: Inlet Pipe Sensor Error . A fault with the indoor unit's inlet pipe thermistor.

: Indoor Temperature Sensor Error . This usually indicates an open or closed circuit in the indoor air thermistor.

: Communication Error . Specifically between the evaporator and condenser units. Quick Troubleshooting Steps Troubleshooting LG AC CH05 Error: A Quick Guide - Ftp

: Input Voltage Error . The CT2 voltage input is too high (above 14 A).

: Inverter/Compressor Error . Points to a problem with the compressor power supply or phase.

: Indoor Fan Motor Error . The indoor fan is not rotating correctly.

: DC Link Low Voltage . The DC voltage has dropped below 140V.

: Outdoor Fan Motor Error . The outdoor fan motor has failed or is blocked.