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Error code reference

LG Refrigerator Error Code 02

Refrigerator sensor error

LG codesLG refrigerator codes

Refrigerator sensor error - connector missing, contact failure, wire cut, short circuit, or sensor failure.

First step from the service manual

Check voltage between MAIN PCB CN40 #8 (GRAY) and #9 (BLACK); should be within 4.5V~1.0V.

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
  • Verified part numbers when replacement is required
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What 02 means on a LG refrigerator

Error code 02 on an LG refrigerator indicates a fault in the refrigerator compartment temperature sensor circuit. This sensor, also called the fridge thermistor, continuously reports compartment temperature to the main PCB so the control board can regulate the cooling cycle. When the board detects a reading outside the expected parameters, it logs error 02 and may limit or halt normal cooling operation to prevent damage to stored food or internal components.

The fault can originate at several points in the sensor circuit. A missing or improperly seated connector at main PCB CN40 pins 8 (GRAY) and 9 (BLACK) is a frequent starting point for diagnosis. These two pins carry the sensor signal voltage, which should fall within the range of 1.0V to 4.5V under normal operating conditions. A reading outside this window, or no voltage at all, points to a break in the circuit. Wire damage such as cuts, chafing against cabinet edges, or rodent damage can interrupt the signal, and internal shorts within the wiring harness can pull the voltage out of range.

When connector and wiring checks pass, attention shifts to the sensor itself. Thermistors can fail due to moisture ingress, physical damage from ice buildup, or simply age-related drift in resistance characteristics. A failed sensor may read as an open circuit or a fixed low resistance, both of which force the signal voltage outside the 1.0V to 4.5V window the board requires. In some cases the main PCB connector CN40 develops corrosion or pin-level contact failure, which mimics a sensor fault even when the sensor and wiring are intact.

Source: manufacturer service documentation.

Common causes of 02

  1. 01

    Loose or missing connector at main PCB CN40

    Wiring / connection

    The connector at pins 8 and 9 of CN40 on the main PCB can work loose over time or may not be fully seated. Inspect the connector for a firm click-in fit and check for bent or pushed-back pins.

  2. 02

    Damaged wiring harness

    Part replacement

    The wire running from the sensor to CN40 can be cut, pinched, or chafed against cabinet components. Visually trace the harness and use a multimeter to check for continuity breaks or shorts between conductors.

  3. 03

    Failed refrigerator compartment thermistor

    Part replacement

    The thermistor itself can fail open or short internally, pushing the signal voltage outside the 1.0V to 4.5V range. Disconnecting the sensor and measuring its resistance at a known temperature can confirm failure.

  4. 04

    Corrosion or contact failure at CN40 pins

    Wiring / connection

    Moisture inside the refrigerator cabinet can cause oxidation at the CN40 connector pins 8 and 9, increasing contact resistance and corrupting the voltage signal. Inspect pins for discoloration and clean with electrical contact cleaner.

  5. 05

    Faulty main PCB

    Part replacement

    If the connector, wiring, and sensor all test within spec but the voltage at CN40 pins 8 and 9 remains outside the 1.0V to 4.5V range, the main PCB itself may have a defective input circuit for the sensor signal.

See the test procedure for each cause

Frequently asked questions about 02

What does 02 mean on a LG refrigerator?
Error code 02 on an LG refrigerator indicates a fault in the refrigerator compartment temperature sensor circuit. The cause can be a disconnected or loose connector at main PCB CN40 pins 8 and 9, damaged wiring, a short circuit in the harness, or a failed thermistor. The board expects to see between 1.0V and 4.5V at those pins, and anything outside that range triggers the error.
Can I fix LG error code 02 myself?
Some causes of error 02 are DIY-friendly. Reseating the connector at CN40, inspecting the wiring harness for visible damage, and cleaning corroded connector pins are tasks a confident DIYer can handle. Replacing the thermistor is also relatively straightforward. However, if the main PCB is the root cause, board replacement or repair is generally a job for an experienced technician.
Will resetting my LG refrigerator clear error code 02?
A power reset may temporarily clear the error display, but it will return if the underlying fault in the sensor circuit has not been corrected. Resetting is useful for confirming whether the fault is intermittent, but it is not a repair. The voltage at CN40 pins 8 and 9 should be measured and the circuit fully diagnosed to resolve the code permanently.
Is it safe to keep using my refrigerator while error code 02 is active?
Error code 02 means the refrigerator cannot reliably measure its internal temperature, which may cause the cooling system to run incorrectly. Food safety could be at risk if the compartment is warmer than the display suggests. It is best to address the fault promptly and use a standalone thermometer to monitor compartment temperature in the meantime.
How much does it cost to repair LG refrigerator error code 02?
Repair cost depends on the failed component. A replacement refrigerator compartment thermistor typically costs in the range of $15 to $50 for the part. If the main PCB requires replacement, parts alone can range from $100 to $300 or more depending on the model. Adding professional labor, a service call generally runs between $100 and $250 in total, though this varies by region and the extent of diagnosis required.

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