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Error code reference

LG Refrigerator Error Code CF-SENSOR

CF compartment sensor error

LG codesLG refrigerator codes

CF compartment sensor error: electric wire cut, short-circuit, contact failure, or sensor housing missing; displayed when sensor temperature is not lower than 122°F nor higher than -58°F.

First step from the service manual

Check the voltage between Main PCB CN 30 No. 5 ↔ 7 to see if it is between 4.5V and 1.0V.

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

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What CF-SENSOR means on a LG refrigerator

The CF-SENSOR error on an LG refrigerator indicates a fault with the CF compartment temperature sensor. This sensor monitors the temperature within the CF (Custom Fresh or convertible) compartment and reports readings back to the main PCB. The error is triggered when the sensor returns a temperature value that falls outside the valid operating range: specifically, when the reported temperature is not below 122°F and not above -58°F. This out-of-range condition tells the control board that the sensor signal is implausible, pointing to an electrical or physical problem rather than an actual temperature extreme.

The most common root causes fall into three categories: an open circuit in the sensor wiring (a cut or broken wire), a short circuit in the harness, poor contact at a connector, or a physically missing or dislodged sensor housing. Any of these conditions will cause the sensor to output a voltage that the main PCB cannot interpret as a valid temperature reading. The first diagnostic step is to measure the voltage across Main PCB connector CN 30, pins 5 and 7. A reading between 1.0V and 4.5V indicates the sensor and wiring are functioning correctly in that range. A voltage outside those bounds, or no voltage at all, confirms a wiring, connector, or sensor fault.

If the voltage at CN 30 No. 5 and 7 is out of specification, technicians should inspect the full wiring harness from the main PCB to the sensor for visible damage, pinching, or corrosion at connector pins. If the wiring and connectors check out, the sensor itself is likely faulty and will need replacement. A missing sensor housing can also cause erratic or absent readings, so confirming the sensor is properly seated and secured in its mounting location is an important part of the physical inspection.

Source: manufacturer service documentation.

Common causes of CF-SENSOR

  1. 01

    Connector contact failure at Main PCB

    Wiring / connection

    Loose, corroded, or improperly seated connector pins at CN 30 on the main PCB are a frequent cause of this error. Inspect pins 5 and 7 on that connector for corrosion, bending, or looseness and reseat the connector firmly.

  2. 02

    Cut or broken sensor wire

    Part replacement

    The wiring harness between the main PCB and the CF compartment sensor can be cut, pinched, or broken, causing an open circuit. Visually trace the harness and use a multimeter to check for continuity along the wire.

  3. 03

    Short circuit in the sensor harness

    Part replacement

    Wiring that has worn insulation or been pinched can short against the refrigerator chassis or other wiring, pulling the sensor signal voltage out of the 1.0V to 4.5V acceptable range. Look for areas where the harness contacts metal edges or moving parts.

  4. 04

    Faulty or failed CF compartment sensor

    Part replacement

    The sensor itself can fail internally, producing a reading that falls outside the valid temperature range of -58°F to 122°F. If wiring and connectors test correctly but the voltage at CN 30 pins 5 and 7 is still out of spec, the sensor unit requires replacement.

  5. 05

    Missing or dislodged sensor housing

    Wiring / connection

    If the sensor housing is absent or has come loose from its mounting point, the sensor cannot accurately read the compartment temperature and may produce an invalid signal. Physically verify that the sensor is present and properly secured in its bracket or housing.

See the test procedure for each cause

Frequently asked questions about CF-SENSOR

What does CF-SENSOR mean on a LG refrigerator?
The CF-SENSOR error means the main control board has detected a problem with the CF compartment temperature sensor. The sensor is reporting a value outside the valid range of -58°F to -122°F, which indicates a cut wire, short circuit, contact failure at a connector, or a missing sensor housing. The refrigerator flags this error to alert you that it cannot reliably monitor or regulate the temperature in that compartment.
Can I fix the CF-SENSOR error myself?
Some causes of this error, such as a loose or unseated connector, can be addressed without special tools by carefully reseating the connector at Main PCB CN 30 pins 5 and 7. However, diagnosing a cut wire, short circuit, or failed sensor requires a multimeter and comfort working around low-voltage electronics. If you are not confident with basic electrical testing, a qualified appliance technician is recommended to avoid further damage.
Is it safe to keep using my refrigerator while the CF-SENSOR error is showing?
With the CF-SENSOR error active, the refrigerator cannot accurately monitor the CF compartment temperature, which means food stored there may not be kept at a safe or consistent temperature. It is best to move temperature-sensitive items to another section of the refrigerator or a separate unit until the sensor issue is resolved. The error does not represent an electrical safety hazard to your home, but it does pose a food safety concern.
Will resetting the refrigerator clear the CF-SENSOR error?
A power reset may temporarily clear the error display, but the code will return if the underlying fault in the wiring, connector, or sensor has not been repaired. Resetting is useful as a first step to confirm the error is active and persistent, but it is not a fix on its own. The root cause must be diagnosed and corrected to permanently resolve the error.
How much does it cost to repair a CF-SENSOR error on an LG refrigerator?
Repair costs vary depending on the cause. If the issue is simply a loose connector, there may be no parts cost at all, though a service call fee typically runs in the range of $75 to $150. If the sensor itself needs replacement, the part cost generally falls in the $20 to $60 range plus labor. Wiring harness repairs can add to the cost depending on the extent of the damage.

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