| E1 21 | Indoor unit room temperature sensor error (Open/Short) | Check indoor room thermistor wiring and connector. Measure resistance and replace sensor if faulty. |
| E1 22 | Indoor unit heat exchanger temperature sensor error (Open/Short) | Inspect evaporator heat exchanger sensor and wiring. Replace thermistor if open or short. |
| E1 23 | Indoor unit heat exchanger out temperature sensor error (Open/Short) | Check outlet thermistor and PCB connector. Replace sensor if resistance is abnormal. |
| E1 28 | Indoor unit sensor error – evaporator pipe IN sensor (Self diagnosis) | Verify sensor mounting and wiring on evaporator inlet pipe. Replace sensor if damaged. |
| E1 29 | Indoor unit sensor error – evaporator pipe OUT sensor (Self diagnosis) | Check outlet pipe thermistor and wiring. Replace sensor if faulty. |
| E1 54 | Indoor unit fan error | Inspect indoor fan motor, wiring, and driver circuit. Replace fan motor if not spinning. |
| E1 63 | Indoor unit EEPROM option error | Power reset system. If error continues, reprogram or replace indoor PCB. |
| E1 71 | EVA-MID break away | Check evaporator middle sensor wiring and connectors. |
| E1 72 | EVA-IN break away | Inspect evaporator inlet sensor harness and replace if damaged. |
| E1 73 | EVA-OUT break away | Check evaporator outlet thermistor wiring and PCB connection. |
| E2 01 | Number of indoor units mismatched | Check configuration settings and system addressing. |
| E2 02 | Communication error between outdoor and indoor unit | Inspect communication cable, terminals, and polarity between units. |
| E2 03 | Outdoor communication error between main MICOM and INV MICOM | Check outdoor PCB communication circuit and connectors. Replace PCB if necessary. |
| E2 06 | Outdoor temperature sensor error (Short/Open) | Measure outdoor air thermistor resistance and replace if defective. |
| E2 37 | Condenser temperature sensor error | Inspect condenser pipe thermistor and wiring. Replace sensor if faulty. |
| E2 46 | Outdoor unit sensor error | Check outdoor sensor harness and PCB connector. |
| E2 51 | Compressor discharge temperature sensor error | Inspect discharge thermistor near compressor and replace if needed. |
| E2 61 | Compressor discharge sensor detached (Self diagnosis) | Reattach discharge sensor properly to pipe and check wiring. |
| E2 62 | Compressor OLP sensor error (Short/Open) | Check overload protection sensor wiring and replace if faulty. |
| E3 20 | Evap IN1 sensor short/open | Check evaporator IN1 thermistor and replace if defective. |
| E3 31 | Evap IN2 sensor short/open | Inspect second evaporator inlet thermistor wiring. |
| E3 32 | Evap IN3 sensor short/open | Test thermistor resistance and replace if abnormal. |
| E3 33 | Evap IN4 sensor short/open | Check sensor connection and replace if faulty. |
| E3 34 | Evap IN5 sensor short/open | Inspect wiring harness and replace thermistor if needed. |
| E3 35 | Evap OUT1 sensor short/open | Check evaporator outlet sensor and replace if defective. |
| E3 36 | Evap OUT2 sensor short/open | Inspect outlet thermistor wiring and connection. |
| E3 37 | Evap OUT3 sensor short/open | Measure sensor resistance and replace if faulty. |
| E3 38 | Evap OUT4 sensor short/open | Check wiring harness and thermistor mounting. |
| E3 39 | Evap OUT5 sensor short/open | Replace outlet thermistor if open/short detected. |
| E4 01 | Outdoor unit freezing (Compressor stop) | Check refrigerant level, airflow, and outdoor coil for icing. |
| E4 04 | Outdoor unit discharge temperature safety control | Inspect refrigerant charge, condenser fan, and airflow. |
| E4 06 | Outdoor unit high discharge temperature safety control | Check compressor load, refrigerant level, and condenser cleanliness. |
| E4 40 | High temperature (above 30°C) outdoor as heating mode | Verify outdoor ambient temperature sensor and system settings. |
| E4 41 | Low temperature (below 0°C) outdoor as cooling mode | Ensure operating mode matches ambient conditions. |
| E4 48 | Outdoor fan error | Check outdoor fan motor, capacitor, and wiring. |
| E4 58 | Inverter compressor starting failure (5 times) | Inspect compressor wiring, inverter PCB, and power supply. |
| E4 61 | Compressor trip by input current control mode | Check compressor current draw and inverter PCB. |
| E4 62 | Compressor trip by OLP temperature control mode | Inspect compressor overload protection and cooling conditions. |
| E4 63 | Over current | Check power supply, inverter module, and compressor load. |
| E4 65 | Compressor V limit error | Check voltage supply and inverter PCB components. |
| E4 67 | DC link voltage error (Under 150V / Over 410V) | Measure DC bus voltage and check rectifier circuit. |
| E4 68 | Abnormal compressor running (Rotation error) | Inspect compressor wiring and inverter drive circuit. |
| E4 69 | Current sensor error | Check current sensor circuit on inverter PCB. |
| E4 70 | DC link voltage sensor error | Inspect voltage sensing circuit and PCB components. |
| E4 71 | IPM error | Check inverter power module and cooling system. |
| E4 72 | Inverter MICOM zero crossing error | Inspect inverter control PCB. Replace if necessary. |
| E4 83 | Over voltage error | Check supply voltage stability and inverter PCB protection circuit. |
