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Error code reference

LG Refrigerator Error Code E 5

Fridge defrost sensor open or short circuit (RSG5B* model display).

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Fridge defrost sensor open or short circuit (RSG5B* model display).

First step from the service manual

Check voltage between MAIN PCB CN30 #10 and #9; should be within 4.5V~1.0V.

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

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What E 5 means on a LG refrigerator

The E 5 error code on LG RSG5B* series refrigerators indicates a fault detected in the fridge compartment defrost sensor circuit. The defrost sensor monitors the temperature of the evaporator coil and signals the main control board when the defrost cycle should end. When the board detects that the sensor circuit is either open (broken or disconnected) or shorted (wiring or sensor failure causing incorrect resistance), it logs this fault and displays E 5 on the control panel. Without accurate input from this sensor, the refrigerator cannot reliably manage defrost cycles, which can lead to ice buildup on the evaporator and reduced cooling performance.

Diagnosis begins at the main PCB connector CN30, specifically between pins 10 and 9. The voltage across these two pins should read within the range of 1.0V to 4.5V under normal operating conditions. A reading outside this range indicates a problem somewhere in the sensor circuit, whether in the sensor itself, the wiring harness, or the PCB. An open circuit typically results in a voltage near the supply rail, while a short to ground will pull the reading toward 0V.

The defrost sensor is a thermistor, meaning its resistance changes with temperature. If the thermistor element has degraded or the wiring to it has been damaged by ice, moisture, or mechanical stress during a service, the circuit will report out-of-range values. Connector corrosion at the PCB or sensor end is also a frequent contributor, particularly in humid environments where condensation can infiltrate connector housings over time.

Source: manufacturer service documentation.

Common causes of E 5

  1. 01

    Failed defrost sensor (thermistor)

    Part replacement

    The thermistor element itself can fail open or short out due to age or thermal stress. This is the most common root cause and will produce a voltage reading outside the 1.0V to 4.5V range at CN30 pins 10 and 9.

  2. 02

    Damaged or broken wiring harness

    Part replacement

    The wiring between the sensor and the main PCB can crack, fray, or break, especially near routing points where wires are exposed to ice or sharp edges. Inspect the full length of the harness for visible damage or breaks.

  3. 03

    Loose or corroded connector at CN30

    Wiring / connection

    Corrosion or a poor connection at the CN30 connector on the main PCB can interrupt the sensor signal. Check that the connector is fully seated and inspect the pins for oxidation or moisture damage.

  4. 04

    Connector corrosion at the sensor end

    Wiring / connection

    The connector at the sensor itself can corrode or loosen over time in humid refrigerator environments. Disconnecting and inspecting the sensor-side connector for green or white oxidation on the terminals can reveal this cause.

  5. 05

    Faulty main PCB

    Part replacement

    If the wiring, connectors, and sensor all test correctly but the voltage at CN30 pins 10 and 9 remains out of range, the main control board may have a defective input circuit. This is the least common cause and should be considered only after ruling out the sensor and harness.

See the test procedure for each cause

Frequently asked questions about E 5

What does E 5 mean on a LG refrigerator?
E 5 on an LG RSG5B* series refrigerator indicates an open or short circuit in the fridge compartment defrost sensor. The main PCB monitors the defrost sensor circuit and triggers this code when the signal voltage at connector CN30 pins 10 and 9 falls outside the expected 1.0V to 4.5V range. The defrost sensor is a thermistor that helps the refrigerator determine when to end a defrost cycle, so a fault here can impact cooling performance over time.
Can I fix the E 5 error on my LG refrigerator myself?
A knowledgeable DIYer can start by inspecting the wiring harness and connectors associated with the defrost sensor for visible damage, corrosion, or loose connections, as these can sometimes be corrected without replacing parts. If the sensor itself has failed, replacing the defrost thermistor is a moderate-difficulty repair that involves accessing the evaporator area. Voltage testing at CN30 pins 10 and 9 on the main PCB requires a multimeter and some comfort working with electronics.
Is it safe to keep using my refrigerator when E 5 is displayed?
The refrigerator may continue to run in a limited capacity, but operating it with a defective defrost sensor carries risks. Without a working defrost sensor, ice can accumulate on the evaporator coil, which will restrict airflow and eventually cause the fridge compartment to lose cooling ability. Food safety could be compromised if temperatures rise, so the issue should be diagnosed and repaired promptly.
How much does it cost to repair the E 5 error on an LG refrigerator?
If the defrost sensor is the cause, the part itself typically costs between $15 and $50 depending on the supplier, making it a relatively affordable repair if done yourself. Professional repair service, including labor, generally runs between $100 and $250 for a sensor replacement. If the main PCB is the faulty component, costs increase significantly, often ranging from $200 to $450 or more including parts and labor.
Will resetting my LG refrigerator clear the E 5 error code?
A power reset may temporarily clear the E 5 code from the display, but the error will return if the underlying fault in the defrost sensor circuit has not been corrected. Resetting does not repair a failed thermistor, damaged wiring, or corroded connector. The code should be treated as an active diagnostic indicator requiring inspection and repair rather than a one-time alert that can be dismissed.

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