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Error code reference

LG Refrigerator Error Code F1+F2+F3+F4+F5

Poor communication between main PCB and display PCB

LG codesLG refrigerator codes

Poor communication between main PCB and display PCB - no communication for 30 consecutive seconds.

First step from the service manual

Check connector between main PCB and display PCB; check TR on communication part.

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

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What F1+F2+F3+F4+F5 means on a LG refrigerator

The F1+F2+F3+F4+F5 error code on an LG refrigerator indicates a complete communication failure between the main PCB (printed circuit board) and the display PCB. Specifically, the control system has detected an absence of valid communication signals between these two boards for 30 or more consecutive seconds. This triggers all five fault flags simultaneously, which is why the full F1 through F5 sequence appears together rather than as individual codes. The communication link between these boards is essential for the display to relay user inputs and for the main board to report operational status, temperature readings, and system alerts.

The communication circuit typically relies on a transistor (TR) on the communication portion of one or both boards to transmit and receive serial data signals. If this transistor fails, becomes thermally degraded, or if the wiring harness connector between the two boards develops a fault, the signal path is broken and the 30-second timeout is triggered. Causes can range from a loose or corroded connector to an open circuit in the wiring harness, a failed communication transistor, or a defective main or display PCB.

Diagnosis should begin at the physical connector linking the main PCB and display PCB. Inspect for bent pins, corrosion, moisture intrusion, or a partially seated connector. If the connector is secure and undamaged, the next step is to evaluate the transistor on the communication circuit of both boards. A failed transistor will typically require board-level repair or PCB replacement. Both boards should be evaluated before replacement to avoid unnecessary part costs.

Source: manufacturer service documentation.

Common causes of F1+F2+F3+F4+F5

  1. 01

    Loose or disconnected wiring harness connector

    Wiring / connection

    The connector linking the main PCB and display PCB may have worked loose over time due to vibration or handling. Inspect the connector for proper seating, bent pins, or partial disconnection.

  2. 02

    Corroded or damaged connector pins

    Wiring / connection

    Moisture or oxidation on the connector pins between the two boards can interrupt the communication signal. Look for discoloration, pitting, or white residue on the connector contacts.

  3. 03

    Failed communication transistor (TR)

    Part replacement

    The transistor responsible for transmitting data signals on the communication circuit of the main or display PCB can fail, completely severing the communication link. This typically requires board-level repair or PCB replacement.

  4. 04

    Defective display PCB

    Part replacement

    The display board itself may have failed, preventing it from sending or receiving communication signals to the main board. If wiring and connectors check out, the display PCB is a likely suspect.

  5. 05

    Defective main PCB

    Part replacement

    A failed main control board can also be the source of the communication breakdown, particularly if the communication transistor or related circuitry on that board has failed. This is typically diagnosed after ruling out the connector and display board.

See the test procedure for each cause

Frequently asked questions about F1+F2+F3+F4+F5

What does F1+F2+F3+F4+F5 mean on a LG refrigerator?
This combined error code signals a loss of communication between the main PCB and the display PCB that has lasted for 30 consecutive seconds or longer. All five fault codes appear together because the communication failure affects the entire status reporting system. It is not five separate faults but one underlying issue: the two boards are no longer exchanging data.
Can I fix the F1+F2+F3+F4+F5 error myself?
If the cause is a loose or disconnected connector between the main PCB and display PCB, a knowledgeable DIYer can reseat or inspect the connector without special tools. However, if the fault lies with a failed transistor on the communication circuit or a defective PCB, that repair is more complex and typically requires a technician or board replacement. Always unplug the refrigerator before inspecting any internal wiring.
Will resetting my LG refrigerator clear the F1+F2+F3+F4+F5 error?
A power reset, such as unplugging the unit for a few minutes and plugging it back in, may temporarily clear the code if the communication dropout was caused by a transient glitch. However, if the underlying cause is a physical connector issue or a failed component, the code will return within 30 seconds of the boards failing to re-establish communication. A reset is a useful first step but is not a fix on its own.
Is it safe to keep using my refrigerator while the F1+F2+F3+F4+F5 code is showing?
When this error is active, the display panel and main board are not communicating, which means the refrigerator may not respond correctly to temperature adjustments or display accurate readings. Food safety could be at risk if the cooling system is also affected. It is best to address the fault promptly and monitor food temperatures in the meantime.
How much does it cost to repair the F1+F2+F3+F4+F5 error on an LG refrigerator?
If the fix is simply reseating a connector, there may be little to no parts cost, though a service call fee typically ranges from $75 to $150. Replacing a display PCB generally costs between $100 and $250 for the part, while a main PCB replacement can range from $150 to $400 or more depending on the model. Labor costs vary by region and technician.

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