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LG Air Conditioner CH05 Error Code

Indoor and outdoor units aren't communicating. Here is what it means and how to clear it, easiest fix first.

CH05
Moderate DIY

The indoor unit has lost its signal link with the outdoor unit on a split system. LG lists a temporary power or communication glitch, a tripped outdoor breaker, a loose connector or wiring fault in the cable between the units, and a main board fault as possible causes.

LG lists CH53 and E0 for the same communication problem on some models. On certain models a display reading "E0" is not a fault at all but means the energy-saving kW Manager feature is active. If the code first appeared right after installation or after the unit was moved, the wiring between the units is the likely cause. LG says its error-code guide covers all models, so the exact code and its meaning can differ on yours; check your owner's manual.

Safety first: unplug the air conditioner (or switch off its breaker) before touching filters, hoses or panels. If you smell burning or gas, or see water near the outlet, stop and call a professional.

How to fix LG CH05

  1. Check the breakers for both units

    Look at your electrical panel for a tripped breaker. Mini-splits often have one breaker for the outdoor unit and another for the indoor unit, and a tripped outdoor breaker alone will trigger this code.

  2. Power both units down together

    Switch off the indoor and outdoor breakers and leave them off for about five minutes. Switch both back on at the same time, then restart the system with the remote.

  3. Note when the code started

    If CH05 showed up right after the system was installed or relocated, contact the installer rather than LG first, because a wiring error at installation is the usual cause.

When to call a technician

If the code returns after a full power reset, or a breaker trips again, stop resetting it and book a technician to test the interconnecting cable and control boards.

Parts that commonly cause CH05

Order parts by your exact model number so they fit.

Other LG air conditioner codes

Frequently asked questions

What does CH05 mean on a LG air conditioner?

The indoor unit has lost its signal link with the outdoor unit on a split system. LG lists a temporary power or communication glitch, a tripped outdoor breaker, a loose connector or wiring fault in the cable between the units, and a main board fault as possible causes.

Can I fix LG CH05 myself?

Often. The first steps above are safe checks a homeowner can do. If they don't clear CH05, the cause is likely a worn part that needs replacing.

What if CH05 keeps coming back?

A code that returns after a reset and the checks above usually means a part is wearing out. Note when CH05 appears (which cycle, how often) and have your model number ready; it helps a technician bring the right part on the first visit.

Last reviewed 2026-10-19. Codes and steps can vary by model; check your owner's manual.

References