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Error code reference

LG Refrigerator Error Code Er 3

Abnormal refrigerator sensor 2 (middle part of refrigerator compartment)

LG codesLG refrigerator codes

Abnormal refrigerator sensor 2 (middle part of refrigerator compartment) - short circuit or open circuit.

First step from the service manual

Check refrigerator sensor 2 resistance with a multimeter.

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 Er 3 means on a LG refrigerator

The Er 3 error code on an LG refrigerator indicates an abnormal reading from refrigerator sensor 2, which monitors temperature at the middle section of the fresh food compartment. This sensor is a negative temperature coefficient (NTC) thermistor, meaning its electrical resistance decreases as temperature rises. The control board continuously reads the sensor's resistance to regulate cooling cycles. When the board detects a resistance value that falls outside the acceptable range, either too low (short circuit) or too high (open circuit), it triggers the Er 3 fault and may disable normal cooling operations to prevent damage.

The two failure modes covered by this code are distinct. A short circuit occurs when the sensor's internal resistance drops near zero, often due to moisture intrusion, physical damage, or internal component failure within the thermistor itself. An open circuit occurs when the circuit is broken entirely, producing infinite resistance, typically caused by a broken wire, corroded connector, or a thermistor that has completely failed. Either condition prevents the control board from receiving accurate temperature data for that zone.

Diagnosis begins with measuring the resistance of refrigerator sensor 2 using a multimeter. A properly functioning NTC thermistor will show a predictable resistance value at a known temperature. If the reading is near zero or infinite (OL), the sensor or its wiring harness is at fault. Inspecting the connector for corrosion, moisture, or bent pins is also essential before condemning the sensor itself.

Source: manufacturer service documentation.

Common causes of Er 3

  1. 01

    Failed thermistor (sensor 2)

    Part replacement

    The thermistor itself has internally short-circuited or opened, producing a resistance reading of near zero or infinite ohms. This is the most common cause and is confirmed by measuring resistance directly at the sensor terminals.

  2. 02

    Damaged or broken wiring harness

    Part replacement

    The wire connecting sensor 2 to the control board may be pinched, cut, or broken, resulting in an open circuit. Inspect the harness along its full length for visible damage or breaks.

  3. 03

    Corroded or loose connector

    Wiring / connection

    The connector at the sensor or control board end can corrode or work loose over time, intermittently or permanently interrupting the signal. Check both connector ends for corrosion, moisture, and secure seating.

  4. 04

    Moisture intrusion at sensor or connector

    Wiring / connection

    Condensation or water from a defrost cycle can enter the sensor housing or connector, causing a short circuit or erratic resistance readings. Look for signs of water damage or ice buildup near the sensor location.

  5. 05

    Control board fault

    Part replacement

    If the sensor and all wiring check out within normal resistance ranges, the control board may be misreading the sensor input due to a failed input circuit. This is the least common cause and should only be considered after all wiring and sensor tests are completed.

See the test procedure for each cause

Frequently asked questions about Er 3

What does Er 3 mean on a LG refrigerator?
Er 3 indicates an abnormal signal from refrigerator sensor 2, the temperature sensor located in the middle section of the fresh food compartment. The control board has detected either a short circuit (resistance too low) or an open circuit (resistance too high) from this sensor. The fault prevents the board from accurately monitoring and controlling the temperature in that zone.
How do I fix the Er 3 error on my LG refrigerator?
Start by using a multimeter to check the resistance of refrigerator sensor 2. If the reading is near zero or shows no continuity, the sensor or its wiring is faulty. Inspect the connector for corrosion or looseness and replace the sensor or repair the harness as needed. If the sensor and wiring test normal, the control board may require further evaluation.
Will resetting my LG refrigerator clear the Er 3 code?
A power reset may temporarily clear the Er 3 code, but the fault will return if the underlying problem with sensor 2 or its wiring has not been corrected. Resetting is useful for confirming whether the error is intermittent, but it is not a repair. Proper diagnosis with a multimeter is necessary to resolve the issue permanently.
Is it safe to keep using my LG refrigerator while Er 3 is displayed?
Operating the refrigerator with an Er 3 fault carries some risk, as the control board cannot accurately monitor the middle compartment temperature without a working sensor. Food safety could be compromised if the unit is not cooling properly. It is advisable to check food temperatures and address the fault as soon as possible.
How much does it cost to repair an Er 3 error on an LG refrigerator?
If only the thermistor sensor needs replacement, parts typically cost between $10 and $40, and the repair is often straightforward for someone comfortable with basic appliance work. If professional labor is needed, total repair costs generally range from $75 to $200 depending on the technician and the extent of the wiring or component work required. Control board replacement, if needed, would increase that range significantly.

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