The indoor unit shows CH and the number in turn. On a head with indicator LEDs and no digits, LG's instruction is that the first LED blinks the ones digit and the second LED blinks the tens, so five blinks on the first LED alone is CH05, and filming it on a phone makes the count easier. The outdoor control board has its own LEDs that blink the same number for a technician. Some LG models and controllers swap the CH for a short code: LG lists E6 as the same fault as CH10, EF as CH67 and F4 alongside CH38.
Sorting the table into two piles makes it less alarming. The reset-and-check pile is CH05, CH10, CH61 and CH67: clean the filters, clear snow, ice, leaves or stored items from around the outdoor unit, and reset the power. LG's own reset is to leave the breaker off for three to five minutes, and for CH05 to switch the indoor and outdoor breakers back on together. The technician-only pile is everything involving refrigerant, sensors inside the casing and the inverter board, and in Ontario anyone who connects gauges or adds refrigerant must hold an ODP card, so CH38 is never a homeowner repair.
Codes vary by model. Single-zone wall units, Multi F multi-zone systems and older LG generations do not all use the full list, and a multi-zone outdoor unit adds codes of its own. The legend in the owner's manual and on the wiring diagram inside the outdoor unit's cover is the authority: where it differs from this page, the unit's label wins. Our LG mini-split repair page describes how we service these systems, and you can contact ZK Mechanical with the code and the model number from the side of the indoor unit.
LG ductless mini-split codes, decoded
| Code | What it means | Safe? | Try first | When to call |
|---|---|---|---|---|
CH01 | Indoor unit room temperature sensor error. | turn it off | Reset the power once. | If CH01 returns. The air thermistor is tested and replaced. |
CH02 | Indoor unit inlet pipe sensor error. | turn it off | One power reset. | If it repeats. The sensor is clipped to the indoor coil. |
CH04 | Float switch or drainage error on units fitted with a drain pump or float. | turn it off | Look for water dripping from the indoor unit and check that the drain hose outside is not blocked or kinked. | If water is backing up. The drain line is cleared and the pump tested. |
CH05 | Communication error between the indoor unit and the outdoor unit. | turn it off | Check both breakers. Turn both off for five minutes, then switch them on together. | If CH05 comes straight back. Wiring between the units or a board is at fault. |
CH06 | Indoor unit outlet pipe sensor error. | turn it off | A single power reset. | If it stays. Sensor resistance is checked against the service data. |
CH09 | Indoor unit EEPROM error: the memory chip on the indoor board cannot be read. | turn it off | Reset the power. | If the code persists, the indoor board needs attention. |
CH10 | Indoor fan motor lock. LG also shows this as E6 on some models. | turn it off | With the power off, open the front panel, wash the filters and look for anything jamming the fan. | If the fan still will not turn. Motor or indoor board. |
CH21 | DC peak, which LG also labels an IPM fault: the inverter power module tripped on the compressor circuit. | turn it off | Clear the outdoor unit of anything blocking airflow, then reset once. | If it trips again. Inverter board and compressor are both tested. |
CH22 | CT2 error: alternating current input is too high. | turn it off | No homeowner check beyond a reset. | Book a repair. |
CH23 | DC link voltage low. | turn it off | Note whether lights dimmed or the power flickered when it happened. | If it repeats on a normal day. Supply voltage and the board are checked. |
CH26 | DC compressor position error: the compressor is not rotating or has locked. | turn it off | Leave the system off. | Yes. Do not keep restarting a compressor that will not turn. |
CH29 | Inverter compressor amperage too high. | turn it off | Wash the filters and clear the outdoor coil of debris. | If it returns with clean coils and filters. |
CH32 | Inverter compressor discharge pipe overheat. | turn it off | Clear the outdoor unit and let it cool before one restart. | If it repeats. Low refrigerant charge is one of the causes a technician checks. |
CH38 | Low refrigerant. LG describes it as the air conditioner being low on gas. | turn it off | None. Do not buy a recharge kit. | Yes. The leak is found and repaired before any refrigerant goes in. |
CH41 | Inverter discharge pipe sensor disconnected or shorted. | turn it off | None. | Book a repair. |
CH44 | Outdoor air sensor disconnected or shorted. | turn it off | Check that nothing has struck or chewed the wiring at the back of the outdoor unit. | Book a repair. |
CH53 | Communication failure from the outdoor unit to the indoor unit. LG groups it with CH05. | turn it off | Same breaker reset as CH05. | If it returns after the reset. |
CH61 | Outdoor condenser coil temperature too high. In heating mode LG ties it to the indoor unit overheating behind a clogged filter. | turn it off | Clean the indoor filters, brush debris off the outdoor coil, clear space on every side, then power off for three minutes. | If CH61 shows again after cleaning. It does not clear by itself. |
CH62 | Inverter heat sink temperature too high. | turn it off | Make sure the outdoor fan is not blocked and the unit has open air around it. | If it repeats. |
CH67 | Outdoor fan motor lock. Shown as EF on some LG models. | turn it off | Breaker off first. Clear snow, ice or sticks from the fan and let ice melt without chipping at it. | If the fan is free and CH67 remains. Fan motor or outdoor board. |
The codes that usually mean a real repair
CH05 or CH53: the wiring between the units, or a board
A communication fault that survives LG's breaker reset is usually physical. The cable between the indoor head and the outdoor unit carries power and signal together, and a loose terminal, a corroded splice or a cable damaged where it leaves the wall will drop the signal. When the wiring tests sound, the indoor or outdoor board is next, and a control board replacement is $400–$800. Our answer on LG mini-split error CH05 covers that one code in more depth.
CH10 or CH67: fan motors
Both codes say a fan was told to spin and did not. Indoors it is often a blower wheel loaded with dust; outdoors it is ice, a stick through the guard, or worn motor bearings. If cleaning and clearing do not free it, a fan motor replacement runs $300–$700 in parts and labour depending on the motor. An outdoor unit under a roof edge with no gutter takes meltwater that refreezes overnight, which is a common way for the fan to ice up.
CH21, CH26, CH29 or CH38: inverter, compressor and refrigerant
These are the expensive end of the table and the reason not to keep resetting. CH21, CH26 and CH29 are tested at the inverter board and the compressor windings before anyone orders parts, and the repair is quoted in writing. CH38 is a leak: finding and fixing it, then recharging, runs $300–$800+ and needs an ODP-certified technician. On an older single-zone system it is worth comparing a major repair with a replacement at $4,000–$7,000 installed, and general figures are on our pricing page.
Licensed technicians, a written price before the repair, no overtime charges.
Common questions
How do I reset an LG mini-split after a CH code?
Use the breaker, not the remote. LG's guidance is to disconnect power for three minutes and restore it; for CH05 it is five minutes with both the indoor and outdoor breakers off, then both on at the same moment. Reset once. If the same CH number returns, write it down with the model number and stop there, because inverter and compressor codes get more costly each time the system is forced to restart.
My LG shows E6 or EF, not a CH code. Is that the same thing?
Yes for those two. LG's support library lists E6 as the same indoor fan fault as CH10 and EF as the same outdoor fan fault as CH67. Which form you see depends on the model and the display. The checks are identical: power off, clean the filters, make sure nothing is jamming the indoor or outdoor fan, then restore power.
Why would CH61 appear in winter when the unit is heating?
In heating mode the indoor coil is the hot side, and LG ties a winter CH61 to the indoor unit overheating behind a filter clogged with dust. Wash the filters, let them dry, refit them and reset the power for three minutes. In summer the same number points outdoors: a coil matted with cottonwood fluff or a unit boxed in by a fence, shrubs or stored items.
Is it safe to leave an LG mini-split running with a code showing?
With most CH codes the system has already stopped itself, so the question is whether to restart it. One reset after cleaning filters and clearing the outdoor unit is fine. Do not cycle the breaker again and again to squeeze out heat or cooling: on CH21, CH26 and CH29 each restart loads a compressor or inverter that has just reported a fault. A mini-split is electric, so there is no gas or carbon monoxide risk from the unit.
Who can repair an LG mini-split in Burlington and the west GTA?
For anything past filters and breakers you need a technician who holds an ODP card for refrigerant work and has the LG service data for your model. ZK Mechanical services ductless and heat pump systems from Burlington across Oakville, Milton, Hamilton, Mississauga and the west side of Toronto. The diagnostic visit is $90–$150 and is credited toward the repair: see heat pump repair.