LG Mini-Split Code CH42
Soft lockoutShown as: Outdoor LED1 blinks 4 times, LED2 blinks 2 times (2-LED type)
Low pressure sensor open or short. The suction-side pressure transducer is not reporting a valid signal.
Manual wording: “Low pressure Sensor open/short”
Documented for: LG single-zone room air conditioner / mini-split outdoor units fitted with pressure sensors
Likely causes, most common first
- Bad wiring of the pressure sensor
- Bad pressure sensor
What you can safely check yourself
- Turn the system off at the breaker for three minutes and back on
When to call a technician
Pressure transducers are mounted on the refrigerant circuit. Replacement is technician work.
A LG mini-split throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Source
- 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