DIY HVAC Tools

LG mini split error code CH34

High pressure too high (pressure sensor). Also shown as CH 34, CH34.

  • TypeProtection
  • SystemRefrigerant circuit
  • Can I fix it?Homeowner checks, then maybe a tech

What CH34 means on a LG

The high-side pressure sensor reads above the limit.

On this platform, CH34 is a protection: the system stopped or throttled itself to prevent damage; many clear on their own once conditions return to normal.

Common causes

  • A dirty outdoor coil.
  • The outdoor fan not running.
  • A service valve not fully open.
  • An overcharge.

How to fix it yourself

Work through the checks below first; they resolve most cases. If they do not, the repair itself may need a technician.

  1. Look at the outdoor unit: clear leaves, cottonwood fluff, snow or ice from the coil and make sure the fan can spin freely and nothing is stacked against the cabinet.
  2. Confirm both service valves are fully open.
  3. Reset the system: switch the breaker (or the outdoor disconnect) off, wait a full five minutes so the boards fully discharge, then switch it back on and restart from the remote.
  4. Anything inside the refrigerant circuit (sensors are fine, but valves, compressors and leaks are not) needs EPA-certified refrigerant handling. That is a technician job.

Switch off power at the breaker before opening either unit. Capacitors in the outdoor unit hold a charge for several minutes after power is cut.

When to call a technician

A technician needs gauges.

Which LG units show CH34

This page applies to LG Art Cool, Standard, Mega and Multi F units. LG's own documentation lists CH34 as "High pressure too high (pressure sensor)", the same definition used across the LG it is built on. If your unit shows a code with a different shape (for example a four-character code, or a plain number), it is from a different table; use the lookup with your exact code.

Where LG shows this code

The indoor display shows CH followed by a number (CH05, CH38). Units without a display blink the indicator lamps in a pattern; the outdoor board LEDs blink the same number. If someone tells you 'CH 5', that is CH05. CH01 to CH12 are indoor-unit faults, CH21 to CH29 are inverter and compressor faults, CH32 to CH38 are refrigerant-side protections, CH40 to CH48 are outdoor sensors, and CH51 to CH73 are outdoor-unit system faults.

Other LG codes

Same part of the system as CH34:

CH24High or low pressure switch operatedCH35Low pressure too low (pressure sensor)CH38Refrigerant leak detected (low charge)CH61Condenser pipe temperature too high
CH01Indoor air (room) temperature sensor fault (open or short circuit)CH02Indoor inlet pipe temperature sensor fault (open or short circuit)CH03Communication error with the wired remote controllerCH04Drain pump or float switch faultCH05Communication error between indoor and outdoor unitsCH06Indoor outlet pipe temperature sensor fault (open or short circuit)CH07Operating mode conflict (multi-split)CH09Indoor unit EEPROM error

All LG error codes

Questions people ask

Can I reset a LG CH34 code myself?

Yes. Turn the system off at the breaker for five minutes, then restart it. If CH34 comes back, the fault is real and needs the checks above.

Is it safe to keep running a LG showing CH34?

Not repeatedly. A protection code means the unit stopped itself to prevent damage, and resetting it over and over can turn a cheap repair into a compressor failure. Reset once, check the basics, and stop if it returns.

Do I need a technician for LG CH34?

Work through the checks below first; they resolve most cases. If they do not, the repair itself may need a technician. A technician needs gauges.

Sources

  • LG residential split service manuals (error code tables)

Updated September 2026. Codes and definitions vary by model year. If your manual disagrees with this page, your manual wins. Send a correction.