CodeRegistry
Brands
  1. Home
  2. LG
  3. Air Conditioning
  4. 05
About·Privacy·Terms

CodeRegistry — Your global library for technical solutions.

For your safety: always follow the equipment manufacturer’s official manuals. CodeRegistry is an independent help site and is not affiliated with the brands listed here.

05

Error 05 - Communication error between indoor and outdoor units

LG · Air Conditioning

What does 05 mean?

This code indicates a communication fault between the indoor and outdoor units. It appears approximately 5 minutes after powering up the system.

Common Causes

  • Incorrectly installed interconnecting wiring
  • Loose or damaged wiring connections
  • Interfering devices connected to the communication line

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Ensure that both 'Comms' and 'Neutral' connections on the interconnecting cable are un-switched.

  2. 2

    Verify that all connections at both the indoor and outdoor units are correct and securely fastened.

  3. 3

    Temporarily remove any other devices connected to the interconnecting cable to see if the fault clears.

  4. 4

    Check the interconnecting cables for any short or open circuits, and ensure connections between the terminal rail and PCB are secure.

Browse all codes in this manual (97)
Verified technical data. Last updated: April 2026

Related Faults

01Error 01 - Indoor air sensor open or short circuit02Error 02 - Inlet pipe sensor open or short circuit03Error 03 - Communication error between indoor unit and wired remote
Source: LG Air Conditioning
Open Manual (Page 1)Search more codes in this manual