mypros+
Error code reference

LG Refrigerator Error Code L1 L3

Room temperature sensor disconnection or short-circuit detected.

LG codesLG refrigerator codes

Room temperature sensor disconnection or short-circuit detected.

First step from the service manual

Check room temperature (RT) sensor wiring and connections; top/bottom maturation heater is off during error.

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

MyPros+ Max

Get the full diagnostic procedure for L1 L3.

  • 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
Get the full procedure

$29/month · Cancel anytime · Or $9.95 3-day pass

What L1 L3 means on a LG refrigerator

The L1 L3 error code on an LG refrigerator indicates that the control system has detected either a disconnection or a short-circuit condition in the room temperature (RT) sensor circuit. This sensor monitors the ambient temperature of the environment surrounding the refrigerator, and its readings are used by the control board to make decisions about compressor operation, defrost cycles, and heater activation. When the sensor signal falls outside the expected resistance or voltage range, the board flags the fault and logs this code.

A key operational consequence of this error is that the top and bottom maturation heaters are switched off while the fault is active. This is a protective response by the control system to prevent uncontrolled heating in the absence of reliable temperature data. The RT sensor itself is a thermistor-based component, meaning its resistance changes predictably with temperature. A disconnected sensor will typically read as an open circuit with very high or infinite resistance, while a shorted sensor will read near zero ohms. Either condition places the signal outside acceptable parameters.

Diagnosing this code begins with a thorough inspection of the RT sensor wiring harness and connectors. Technicians should check for loose pins, corroded terminals, pinched wires, or damaged insulation along the full length of the sensor circuit. If wiring checks out, the sensor itself should be tested with a multimeter to confirm its resistance value matches expected specifications at the current room temperature. A faulty sensor or a damaged wiring harness will require parts replacement to resolve the fault permanently.

Source: manufacturer service documentation.

Common causes of L1 L3

  1. 01

    Loose or disconnected sensor connector

    Wiring / connection

    The wiring harness connector for the room temperature sensor may have worked loose over time due to vibration or handling during prior service. Inspect the connector at both the sensor and control board ends for a secure fit.

  2. 02

    Damaged or pinched sensor wiring

    Part replacement

    The wire leading to the RT sensor can become pinched, cut, or abraded, creating either an open circuit or a short to ground. Trace the full length of the harness and look for visible damage or chafing against cabinet edges.

  3. 03

    Failed room temperature sensor

    Part replacement

    The thermistor element inside the sensor can fail internally, producing a resistance value outside the acceptable range even when the wiring is intact. Test the sensor resistance with a multimeter and compare it against the expected value for the current ambient temperature.

  4. 04

    Corroded or oxidized connector terminals

    Wiring / connection

    Moisture exposure can cause terminal pins inside the sensor connector to oxidize, increasing resistance or breaking continuity in the circuit. Clean or replace affected connectors if corrosion is present.

  5. 05

    Faulty main control board

    Part replacement

    If the sensor and all wiring test within normal specifications, the control board itself may be misreading the sensor signal due to a damaged input circuit. This is the least likely cause and should be investigated only after all other components are confirmed good.

See the test procedure for each cause

Frequently asked questions about L1 L3

What does L1 L3 mean on a LG refrigerator?
The L1 L3 code means the refrigerator's control system has detected a disconnection or short-circuit in the room temperature sensor circuit. This sensor monitors the ambient temperature around the unit and provides data the control board uses to manage heating and cooling operations. When the fault is active, the top and bottom maturation heaters are automatically turned off as a protective measure. The issue typically lies in the sensor wiring, the connector, or the sensor component itself.
Can I fix the L1 L3 error on my LG refrigerator myself?
Some causes of this error, such as a loose connector, can be addressed without special tools by carefully inspecting and reseating the room temperature sensor wiring harness. However, if the sensor itself has failed or a wire is damaged, replacement parts will be needed. Using a multimeter to test sensor resistance is recommended before purchasing any parts. If you are not comfortable working with appliance wiring, a qualified technician should perform the diagnosis.
Is it safe to continue using my refrigerator while the L1 L3 code is active?
The refrigerator may continue to cool to some degree while this code is active, but the maturation heaters are disabled during the fault, which can affect certain functions. Operating the unit for an extended period without resolving the error is not recommended, as the control system is working without reliable ambient temperature data. Food safety should be monitored, and the fault should be addressed promptly.
How much does it cost to repair the L1 L3 error on an LG refrigerator?
If the fix is simply reseating a loose connector, there may be no parts cost, though a service call fee will typically apply if a technician is involved. Replacing a faulty room temperature sensor generally costs between $20 and $60 for the part, plus labor. If the control board is at fault, parts and labor costs can range from $150 to $400 or more depending on the model and service provider.
Will resetting my LG refrigerator clear the L1 L3 error code?
A power reset may temporarily clear the error code from the display, but if the underlying fault in the sensor circuit is still present, the code will return. Resetting the unit does not repair a damaged wire, corroded connector, or failed sensor. A lasting fix requires identifying and correcting the root cause of the disconnection or short-circuit in the room temperature sensor circuit.

Related LG refrigerator codes

All LG refrigerator codes
View all 485 LG refrigerator codes

78,000+ service manuals · 160,000+ error codes · 55+ brands

Get Started

$29/month · Cancel anytime · Or $9.95 3-day pass