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Error code reference

LG Refrigerator Error Code RT sensor error

Failure of RT (Room Temperature) sensor due to cut or short circuit wire.

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Failure of RT (Room Temperature) sensor due to cut or short circuit wire.

First step from the service manual

Press and hold SUPER FRZ button and FRZ Temp button for 1 second or longer to display RT sensor error code; inspect connecting wires on the RT sensor.

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

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What RT sensor error means on a LG refrigerator

The RT sensor error on an LG refrigerator indicates a failure in the Room Temperature (RT) sensor circuit. This sensor monitors the ambient temperature surrounding the unit and feeds that data to the control board, which uses it to regulate cooling performance and compressor operation. When the control board detects a signal outside the expected range, whether due to an open circuit (wire cut) or a short circuit condition, it triggers this error code to alert the technician to a fault in that specific sensor loop.

The two primary electrical failure modes are a cut wire, which causes the circuit to read as open and sends an out-of-range high resistance signal to the board, and a short circuit, where two conductors make unintended contact and drive resistance abnormally low. Both conditions produce readings the control board interprets as invalid, making them functionally distinct faults that present under the same error code. The wiring harness connecting the RT sensor to the control board is often the first place to inspect, as wires can fray, pinch, or corrode over time.

To confirm this error is active and not a transient fault, the diagnostic entry procedure requires pressing and holding the SUPER FRZ button and the FRZ Temp button simultaneously for at least one second. This puts the refrigerator into a diagnostic display mode that will show the RT sensor error code if the fault is present. After confirming the code, the next step is a physical inspection of the RT sensor connecting wires, checking for visible damage, corrosion, or disconnection at the harness connector.

Source: manufacturer service documentation.

Common causes of RT sensor error

  1. 01

    Cut or broken wire in the RT sensor harness

    Part replacement

    Physical damage to the wiring between the RT sensor and the control board creates an open circuit. Inspect the full length of the connecting harness for frayed insulation, pinched sections, or a clean break in the wire.

  2. 02

    Short circuit in the RT sensor wiring

    Part replacement

    Two conductors in the sensor harness making unintended contact will cause an abnormally low resistance reading that the control board flags as invalid. Look for areas where wiring is routed near sharp edges or heat sources that could wear through insulation.

  3. 03

    Loose or corroded connector at the RT sensor

    Wiring / connection

    The plug connecting the RT sensor to the wiring harness can loosen over time or develop corrosion at the terminals, interrupting the signal. Disconnect and reseat the connector, and check the terminals for oxidation or bent pins.

  4. 04

    Failed RT sensor

    Part replacement

    The sensor itself can fail internally, producing a resistance value that falls outside acceptable limits even when the wiring is intact. If wiring and connectors check out, the sensor component should be tested and replaced if out of specification.

  5. 05

    Control board fault misreading the sensor circuit

    Part replacement

    In less common cases, the main control board may have a damaged input circuit that incorrectly reports a sensor error even when the RT sensor and wiring are functional. This is typically considered only after the sensor and all wiring have been ruled out.

See the test procedure for each cause

Frequently asked questions about RT sensor error

What does RT sensor error mean on a LG refrigerator?
The RT sensor error means the refrigerator has detected a failure in the Room Temperature sensor circuit. The fault is caused by either a cut wire creating an open circuit or a short circuit in the sensor wiring, both of which produce a signal the control board cannot interpret as valid. You can confirm the error is active by pressing and holding the SUPER FRZ and FRZ Temp buttons together for at least one second to enter diagnostic mode.
Can I fix the RT sensor error myself?
A knowledgeable DIYer can address this error by inspecting and reseating the RT sensor connector, which requires no special tools and no parts. If the wiring harness is visibly damaged or the sensor itself has failed, repairs require splicing wires or replacing components, which is more involved but still achievable with basic electrical skills. If the fault traces back to the control board, professional diagnosis is recommended.
Is my refrigerator safe to use while the RT sensor error is displayed?
The RT sensor monitors ambient room temperature rather than internal cabinet temperature, so the refrigerator may continue cooling food in the short term. However, the control board relies on this data to optimize operation, so running the unit with an unresolved sensor fault for an extended period is not recommended. Address the error as soon as practical to avoid potential performance issues.
How much does it cost to repair an RT sensor error on an LG refrigerator?
If the fix is simply reseating a loose connector, there is no parts cost and only the time investment of a DIY repair. Replacing a damaged wiring harness or the RT sensor itself typically involves parts costs in the range of $15 to $60 depending on the component, plus labor if a technician is hired. A control board replacement, if needed, is the most expensive scenario and can range from $100 to $300 or more for parts alone.
Will resetting my LG refrigerator clear the RT sensor error?
A power reset may temporarily clear the error code display, but if the underlying wiring or sensor fault is still present, the error will return once the control board re-evaluates the circuit. Clearing the code without fixing the root cause does not resolve the problem. The sensor wiring and connector should be inspected and repaired before assuming the reset has resolved the fault.

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