corrosion, looseness, or heat damage.

See the test procedure for each cause

Frequently asked questions about 87E

What does 87E mean on a LG refrigerator?
The 87E code on an LG refrigerator indicates a compressor over voltage error. The inverter control board has detected that the voltage at the compressor circuit is outside the acceptable range. This triggers a protective shutdown to prevent compressor damage. The first diagnostic step is to check the resistance of sensing resistors R501, R505, and R509 on the inverter board for short or open failures.
Can I fix the 87E error myself?
Diagnosing this error requires a multimeter and some comfort working with electronic components on the inverter board. A knowledgeable DIYer can test the sensing resistors R501, R505, and R509 for short or open conditions, and check the line voltage at the outlet. Replacing individual resistors or the full inverter board is possible for those with soldering skills or board-swap experience, but if you are not comfortable with live electrical components, a qualified technician is recommended.
Is it safe to use my LG refrigerator while it is showing the 87E error?
The 87E error indicates the compressor circuit is experiencing an over voltage condition, which means the compressor may not be running properly. The refrigerator will likely not maintain safe food storage temperatures while this fault is active. It is best to address the error promptly and transfer perishable food to another refrigerator until the repair is complete.
How much does it cost to repair an LG refrigerator with the 87E error?
Repair costs depend on the root cause. If only resistors on the inverter board need replacement, the parts cost is minimal, though a technician's labor fee will apply. If the full inverter control board requires replacement, parts and labor typically range from $150 to $400 or more depending on the model and service provider. Checking line voltage and wiring connections costs nothing beyond a service call fee if those turn out to be the issue.
Will resetting my LG refrigerator clear the 87E error code?
Unplugging the refrigerator for a few minutes may temporarily clear the 87E code, but if the underlying cause has not been repaired, the error will return once the compressor attempts to run again. A reset should only be used as part of the diagnostic process, not as a long-term fix. The sensing resistors and incoming voltage must be properly evaluated and any faulty components replaced to resolve the fault permanently.

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