mypros+
Error code reference

LG Refrigerator Error Code R-1-ⓐ

Ice Maker Sensor part error

LG codesLG refrigerator codes

Ice Maker Sensor part error - sensor housing separation, contact error, disconnection, or short circuit; detected when temperature reads more than 149°F (+65°C) or less than -58°F (-50°C).

First step from the service manual

Check if MAIN PCB Connector CN90 is inserted correctly; measure resistance at CN90#8 ↔ #4 and compare to temperature table.

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 R-1-ⓐ.

  • 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 R-1-ⓐ means on a LG refrigerator

The R-1-ⓐ error code on an LG refrigerator indicates a fault in the ice maker temperature sensor circuit. This sensor monitors the thermal conditions inside the ice maker assembly, and the control system flags an error when the sensor reports a temperature reading outside the plausible operating range: above 149°F (+65°C) or below -58°F (-50°C). These threshold values are well outside any realistic operating condition, which tells the main PCB that the sensor signal itself is invalid rather than reflecting a true temperature extreme.

The fault can originate from several points in the sensor circuit. Physical separation of the sensor from its housing, a loose or improperly seated connector at the main PCB, an open circuit caused by wire breakage or disconnection, or a short circuit within the wiring harness can all produce out-of-range resistance readings that trigger this code. The sensor itself is a thermistor, meaning its resistance changes predictably with temperature. When the resistance falls outside the values mapped in the temperature table, the PCB interprets the reading as a sensor part error.

Diagnosis begins at connector CN90 on the main PCB. Pins CN90#8 and CN90#4 carry the ice maker sensor signal, and the connector must be fully and correctly seated before any resistance measurement is taken. With the connector checked, measuring resistance across those two pins and comparing the result to the published temperature-to-resistance table will confirm whether the sensor is within specification, or whether the fault lies in the wiring, connector, or the sensor component itself.

Source: manufacturer service documentation.

Common causes of R-1-ⓐ

  1. 01

    Loose or improperly seated connector at CN90

    Wiring / connection

    The CN90 connector on the main PCB can work loose over time due to vibration or during a previous service. A partially seated connector creates intermittent or completely invalid resistance readings across pins #8 and #4.

  2. 02

    Ice maker sensor housing separation

    Part replacement

    The thermistor can physically separate from its mounting housing inside the ice maker assembly, breaking or straining the connection. Visually inspect the sensor for signs of dislodgement or mechanical damage.

  3. 03

    Open circuit in the sensor wiring harness

    Wiring / connection

    A broken or disconnected wire between the ice maker sensor and the main PCB will cause the resistance reading to go out of range entirely. Inspect the harness for pinched, cut, or pulled wires along its routing path.

  4. 04

    Short circuit in the sensor circuit

    Part replacement

    A short within the wiring harness or at the sensor itself collapses resistance to near zero, which the PCB reads as an impossible temperature value. A short is often caused by wire insulation damage from ice buildup or mechanical abrasion.

  5. 05

    Failed ice maker thermistor

    Part replacement

    The thermistor itself can fail internally, producing a resistance value that does not correspond to any valid temperature in the lookup table. If wiring and connectors test normal, the sensor component requires replacement.

See the test procedure for each cause

Frequently asked questions about R-1-ⓐ

What does R-1-ⓐ mean on a LG refrigerator?
R-1-ⓐ is an ice maker sensor fault code. It means the main PCB has received a temperature reading from the ice maker sensor that is above 149°F (+65°C) or below -58°F (-50°C), which are impossible under normal operation. The code indicates the sensor circuit has a physical or electrical problem such as a disconnection, housing separation, or short circuit rather than an actual extreme temperature condition.
Can I fix the R-1-ⓐ error code myself?
Some causes of this error are DIY-friendly. Start by checking that connector CN90 on the main PCB is fully seated, as a loose connector is a common and easy fix. If the connector is secure, inspecting the wiring harness for visible damage is also within reach for a careful DIYer. Replacing the thermistor sensor itself requires basic appliance repair skills and disconnecting power before working on the unit.
Is it safe to keep using my refrigerator while the R-1-ⓐ code is active?
The refrigerator's main cooling function is typically separate from the ice maker circuit, so food stored in the refrigerator and freezer compartments is generally not at immediate risk. However, the ice maker will likely not operate correctly while this fault is present. It is still advisable to address the error promptly to avoid any secondary issues and to restore full ice maker function.
How much does it cost to repair an R-1-ⓐ error on an LG refrigerator?
If the fix is simply reseating the CN90 connector, there may be no parts cost at all. Replacing a damaged ice maker thermistor sensor typically costs between $15 and $60 for the part depending on the specific model. If a professional technician is needed for diagnosis and repair, total service costs including labor generally range from $100 to $300.
Will resetting my LG refrigerator clear the R-1-ⓐ error code?
A reset may temporarily clear the code from the display, but if the underlying sensor circuit problem has not been corrected, the error will return. The main PCB continuously monitors the sensor signal, so any persistent wiring fault, bad connector, or failed thermistor will trigger the code again once the refrigerator resumes normal operation. The root cause must be diagnosed and repaired for the error to stay cleared.

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