LG CH Code Library
LG Air Conditioner Error Codes
LG air conditioner error codes appear as the letters CH followed by a number, and each one points to a part or a protection system inside your unit. This guide explains how LG codes are organised, how to read them on your system, and what you can safely check before a licensed technician is needed.
Start Here
What Are LG Air Conditioner Error Codes?
Every modern LG split system and ducted system watches itself constantly. Sensors report temperatures, the control boards check voltage and current, and the indoor and outdoor units talk to each other many times a minute. When one of those readings goes outside its safe window, the unit stops and shows a code.
That code is not a random number. It is a short message from the control board telling you, and the technician, which circuit raised the alarm. Reading it correctly saves time, because the technician can bring the right test gear and often the right part on the first visit.
Rapid Air Cooling is a booking service. We take your call, note the LG fault code, and arrange a licensed technician to attend. We are not affiliated with LG and are not an authorised service agent for LG. The technicians we send hold the licences their work requires.
Use the cards below to jump straight to the code showing on your unit. Each page explains the fault in plain words, lists likely causes, and covers the checks that are safe for a homeowner.
LG CH01
Indoor room air sensor reading fault.
LG CH02
Indoor coil inlet pipe sensor fault.
LG CH05
Lost communication between indoor and outdoor units.
LG CH10
Indoor fan motor locked or not turning properly.
LG CH21
DC peak current trip in the outdoor inverter.
LG CH26
Inverter compressor failed to start or rotate.
LG CH38
Low refrigerant protection has stopped the system.
LG CH41
Compressor discharge pipe sensor fault.
LG CH44
Outdoor air temperature sensor fault.
LG CH61
Outdoor condenser coil running too hot.
LG CH62
Inverter board heat sink overheating.
LG CH67
Outdoor fan motor locked or stalled.
Code Structure
How Are LG CH Codes Organised?
LG groups its codes by number range, and once you know the pattern, the code itself tells you roughly where to look. The ranges below are a general guide for residential split and ducted systems. Some commercial and multi split equipment uses extra codes, and a few numbers change meaning between model generations.
Single Digits: Indoor Unit
- Indoor temperature sensors, such as the room air and coil pipe sensors
- Indoor to outdoor communication
- Wired controller and drain related alerts on some models
- Indoor memory chip faults
Tens: Fans and Inverter Power
- The indoor fan motor
- Current and voltage protection on the outdoor inverter board
- Compressor start and rotation monitoring
- Supply voltage that is too high or too low
Thirties and Forties: Refrigerant and Outdoor Sensors
- Discharge temperature and low refrigerant protection
- Outdoor sensors on the discharge pipe, coil, suction line and ambient air
- Current sensing parts on the outdoor board
Fifties and Sixties: Outdoor Protection
- Outdoor side communication
- Condenser coil and heat sink overheating
- Heat sink sensor faults
- The outdoor fan motor
A useful rule of thumb is that sensor codes are usually the least urgent, while inverter, compressor and refrigerant codes deserve prompt attention. Communication codes sit in between, because the cause can be as simple as a tripped breaker or as involved as a failed board.
Reading the Display
How Do I Find the Error Code on My LG Unit?
How the code appears depends on the age and style of your LG system. Most wall mounted splits sold in Australia over recent years show the code directly on the indoor display. Older units and some slimline models without a numeric screen use flashing lights instead.
Indoor Unit Display
On models with a numeric display, the unit alternates between CH and a number, such as CH and then 05. Some displays show only the number. Write down exactly what you see, including any leading zero.
Flashing Indicator Lights
Units without a numeric display blink one or more indicator lights in a repeating pattern. The number of blinks, and which light blinks, maps to a code. The pattern differs between generations, so record a short video on your phone and let the technician decode it.
Wired Wall Controller
Ducted systems and many cassette units report codes on the wall controller. The screen usually shows the code number along with the address of the indoor unit that raised it.
Outdoor Board Lights
The outdoor inverter board also has status lights that technicians read during diagnosis. These sit behind a sealed electrical cover and are not something a homeowner should open.
Before you reset anything, take a photo of the display. Turning the unit off at the breaker can clear the code from the screen, and the technician will want to know exactly what appeared and when.
Quick Reference
What Does Each Common LG Code Mean?
The table below summarises the twelve codes we cover in detail. Meanings are described in general terms for residential LG split systems. If your unit is a multi split, a commercial model or a much older design, the technician will confirm the meaning against the service data for that series.
CH01: Room Air Sensor
The thermistor that reads air returning into the indoor unit has opened or shorted. The unit cannot judge room temperature.
CH02: Coil Inlet Sensor
The sensor on the indoor coil inlet pipe is reading out of range. This affects frost protection and heating control.
CH05: Communication
The indoor unit is not receiving valid signals from the outdoor unit. Power, wiring or a board can be the cause.
CH10: Indoor Fan
The indoor fan motor is locked, too slow, or not sending its speed feedback to the board.
CH21: DC Peak
The outdoor inverter detected a sudden current spike and shut the compressor drive down for protection.
CH26: Compressor Start
The inverter tried to start the compressor but could not detect proper rotation.
CH38: Low Refrigerant
The system has judged that the refrigerant charge is too low to run safely.
CH41: Discharge Sensor
The thermistor on the compressor discharge pipe has opened or shorted.
CH44: Outdoor Air Sensor
The outdoor ambient air thermistor is giving an impossible reading.
CH61: Condenser High Temperature
The outdoor coil is running hotter than its protection limit, usually from poor airflow or a charge problem.
CH62: Heat Sink Overheat
The heat sink on the outdoor inverter board has become too hot.
CH67: Outdoor Fan Lock
The outdoor brushless fan motor is not turning when the board expects it to.
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LG also uses codes outside this list. CH04 relates to drainage on many indoor units. CH07 appears on some multi split and dual systems when two indoor units ask for conflicting modes, such as one heating while another cools. CH53 is the outdoor side version of a communication fault. CH23 relates to low DC voltage on the inverter, and CH29 to excessive compressor current.
Some LG models also display letter codes such as E or F series codes, particularly on portable and window units. Those follow a different scheme and are not covered on these pages. If you see a code we have not listed, write it down and call us. The technician will look it up for your exact model.
Before You Call
What Can I Safely Check Myself?
A handful of simple checks clear a surprising number of LG faults, especially after storms or power interruptions. None of them involve opening the unit. Work through them in order and stop if anything looks damaged, smells burnt or makes unusual noises.
- Photograph or film the code on the display before doing anything else.
- Turn the unit off with the remote, then switch it off at the circuit breaker or outdoor isolator. Wait a few minutes before restoring power.
- Check the switchboard for a tripped breaker or safety switch, and note whether it trips again.
- Remove and rinse the indoor filters if they look dusty, then let them dry fully before refitting.
- Look at the outdoor unit from a safe distance. Clear leaves, plastic bags, garden growth and stored items away from the coil and fan grille.
- Check the visible end of the drain hose outside is not blocked, crushed or sitting in a puddle.
- Replace the remote batteries if the display or remote is behaving oddly.
If the code comes straight back after a power reset, or if the breaker trips again, leave the unit off. Repeated restarts can turn a minor electrical fault into a more expensive one, particularly with compressor and inverter codes.
Leave These Alone
What Should a Homeowner Never Attempt?
LG inverter systems carry mains voltage and store high DC voltage on the outdoor board long after the power is switched off. The refrigerant circuit is under pressure, and in Australia any work on it must be done by an ARCtick licensed technician. For those reasons, a few tasks are firmly off limits.
Opening Electrical Covers
Do not remove the cover over the indoor or outdoor control boards. Capacitors on the inverter board can hold a dangerous charge.
Touching Refrigerant Lines
Do not loosen flare nuts, service valves or caps. Refrigerant can cause cold burns, and releasing it is illegal.
Bypassing Protection
Never bridge a sensor, disconnect a switch or force the unit to run. Protection codes exist to stop serious damage.
The Service Visit
What Happens When a Technician Diagnoses an LG Code?
The process is similar for most LG faults, though the tests vary with the code. Knowing what to expect helps you prepare the space and answer the right questions.
You Call and Share the Code
We note the model, the code, when it started and anything you have already tried. Photos of the display and the outdoor unit are helpful.The Technician Confirms the Fault
On arrival, they check the code history, confirm the meaning for your model and listen to how the system behaves on start up.Targeted Testing
Depending on the code, that may mean measuring sensor resistance, checking supply voltage, testing communication wiring, reading refrigerant pressures or checking fan motor feedback.Explaining the Options
You receive a plain explanation of the cause and the repair choices before any work goes ahead.Repair and Test Run
After the repair, the system is run in both cooling and heating where possible to confirm the code does not return.
Australian Conditions
Why Do Some LG Codes Show Up More in Summer?
Australian weather puts real strain on outdoor units. Long stretches of extreme heat push condenser and inverter temperatures towards their limits, which is why high temperature and heat sink codes cluster in January and February. Storm season brings power dips and surges that can trigger inverter current codes or communication faults.
Coastal homes face a different problem. Salt air slowly corrodes outdoor coils, fan motors and electrical connections, and corrosion often shows up first as a sensor or communication code. Inland and dry areas see dust building up on coils, which reduces airflow and raises running temperatures. Humid summers load up indoor drains and coils, and smoke from bushfires can clog filters faster than usual.
None of this means the unit is faulty from new. It simply means regular servicing, a clear space around the outdoor unit and clean filters matter more here than in milder climates.
Getting Help
Where Can I Book an LG Technician?
We arrange licensed technicians for LG fault finding in all five major capitals. Each city page explains local conditions and the suburbs covered. You can also read about our general LG air conditioning service or browse the full error code library for other brands.
Sydney Repairs
LG fault diagnosis across greater Sydney, from the coast to the western suburbs.
Melbourne Repairs
Technicians arranged across metropolitan Melbourne.
Brisbane Repairs
Help with humid weather faults and storm season codes.
Perth Repairs
Support for units working hard through long dry summers.
Adelaide Repairs
Diagnosis for systems facing very hot, dry spells.
Good to Know
Is It Safe to Keep Using an LG Unit With an Error Code?
It depends on the code. A sensor fault such as CH01 or CH44 rarely causes harm by itself, although the unit may refuse to run or behave strangely. A drain alert risks water damage to ceilings and walls. Compressor, inverter and refrigerant codes are different again, because forcing repeated restarts can damage expensive parts.
As a general approach, try one power reset. If the code returns, leave the unit switched off at the breaker and book a technician. Running a system that keeps tripping rarely fixes anything and can make the eventual repair larger.
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Keep a simple log if your LG unit throws codes intermittently. Note the date, the time, the weather, the mode and how long the unit had been running. Intermittent faults are among the hardest to diagnose, and a log often reveals a pattern, for example a code that only appears on very hot afternoons or after a thunderstorm.
If your unit is still within its warranty period, check the warranty documents before booking any repair. Some manufacturers require warranty work to go through their own service network. We are happy to help with out of warranty systems and routine faults.
Questions
Frequently Asked Questions
Why does my LG unit show CH and then a number?
CH stands for check. The number that follows identifies the fault. Some displays alternate between the letters and the number, so watch the screen for a few seconds to read the full code.
Will turning the power off clear an LG error code?
A power reset clears the code from the display and sometimes clears a one off fault. If the underlying problem remains, the code returns once the unit tries to run again.
Do LG codes mean the same thing on every model?
Most core codes are consistent across LG residential splits. A few numbers change meaning on multi split, commercial or older models, so the technician confirms the meaning for your series.
Which LG codes are the most serious?
Compressor, inverter current and refrigerant codes generally need the fastest attention. Examples include CH21, CH26 and CH38. Leave the unit off and book a technician.
Can I fix a sensor code myself?
No. Testing and replacing sensors means opening the unit and working near live electrical parts. You can try a power reset, but the repair belongs with a licensed technician.
My LG unit has no display. How do I read the code?
Watch the indicator lights. They blink in a repeating pattern that maps to a code. Film a full cycle on your phone and share it when you book.
Does Rapid Air Cooling repair LG systems Australia wide?
We arrange licensed technicians in Sydney, Melbourne, Brisbane, Perth and Adelaide. Visit the troubleshooting guide or our page on air conditioning service Australia for more.
Code Lookup
Look Up a Code Across Brands
The same code can mean different things on different brands. These pages compare what each code means on Daikin, Mitsubishi, Panasonic, Samsung, Fujitsu, LG and Actron.
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Seeing a CH Code on Your LG System?
Tell us the code and the model, and we will arrange a licensed technician to find the cause and talk you through the fix.
Reviewed by AC repair and service specialist on 22 October 2026. How we write our articles