Ad Space — Top Banner

Error Code CH05

LG Air Conditioner

Severity:

Source: OnlyErrorCodes.com — Every error code. One place.

LG Air Conditioner Error Code CH05 — Fix

What Does This Error Mean?

LG Error Code CH05 means the indoor unit has lost communication with the outdoor unit. A power reset clears CH05 caused by a power glitch. If it returns, the communication wiring or a PCB requires professional inspection.

Affected Models

  • LG Artcool Series
  • LG Dualcool Series
  • LG Standard Plus Series
  • LG DUALCOOL Premium

Common Causes

  • Communication wiring between indoor and outdoor units loose or damaged
  • Indoor unit PCB communication fault
  • Outdoor unit PCB communication fault
  • Power surge disrupting communication settings

How to Fix It

  1. Perform a full power reset.

    Turn the AC off at the remote. Turn off the circuit breaker or isolator supplying the indoor unit and wait 5 minutes. Restore power and switch the unit on. If CH05 was caused by a transient communication glitch, it will not return.

  2. Inspect the communication cable connection.

    The indoor and outdoor units connect via a communications cable (typically cores 3 and 4 in the inter-unit cable). If accessible, check that the connector terminals are fully seated on both units. Do not work on live wiring — isolate first.

  3. Check for storm or surge history.

    CH05 commonly follows a power surge or lightning strike. Mention any recent electrical events to the technician — it helps identify which PCB is more likely affected.

  4. Check the ThinQ app for more detail.

    LG ThinQ-enabled units display additional diagnostic information in the app. Open the LG ThinQ app, select the air conditioner, and check the Smart Diagnosis or error log section for any sub-codes.

  5. Book an LG-authorised service agent.

    Use the LG website to find a certified service agent. Provide the CH05 code and any sub-codes. CH05 repair typically involves testing both PCBs and the inter-unit wiring before replacing the faulty component.

When to Call a Professional

If a power reset does not clear CH05, the communication wiring or PCB has failed. Contact an LG-authorised service agent — do not attempt to repair wiring without electrical qualifications.

Frequently Asked Questions