Lg Mini Split H05 Error Code

Updated 2026-08-29 · review status: manual-verified Last verified: 2026-08-29

Quick answer

H05 on LG units (displayed as CH05) is a communication error between the indoor and outdoor units. Check the outdoor breaker and power both breakers off for 5 minutes, then back on together - if the code persists, wiring or board service is required.

Severity: high · DIY difficulty: beginner

Safety

Stop after the 5-minute dual-breaker reset and checking that the outdoor unit powers on. Do not open panels, meter the signal wiring, or inspect control boards - communication wiring and board diagnosis is technician-only.

What H05 means

H05/CH05 means the indoor and outdoor units are not exchanging signals normally. LG's official guidance is to check whether the outdoor-unit breaker tripped, switch both indoor and outdoor breakers off for 5 minutes, restore them together, and call for service if the code persists.

Code meaning varies by series

  • Models that display codes without the CH prefix: Shown as H05 or 05 - same indoor/outdoor communication error

Causes, ranked

  1. 1. Temporary communication or power error occasional diy-ok

    Check: Check whether the outdoor-unit breaker tripped; if so (or regardless), turn both indoor and outdoor breakers off for 5 minutes, then turn both on at the same time and retry.

    Fix: If the code clears, run the system and watch for recurrence; a returning code needs service.

  2. 2. Faulty, loose, or miswired connecting cable between units occasional pro-only

    Check: Terminal and continuity checks are not homeowner work.

    Fix: Technician: verify wiring at both terminal blocks, repair or replace the interconnecting cable.

  3. 3. Loose connector or damaged signal wire occasional pro-only

    Check: Connectors sit behind panels that must not be opened by homeowners.

    Fix: Technician: reseat or replace connectors and damaged conductors.

  4. 4. Indoor or outdoor main circuit board fault occasional pro-only

    Check: Board diagnosis requires service-mode readings.

    Fix: Technician: diagnose the main PCB on whichever unit dropped the signal, replace if failed.

Related codes

lg/e0 · lg/h53 · lg/h32 · lg/h33

Commonly searched as: "lg h05" · "lg error code h05" · "lg air conditioner h05"

Sources

  • LG Air Conditioner - Troubleshooting a CH05 Error Code - LG USA Support — verified 2026-08-29
  • LG Mini Split Error Codes: CH05, CH38 and What Each Means - Heat Pump Answers — verified 2026-08-29
  • LG Mini Split Error Codes - All CH Codes Explained - ErrorCodeFixes — verified 2026-08-29