mypros+
Error code reference

LG Refrigerator Error Code Er 5

Communication error between main PCB and display PCB (continuous information exchange fails for more than 2…

LG codesLG refrigerator codes

Communication error between main PCB and display PCB (continuous information exchange fails for more than 2 minutes)

First step from the service manual

Check lead wire connections between main PCB and display PCB

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 Er 5.

  • 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 Er 5 means on a LG refrigerator

Er 5 on an LG refrigerator indicates a communication failure between the main PCB (printed circuit board) and the display PCB. These two boards continuously exchange data signals, and when that exchange is interrupted or corrupted for more than 2 minutes, the refrigerator triggers the Er 5 fault code. The communication link between these boards is essential for the display to show temperature readings, receive user input, and report operational status back to the main control board.

The most common starting point for diagnosing Er 5 is the lead wire harness that connects the main PCB to the display PCB. This wiring can become loose at the connectors, develop breaks from repeated door operation, or suffer damage from moisture or pinching. A compromised connection interrupts the data signal and triggers the fault after the 2-minute threshold is reached.

If the wiring and connectors are intact and properly seated, the fault may point to a failure within one of the two boards themselves. Either the main PCB or the display PCB can develop internal faults that prevent them from maintaining continuous communication. In these cases, the defective board must be identified through systematic testing and replaced. Environmental factors like voltage irregularities or power surges can also contribute to board-level failures that produce this error.

Source: manufacturer service documentation.

Common causes of Er 5

  1. 01

    Loose or disconnected lead wire harness

    Wiring / connection

    The wire connector linking the main PCB to the display PCB may have come loose or partially disconnected. Inspect both ends of the harness for secure seating at each connector port.

  2. 02

    Damaged lead wire harness

    Part replacement

    Repeated door opening and closing can stress, pinch, or fray the wire harness between the boards. Visually trace the harness for breaks, cuts, or areas where insulation has worn through.

  3. 03

    Faulty display PCB

    Part replacement

    The display PCB may have failed internally and is unable to send or receive communication signals. If wiring checks out, the display board is a likely suspect.

  4. 04

    Faulty main PCB

    Part replacement

    The main control board may have developed an internal fault that prevents it from maintaining the communication signal. This is typically diagnosed after the wiring and display PCB have been ruled out.

  5. 05

    Power surge or voltage irregularity

    Part replacement

    A power surge can disrupt or permanently damage communication circuits on either board. If the error appeared after a power event, both boards should be evaluated for damage.

See the test procedure for each cause

Frequently asked questions about Er 5

What does Er 5 mean on a LG refrigerator?
Er 5 indicates a communication error between the main PCB and the display PCB. The refrigerator monitors the data exchange between these two boards continuously, and if that communication fails for more than 2 minutes, Er 5 is triggered. The issue is most often related to the lead wire connections between the two boards, though a faulty board can also be the cause.
How do I fix the Er 5 error on my LG refrigerator?
Start by checking the lead wire harness that connects the main PCB to the display PCB. Make sure the connectors are fully seated at both ends and that the wiring is not damaged or pinched. If the connections are secure and undamaged, the next step is testing or replacing the display PCB, followed by the main PCB if the display board is not the issue.
Will resetting my LG refrigerator clear the Er 5 code?
A power reset may temporarily clear the Er 5 code, but if the underlying wiring or board problem has not been corrected, the error will return once the communication failure persists for more than 2 minutes again. A reset is a useful first step to confirm whether the fault is intermittent, but it is not a fix for a hardware problem.
Is it safe to keep using my LG refrigerator when it shows Er 5?
The refrigerator may continue cooling in some cases when Er 5 is active, but without reliable communication between the main board and display, you lose the ability to accurately monitor temperatures or control settings. Food safety can be at risk if the cooling system is also affected. It is best to address the error promptly rather than relying on the unit to operate normally.
How much does it cost to repair an Er 5 error on an LG refrigerator?
If the fix is simply reseating or replacing the wire harness, costs are relatively low, typically in the range of $20 to $80 for parts and minimal labor. Replacing a display PCB generally runs between $100 and $250 including parts and labor, while a main PCB replacement can range from $150 to $400 or more depending on the model and service provider.

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