LG Mini-Split Code CH01
Soft lockoutShown as: Indoor unit LED1 (units place) blinks 1 time
Indoor unit room (return air) temperature sensor error. The thermistor that reads the room temperature is disconnected, shorted or open, so the indoor unit cannot tell how warm the room is and shuts down.
Manual wording: “Indoor unit air temperature sensor is disconnected, shorted, or opened.”
Documented for: All LG residential mini-split indoor units (wall-mount, Art Cool, cassette, ducted)
Likely causes, most common first
- Sensor mis-wiring or short at the connector
- Moisture penetration into the sensor
- Bad sensor canning sheath (damaged sensor sheath or insulation)
- Sensor housing removed so the sensor is out of its holder
- Indoor unit PCB fault (only after the sensor itself checks good)
What you can safely check yourself
- Turn the system off at the breaker for one minute, then back on, to see if the code clears
- Check that the indoor unit's front panel and filter access door are fully closed and latched
When to call a technician
A thermistor that reads open or shorted has to be measured and replaced by a technician. There is no homeowner adjustment for this code.
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