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Error code reference

LG Refrigerator Error Code Error1

Freezer sensor abnormal

LG codesLG refrigerator codes

Freezer sensor abnormal - short circuit or open circuit in freezer sensor.

First step from the service manual

Check resistance at both ends of the freezer sensor at CON7 PIN 1,2.

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 Error1 means on a LG refrigerator

The LG refrigerator Error1 code indicates an abnormal condition in the freezer temperature sensor, specifically either a short circuit or an open circuit in that sensor's electrical circuit. The freezer sensor is a thermistor, a resistive component whose resistance value changes predictably with temperature. The refrigerator's control board continuously monitors this resistance to determine the freezer compartment temperature and regulate the compressor and fan cycles accordingly. When the measured resistance falls outside the expected range due to a short or open fault, the control board logs Error1 and may disable normal operation to prevent damage.

The primary diagnostic starting point is measuring resistance at CON7 PIN 1 and PIN 2, which are the connector terminals for the freezer sensor circuit. A short circuit will produce a resistance reading near zero ohms, while an open circuit will produce an infinite or unmeasurable resistance reading. A properly functioning thermistor should read within a defined resistance range that corresponds to the actual freezer temperature at the time of testing. Resistance values outside this range confirm a fault in either the sensor itself or the wiring harness connecting it to the control board.

Common causes include a failed thermistor element, damaged wiring between the sensor and the connector, or a corroded or loose connection at CON7. Physical damage from ice buildup around the sensor, improper defrost cycles, or rodent damage to the wiring can all produce the same short or open circuit result. Isolating whether the fault is in the sensor itself or the wiring harness is essential before ordering replacement components.

Source: manufacturer service documentation.

Common causes of Error1

  1. 01

    Failed freezer thermistor

    Part replacement

    The thermistor itself has failed internally, producing either a near-zero resistance reading (short) or an infinite resistance reading (open). Resistance measured directly at the sensor leads will confirm this if it falls outside the expected range for the current freezer temperature.

  2. 02

    Damaged or broken wiring harness

    Part replacement

    The wiring between the freezer sensor and CON7 PIN 1 and PIN 2 may be cut, pinched, or broken, creating an open circuit. Visually inspect the harness for kinks, chafing, or breaks, particularly where it passes through refrigerator cabinet walls or near moving components.

  3. 03

    Corroded or loose connector at CON7

    Wiring / connection

    Moisture intrusion or vibration can cause the connector at CON7 to corrode or become unseated, interrupting the circuit. Inspect the connector pins for oxidation, bent contacts, or incomplete seating and clean or reseat as needed.

  4. 04

    Ice buildup encasing the sensor

    Wiring / connection

    Excessive frost or ice accumulation around the freezer sensor can physically damage the sensor body or its leads over time. If a defrost issue has allowed heavy ice buildup, the sensor should be inspected for physical damage after the ice is cleared.

  5. 05

    Faulty main control board

    Part replacement

    If the sensor and wiring both test within normal resistance values at CON7 PIN 1 and PIN 2, the control board itself may be misreading the signal due to a board-level fault. This is the least common cause and should only be considered after sensor and wiring are confirmed good.

See the test procedure for each cause

Frequently asked questions about Error1

What does Error1 mean on a LG refrigerator?
Error1 on an LG refrigerator indicates that the freezer temperature sensor has been detected as abnormal due to a short circuit or open circuit condition. The control board monitors the sensor's resistance through connector CON7 PIN 1 and PIN 2 to track freezer temperature, and when that resistance is out of range, it triggers this error. The fault can be in the sensor itself, the wiring harness, or the connector.
Can I fix the Error1 code myself on my LG refrigerator?
A knowledgeable DIYer with a multimeter can perform the initial diagnostic by checking resistance at CON7 PIN 1 and PIN 2 on the freezer sensor connector. If the connector is simply loose or corroded, reseating or cleaning it may resolve the issue without parts. However, replacing the thermistor or repairing a damaged wiring harness requires some comfort with appliance disassembly and electrical work.
Is it safe to keep using my LG refrigerator when Error1 is showing?
Operating the refrigerator with an active Error1 code is not recommended for extended periods. Without a functioning freezer sensor, the control board cannot accurately regulate freezer temperature, which can lead to food safety issues and potential compressor or component damage from uncontrolled cycling. It is best to address the fault promptly.
Will resetting my LG refrigerator clear the Error1 code?
A power reset may temporarily clear the Error1 display, but the code will return if the underlying sensor fault is still present. Because the error is triggered by an actual electrical condition in the sensor circuit, a reset does not fix the problem. The sensor resistance at CON7 PIN 1 and PIN 2 must be within the normal range for the error to stay cleared.
How much does it cost to repair an LG refrigerator Error1 code?
If only the freezer thermistor needs replacement, parts typically cost in the range of $15 to $50 depending on the specific model. If a service technician is needed, labor plus parts can bring the total repair cost to roughly $100 to $250. Wiring harness repairs or control board replacement would fall toward the higher end of that range.

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