LG Mini-Split: 1 Flashes
A LG mini-split LED pattern starting with 1 flashes matches 3 documented codes: CH01, CH10, CH12. Watch the full pattern (short vs. long flashes) to tell them apart — all 3 are explained below.
Code CH01: Indoor unit room
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
Code CH10: Indoor unit BLDC fan motor lock
Indoor unit BLDC fan motor lock. The indoor blower is not turning when the board commands it - either something is physically jamming it, the motor plug is loose, or the motor has failed.
Manual wording: “Indoor unit fan motor connection is disconnected. Indoor unit fan motor lock has failed.”
Documented for: All LG residential mini-split indoor units with BLDC fan motors
Likely causes, most common first
- Fan locked by physical force (foreign object stuck in the motor or blower wheel)
- Poor connection of the motor connector
- Motor failure
- PCB failure
What you can safely check yourself
- Turn the unit off at the breaker, then look for anything obviously blocking the indoor fan or the air path
- Check and clean the indoor air filters
- Make sure the supply louvers are not jammed shut or blocked by furniture or curtains
- Restore power and try once more
When to call a technician
If nothing is jamming the blower and CH10 returns, the fan motor or the control board has failed. Do not reach into the blower housing on a powered unit.
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 CH12: Indoor unit middle pipe sensor error
Indoor unit middle pipe sensor error. The thermistor on the middle of the indoor coil is disconnected or shorted out.
Manual wording: “Indoor unit middle pipe thermistor has disconnected or has shorted out.”
Documented for: LSN091HSV / LSN121HSV and other LG single-zone indoor units fitted with a middle pipe sensor
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 off the pipe
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
When to call a technician
Thermistor replacement inside the indoor coil housing is 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
- 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