LG Mini-Split Code CH34
Soft lockoutShown as: Outdoor LED1 blinks 3 times, LED2 blinks 4 times (2-LED type; the service manual pairs CH34 with CH35 in one row)
High pressure sensor error (high) - the outdoor unit is reading discharge pressure above its limit. Typically the condenser cannot reject heat, or the charge is off.
Manual wording: “High pressure sensor error (high)”
Documented for: LG single-zone room air conditioner / mini-split outdoor units fitted with pressure sensors
Likely causes, most common first
- Overload operation - outdoor fan restricted, screened, or blocked
- Refrigerant leakage (insufficient charge)
- Bad connection of the pressure sensor
- Bad compressor sensor
- Bad PCB
What you can safely check yourself
- Clear leaves, grass clippings, snow, or debris away from the outdoor coil and fan
- Remove anything stacked against or on top of the outdoor unit
- Check and clean the indoor air filters
When to call a technician
Pressure faults require gauges and a licensed technician. Do not open, tighten or bypass anything on the refrigerant side.
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