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Error code reference

LG Refrigerator Error Code 81

Compressor start-up failure error

LG codesLG refrigerator codes

Compressor start-up failure error — short between COMP U/V/W terminals, short between IPM pins #1-33, IPM voltage drop (DC 13.5V or lower), or COMP/cycle error.

First step from the service manual

Check between compressor terminals for short; check IPM voltage (13.5V or lower); check between IPM pins #1-33 for short; 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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  • Wiring diagram references and connector pinouts from the OEM service manual
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What 81 means on a LG refrigerator

Error code 81 on an LG refrigerator indicates a compressor start-up failure. This code is generated by the inverter control system when the compressor fails to start or complete its start-up sequence properly. The error points to one of several specific electrical faults: a short circuit between the compressor terminals (labeled U, V, and W), a short between pins 1 and 33 of the Intelligent Power Module (IPM), a voltage drop at the IPM below the 13.5V DC threshold, or an error in the compressor or refrigeration cycle itself.

The IPM is a critical component in LG inverter refrigerators. It controls the variable-speed compressor by converting DC voltage into the precise AC waveforms needed to drive the compressor motor at different speeds. When the IPM supply voltage drops to 13.5V DC or below, the module cannot deliver adequate power to initiate compressor rotation, triggering error 81. A short between IPM pins 1 and 33 disrupts the internal gate drive circuitry and similarly prevents a successful start.

A short between the compressor U, V, and W terminals indicates a winding fault inside the compressor motor itself. These three terminals correspond to the three phases of the brushless DC motor inside the sealed compressor unit. A measurable short between any two of these terminals typically means the compressor motor has failed internally and requires compressor replacement. Cycle errors can also trigger this code if there is an abnormal refrigerant pressure condition that creates excessive load during start-up.

Source: manufacturer service documentation.

Common causes of 81

  1. 01

    Compressor winding short (U/V/W terminals)

    Part replacement

    A short circuit between any two of the three compressor motor terminals (U, V, W) indicates an internal motor winding failure. Use a multimeter to check resistance between each pair of terminals; a near-zero reading confirms a shorted winding, and compressor replacement is required.

  2. 02

    IPM voltage drop below 13.5V DC

    Part replacement

    If the DC supply voltage to the Intelligent Power Module falls to 13.5V or lower, the IPM cannot drive the compressor motor. Check the voltage at the IPM power input; a low reading points to a failing power supply board or wiring issue feeding the IPM.

  3. 03

    Short between IPM pins 1 and 33

    Part replacement

    A short between these two specific IPM pins disrupts the module's internal gate driver circuitry, preventing compressor start. Inspect the IPM connector and pins for physical damage, corrosion, or bridging, and test continuity between pins 1 and 33.

  4. 04

    Abnormal refrigeration cycle conditions

    Part replacement

    Excessive refrigerant pressure or a blocked refrigeration cycle can create too much mechanical load for the compressor to overcome during start-up. This may be caused by a refrigerant overcharge, a blocked capillary tube, or a failed check valve.

  5. 05

    Wiring harness damage between IPM and compressor

    Wiring / connection

    Damaged, corroded, or loose wiring between the IPM and the compressor terminals can create intermittent or direct short conditions that trigger error 81 without indicating a true compressor failure. Visually inspect and test all wiring in this circuit before replacing major components.

See the test procedure for each cause

Frequently asked questions about 81

What does 81 mean on a LG refrigerator?
Error code 81 on an LG refrigerator means the compressor failed to start successfully. The control system detected one of four specific faults: a short between the compressor U, V, or W terminals; a short between IPM pins 1 and 33; IPM supply voltage at or below 13.5V DC; or an error in the compressor or refrigeration cycle. The refrigerator will not cool until this fault is diagnosed and repaired.
Can I fix error code 81 on my LG refrigerator myself?
Some portions of the diagnosis can be done by a knowledgeable DIYer, such as inspecting wiring harnesses and checking for visible damage or corrosion. However, testing IPM voltages, checking resistance between compressor terminals, and any work involving refrigerant requires specialized tools and, in the case of refrigerants, EPA certification. Most repairs associated with error 81 are best handled by a qualified appliance technician.
Will resetting my LG refrigerator clear error code 81?
Unplugging the refrigerator for a few minutes may temporarily clear the error code display, but error 81 points to a specific electrical or mechanical fault. If the underlying cause such as a shorted compressor winding, low IPM voltage, or a short between IPM pins is not corrected, the error will return as soon as the refrigerator attempts to restart the compressor.
Is it safe to use my LG refrigerator while it is showing error code 81?
Error 81 means the compressor is not running, so the refrigerator is not cooling properly. Food safety is the immediate concern, as perishables will warm to unsafe temperatures within a few hours. You should transfer perishable food to another cooler or refrigerator promptly and arrange for repairs. There is no immediate safety hazard to people in the home, but continued operation attempts will not restore cooling.
How much does it cost to repair error code 81 on an LG refrigerator?
Repair costs vary significantly depending on the root cause. If the fix involves a wiring harness repair or an IPM board replacement, costs typically range from around $150 to $400 including labor. If the compressor itself has failed due to shorted windings, compressor replacement is a major repair and costs can range from $400 to $700 or more depending on the model and local labor rates. A technician diagnosis is the best way to get an accurate estimate.

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