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Error code reference

LG Refrigerator Error Code Er r1

Refrigerator sensor 1 (upper part in refrigerator compartment) short or open circuit detected.

LG codesLG refrigerator codes

Refrigerator sensor 1 (upper part in refrigerator compartment) short or open circuit detected.

First step from the service manual

Check for a loose connection in CON9, then check resistance between White to White wires.

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

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What Er r1 means on a LG refrigerator

The Er r1 error code on an LG refrigerator indicates that the control board has detected either a short circuit or an open circuit condition in Refrigerator Sensor 1, which is the temperature sensor located in the upper portion of the refrigerator compartment. This sensor is a thermistor, meaning its electrical resistance changes in a predictable way with temperature. The control board continuously monitors this resistance to determine the compartment temperature and regulate the cooling cycle accordingly.

When the board reads a resistance value that falls outside the expected range, either too low (indicating a short) or infinitely high (indicating an open or broken circuit), it triggers the Er r1 fault. A short circuit occurs when the sensor or its wiring makes unintended contact, causing abnormally low resistance. An open circuit occurs when there is a break in the sensor element or wiring, resulting in no continuity. Both conditions prevent the board from obtaining a valid temperature reading, which compromises proper refrigerator temperature control.

Diagnosis begins at connector CON9, which is the harness connection associated with this sensor circuit. The first step is to inspect CON9 for any loose, corroded, or unseated terminals. If the connection is secure, resistance should be measured between the White and White wires on the sensor circuit. The resistance reading will indicate whether the thermistor itself has failed or whether the fault lies in the wiring harness between the sensor and the board.

Source: manufacturer service documentation.

Common causes of Er r1

  1. 01

    Loose or disconnected wiring at CON9

    Wiring / connection

    A loose or unseated connector at CON9 is the first thing to check, as vibration or improper reassembly can cause the harness to lose contact. Reseating the connector firmly may clear the error without any part replacement.

  2. 02

    Failed refrigerator thermistor (Sensor 1)

    Part replacement

    The thermistor itself can fail due to age, moisture exposure, or physical damage, resulting in either a short or open resistance reading. Measuring resistance across the White to White wires will confirm if the sensor has drifted outside its acceptable range.

  3. 03

    Damaged or broken wiring harness

    Part replacement

    The wire harness running from CON9 to the upper refrigerator compartment sensor can develop breaks or shorts from pinching, freezing, or chafing against components. A visual inspection along the full harness length and a continuity test will identify any breaks.

  4. 04

    Corroded or oxidized connector terminals

    Wiring / connection

    Moisture inside the refrigerator compartment can cause the terminals at CON9 to corrode, increasing resistance or breaking the circuit entirely. Corroded terminals often appear discolored or have a white or greenish buildup and may require terminal cleaning or connector replacement.

  5. 05

    Faulty main control board

    Part replacement

    If the sensor and all wiring check out within spec, the control board itself may be misreading the sensor circuit due to a damaged input circuit. This is the least common cause and should only be considered after the sensor and harness have been confirmed good.

See the test procedure for each cause

Frequently asked questions about Er r1

What does Er r1 mean on a LG refrigerator?
Er r1 indicates that the control board has detected a short circuit or open circuit in Refrigerator Sensor 1, the temperature thermistor located in the upper part of the refrigerator compartment. The board cannot get a valid resistance reading from the sensor, so it cannot accurately monitor compartment temperature. This may result in improper cooling or the refrigerator running abnormally.
Can I fix the Er r1 error myself?
In many cases, yes. Start by checking the wiring connector at CON9 for a loose or unseated connection, which is a straightforward fix that requires no parts. If the connection is secure, you can test the resistance of the White to White wires on the sensor circuit to determine if the thermistor has failed. Replacing a thermistor is a moderate DIY repair, though working near refrigerant lines requires caution.
Will resetting my LG refrigerator clear the Er r1 code?
A reset may temporarily clear the display, but the code will return if the underlying fault in the sensor circuit has not been resolved. The control board will detect the short or open circuit again as soon as it runs its next diagnostic check. The root cause, whether a loose connector, failed thermistor, or damaged wiring, must be corrected for the error to stay cleared.
Is it safe to keep using my refrigerator while Er r1 is active?
It is not recommended to rely on the refrigerator for extended periods while this error is active. Without a valid reading from the upper compartment sensor, the control board cannot properly regulate temperature, which means food safety could be compromised. Check the actual temperature inside the compartment with a separate thermometer and address the fault as soon as possible.
How much does it cost to repair an Er r1 error on an LG refrigerator?
If only a loose connection needs to be reseated, there may be no parts cost at all, with only a service call fee if a technician is involved, typically in the range of $75 to $150. A replacement thermistor sensor is generally an inexpensive part, often in the $15 to $50 range, with labor adding $100 to $200 if professionally installed. If the main control board is at fault, total repair costs could range from $200 to $450 or more depending on the specific board and labor rates in your area.

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