LG Mini Split Error Codes: CH05, CH38 and What Each Means

LG mini-split and air conditioning systems show a “CH” code — short for “Check” — followed by a number on the indoor unit’s display or wireless remote when they detect a fault. The number points to the affected area: low CH numbers usually mean indoor sensors, the CH05/CH53 range means communication between the indoor and outdoor units, the CH20s point to the compressor and inverter, and CH38 flags low refrigerant or a power problem. Use the quick-answer table above to find your exact LG error code, what it means, and the safe first step. Some codes clear after a simple power cycle or a basic fix like cleaning the filter; others — especially compressor, refrigerant, and communication faults — need a licensed technician. Always confirm the code against the list in your model’s LG manual, as meanings can vary by unit.

How to read an LG error code

LG shows the fault as a CH (Check) code on the indoor unit’s display, or signals it by blinking the indicator LEDs. On systems with a wired controller, the code shows on the controller screen. Note the exact number, then match it to the table above.

What the CH number points to

What to do first

For sensor, fan, and communication codes, start simple:

1. Turn the unit off with the remote.
2. Switch off the circuit breaker for about a minute.
3. Restore power and let the unit restart.
4. Clean the air filter and clear any obstruction around the indoor and outdoor units.

If the same code returns, stop — a repeating code means the underlying problem is still present. Don’t keep resetting compressor or refrigerant codes.

The codes people look up most, step by step

LG CH05

LG systems run a constant data link between the indoor and outdoor control boards over the connecting cable. When that signal is lost or unreadable, the unit reports CH05 (“CH” = Check) and usually stops heating or cooling until the link is restored. Because the indoor unit often signals it as 5 flashes of the operation light, count the flashes if you don’t have a digital display — but confirm against your model’s LG manual.

Common causes

• Communication wiring fault — loose, damaged, or mismatched connecting wires (the most common cause, especially after an install or repair).
• Power-supply problem — a tripped breaker, blown fuse, or faulty socket leaving the outdoor unit without stable power.
• Power-up timing — the units energizing at different times after an outage.
• Outdoor control board (PCB) fault — a defective transmit/receive circuit.

How to fix it

1. Power-cycle BOTH units together — switch OFF the breakers for the indoor and outdoor units, wait 5 minutes, then switch them both ON at the same time so they boot and re-link together. (This is LG’s recommended first step.)
2. Confirm outdoor power — breaker not tripped, fuse and socket good. A dead outdoor unit reads as a communication loss; see outdoor unit not running.
3. If CH05 returns, stop resetting and have a technician inspect the connecting wiring/harness and test the outdoor board.

LG CH38

CH38 is a protection code: the system sees that refrigerant pressure/charge is too low (or that the power supply is unstable) and stops to protect itself. Because the circuit is sealed, “low refrigerant” = a leak. Running a unit low on refrigerant makes it cool poorly and can overheat the compressor — the most expensive part — so it’s not a code to ignore or repeatedly reset.

Common causes

• Refrigerant leak — a crack in the copper line, a loose flare nut, or a failed joint (the most common cause). Often follows weak cooling.
• Unstable or incorrect power — CH38 can also flag an electrical/voltage problem, so a dedicated, correctly sized circuit matters.
• A temporary glitch — occasionally a one-off power event sets it and a reset clears it.

How to fix it

1. Power-cycle once — off at the breaker for ~5 minutes, then back on. If CH38 was a temporary power glitch, it clears and stays clear.
2. Check the power — confirm a stable, correctly sized dedicated circuit.
3. If CH38 returns, stop running the unit in that mode and call an EPA-608 technician to find and repair the leak, then recharge. If you also see weak cooling or ice, read mini split not cooling.

Trademark note: “LG” is a trademark of LG Electronics. This page is an independent homeowner resource and is not affiliated with, authorized by, or endorsed by LG. Brand and code references are used factually for identification and troubleshooting only.