LG Mini-Split: 9 Flashes
A LG mini-split LED pattern starting with 9 flashes matches 2 documented codes: CH09, CH93. Watch the full pattern (short vs. long flashes) to tell them apart — all 2 are explained below.
Code CH09: Indoor unit EEPROM error
Indoor unit EEPROM error. The memory chip on the indoor control board that stores the unit's model and setup data is unreadable, so the board does not know what unit it is controlling.
Manual wording: “Indoor unit EEPROM serial number marked on is 0 or FFFFFF.”
Documented for: All LG residential mini-split indoor units
Likely causes, most common first
- Poor connection of the option PCB
- Indoor unit EEPROM serial number reads 0 or FFFFFF (corrupted or blank memory chip)
What you can safely check yourself
- Turn the system off at the breaker for one minute, then back on
When to call a technician
CH09 is a control board / memory chip fault. The service manual's only remedy is to check the option PCB connection and replace the board - a technician job.
A LG mini-split throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Sources
- Single Zone Four-Way Ceiling-Cassette Installation Manual (LG Electronics U.S.A., Inc., Single-zone four-way ceiling cassette indoor units with LUU090HV through LUU420HV outdoor units) · checked 2026-08-25
- MULTI F / MULTI F MAX Outdoor Unit Installation Manual (LG Electronics U.S.A., Inc., Multi F and Multi F MAX multi-zone heat pump outdoor units (LMU series) with standard wall-mount, Art Cool, cassette and ducted indoor units) · checked 2026-08-25
- Convertible Mid-Static Ducted LGRED Degree System Installation Manual (LG Electronics U.S.A., Inc., LGRED single-zone convertible mid-static ducted indoor units with LUU180HHV / LUU240HHV outdoor units) · checked 2026-08-25
- Defining Common Error Codes - Standard Wall-Mounted High-Efficiency Single Zone Systems (LG Electronics U.S.A. - Commercial Air Conditioning, LS091HSV and LS121HSV systems (LSN091HSV / LSN121HSV indoor units, LSU091HSV / LSU121HSV outdoor units)) · checked 2026-08-25
- Room Air Conditioner SVC Manual (General) - Trouble Shooting Guide with Error Code (LG Electronics, All LG single-zone room air conditioner / mini-split chassis (SW, SB, SC, S4, S5, SH, SA, SJ, SK)) · checked 2026-08-25
Code CH93: Indoor / outdoor unit communication error
Indoor / outdoor unit communication error. LG's consumer support page describes CH93 as a communication problem between the indoor and outdoor units; the service manual handles it with the same troubleshooting flow as CH05 and CH53.
Manual wording: “Indoor / outdoor unit communication error”
Documented for: LG single-zone room air conditioner / mini-split systems
Likely causes, most common first
- No power on the indoor unit
- Indoor/outdoor unit power connection error, or the communication line not installed
- Improper connection at the terminal block for the communication wire
- Improper wiring of the communication L-N wire between indoor and outdoor units
- Communication error caused by external electrical noise
- Indoor/outdoor communication circuit parts burned, or no power due to a burned indoor or outdoor PCB
What you can safely check yourself
- Check the breakers for BOTH the indoor and outdoor unit are on and not tripped
- Check the outdoor disconnect switch next to the condenser is switched on
- Turn the system off at the breaker for three minutes, then back on
When to call a technician
If power is confirmed on at both units and CH93 stays, the interconnecting communication wiring or a control board needs a technician.
A LG mini-split throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Sources
- Room Air Conditioner SVC Manual (General) - Trouble Shooting Guide with Error Code (LG Electronics, All LG single-zone room air conditioner / mini-split chassis (SW, SB, SC, S4, S5, SH, SA, SJ, SK)) · checked 2026-08-25
- LG Air Conditioner - Guide to Error Codes (LG USA Support help library) (LG Electronics U.S.A., Inc., LG residential single-split and multi-split air conditioners / heat pumps) · checked 2026-08-25