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Error code reference

LG Refrigerator Error Code rt

Abnormal Room Temperature Sensor

LG codesLG refrigerator codes

Abnormal Room Temperature Sensor – wire open, short circuit, temperature sensor damaged, or Main PCB damaged (secondary error).

First step from the service manual

Check for loose connection in CON8; check resistance value between brown to brown wires (expected 7.0–30 kΩ).

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

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What rt means on a LG refrigerator

The rt error code on an LG refrigerator indicates an abnormal reading from the room temperature sensor, also called the ambient temperature sensor. This sensor monitors the environmental temperature surrounding the refrigerator and sends that data to the Main PCB so the unit can make operational adjustments based on ambient conditions. When the control board detects a signal from this sensor that falls outside of normal parameters, it flags the rt code to alert the technician that the sensor circuit is not functioning correctly.

The fault can originate from three distinct points in the circuit: an open wire or broken connection, a short circuit within the wiring harness, or a physically damaged sensor element itself. The first diagnostic step is to inspect connector CON8 for any loose, corroded, or displaced terminals. From there, a resistance check between the brown and brown wires at the sensor connector should read between 7.0 and 30 kilohms, depending on the ambient temperature at the time of testing. A reading of zero or near-zero suggests a short circuit, while an open circuit or infinite resistance reading points to a broken wire or failed sensor.

If the wiring and connector check out within spec but the error persists, the Main PCB itself may be misreading the sensor signal due to internal component failure. This is considered a secondary cause, meaning the board should only be suspected after the sensor circuit has been ruled out as the source of the fault. Replacing the Main PCB without first confirming sensor and wiring integrity is a common and costly diagnostic mistake.

Source: manufacturer service documentation.

Common causes of rt

  1. 01

    Loose or disconnected wiring at CON8

    Wiring / connection

    The connector at CON8 in the wiring harness can work loose over time, interrupting the sensor signal. Inspect CON8 for terminals that are not fully seated, corroded, or physically damaged.

  2. 02

    Open circuit in sensor wiring

    Part replacement

    A broken or severed wire in the brown-to-brown sensor circuit will cause the resistance reading to measure as infinite or open. Carefully inspect the full wire run for any visible breaks, pinches, or chafing.

  3. 03

    Damaged room temperature sensor

    Part replacement

    The sensor element itself can fail due to age, moisture, or physical damage, causing out-of-range resistance values. If the resistance between the brown and brown wires falls outside the 7.0 to 30 kilohm range, the sensor requires replacement.

  4. 04

    Short circuit in the sensor circuit

    Part replacement

    A short circuit in the wiring harness will produce a resistance reading near zero ohms, which is well below the expected 7.0 to 30 kilohm range. Look for wires that are pinched, melted together, or in contact with a metal surface.

  5. 05

    Faulty Main PCB

    Part replacement

    If the sensor and all wiring test within normal specifications, the Main PCB may be incorrectly interpreting the sensor signal due to an internal board failure. This is a secondary cause and should only be considered after the sensor circuit has been fully eliminated.

See the test procedure for each cause

Frequently asked questions about rt

What does rt mean on a LG refrigerator?
The rt code on an LG refrigerator signals an abnormal reading from the room temperature sensor, which monitors the ambient temperature around the unit. The fault can be caused by a loose connector at CON8, an open or shorted wire in the sensor circuit, a damaged sensor, or in secondary cases, a failed Main PCB. A resistance check between the brown and brown wires at the sensor should read between 7.0 and 30 kilohms. If it falls outside that range, the sensor or wiring is the likely culprit.
Can I fix the rt error code on my LG refrigerator myself?
Some causes of the rt code are DIY-accessible, particularly checking and reseating the connector at CON8, which requires no special tools. Testing resistance with a multimeter between the sensor wires is also within reach for someone comfortable with basic electrical diagnostics. However, replacing the sensor or the Main PCB involves working with internal components and is generally better handled by a qualified technician if you are not experienced with appliance repair.
Is it safe to keep using my refrigerator while the rt code is active?
A faulty room temperature sensor does not immediately make the refrigerator unsafe, but it can affect how efficiently the unit operates since it relies on accurate ambient readings to manage cooling. Food safety depends on whether the refrigerator is still maintaining proper internal temperatures, so monitor the compartment temperatures closely. It is best to resolve the rt error promptly to avoid compressor strain or potential food spoilage.
How much does it cost to repair the rt error code on an LG refrigerator?
Repair costs vary depending on the root cause. If only a connector needs reseating, there may be no parts cost at all, though a service call fee typically runs between $75 and $150. A replacement room temperature sensor generally costs between $15 and $50 for the part, with labor on top. A Main PCB replacement is significantly more expensive, with parts ranging from $100 to $300 or more depending on the model, plus labor.
Will resetting my LG refrigerator clear the rt error code?
A power reset may temporarily clear the rt code from the display, but the error will return if the underlying cause has not been resolved. The Main PCB continuously monitors the room temperature sensor, so any persistent wiring fault, short circuit, or sensor failure will trigger the code again after the unit powers back up. A reset should be used only after the actual repair has been completed, as a way to confirm the fault is gone.

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