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LG air conditioner error codes

13 codes that LG publishes for its air conditioners, each with what it means, the likely cause, what you can safely check and when to call an installer. Tap your code:

Air conditioner: do only the checks the maker gives the owner for that code — clean the air filter, clear the air path, switch the power off and on at the plug or circuit breaker. Keep the covers on: refrigerant, wiring and circuit boards are not owner work. Anything else is for the installer or the maker’s service engineer: in the UK and EU only an F-gas certified technician may open the refrigerant circuit. Codes that need one are marked Installer.

Read this first

LG air conditioners show a fault as CH and a number — CH05, CH38 — on the indoor unit’s display, and some LG models show a short letter code (E0, F4, E6) instead. The codes and what to do come from LG’s own guide to air-conditioner error codes on its US support site, written for owners; LG says a blinking LED or a CH code means the unit needs inspection. The guide covers LG split, window and portable units, and a few codes apply only to some of them (CH04 on window and portable units, CH07 on systems with several indoor units). Models differ: your model’s manual is the authority.

CH05 E0 CH53 Indoor and outdoor unit not communicating

What it means
The indoor and outdoor units have lost communication with each other.
Likely cause
A communication error between the indoor and outdoor units.
What you can safely check

Air conditioner: do only the checks the maker gives the owner for that code — clean the air filter, clear the air path, switch the power off and on at the plug or circuit breaker. Keep the covers on: refrigerant, wiring and circuit boards are not owner work.

  • Power-cycle the unit the way LG says: unplug the power cord or switch off the circuit breaker, wait 5 minutes, then restore the power.
When to call an installer
If the code persists after the reset, LG says to request service: call an installer or LG service.

Source: LG, LG USA Support — [LG Air Conditioner] Guide to Error Codes (updated 02/23/2026) Checked 2026-09-29.

CH38 Low on refrigerant

LG’s guide also lists F4 with this fault on some models, and lists F4 again under test-run errors, so F4 alone does not tell you which.

What it means
The air conditioner is low on refrigerant gas, and stops to protect itself from damage.
Likely cause
Too little refrigerant; straight after installation, LG also points to the piping connections.
What you can safely check

Air conditioner: do only the checks the maker gives the owner for that code — clean the air filter, clear the air path, switch the power off and on at the plug or circuit breaker. Keep the covers on: refrigerant, wiring and circuit boards are not owner work.

  • If the code appeared during normal use (not just after installation), power-cycle the unit: unplug it or switch off the breaker, wait 5 minutes, then restore the power.
When to call an installer
If the code appeared after installation, LG says to have the installation technician check for a refrigerant shortage and the piping connections; if it comes back during normal use, contact LG support. Only an F-gas certified technician may recharge refrigerant.

Source: LG, LG USA Support — [LG Air Conditioner] Guide to Error Codes (updated 02/23/2026) Checked 2026-09-29.

CH61 Overheating

What it means
The outdoor unit is overheating in cooling mode, or the indoor unit is overheating in heating mode.
Likely cause
Air cannot get to or away from the unit: poor ventilation around the outdoor unit when cooling, or a dirty indoor filter when heating.
What you can safely check

Air conditioner: do only the checks the maker gives the owner for that code — clean the air filter, clear the air path, switch the power off and on at the plug or circuit breaker. Keep the covers on: refrigerant, wiring and circuit boards are not owner work.

  • Cooling: check the ventilation around the outdoor unit — clear obstacles and make sure its air can escape.
  • Heating: clean the indoor unit’s filter.
  • Then power-cycle the unit to clear the code: unplug it or switch off the breaker, wait 5 minutes, then restore the power.
When to call an installer
If the code persists, LG says to request a service technician.

Source: LG, LG USA Support — [LG Air Conditioner] Guide to Error Codes (updated 02/23/2026) Checked 2026-09-29.

CH10 E6 Indoor fan fault

What it means
There is a problem with the indoor unit’s fan.
Likely cause
Something is stopping the fan or its air path, or the fan itself has a fault.
What you can safely check

Air conditioner: do only the checks the maker gives the owner for that code — clean the air filter, clear the air path, switch the power off and on at the plug or circuit breaker. Keep the covers on: refrigerant, wiring and circuit boards are not owner work.

  • LG says to check for debris around the fan and remove it. Keep the covers on and keep fingers out of the unit.
When to call an installer
If the problem continues, LG says to contact a service technician.

Source: LG, LG USA Support — [LG Air Conditioner] Guide to Error Codes (updated 02/23/2026) Checked 2026-09-29.

CH67 EF Outdoor fan fault

What it means
There is a problem with the outdoor unit’s fan.
Likely cause
Debris or snow around the outdoor fan, or a fault in the fan itself.
What you can safely check

Air conditioner: do only the checks the maker gives the owner for that code — clean the air filter, clear the air path, switch the power off and on at the plug or circuit breaker. Keep the covers on: refrigerant, wiring and circuit boards are not owner work.

  • Clear debris or snow built up around the outdoor unit and its fan grille, from outside the unit. Keep hands and tools out of the grille.
When to call an installer
If the problem continues, LG says to contact a service technician.

Source: LG, LG USA Support — [LG Air Conditioner] Guide to Error Codes (updated 02/23/2026) Checked 2026-09-29.

CH54 Reverse phase detected

What it means
The unit has detected the wrong phase order on its power supply (three-phase units).
Likely cause
LG says it can follow a temporary power outage or electrical work.
What you can safely check

Air conditioner: do only the checks the maker gives the owner for that code — clean the air filter, clear the air path, switch the power off and on at the plug or circuit breaker. Keep the covers on: refrigerant, wiring and circuit boards are not owner work.

  • Reset the air conditioner’s circuit breaker.
When to call an installer
If the error persists, LG says the unit needs inspection: request LG service or call your installer. If electrical work was done, tell the electrical contractor about the reverse-phase error.

Source: LG, LG USA Support — [LG Air Conditioner] Guide to Error Codes (updated 02/23/2026) Checked 2026-09-29.

CH93 Indoor–outdoor communication problem

What it means
Another code for a communication problem between the indoor and outdoor units, mostly on post-2021 models.
Likely cause
Loose power connections after installation, or a temporary fault during use.
What you can safely check

Air conditioner: do only the checks the maker gives the owner for that code — clean the air filter, clear the air path, switch the power off and on at the plug or circuit breaker. Keep the covers on: refrigerant, wiring and circuit boards are not owner work.

  • During normal use, power-cycle the unit: unplug it or switch off the breaker, wait about 5 minutes, then restore the power.
When to call an installer
Straight after installation, LG says the power connections need checking — that is for the installer. Request service if the code persists.

Source: LG, LG USA Support — [LG Air Conditioner] Guide to Error Codes (updated 02/23/2026) Checked 2026-09-29.

CH04 Drainage problem or condensate tank full

What it means
The unit has a drain problem, or its condensate tank is too full.
Likely cause
A malfunction of the indoor unit’s drain, or — on window and portable units — more condensate than usual on rainy or very humid days.
What you can safely check

Air conditioner: do only the checks the maker gives the owner for that code — clean the air filter, clear the air path, switch the power off and on at the plug or circuit breaker. Keep the covers on: refrigerant, wiring and circuit boards are not owner work.

  • On a window or portable unit, drain the condensate water.
  • Then power-cycle the unit: unplug it or switch off the breaker, wait 5 minutes, then restore the power.
When to call an installer
If the code returns, request LG service or call your installer: on a split unit the drain is inside the indoor unit.

Source: LG, LG USA Support — [LG Air Conditioner] Guide to Error Codes (updated 02/23/2026) Checked 2026-09-29.

CH07 Indoor units set to different modes

What it means
Two or more indoor units on the same outdoor unit are set to conflicting modes.
Likely cause
One indoor unit is cooling while another is heating, and a shared outdoor unit cannot do both.
What you can safely check

Air conditioner: do only the checks the maker gives the owner for that code — clean the air filter, clear the air path, switch the power off and on at the plug or circuit breaker. Keep the covers on: refrigerant, wiring and circuit boards are not owner work.

  • Set every indoor unit to the same mode — all cooling or all heating.
When to call an installer
No installer needed once the modes match; if the code stays, request LG service.

Source: LG, LG USA Support — [LG Air Conditioner] Guide to Error Codes (updated 02/23/2026) Checked 2026-09-29.

A code that is not listed here

For a CH code not listed here, LG’s guide gives the same first step as for most codes: unplug the unit or switch it off at the circuit breaker, wait 5 minutes, restore the power, and request service if the code comes back.

We list only codes the source below states. If your code is not here, it may belong to a model the source does not cover: your model’s manual is the authority.

Related pages

Source

Every code on this page comes from this page, published by LG and read on the date shown. Meanings are written in our own words; nothing is taken from other makes, other models or third-party code sites.