An LG air conditioner error code is a CH number. CH05 and CH53 mean the indoor and outdoor units have lost communication, CH32, CH33, CH36, CH38 and F4 point to a refrigerant or compressor problem, and CH66 and CH90 to CH93 mean a wiring or test run problem after installation.
LG's codes are some of the more readable ones out there, because LG groups them by what has gone wrong rather than leaving you to decode a sensor name. Even so, the same fault shows up differently depending on where the unit was sold, which is how so many lists online end up contradicting each other. For this 2026 update we checked every code on this page against LG's own published help pages and removed the ones we could not find there.
At a glance
| Question | Answer |
|---|---|
| Communication fault | CH05, CH53 or E0 |
| Refrigerant or compressor problem | CH32, CH33, CH36, CH38 or F4 |
| Installation or test run problem | CH66, CH90, CH91, CH92 or CH93 |
| Outdoor unit has no power | CH237 or CH247 |
| LG's first step | Switch off, wait about five minutes, restore power and see if the code clears |
| If it comes back | Stop using the unit and get it checked; LG warns against opening it yourself |
How LG displays an error code
LG's help page for single and multi-split air conditioners explains that units sold in North America show faults as a sequence of blinking LEDs, while units everywhere else display the code as an actual number. Its example is a unit showing 38, which LG says signifies low refrigerant and means the unit has stopped to protect itself. LG's other help pages write the same codes with a CH prefix, so a 5 on one unit and CH05 in a guide are the same fault.
LG single and multi-split error codes
These are the indoor and outdoor unit error codes from LG's single and multi-split help page. We have written them with the CH prefix used on LG's other help pages.
| Code | What LG says it means |
|---|---|
| CH01 | Indoor unit return air thermistor has disconnected or has shorted out |
| CH02 | Indoor unit inlet pipe thermistor has disconnected or has shorted out |
| CH05 | Communication failure from indoor unit to outdoor unit |
| CH06 | Indoor unit outlet pipe thermistor has disconnected or has shorted out |
| CH09 | Indoor unit EEPROM error |
| CH10 | Indoor unit fan has locked up (fan motor operation failure) |
| CH12 | Indoor unit middle pipe thermistor has disconnected or has shorted out |
| CH21 | DC peak error / IPM fault; compressor DC voltage was too high |
| CH22 | Current transformer 2 (CT2) error; AC input current is too high |
| CH23 | DC link voltage is too low |
| CH25 | Voltage to the system is too low or too high |
| CH26 | Inverter compressor has seized up or is not providing rotation |
| CH27 | Prospective short circuit (PSC) fault; current to the inverter compressor between the AC and DC converter circuit is too high |
| CH28 | Inverter compressor DC voltage is too high |
| CH29 | Inverter compressor amperage is too high |
| CH31 | Current to the current transformer (CT) thermistor is too low |
| CH32 | Inverter compressor discharge pipe temperature is too high |
| CH40 | Current transformer (CT) thermistor has disconnected or has shorted out |
| CH41 | Inverter compressor discharge pipe thermistor has disconnected or has shorted out |
| CH44 | Outdoor unit inlet air thermistor has disconnected or has shorted out |
| CH45 | Outdoor unit condenser coil middle thermistor has disconnected or has shorted out |
| CH46 | Outdoor unit suction line thermistor has disconnected or has shorted out |
| CH48 | Outdoor unit coil outlet (liquid line) thermistor has disconnected or has shorted out |
| CH53 | Communication failure from outdoor unit to indoor unit |
| CH60 | Outdoor unit PCB EEPROM check sum error |
| CH61 | Outdoor unit condenser coil temperature is too high |
| CH62 | Outdoor unit inverter compressor PCB heat sink temperature is too high |
| CH63 | Condenser coil pipe thermistor temperature is too low |
| CH65 | Heat sink thermistor has disconnected or has shorted out |
| CH67 | Outdoor BLDC fan motor lock error |
Source: LG Help Library, Single/Multi-Split air conditioner error codes
The thermistor codes make up most of that list. A thermistor is a temperature sensor, and "disconnected or shorted out" means the board is getting a reading that cannot be real. Sometimes it is the sensor, sometimes the plug on the board, and occasionally the board itself. It is a quick multimeter test for an engineer and a guessing game for everyone else.
LG's code groups, and what LG says causes them
A separate LG help page groups the most common codes by cause, which is the more useful way to think about them when you are deciding what to do next.
| Codes | What LG says they indicate | Causes LG lists |
|---|---|---|
| CH05, CH53, E0 | Communication problem between the indoor and outdoor units | Temporary communication or power error, faulty wiring, a loose connector, or an issue with the main circuit board |
| CH32, CH33, CH36, CH38, F4 | Refrigerant or compressor-related problem | Temporary power issue, or a malfunction in the outdoor unit's compressor, drive, protection circuit or internal electronic components |
| CH66, CH90, CH91, CH92, CH93 | Installation or test run problem | Incorrect wiring, an incomplete test run after installation, or restricted refrigerant flow during the test run |
| CH237, CH247 | Communication error caused by a lack of power to the outdoor unit | Outdoor unit power not connected |
LG also says that if one of these codes appears shortly after installation, you should go straight back to your installer, because it often points to a loose connection or a refrigerant leak from the installation itself. Worth remembering on a new fit-out: the installer is the first call, not a stranger off the internet.
What you can check, and what needs an engineer
LG's own advice for these codes is short: turn the power off at the plug or the circuit breaker, wait about five minutes, restore power and see whether the code has cleared. If it has, LG says you can carry on using the unit, while noting that a repeated error may indicate an internal circuit or wiring problem. For CH237 or CH247, it suggests checking that the outdoor unit's power is connected.
Past that, LG's warning is direct: "Do not disassemble the air conditioner or replace internal parts yourself." And any work on the refrigerant circuit is regulated in the UK. GOV.UK says: "You must have your own qualifications to work on equipment containing F gas, even if you work for someone else." The refrigerant group of codes, CH32 to CH38 and F4, belongs squarely in that territory.
| Code group | Reasonable first check | Needs a qualified engineer |
|---|---|---|
| CH05, CH53, E0 | Power reset as LG describes | If it returns: wiring, connectors, boards |
| CH237, CH247 | Check the outdoor unit's power supply | If power is fine and it persists |
| CH01 to CH12, CH40 to CH48, CH65 | Power reset | Yes, sensor and board testing |
| CH32, CH33, CH36, CH38, F4 | Power reset once, then stop | Yes, refrigerant and compressor work under F gas rules |
| CH21 to CH31, CH60 to CH67 | Note when it happens | Yes, inverter, power and fan diagnosis |
| CH66, CH90 to CH93 | Call the installer | Yes, commissioning or wiring correction |
Sources: LG Help Library and GOV.UK, Qualifications to work with F gas
When to call an engineer
If the code survives LG's five-minute reset, or it is one of the refrigerant group, it needs a proper look. Be Cool's F-Gas certified engineers have repaired air conditioning across London and the South East since 2004, and our air conditioning repair service covers LG split, multi-split and commercial systems along with the other major brands. If water is coming out of the indoor unit as well, our guide to air conditioning leaking water explains the usual causes.
Frequently asked questions
What does CH05 mean on an LG air conditioner?
LG lists CH05 as a communication failure from the indoor unit to the outdoor unit. LG's first step is a five-minute power reset; if it returns, the wiring, connectors or main board need checking.
What does CH38 mean on an LG air conditioner?
LG groups CH38 with the refrigerant or compressor-related codes, and its single and multi-split page uses code 38 as its example of low refrigerant. It needs a qualified engineer.
What does CH10 mean on LG?
CH10 is the indoor unit fan locking up, which LG describes as a fan motor operation failure.
Can I reset an LG error code myself?
Yes. LG says to switch off at the plug or circuit breaker, wait about five minutes and restore power. If the code comes back, LG advises getting the unit checked rather than continuing to reset it.
Why does my LG show a code right after installation?
LG says codes appearing shortly after installation often point to a loose connection or a refrigerant leak from the installation, and that you should contact your installer directly.
One reset, then a phone call
LG's guidance is sensible and it is worth following: one proper reset, then stop. A code that keeps returning is the unit doing its job and protecting the compressor. Our error code library covers the other brands, and our air conditioning maintenance visits are the way to stop the same code turning up every summer.
About the author: Ali Elm runs Be Cool Refrigeration & Air Conditioning, a family-run London firm that has been installing, servicing and repairing commercial refrigeration and air conditioning since 2004. His F-Gas certified team has delivered more than 2,000 projects across London and the South East.
Last updated: 2 November 2026
Written by
Ali Elm
Ali is the Head of Operations at Be Cool Refrigeration with over a decade of hands-on experience in HVAC and commercial refrigeration. He oversees every installation, repair, and maintenance project, making sure the work meets the highest standards. Ali holds full F-Gas certification and has worked across residential, commercial, and industrial refrigeration systems throughout London and the South East. When he is not on site, he writes these guides to help business owners and homeowners understand their cooling systems better.