LG Mini-Split Code CH45
Soft lockoutShown as: Outdoor LED01 (red) blinks 4 times, LED02 (green) blinks 5 times
Mid-pipe thermistor of the outdoor unit condenser coil is disconnected or shorted out. This is the sensor the unit uses to judge coil temperature for defrost.
Manual wording: “Mid-pipe thermistor of outdoor unit condenser is disconnected or has shorted out”
Documented for: All LG residential mini-split outdoor units
Likely causes, most common first
- Sensor mis-wiring or short at the connector
- Moisture penetration into the sensor or bad canning sheath on the sensor wire
What you can safely check yourself
- Turn the system off at the breaker for three minutes and back on
When to call a technician
The coil sensor is clamped to refrigerant piping inside the outdoor cabinet. Technician only.
A LG mini-split throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Sources
- 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
- 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
- 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