What does LG Multi V error code CH03 mean?

CH03 on LG Multi V systems indicates an outdoor unit high pressure fault. The refrigerant circuit high pressure switch has tripped. Check condenser coil for fouling, verify condenser fan motor operation and blade rotation direction, check for refrigerant overcharge, and confirm ambient temperature is within the unit's rated operating range. Access the fault log via the LG Multi V service tool.

How do I address LG HVAC fault code CH05?

CH05 on LG systems is a low pressure fault. Common causes: low refrigerant charge (check for leaks), restricted filter or strainer on suction line, excessively low ambient temperature causing low evaporating pressure, or expansion valve malfunction. Use the LG Multi V service tool to check suction pressure at the outdoor unit and compare against the saturation temperature chart.

How do I perform an LG Multi V system auto-addressing?

LG Multi V auto-addressing is triggered by powering the system on for the first time or after adding/removing indoor units. Connect all indoor units to the system wiring, ensure all units are powered, and power on the outdoor unit. The system will automatically assign addresses over 3-5 minutes. If auto-addressing fails, use the LG Multi V PQNFB17C0 service tool to manually assign addresses.

HVAC

LG HVAC error codes, decoded.

Look up any LG HVAC fault code below. Each one is grounded in LG HVAC's own service documentation — the meaning, the symptoms, the causes, and the steps to clear it.

By Octavian Ghindea

Co-founder & CTO · Reviewed August 2026

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LG HVAC sits in our HVAC coverage. Every page here is transcribed from the manufacturer's manuals, not scraped from forums.

What error codes does LG HVAC display?

Tap a code for the full breakdown — meaning, symptoms, causes, and fix steps.

CH03

High pressure fault — check condenser and refrigerant charge

CH05

Low pressure fault — check refrigerant charge and expansion valve

CH21

Communication fault between indoor and outdoor units

CH38

Outdoor temperature sensor fault

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