LG Mini-Split Code CH03
Soft lockoutShown as: Indoor unit LED1 (units place) blinks 3 times
Wired remote controller (thermostat) communication error. The indoor unit's control board is not receiving a signal from the wired wall controller. On systems that never had a wired controller, it usually means the controller connector on the board is dirty, wet or shorted.
Manual wording: “Indoor unit PCB is not receiving a signal from the wired remote controller (if installed).”
Documented for: All LG residential mini-split indoor units with an optional wired remote controller
Likely causes, most common first
- Interference between the AC power line and the wired remote control line (wires twisted together or not separated)
- Poor contact or disconnection between the wired remote control DC line and the PCB harness
- PCB harness flooding or corrosion
- Wired remote control fault
- Indoor unit PCB fault
What you can safely check yourself
- Turn the system off at the breaker for one minute, then back on
- If a wired wall controller is installed, check it is not physically damaged or wet
- Check the wall controller's display is lit at all
When to call a technician
Anything past a power cycle means opening the indoor unit or the controller and checking low-voltage wiring - call a technician.
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
- 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