What each error code means, what you can safely check yourself, and when the fault needs a technician. Covers LG, Samsung, Daikin, Voltas, Blue Star, Hitachi, Carrier, Godrej, Haier, and more.
Important: Error codes are diagnostic signals, not faults you can fix by switching the AC off and on. Clearing a code without resolving its root cause usually means it returns — sometimes within minutes. If your AC shows an error code repeatedly, that's the unit telling you something specific needs attention.
| Code | Meaning | What To Check |
|---|---|---|
| CH01 | Indoor unit temperature sensor fault | Check that the air filter is clean and airflow to the indoor unit is not blocked. If the code persists, the sensor needs replacement. |
| CH02 | Outdoor unit temperature sensor fault | This is an outdoor sensor — check that the outdoor unit is not obstructed and has ventilation. Needs a technician if it persists. |
| CH03 | Discharge temperature sensor fault | Indicates a fault with the compressor discharge sensor. Call a technician — this is not a safe DIY check. |
| CH05 | AC not cooling / low pressure in refrigerant circuit | Likely a gas leak or low refrigerant. Do not attempt to check gas levels yourself — requires a licensed technician with pressure testing equipment. |
| CH10 | Indoor fan motor fault | The indoor fan is not running or running slowly. Check that nothing is physically blocking the fan blades before calling a technician. |
| CH38 | Outdoor unit fan motor fault | Check that the outdoor unit fan is not obstructed. If the fan is not spinning at all, this needs a technician. |
| CH67 | Communication error between indoor and outdoor units | Often caused by a loose or damaged signal wire between units. Needs a technician to inspect the wiring. |
| Code | Meaning | What To Check |
|---|---|---|
| E1 | Indoor room temperature sensor fault | Sensor may be faulty or have a loose connection. Clean the air filter first — a clogged filter can cause false temperature readings. |
| E2 | Evaporator coil temperature sensor fault | Needs a technician to inspect the evaporator sensor and wiring. |
| E3 | Outdoor unit temperature sensor fault | Check outdoor unit has adequate ventilation. Sensor replacement needs a technician. |
| E4 | Compressor discharge temperature too high | Can indicate blocked airflow to outdoor unit or a refrigerant issue. Do not run the AC — call a technician. |
| E5 | Outdoor unit thermal overload / overcurrent | Switch the AC off and check that the outdoor unit is not covered or blocked. If the code returns immediately after restart, needs a technician. |
| E6 | Communication error between indoor and outdoor units | Check that the AC has not tripped at the circuit breaker. If power is fine, the wiring between units needs inspection by a technician. |
| Code | Meaning | What To Check |
|---|---|---|
| A1 | Indoor PCB fault | PCB (main control board) fault — this is not a DIY fix. Call a technician. |
| A5 | Freeze protection / high load cut-off | Check that the air filter is clean. A heavily clogged filter can trigger this code by reducing airflow over the evaporator coil. |
| C4 | Evaporator (heat exchanger) temperature sensor fault | Needs a technician to test and replace the sensor. |
| C9 | Room temperature sensor fault | Sensor may be faulty. A technician will test resistance and replace if needed. |
| E1 | Outdoor PCB fault | Main outdoor board fault — call a technician. |
| E3 | High pressure in refrigerant circuit | Can indicate a blocked condenser or refrigerant overcharge. Do not run the AC — needs a technician with pressure gauges. |
| E4 | Compressor discharge temperature too high | Check outdoor unit ventilation. If airflow is clear, call a technician — compressor may be at risk. |
| L8 | Compressor overcurrent protection | Switch off and allow to cool. If it trips again on restart, needs a technician. |
| Code | Meaning | What To Check |
|---|---|---|
| E0 | EEPROM (memory chip) data error | A reset may temporarily clear it, but if it recurs the PCB likely needs replacement. |
| E1 | Indoor temperature sensor fault | Needs a technician to check and replace the sensor. |
| E2 | Indoor coil (evaporator) sensor fault | Sensor fault — needs technician inspection. |
| E3 | Outdoor coil (condenser) sensor fault | Outdoor sensor — needs a technician. |
| E4 | Outdoor ambient temperature sensor fault | Needs technician inspection. |
| E5 | Compressor discharge temperature sensor fault | Do not run AC — call a technician. |
| E6 | Communication fault between indoor and outdoor units | Check circuit breaker first. If power is normal, the signal cable between units needs inspection. |
| Code | Meaning | What To Check |
|---|---|---|
| E1 | Room temperature sensor fault | Clean the filter first. If code persists, sensor needs replacement. |
| E2 | Evaporator coil sensor fault | Needs technician inspection. |
| E3 | Condenser coil sensor fault | Outdoor sensor — needs a technician. |
| E4 | Compressor discharge temperature fault | Switch off immediately. Needs a technician. |
| E6 | Communication error | Check power supply and connections. Needs a technician if code persists. |
| Code | Meaning | What To Check |
|---|---|---|
| 00 | Normal operation (no fault) | No action needed — this is the normal state indicator on some Hitachi models. |
| 01 | Room temperature thermistor fault | Sensor needs testing and likely replacement by a technician. |
| 02 | Evaporator thermistor fault | Needs a technician. |
| 06 | Communication error between indoor and outdoor units | Check circuit breaker. If power is normal, signal wiring between units needs inspection. |
| 17 | Compressor discharge temperature too high | Switch off immediately. Likely a refrigerant or compressor fault — needs a technician. |
| Code | Meaning | What To Check |
|---|---|---|
| P1 | High/low voltage protection (power supply issue) | Check if other appliances in your home are having power issues. If only the AC is affected, the power supply board may be faulty. |
| E1 | Indoor PCB fault | Needs a technician to diagnose. |
| E2 | Temperature sensor fault | Sensor needs testing and replacement. |
| E3 | High pressure protection | Do not run AC — check outdoor unit is not obstructed. Needs a technician. |
| E5 | Overcurrent protection | Switch off and allow to cool. Needs a technician if it recurs. |
Our technicians handle AC error codes, sensor faults, PCB repairs, and refrigerant issues across Tamil Nadu and Puducherry.
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