LG Mini Split Error Codes:
Decoding the Blinking Lights
Is your LG unit flashing lights at you like a disco? It’s trying to tell you something. We decode the CH05, CH10, and blinking patterns to save you a $300 service call.
System Halted
Don’t Panic. Reset First.
LG mini splits are essentially wall-mounted computers. 50% of errors are just “software glitches” caused by power fluctuations. Before you tear the unit apart, try the Hard Reset Protocol.
How to Read “Blink Codes”
Unlike MrCool which shows a number (e.g., E1), older LG units use blinking LEDs. This is where people get confused.
Operation LED (1st Digit)
Counts the “Tens”.
If it blinks 2 times = 20.
Timer LED (2nd Digit)
Counts the “Ones”.
If it blinks 3 times = 3.
Critical LG Error Codes (CH Series)
| Code | Meaning | Likely Fix |
|---|---|---|
| CH05 |
Communication Error Indoor and Outdoor units can’t “talk”. |
Check the 4-wire connection cable. Usually a loose wire at terminal 3.
See Wiring Guide |
| CH10 |
Indoor Fan Motor Issue Fan is stuck or dirty. |
Spin the blower wheel by hand. If stiff, replace motor. If dirty, clean it.
Cleaning Guide |
| CH21 |
IPM Fault (Inverter Board) High DC Voltage or Short Circuit. |
The “Death” Code. Usually means a fried PCB board due to a power surge.
Prevent this with a Surge Protector |
| CH38 |
Refrigerant Leak System is low on Freon. |
Look for oily residue on flare connections. Requires a technician to re-charge.
Check for Leaks |
| CH67 |
Fan Motor Lock (Outdoor) Outdoor fan blocked. |
Check for sticks, debris, or snow/ice blocking the outdoor fan blade. |
Problem But No Error Code?
Leaking Water Inside
This is rarely an electronic error. It’s usually a clogged drain line or a dirty filter causing the coil to freeze.
Fix Leaking Water →Running But Not Cooling
If the fan runs but air isn’t cold, check if the outdoor compressor is turning on. If not, it could be a capacitor or refrigerant issue.
Troubleshoot Cooling →Use the LG ThinQ App
Stop guessing. Modern LG units (2020+) have built-in WiFi. The Smart Diagnosis feature in the LG ThinQ app will tell you exactly what is wrong in plain English.
Smart Diagnostics
FAQ: LG Troubleshooting
How do I reset my LG mini split?
Locate your home’s main electrical panel (breaker box). Flip the breaker labeled “AC” or “Heat Pump” to the OFF position. Wait at least 5 minutes to let the capacitors discharge. Flip it back ON. This clears the memory buffer.
Why is the green light flashing 5 times?
5 flashes usually indicates Code CH05 (Communication Error). This means the indoor unit is not receiving a signal from the outdoor unit, often due to a loose wire or a power surge damaging the board.
Can I replace the PCB board myself?
It is possible but risky. LG boards are sensitive. If you are comfortable with electronics, see our DIY Truth Guide. Otherwise, call a certified LG tech to preserve your warranty.
Fix it or Replace it?
If your LG unit is over 10 years old and has a bad compressor (CH21), repair might cost more than a new DIY unit.
