Inverter AC Error Codes
Fault code database for VRF and mini-split systems
Found 502 error codes
Daikin
Japan • 30 error codes
| Code | Description | Cause | Action |
|---|---|---|---|
| A0 | External protection device activated | External protection relay triggered | Check external protection device, reset if safe |
| A1 | Indoor PCB defect | Indoor unit control board failure | Replace indoor PCB |
| A3 | Drain level abnormal | Condensate drain blocked or float switch activated | Clean drain line, check float switch |
| A5 | Heat exchanger freeze-up | Evaporator coil freezing | Check airflow, refrigerant charge, expansion valve |
| A6 | Fan motor abnormal | Indoor fan motor locked or abnormal | Check fan motor, capacitor, wiring |
| A7 | Swing motor abnormal | Louver/swing motor failure | Check swing motor and drive circuit |
| C4 | Heat exchanger sensor fault | Indoor coil thermistor open/short | Check thermistor resistance, replace if out of spec |
| C9 | Room temperature sensor fault | Room temperature thermistor failure | Check sensor connection and resistance |
| E0 | External protection device | Outdoor external protection activated | Check external protection circuit |
| E1 | Outdoor PCB fault | Outdoor control board failure | Replace outdoor PCB |
| E3 | High pressure switch activated | High discharge pressure | Check condenser, fan, refrigerant charge, ambient |
| E4 | Low pressure switch activated | Low suction pressure | Check refrigerant charge, expansion valve, airflow |
| E5 | Inverter compressor overload | Compressor motor overcurrent | Check compressor, power supply, refrigerant |
| E6 | Standard compressor overload | Fixed speed compressor overcurrent | Check compressor, capacitor, power supply |
| E7 | Fan motor overcurrent | Outdoor fan drawing excess current | Check fan motor, blade, bearings |
| E9 | Electronic expansion valve fault | EEV driver or valve failure | Check EEV wiring, driver, replace valve if needed |
| F3 | Discharge pipe temperature high | Compressor discharge overheating | Check superheat, refrigerant charge, airflow |
| F6 | High pressure abnormal | Pressure sensor detecting high pressure | Check refrigerant charge, condenser, ambient |
| H6 | Position sensor fault | Compressor position sensor failure | Check sensor wiring, replace compressor if internal |
| H8 | CT sensor fault | Current transformer failure | Check CT sensor and wiring |
| H9 | Outdoor air sensor fault | Outdoor ambient thermistor failure | Check thermistor resistance and connection |
| J3 | Discharge pipe sensor fault | Discharge temperature thermistor failure | Replace discharge temperature sensor |
| J6 | Heat exchanger sensor fault | Outdoor coil thermistor failure | Check thermistor, replace if needed |
| L3 | Electrical box temperature high | Control box overheating | Check ventilation, clean control box |
| L4 | Heat sink temperature high | Inverter heat sink overheating | Check airflow around outdoor unit |
| L5 | Compressor overcurrent | Instantaneous overcurrent trip | Check compressor, wiring, voltage |
| P4 | Inverter heat sink sensor fault | Heat sink thermistor failure | Replace heat sink temperature sensor |
| U0 | Low refrigerant | System undercharged | Check for leaks, recharge system |
| U2 | Abnormal power supply voltage | Low or high voltage detected | Check power supply voltage, connections |
| U4 | Communication error | Indoor-outdoor communication failure | Check communication wiring, connectors |
Mitsubishi Electric
Japan • 29 error codes
| Code | Description | Cause | Action |
|---|---|---|---|
| E0 | Remote controller signal error | Communication issue with remote | Check remote controller and receiver |
| E1 | Remote controller PCB error | Remote control board fault | Replace remote controller |
| E3 | Communication error | No communication between units | Check wiring between indoor and outdoor |
| E6 | Indoor/outdoor communication error | Serial communication failure | Check S21/S22 communication lines |
| E7 | Indoor fan motor error | Fan motor failure | Check fan motor, hall sensor, connections |
| E9 | Indoor/outdoor communication error | Communication timeout | Check wiring polarity and connections |
| Eb | Indoor PCB error | Indoor control board failure | Replace indoor PCB |
| F1 | Room thermistor open/short | Room temperature sensor fault | Check/replace room thermistor |
| F2 | Indoor coil thermistor fault | Evaporator sensor open/short | Check/replace coil thermistor |
| P1 | Power supply peak detection | Input voltage variation | Check power supply stability |
| P2 | Current sensor error | CT sensor failure | Check CT sensor and wiring |
| P4 | Drain sensor error | Float switch activated | Clean condensate drain |
| P5 | Drain pump error | Condensate pump failure | Check drain pump operation |
| P6 | Freeze/overheat protection | Coil temperature abnormal | Check airflow, refrigerant charge |
| P8 | Pipe thermistor error | Liquid pipe sensor fault | Check pipe thermistor |
| P9 | Outdoor unit protection | Outdoor unit fault | Check outdoor unit error codes |
| U1 | High pressure switch | High pressure protection | Check condenser, refrigerant, airflow |
| U2 | Low pressure switch | Low pressure protection | Check refrigerant charge, filter |
| U3 | Short cycle | Compressor short cycling | Check timer settings, pressure |
| U4 | Discharge pipe temp high | Compressor overheat | Check refrigerant, airflow |
| U5 | Heat sink overheat | Inverter overheating | Check outdoor unit airflow |
| U6 | Compressor overcurrent | Compressor drawing excess current | Check compressor, voltage, refrigerant |
| U7 | Low superheat | Possible liquid flooding | Check expansion valve, charge |
| U8 | Outdoor fan error | Outdoor fan motor fault | Check fan motor, capacitor |
| U9 | Power voltage error | Input voltage out of range | Check power supply voltage |
| UA | Compressor overcurrent (CT) | Current transformer detected overcurrent | Check compressor, wiring |
| Ub | Outdoor coil thermistor error | Condenser sensor fault | Check/replace outdoor coil thermistor |
| Ud | Discharge thermistor error | Discharge sensor open/short | Check/replace discharge thermistor |
| UF | Compressor overcurrent (peak) | Instantaneous overcurrent | Check compressor, wiring, voltage |
LG
South Korea • 24 error codes
| Code | Description | Cause | Action |
|---|---|---|---|
| CH01 | Indoor room temp sensor error | Thermistor open/short | Check/replace room thermistor |
| CH02 | Indoor inlet temp sensor error | Evaporator inlet sensor fault | Check sensor connection and resistance |
| CH03 | Indoor outlet temp sensor error | Evaporator outlet sensor fault | Check/replace outlet thermistor |
| CH05 | Communication error | Wired remote communication fail | Check communication wiring |
| CH06 | Indoor outlet temp sensor error | Sensor fault | Check outlet pipe sensor |
| CH07 | Indoor BLDC motor error | Fan motor failure | Check BLDC motor, hall sensor |
| CH10 | Indoor BLDC motor error | Motor locked rotor | Check for obstructions, replace motor |
| CH21 | Outdoor DC link voltage error | DC bus voltage abnormal | Check power supply, inverter board |
| CH22 | Outdoor current detection error | CT sensor fault | Check CT sensor |
| CH23 | Outdoor DC link low voltage | Low DC bus voltage | Check power supply voltage |
| CH26 | Outdoor fan BLDC error | Outdoor fan motor fault | Check fan motor operation |
| CH27 | Outdoor PSC motor error | PSC fan motor fault | Check fan motor, capacitor |
| CH32 | Outdoor discharge temp high | Compressor overheat | Check refrigerant, airflow |
| CH33 | Outdoor discharge temp sensor error | Discharge thermistor fault | Check/replace sensor |
| CH34 | High pressure sensor error | Pressure transducer fault | Check pressure sensor |
| CH35 | Low pressure sensor error | Pressure transducer fault | Check pressure sensor |
| CH38 | Outdoor compressor temp sensor error | Compressor thermistor fault | Check sensor on compressor shell |
| CH40 | Outdoor CT sensor error | Current transformer fault | Check CT sensor and wiring |
| CH44 | Outdoor air temp sensor error | Ambient thermistor fault | Check/replace outdoor thermistor |
| CH45 | Outdoor condenser temp sensor error | Condenser thermistor fault | Check/replace coil thermistor |
| CH53 | Communication error between PCBs | Internal communication fault | Check outdoor PCB connections |
| CH61 | Outdoor condenser temp high | High condensing temperature | Clean condenser, check fan |
| CH62 | Inverter module temp high | IPM overheating | Check airflow around outdoor unit |
| CH67 | Outdoor fan motor lock | Fan motor locked | Check for obstructions, replace motor |
Samsung
South Korea • 19 error codes
| Code | Description | Cause | Action |
|---|---|---|---|
| E101 | Communication error | Indoor-outdoor communication fail | Check communication wiring |
| E121 | Indoor room sensor error | Room thermistor fault | Check/replace room sensor |
| E122 | Indoor coil sensor error | Evaporator thermistor fault | Check/replace coil sensor |
| E154 | Indoor fan error | Fan motor failure | Check fan motor, connections |
| E162 | Indoor EEPROM error | Memory chip fault | Replace indoor PCB |
| E201 | Communication error | Outdoor communication fault | Check wiring polarity |
| E221 | Outdoor TH1 sensor error | Outdoor coil sensor fault | Check/replace TH1 |
| E231 | Abnormal high pressure | High pressure detected | Check refrigerant, condenser |
| E237 | Inverter overcurrent | IPM overcurrent trip | Check compressor, wiring |
| E251 | Outdoor EEPROM error | Memory chip fault | Replace outdoor PCB |
| E416 | Compressor discharge temp high | Compressor overheat | Check refrigerant, superheat |
| E440 | Low pressure switch open | Low pressure protection | Check refrigerant charge |
| E441 | High pressure switch open | High pressure protection | Check condenser, charge |
| E461 | Compressor startup failure | Compressor failed to start | Check compressor, voltage, wiring |
| E464 | Compressor overcurrent | Excessive compressor current | Check compressor, refrigerant |
| E465 | DC link voltage error | DC bus voltage abnormal | Check power supply |
| E466 | Outdoor fan error | Fan motor fault | Check fan motor operation |
| E468 | CT sensor error | Current sensor fault | Check CT sensor |
| E554 | Inverter module temp high | IPM overheating | Improve ventilation |
Gree
China • 20 error codes
| Code | Description | Cause | Action |
|---|---|---|---|
| E1 | High pressure protection | High discharge pressure | Check condenser, fan, refrigerant |
| E2 | Indoor freeze protection | Evaporator freezing | Check airflow, charge, expansion valve |
| E3 | Low pressure protection | Low suction pressure | Check refrigerant charge, filter |
| E4 | Compressor discharge temp high | Compressor overheating | Check superheat, refrigerant |
| E5 | Overcurrent protection | Compressor overcurrent | Check compressor, voltage |
| E6 | Communication error | Indoor-outdoor communication fail | Check wiring connections |
| E7 | Mode conflict | Multi-split mode mismatch | Set all units to same mode |
| E8 | Overload protection | System overload | Check load, reduce demand |
| E9 | Full water protection | Condensate tank full | Empty condensate tank |
| F0 | Refrigerant shortage | Low refrigerant | Check for leaks, recharge |
| F1 | Indoor ambient sensor error | Room thermistor fault | Check/replace sensor |
| F2 | Indoor coil sensor error | Evaporator thermistor fault | Check/replace sensor |
| F3 | Outdoor ambient sensor error | Outdoor thermistor fault | Check/replace sensor |
| F4 | Outdoor coil sensor error | Condenser thermistor fault | Check/replace sensor |
| F5 | Discharge temp sensor error | Discharge thermistor fault | Check/replace sensor |
| F6 | Overcharge protection | System overcharged | Recover excess refrigerant |
| H1 | Defrost mode | Heat pump defrosting (normal) | Wait for defrost to complete |
| H3 | Compressor overload | Compressor thermal protection | Check compressor, charge |
| H5 | IPM protection | Inverter module fault | Check inverter board |
| H6 | Fan motor feedback error | Indoor fan motor fault | Check fan motor, connections |
Panasonic
Japan • 24 error codes
| Code | Description | Cause | Action |
|---|---|---|---|
| H00 | No abnormality | Normal operation | No action required |
| H11 | Communication error | Indoor-outdoor communication fail | Check communication wiring |
| H12 | Indoor unit capacity error | Capacity mismatch | Check system configuration |
| H14 | Indoor air sensor error | Room thermistor fault | Check/replace room sensor |
| H15 | Indoor compressor sensor error | Sensor fault | Check indoor sensors |
| H16 | Indoor current sensor error | CT sensor fault | Check CT sensor |
| H19 | Indoor fan motor error | Fan motor locked | Check fan motor operation |
| H23 | Indoor gas pipe sensor error | Thermistor fault | Check/replace gas pipe sensor |
| H25 | Indoor filter cleaning error | Auto-clean function error | Clean filter, check mechanism |
| H27 | Outdoor air sensor error | Ambient thermistor fault | Check/replace outdoor sensor |
| H28 | Outdoor coil sensor error | Condenser thermistor fault | Check/replace coil sensor |
| H30 | Outdoor discharge sensor error | Discharge thermistor fault | Check/replace discharge sensor |
| H33 | Connection mistake | Wiring connection error | Check indoor/outdoor wiring |
| H38 | Indoor/outdoor mismatch | Unit mismatch | Verify compatible units |
| H98 | Indoor high pressure protection | Indoor unit pressure high | Check airflow, filter |
| H99 | Indoor freeze protection | Evaporator freezing | Check airflow, charge |
| F11 | 4-way valve error | Reversing valve malfunction | Check 4-way valve coil, operation |
| F17 | Indoor freeze protection | Freezing detected | Defrost, check airflow |
| F90 | Outdoor inverter error | Inverter circuit fault | Check inverter board |
| F91 | Refrigerant cycle error | Refrigerant system fault | Check charge, valves, piping |
| F93 | Compressor rotor position error | Position sensor fault | Check compressor, inverter |
| F95 | Outdoor cooling error | Condenser performance issue | Clean condenser, check fan |
| F96 | IPM overheat | Inverter module overheating | Check ventilation, heat sink |
| F97 | Compressor overheat | Compressor overheating | Check refrigerant, superheat |
Hitachi
Japan • 36 error codes
| Code | Description | Cause | Action |
|---|---|---|---|
| 02 | High pressure protection | High pressure cut activated | Check refrigerant charge, condenser, fan operation |
| 03 | Indoor/outdoor communication error | Disconnected wires, loose terminals, incorrect wiring | Check communication wiring between units |
| 04 | Outdoor PCB to fan controller error | Blown fuse, loose connectors, broken wires | Check outdoor fan controller circuit |
| 06 | Phase detection failure | Phase sequence error or missing phase | Check 3-phase power supply, correct phase sequence |
| 0A | Outdoor to outdoor communication error | Damaged wiring, incorrect connections (multi-split) | Check wiring between outdoor units |
| 0B | Main unit address error | Multiple units set as main unit | Check address settings, set only one main |
| 0C | Sub unit address error | Address setting conflict | Correct address settings on sub units |
| 11 | Indoor inlet air thermistor error | Thermistor open/short circuit | Check/replace inlet air thermistor |
| 12 | Indoor outlet air thermistor error | Thermistor failure | Check/replace outlet air thermistor |
| 13 | Indoor freeze protection thermistor error | Evaporator thermistor fault | Check/replace evaporator thermistor |
| 14 | Indoor gas piping thermistor error | Gas pipe sensor failure | Check/replace gas pipe thermistor |
| 21 | Outdoor high pressure sensor error | Pressure transducer fault | Check/replace high pressure sensor |
| 22 | Outdoor low pressure sensor error | Pressure transducer fault | Check/replace low pressure sensor |
| 23 | Outdoor discharge gas thermistor error | Discharge temperature sensor fault | Check/replace discharge thermistor |
| 24 | Outdoor heat exchanger thermistor error | Condenser thermistor fault | Check/replace condenser thermistor |
| 25 | Outdoor suction gas thermistor error | Suction temperature sensor fault | Check/replace suction thermistor |
| 29 | Outdoor air thermistor error | Ambient temperature sensor fault | Check/replace outdoor air thermistor |
| 31 | Capacity setting mismatch | Indoor/outdoor capacity code incorrect | Verify capacity code settings match |
| 35 | Indoor unit number duplicated | Multiple units with same address | Assign unique addresses to each unit |
| 36 | Incompatible unit combination | Mismatched indoor/outdoor units | Verify unit compatibility |
| 39 | Constant compressor overcurrent | Running current abnormal | Check compressor, current sensor, power supply |
| 43 | Low pressure protection | Low suction pressure | Check refrigerant charge, filter, expansion valve |
| 44 | High pressure protection (repeat) | Repeated high pressure trips | Check condenser, refrigerant charge, ambient conditions |
| 45 | Discharge temperature protection | Compressor discharge overheat | Check superheat, refrigerant charge, airflow |
| 46 | Inverter compressor overcurrent | Inverter compressor drawing excess current | Check compressor, voltage, refrigerant |
| 47 | Valve locking protection | Service valve closed or restricted | Open service valves, check for restriction |
| 48 | Electrical overload | System drawing excessive power | Check power supply, reduce load |
| 53 | Inverter PCB failure | Inverter board malfunction | Replace inverter PCB |
| 54 | Inverter overheating | IPM module overheat | Check ventilation around outdoor unit |
| 55 | Fan motor error | Outdoor fan motor failure | Check fan motor, replace if necessary |
| E0 | Water pump error | Condensate pump failure | Check drain pump operation |
| E1 | Compressor thermal protection | Compressor internal protection | Check refrigerant charge, superheat |
| E3 | High pressure protection | High discharge pressure | Check condenser, fan, refrigerant |
| E5 | Inverter compressor error | Compressor startup failure | Check compressor, inverter, wiring |
| E9 | Indoor fan motor error | Indoor fan locked rotor | Check fan motor, obstructions |
| EE | Compressor protection alarm | Repeated compressor trips (3x in 6 hours) | Professional service required, check compressor |
Mitsubishi Heavy Industries
Japan • 32 error codes
| Code | Description | Cause | Action |
|---|---|---|---|
| E01 | Remote controller communication error | Wired remote controller wiring failure | Check remote controller wiring connections |
| E02 | Duplicate indoor unit address | Multiple units have same address | Assign unique address to each indoor unit |
| E03 | Indoor/outdoor communication error | Communication not established | Check wiring between indoor and outdoor units |
| E05 | Indoor/outdoor transmission abnormal | Serial communication failure | Check communication line polarity and connections |
| E06 | Indoor heat exchanger thermistor error | Evaporator sensor fault | Check/replace evaporator thermistor |
| E07 | Indoor return air thermistor error | Room temperature sensor fault | Check/replace return air thermistor |
| E08 | Heating overload protection | Overheat during heating mode | Check airflow, thermistor operation |
| E09 | Drain float switch activated | Condensate drain blocked | Clean drain line, check float switch |
| E10 | Too many indoor units connected | Over 17 indoor units on system | Reduce number of connected units |
| E16 | Indoor fan motor error | Fan motor failure or locked rotor | Check fan motor, capacitor, wiring |
| E28 | Remote controller thermistor error | Remote controller sensor fault | Replace remote controller |
| E32 | Phase wiring open or reversed | 3-phase connection error | Check phase wiring, correct phase sequence |
| E33 | Inverter current abnormal | Compressor current out of range | Check compressor, inverter board |
| E34 | L3-phase wiring open | Missing phase connection | Check 3-phase power supply connections |
| E35 | Heat exchanger temperature high | Condenser overheat | Clean condenser, check fan operation |
| E36 | Discharge temperature abnormal | Compressor discharge overheat | Check superheat, refrigerant charge |
| E37 | Outdoor heat exchanger thermistor error | Condenser thermistor fault | Check/replace condenser thermistor |
| E38 | Outdoor air thermistor error | Ambient temperature sensor fault | Check/replace outdoor air thermistor |
| E39 | Discharge pipe thermistor error | Discharge temperature sensor fault | Check/replace discharge thermistor |
| E40 | High pressure protection | High pressure switch activated | Check condenser, fan, refrigerant charge |
| E42 | Compressor overcurrent | Compressor drawing excess current | Check compressor, power supply, refrigerant |
| E43 | Low pressure protection | Low pressure switch activated | Check refrigerant charge, filter, expansion valve |
| E47 | Inverter overvoltage | DC bus voltage too high | Check power supply voltage, inverter board |
| E48 | DC fan motor abnormal | Outdoor DC fan motor fault | Check fan motor, hall sensor, wiring |
| E52 | Control circuit abnormal | Outdoor PCB fault | Check/replace outdoor control board |
| E56 | Power transistor thermistor error | IPM temperature sensor fault | Check IPM thermistor, replace if needed |
| E57 | Insufficient refrigerant | Low refrigerant charge detected | Check for leaks, recharge system |
| E59 | Compressor startup error | Compressor failed to start | Check compressor, inverter, wiring |
| E60 | Compressor position detection error | Rotor position sensor fault | Check compressor, inverter board |
| E63 | Emergency stop activated | Emergency stop input received | Check emergency stop circuit, reset |
| E64 | High pressure protection (sensor) | High pressure transducer trip | Check condenser, refrigerant, ambient |
| E68 | Current sensor abnormal | CT sensor fault | Check current transformer sensor |
Carrier
USA • 23 error codes
| Code | Description | Cause | Action |
|---|---|---|---|
| E0 | EEPROM parameter error | Indoor unit EEPROM data corrupted | Reset power; if persists, replace indoor PCB |
| E1 | Indoor/outdoor communication error | Communication line fault between units | Check signal wiring, connectors, and PCB |
| E2 | Zero crossing detection error | Power supply frequency abnormal | Check power supply voltage and frequency |
| E3 | Indoor fan speed out of control | Fan motor or driver fault | Check fan motor, capacitor, and driver IC |
| E4 | Room temperature sensor fault | T1 thermistor open or short circuit | Check T1 sensor resistance, replace if out of range |
| E5 | Evaporator coil sensor fault | T2 thermistor open or short circuit | Check T2 sensor resistance, replace if needed |
| E6 | Outdoor coil sensor fault | T3 thermistor open or short circuit | Check outdoor coil sensor and wiring |
| E8 | Indoor unit address duplicate | Multiple indoor units with same address | Reset indoor unit addresses to unique values |
| EC | Refrigerant leak detection | Refrigerant leak sensor triggered | Check for leaks, repair and recharge |
| F1 | Outdoor ambient sensor fault | T4 thermistor open or short circuit | Check outdoor ambient sensor and wiring |
| F2 | Condenser coil sensor fault | T3 thermistor open or short circuit | Check condenser coil sensor, replace if faulty |
| F3 | Discharge temperature sensor fault | T5 thermistor open or short circuit | Check compressor discharge sensor |
| F4 | Outdoor EEPROM parameter error | Outdoor unit EEPROM data corrupted | Reset power; if persists, replace outdoor PCB |
| F5 | Outdoor unit overload | Compressor or system overload condition | Check refrigerant charge, airflow, voltage |
| H1 | Defrost mode active | Normal defrost operation in heat mode | Normal operation, wait for defrost to complete |
| H3 | Compressor overload protection | Compressor overcurrent detected | Check compressor, refrigerant charge, voltage |
| H6 | No feedback from compressor | Inverter compressor not running | Check compressor wiring, inverter board |
| P0 | IPM module protection | Inverter power module fault | Check IPM module, DC bus voltage, compressor |
| P1 | Over/under voltage protection | Power supply voltage out of range | Check voltage at outdoor unit terminals |
| P2 | Compressor top temperature protection | Compressor discharge overheating | Check superheat, refrigerant charge, airflow |
| P4 | Inverter compressor drive error | Inverter drive board fault | Check inverter board and compressor wiring |
| P5 | Outdoor DC fan motor fault | Fan motor speed feedback error | Check DC fan motor and wiring |
| P6 | Outdoor unit overheating | Control box temperature too high | Check ventilation around outdoor unit |
Fujitsu General
Japan • 27 error codes
| Code | Description | Cause | Action |
|---|---|---|---|
| E:EE | Communication error between indoor and outdoor | Signal wiring fault | Check communication wiring between units |
| E:01 | Communication error (indoor PCB) | Indoor control board fault | Check indoor PCB, reset power |
| E:02 | Communication error (outdoor PCB) | Outdoor control board fault | Check outdoor PCB, signal wiring |
| E:03 | Remote controller communication error | Remote signal not received | Check remote controller and receiver |
| E:04 | Indoor/outdoor mismatch | Incompatible indoor and outdoor units | Verify unit compatibility and capacity |
| E:06 | Indoor fan motor error | Fan motor locked or abnormal speed | Check fan motor, blade, and wiring |
| E:07 | Outdoor fan motor error | Outdoor fan motor fault | Check outdoor fan motor and drive circuit |
| E:08 | Compressor overcurrent | Compressor drawing excess current | Check compressor, refrigerant charge, voltage |
| E:09 | Electronic expansion valve error | EEV driver or valve fault | Check EEV wiring and operation |
| E:0A | Compressor overcurrent at startup | Locked rotor or high starting current | Check compressor, starting circuit |
| E:0C | Compressor current sensor fault | CT sensor failure | Check current transformer and wiring |
| E:0d | Compressor position error | Inverter cannot detect rotor position | Check compressor and inverter board |
| E:11 | Room temperature sensor error | Thermistor open or short | Check room temperature sensor |
| E:12 | Indoor coil temperature sensor error | Evaporator thermistor fault | Check coil temperature sensor |
| E:13 | Outdoor coil temperature sensor error | Condenser thermistor fault | Check outdoor coil sensor |
| E:14 | Outdoor ambient sensor error | Outdoor temperature thermistor fault | Check outdoor ambient sensor |
| E:15 | Compressor discharge sensor error | Discharge thermistor fault | Check discharge temperature sensor |
| E:16 | Heat sink temperature sensor error | IPM heat sink thermistor fault | Check heat sink sensor on inverter |
| E:20 | Compressor overload (high discharge temp) | Compressor overheating | Check superheat, refrigerant charge, airflow |
| E:21 | IPM overheat protection | Inverter module overheating | Check airflow around outdoor unit |
| E:23 | Freeze protection activated | Evaporator coil freezing | Check airflow, filter, refrigerant charge |
| E:24 | High pressure protection | System high pressure exceeded limit | Check condenser, fan, refrigerant charge |
| E:25 | Low pressure protection | System low pressure below limit | Check for leaks, refrigerant charge |
| E:28 | DC voltage abnormal | Inverter DC bus voltage fault | Check power supply, rectifier circuit |
| E:31 | Power module protection | IPM module fault | Check inverter module and compressor |
| E:33 | DC bus voltage high | DC voltage exceeds limit | Check power supply voltage stability |
| E:53 | Drain pump or float switch error | Condensate drainage blocked | Clean drain line, check float switch and pump |
Trane
USA • 20 error codes
| Code | Description | Cause | Action |
|---|---|---|---|
| E0 | EEPROM parameter error | Unit EEPROM data corrupted | Reset power; replace PCB if persists |
| E1 | Indoor/outdoor communication error | Communication line disconnected | Check signal wiring between units |
| E2 | Zero crossing detection error | Power supply frequency abnormal | Check power supply quality |
| E3 | Fan speed out of control | Indoor fan motor abnormal | Check fan motor, capacitor, driver |
| E4 | Room temperature sensor fault | T1 thermistor open or short | Check and replace room sensor |
| E5 | Evaporator coil sensor fault | T2 thermistor open or short | Check and replace coil sensor |
| E6 | Condenser coil sensor fault | Outdoor coil thermistor fault | Check outdoor coil temperature sensor |
| E109 | Communication timeout during startup | Indoor-outdoor communication failed at startup | Verify all wiring and power connections |
| E201 | Indoor/outdoor tracking communication error | Indoor unit powered off or wire break | Check indoor power and daisy-chain wiring |
| E320 | OLP sensor open or short | Compressor top sensor or circuit board defective | Check OLP sensor, replace PCB if needed |
| F1 | Outdoor ambient sensor fault | Outdoor temperature sensor failure | Check outdoor ambient thermistor |
| F2 | Condenser temperature sensor fault | Condenser coil thermistor failure | Check condenser sensor resistance |
| F3 | Discharge temperature sensor fault | Compressor discharge thermistor failure | Check discharge temperature sensor |
| H1 | Defrost mode | Normal defrost operation | Normal, wait 5-10 minutes to complete |
| H3 | Compressor overload protection | Overcurrent or overheating | Check compressor and refrigerant charge |
| P0 | IPM module protection | Inverter module fault | Check IPM module and compressor |
| P1 | Over/under voltage protection | Supply voltage out of range | Check power supply voltage at unit |
| P2 | Compressor top temperature high | Compressor discharge overheating | Check superheat, charge, clean condenser |
| P4 | Inverter compressor drive error | Drive board failure | Check inverter drive board |
| P5 | DC fan motor fault | Outdoor fan motor feedback error | Check DC fan motor wiring and bearings |
York
USA • 20 error codes
| Code | Description | Cause | Action |
|---|---|---|---|
| E0 | EEPROM malfunction | EEPROM data error | Reset power; replace PCB if persists |
| E1 | Indoor/outdoor communication error | Communication line fault | Check signal wiring and connectors |
| E2 | Zero crossing signal error | Power supply issue | Check power supply voltage and frequency |
| E3 | Indoor fan speed error | Fan motor abnormal | Check fan motor and driver circuit |
| E4 | Room temperature sensor open/short | T1 sensor fault | Check and replace room sensor |
| E5 | Indoor coil sensor open/short | T2 sensor fault | Check and replace coil sensor |
| E6 | Outdoor coil sensor fault | Outdoor thermistor failure | Check outdoor coil temperature sensor |
| E7 | Outdoor discharge sensor fault | Discharge thermistor open or short | Check compressor discharge sensor |
| E8 | Outdoor ambient sensor fault | Outdoor temperature sensor failure | Check outdoor ambient thermistor |
| EC | Refrigerant leak detected | Leak sensor triggered | Check for leaks, repair and recharge |
| F1 | Condenser high temperature protection | Condenser coil overheating | Clean condenser, check fan operation |
| F2 | Evaporator freeze protection | Evaporator coil freezing | Check airflow, filter, refrigerant charge |
| F3 | Discharge temperature protection | High discharge temperature | Check superheat and refrigerant charge |
| F4 | Compressor overload protection | Compressor overcurrent | Check compressor and power supply |
| H1 | Defrost in progress | Normal defrost cycle | Normal operation, wait for completion |
| H5 | IPM module protection | Inverter module fault | Check IPM and compressor |
| P0 | IPM overcurrent protection | Inverter overcurrent | Check compressor and inverter board |
| P1 | High/low voltage protection | Supply voltage abnormal | Check voltage at outdoor unit |
| P2 | Compressor overheating protection | Compressor top temperature high | Check superheat, charge, airflow |
| P4 | Compressor drive error | Inverter drive fault | Check inverter board, compressor wiring |
Midea
China • 22 error codes
| Code | Description | Cause | Action |
|---|---|---|---|
| E0 | EEPROM parameter error | Indoor EEPROM data corrupted | Reset power; replace PCB if persists |
| E1 | Indoor/outdoor communication error | Signal wiring disconnected | Check communication wiring between units |
| E2 | Zero crossing error | Power supply frequency abnormal | Check power supply quality |
| E3 | Indoor fan speed error | Fan motor speed out of control | Check fan motor and drive circuit |
| E4 | Room temperature sensor fault | T1 sensor open or short | Check room temperature sensor |
| E5 | Evaporator temperature sensor fault | T2 sensor open or short | Check evaporator coil sensor |
| E6 | Outdoor temperature sensor fault | T3 sensor open or short | Check outdoor coil sensor |
| E8 | Duplex communication error | Address conflict on communication bus | Reset unit addresses |
| E9 | Expansion valve fault | EEV driver or valve failure | Check EEV coil and wiring |
| EC | Refrigerant leak detection | Leak sensor activated | Leak test, repair, and recharge system |
| F0 | Outdoor EEPROM error | Outdoor unit EEPROM fault | Reset power; replace outdoor PCB if needed |
| F1 | Outdoor ambient sensor fault | T4 thermistor failure | Check outdoor ambient sensor |
| F2 | Condenser coil sensor fault | Condenser thermistor failure | Check condenser sensor |
| F3 | Discharge temperature sensor fault | T5 thermistor failure | Check compressor discharge sensor |
| F4 | Suction temperature sensor fault | Suction line thermistor failure | Check suction line sensor |
| P0 | IPM module protection | Inverter module overcurrent | Check IPM module and compressor |
| P1 | Over/under voltage protection | Supply voltage out of range | Check power supply voltage |
| P2 | Compressor top temperature protection | Compressor overheating | Check superheat, charge, airflow |
| P3 | High current protection | System drawing excess current | Check compressor and wiring |
| P4 | Inverter drive error | Drive board fault | Check inverter board and compressor wiring |
| P5 | DC fan motor fault | Outdoor fan feedback error | Check DC fan motor and wiring |
| P6 | Heat sink temperature high | Inverter heat sink overheating | Check outdoor unit ventilation |
Haier
China • 19 error codes
| Code | Description | Cause | Action |
|---|---|---|---|
| E0 | EEPROM parameter error | EEPROM data corrupted | Reset power; replace board if persists |
| E1 | Indoor/outdoor communication error | Communication line fault | Check signal wiring and connectors |
| E2 | Zero crossing error | Power supply issue | Check power supply stability |
| E3 | Fan speed error | Indoor fan speed abnormal | Check fan motor and circuit |
| E4 | Room temperature sensor fault | T1 sensor open/short | Check room sensor |
| E5 | Evaporator sensor fault | T2 sensor open/short | Check evaporator sensor |
| E6 | Outdoor sensor fault | Outdoor thermistor failure | Check outdoor coil sensor |
| E7 | Humidity sensor fault | Humidity sensor failure | Check and replace humidity sensor |
| E8 | Address error | Unit address conflict | Check and reset unit addresses |
| F1 | Ambient temperature sensor fault | Outdoor ambient sensor failure | Check outdoor ambient sensor |
| F2 | Condenser sensor fault | Condenser thermistor failure | Check condenser sensor |
| F3 | Discharge sensor fault | Discharge thermistor failure | Check discharge temperature sensor |
| F4 | Suction sensor fault | Suction line sensor failure | Check suction temperature sensor |
| P0 | IPM protection | Inverter module fault | Check IPM module and compressor |
| P1 | Voltage protection | Supply voltage abnormal | Check power supply voltage |
| P2 | Compressor overheating | Compressor top temperature high | Check charge, superheat, airflow |
| P3 | High current protection | System overcurrent | Check compressor and wiring |
| P4 | Inverter drive error | Drive board fault | Check inverter drive board |
| P5 | Fan motor fault | Outdoor DC fan error | Check outdoor fan motor |
Toshiba
Japan • 22 error codes
| Code | Description | Cause | Action |
|---|---|---|---|
| E01 | Indoor PCB failure | Indoor control board fault | Replace indoor PCB |
| E02 | Indoor/outdoor communication error | Communication line disconnected | Check signal wiring |
| E03 | Remote controller communication error | Remote signal fault | Check remote and receiver |
| E04 | Indoor fan motor error | Fan motor locked or abnormal | Check fan motor and wiring |
| E05 | Indoor thermistor fault | Room temperature sensor failure | Check room sensor resistance |
| E06 | Indoor coil sensor fault | Evaporator thermistor failure | Check coil temperature sensor |
| E07 | Drain sensor/pump fault | Drainage system error | Check drain line and float switch |
| E09 | Indoor EEPROM error | EEPROM data corrupted | Reset power; replace PCB if needed |
| E10 | Multi-indoor capacity error | Indoor capacity exceeds outdoor | Verify unit capacity matching |
| E15 | Outdoor PCB fault | Outdoor control board failure | Replace outdoor PCB |
| E16 | Compressor overcurrent | Compressor drawing excess current | Check compressor, charge, voltage |
| E17 | Outdoor fan motor fault | Fan motor error | Check outdoor fan motor and wiring |
| E18 | Outdoor coil sensor fault | Condenser thermistor failure | Check outdoor coil sensor |
| E19 | Outdoor ambient sensor fault | Outdoor temperature sensor failure | Check outdoor ambient sensor |
| E20 | Discharge temperature sensor fault | Discharge thermistor failure | Check discharge temperature sensor |
| E21 | High pressure protection | System high pressure exceeded | Check condenser, fan, charge |
| E22 | Compressor overheating | Compressor discharge temperature high | Check superheat, charge, airflow |
| E23 | Low pressure protection | System low pressure detected | Check for leaks, verify charge |
| E24 | Inverter overcurrent | IPM module overcurrent | Check inverter module and compressor |
| E27 | Outdoor EEPROM error | Outdoor EEPROM corrupted | Reset power; replace outdoor PCB |
| E28 | DC voltage abnormal | Inverter DC bus fault | Check power supply, rectifier |
| E31 | Heat sink temperature high | Inverter overheating | Check outdoor unit ventilation |
Hisense
China • 20 error codes
| Code | Description | Cause | Action |
|---|---|---|---|
| E0 | EEPROM error | EEPROM data fault | Reset power; replace PCB if persists |
| E1 | Indoor/outdoor communication error | Signal wiring fault | Check communication wiring |
| E2 | Zero crossing error | Power supply issue | Check power supply quality |
| E3 | Fan speed error | Indoor fan abnormal | Check fan motor and circuit |
| E4 | Room temperature sensor fault | T1 sensor open/short | Check room temperature sensor |
| E5 | Evaporator sensor fault | T2 sensor open/short | Check evaporator sensor |
| E6 | Condenser sensor fault | Outdoor coil sensor fault | Check condenser sensor |
| E8 | Duplex communication error | Address conflict | Reset unit addresses |
| EC | Refrigerant leak detected | Leak sensor triggered | Check for leaks, repair, recharge |
| F0 | Outdoor EEPROM error | Outdoor EEPROM fault | Reset; replace outdoor PCB if needed |
| F1 | Outdoor ambient sensor fault | T4 thermistor failure | Check outdoor ambient sensor |
| F2 | Condenser sensor fault | Condenser thermistor failure | Check condenser temperature sensor |
| F3 | Discharge sensor fault | Discharge thermistor failure | Check discharge temperature sensor |
| F4 | Suction sensor fault | Suction thermistor failure | Check suction line sensor |
| P0 | IPM module protection | Inverter overcurrent | Check IPM module and compressor |
| P1 | Voltage protection | Voltage out of range | Check power supply voltage |
| P2 | Compressor overheating | Compressor discharge temp high | Check superheat, charge, airflow |
| P3 | Overcurrent protection | System drawing excess current | Check compressor and wiring |
| P4 | Inverter drive error | Drive board fault | Check inverter drive board |
| P5 | DC fan motor fault | Fan motor feedback error | Check outdoor DC fan motor |
Lennox
USA • 32 error codes
| Code | Description | Cause | Action |
|---|---|---|---|
| E1 | High pressure protection | Discharge pressure too high, condenser blockage or overcharge | Check condenser coil, clean if dirty, verify refrigerant charge and outdoor fan operation |
| E2 | Anti-freezing protection | Evaporator coil temperature too low, low airflow or low charge | Check air filter, indoor fan, refrigerant charge, and expansion valve |
| E3 | Low pressure protection | Suction pressure too low, refrigerant leak or restriction | Check for leaks, verify charge, inspect filter drier and expansion valve |
| E4 | High discharge temperature protection | Compressor discharge temperature excessive | Check refrigerant charge, condenser airflow, and compressor valves |
| E5 | Whole unit overcurrent protection | System drawing excess current | Check power supply voltage, compressor windings, and wiring connections |
| E6 | Indoor/outdoor communication error | Communication wire fault between indoor and outdoor units | Check communication wiring, connectors, and PCB boards on both units |
| E7 | Running mode conflict | Multiple indoor units requesting conflicting modes (heat vs cool) | Set all indoor units to same mode, check mode settings via remote |
| E8 | Overload protection | Compressor overload due to high pressure or mechanical issue | Check condenser, refrigerant charge, compressor, and ambient conditions |
| E9 | Indoor unit full water error | Condensate drain pan full, float switch triggered | Clean drain line, check drain pump, clear blockage in condensate piping |
| EU | IPM temperature protection / frequency limited | Inverter power module overheating | Check outdoor unit airflow, clean heat sink, verify fan operation |
| F0 | System charge shortage or blockage | Low refrigerant or restriction in refrigerant circuit | Check for leaks, recharge system, inspect filter drier and capillary tube |
| F1 | Return air temperature sensor fault | Room temperature thermistor open or short circuit | Check sensor wiring, measure resistance, replace thermistor if out of spec |
| F2 | Evaporator temperature sensor fault | Indoor coil thermistor open or short circuit | Check sensor connection, measure resistance, replace if faulty |
| F3 | Outdoor ambient temperature sensor fault | Outdoor ambient thermistor open or short circuit | Inspect sensor wiring at outdoor unit, replace thermistor |
| F4 | Condenser coil temperature sensor fault | Outdoor coil mid-tube thermistor open or short circuit | Check sensor attached to condenser coil, replace if needed |
| F5 | Discharge temperature sensor fault | Compressor discharge thermistor open or short circuit | Inspect sensor on discharge line, replace if faulty |
| H1 | Defrosting in progress | Normal defrost cycle active in heat mode | No action needed, unit will resume heating after defrost completes |
| H3 | Compressor overheating protection | Compressor body temperature too high | Check refrigerant charge, airflow, and compressor for mechanical failure |
| H5 | IPM current protection | Inverter power module overcurrent detected | Check compressor windings, wiring, and inverter board |
| H6 | Compressor motor stalling | Compressor rotor locked or unable to start | Check compressor, starting circuit, refrigerant pressures, and power supply |
| H7 | Compressor desynchronizing | Inverter compressor lost synchronization | Check compressor winding resistance, inverter board, and power supply voltage |
| HC | PFC protection | Power factor correction circuit fault | Check PFC module on outdoor PCB, input voltage, and capacitors |
| P1 | High pressure switch open | High pressure switch tripped due to excessive pressure | Check condenser, outdoor fan, refrigerant charge, reset switch after cooling |
| P2 | Low pressure switch open | Low pressure switch tripped due to low suction pressure | Check for refrigerant leaks, verify charge, inspect expansion valve |
| P3 | Compressor current overload | Outdoor compressor drawing excessive current | Check compressor windings, voltage, and mechanical condition |
| P4 | High compressor discharge temperature | Discharge line temperature exceeds limit | Check superheat, refrigerant charge, compressor valves |
| P5 | Over phase current protection | Phase current exceeds safe limit | Check power supply, compressor, and inverter board |
| PH | DC bus over-voltage protection | DC bus voltage too high in inverter circuit | Check input voltage, rectifier, and DC bus capacitors |
| PL | DC bus under-voltage protection | DC bus voltage too low in inverter circuit | Check input voltage, power supply wiring, and rectifier circuit |
| LC | Compressor startup failure | Compressor failed to start within time limit | Check compressor windings, power supply, refrigerant pressures |
| LD | Compressor phase loss/reversal | Phase sequence incorrect or phase missing (3-phase units) | Check 3-phase wiring, swap two phases if reversed |
| L3 | Outdoor fan motor error | Outdoor fan motor 1 failure or speed abnormal | Check fan motor, wiring, capacitor, and fan blade for obstruction |
Bosch
Germany • 29 error codes
| Code | Description | Cause | Action |
|---|---|---|---|
| E0 | Indoor unit EEPROM parameter error | Indoor PCB EEPROM data corrupted or missing | Power cycle the unit, replace indoor PCB if error persists |
| E1 | Indoor/outdoor communication error | Communication wire fault between indoor and outdoor units | Check communication wiring, polarity, connectors, and both PCBs |
| E2 | Zero-crossing signal detection error | AC power zero-crossing circuit failure on indoor PCB | Check power supply, replace indoor PCB if error continues |
| E3 | Indoor fan speed out of control | Indoor fan motor not running at correct speed | Check fan motor, wiring, capacitor, and indoor PCB fan driver |
| E4 | Room temperature sensor T1 fault | Indoor room thermistor open or short circuit | Check sensor wiring, measure resistance, replace thermistor if faulty |
| E5 | Evaporator coil temperature sensor T2 fault | Indoor coil thermistor open or short circuit | Inspect sensor on evaporator coil, replace if resistance out of spec |
| E6 | Indoor/outdoor unit communication fault | Serial communication failure between units | Check communication cable, verify correct wiring, inspect PCB connectors |
| EC | Refrigerant leakage detection | Built-in refrigerant leak sensor triggered | Perform leak test with electronic detector, repair leak, recharge system |
| F0 | Overload current protection | System drawing excessive current beyond rated limit | Check compressor, power supply voltage, and wiring connections |
| F1 | Outdoor ambient temperature sensor T4 fault | Outdoor ambient thermistor open or short circuit | Check sensor wiring on outdoor unit, replace thermistor if needed |
| F2 | Condenser coil temperature sensor T3 fault | Condenser coil thermistor open or short circuit | Inspect sensor on condenser coil, check connector, replace if faulty |
| F3 | Discharge temperature sensor T5 fault | Compressor discharge thermistor open or short circuit | Check sensor on discharge line, replace if resistance out of range |
| F4 | Outdoor unit EEPROM parameter error | Outdoor PCB EEPROM data corrupted or missing | Power cycle outdoor unit, replace outdoor PCB if error persists |
| F5 | Outdoor fan speed out of control | Outdoor fan motor not running at expected speed | Check fan motor, blade obstruction, wiring, and outdoor PCB |
| F6 | T2b sensor error | Indoor coil outlet pipe temperature sensor fault | Check T2b sensor wiring and connector, replace if faulty |
| P0 | Inverter module (IPM) malfunction | IPM overcurrent or overtemperature protection | Check compressor windings, inverter board, heat sink, and wiring |
| P1 | Over-voltage or under-voltage protection | Input voltage or DC bus voltage out of range | Check incoming voltage with multimeter, inspect rectifier and capacitors |
| P2 | Compressor top high temperature protection | Compressor shell temperature exceeds safe limit (OLP) | Check refrigerant charge, superheat, condenser airflow, compressor valves |
| P3 | Low ambient temperature cut-off | Outdoor temperature below minimum operating threshold | Unit cannot operate in extreme cold; check ambient sensor for accuracy |
| P4 | High compressor discharge temperature protection | Discharge line temperature exceeds safe limit | Check superheat, refrigerant charge, and condenser coil cleanliness |
| P5 | Condenser coil temperature protection in cooling | Condenser coil temperature too high during cooling mode | Clean condenser coil, check outdoor fan motor, verify charge |
| P6 | Evaporator overheating protection in cooling | Evaporator coil temperature too high in cooling mode | Check indoor airflow, filter, fan motor, and refrigerant charge |
| P7 | Overheating protection in heating mode | Condenser (indoor coil in heating) temperature too high | Check indoor airflow, air filter, and fan motor operation |
| P8 | DC fan motor hurricane protection | Outdoor DC fan motor reverse rotation detected from strong wind | Check fan motor and blade, verify no extreme wind condition |
| E7 | Outdoor DC fan motor fault | DC fan motor failure or speed signal lost | Check fan motor wiring, hall sensor, replace motor if faulty |
| E8 | Compressor discharge sensor unseated | T5 sensor not properly attached to discharge line | Reattach discharge sensor securely to pipe, use thermal paste and insulation |
| E9 | Outdoor EEPROM fault | Outdoor unit EEPROM chip failure | Replace outdoor control board |
| CF | Anti-cold wind mode | Normal startup delay to prevent cold air in heating mode | No action needed, system will begin heating once coil warms up |
| dF | Defrost mode active | Normal defrost cycle running in heating mode | No action needed, unit will resume heating after defrost completes |
Rheem
USA • 28 error codes
| Code | Description | Cause | Action |
|---|---|---|---|
| E1 | Indoor/outdoor communication error | Communication wire fault or PCB failure between units | Check communication wiring, connectors, and control boards on both units |
| E2 | Room temperature sensor failure | Indoor room thermistor open or short circuit | Check sensor wiring and resistance, replace thermistor if faulty |
| E3 | Evaporator coil sensor failure | Indoor coil thermistor open or short circuit | Inspect sensor connection on evaporator, replace if out of spec |
| E4 | Outdoor coil sensor abnormality | Outdoor unit condenser coil thermistor failure | Check outdoor coil sensor wiring, measure resistance, replace sensor |
| E5 | Over-voltage or under-voltage protection | Input power supply voltage out of acceptable range | Check incoming voltage with multimeter, verify power supply stability |
| E6 | Evaporator temperature sensor open circuit | Indoor evaporator thermistor disconnected or broken | Inspect sensor wiring, check connector, replace thermistor |
| E7 | Indoor/outdoor unit miscommunication | Serial communication failure between units | Check communication cable, verify polarity, inspect PCB connectors |
| E8 | Overheating protection | Compressor or system temperature exceeds safe limit | Check refrigerant charge, condenser airflow, compressor condition |
| EC | Refrigerant leak detection | Refrigerant leak sensor triggered or low charge detected | Perform leak test, repair leak, recharge system to nameplate spec |
| E0 | EEPROM parameter error | Indoor or outdoor unit EEPROM data corrupted | Power cycle the unit, replace main PCB if error persists |
| F1 | Outdoor ambient temperature sensor fault | Outdoor ambient thermistor open or short circuit | Check sensor wiring on outdoor unit, replace thermistor |
| F2 | Condenser coil temperature sensor fault | Condenser coil thermistor (T3) open or short circuit | Inspect sensor on condenser coil, replace if resistance out of spec |
| F3 | Discharge temperature sensor fault | Compressor discharge thermistor (T5) open or short circuit | Check sensor on compressor discharge line, replace if needed |
| F4 | Outdoor unit EEPROM error | Outdoor PCB EEPROM data corrupted or missing | Power cycle outdoor unit, replace outdoor PCB if error persists |
| F5 | Outdoor fan speed out of control | Outdoor fan motor not running at expected speed | Check fan motor, wiring, and fan blade for obstruction |
| P0 | Inverter module (IPM) protection | IPM overcurrent or overheat protection triggered | Check compressor windings, inverter board, and heat sink cooling |
| P1 | Over-voltage / under-voltage protection | DC bus voltage out of normal operating range | Check input voltage, rectifier circuit, DC bus capacitors |
| P2 | Compressor top high temperature protection | Compressor shell temperature exceeds safe limit | Check refrigerant charge, suction superheat, and compressor valves |
| P3 | Outdoor high/low pressure protection | Refrigerant pressure exceeds high or low pressure limit | Check refrigerant charge, condenser/evaporator, and expansion valve |
| P4 | Compressor drive error | Inverter compressor drive circuit malfunction | Check inverter board, compressor winding insulation, and wiring |
| P5 | Condenser coil high temperature protection | Condenser coil temperature too high in cooling mode | Clean condenser coil, check outdoor fan, verify refrigerant charge |
| DF | Defrost mode active | Normal defrost cycle running in heating mode | No action needed, wait for defrost cycle to complete |
| H1 | Defrost protection | Outdoor coil frosted, triggering defrost | Normal in heating mode; if frequent, check outdoor coil sensor and refrigerant |
| L4 | Locked rotor condition | Compressor rotor mechanically locked | Check compressor, starting components, and refrigerant pressures |
| 02 | High pressure fault | High pressure switch tripped or pressure too high | Check condenser, outdoor fan, refrigerant overcharge, non-condensables |
| 21 | Low pressure control open | Low pressure switch tripped or loss of charge | Check for leaks, verify refrigerant charge, inspect expansion device |
| 83 | Condenser coil temperature fault | Condenser sensor reading abnormal | Check sensor placement, measure resistance, replace if out of range |
| 84 | Outdoor ambient temperature fault | Outdoor temp sensor reading out of range | Check sensor placement, ensure not near heat source, replace if faulty |
TCL
China • 26 error codes
| Code | Description | Cause | Action |
|---|---|---|---|
| E0 | Indoor/outdoor communication fault | Communication wire fault or PCB failure between units | Check communication wiring, connectors, and control boards on both units |
| E1 | Room temperature sensor (IRT) fault | Indoor room thermistor open or short circuit | Check sensor wiring and connector, measure resistance, replace if faulty |
| E2 | Indoor coil temperature sensor (IPT) fault | Indoor pipe/coil thermistor open or short circuit | Inspect sensor on evaporator coil, replace if resistance out of spec |
| E3 | Outdoor coil temperature sensor (OPT) fault | Outdoor pipe/coil thermistor open or short circuit | Check sensor on condenser coil at outdoor unit, replace if needed |
| E4 | System abnormality | General system fault detected by control board | Power cycle the unit, check all sensors and wiring, inspect for refrigerant issues |
| E5 | Model configuration mismatch | Indoor and outdoor unit model types do not match | Verify correct indoor/outdoor unit pairing, check DIP switch settings |
| E6 | Indoor fan motor fault | Indoor fan motor failure or speed signal lost | Check fan motor wiring, capacitor, hall sensor, replace motor if faulty |
| E7 | Outdoor ambient temperature sensor fault | Outdoor ambient thermistor open or short circuit | Check sensor wiring on outdoor unit, replace thermistor |
| E8 | Discharge temperature sensor fault | Compressor discharge thermistor open or short circuit | Inspect sensor on discharge line, replace if resistance out of range |
| E9 | Inverter power module (IPM) fault | IPM drive module failure or abnormality | Check compressor windings, inverter board, and power supply to module |
| EA | Current sensor fault | Current transformer (CT) sensor failure on outdoor board | Check CT sensor wiring and connection, replace outdoor power board if faulty |
| EC | Outdoor unit communication fault | Communication failure within outdoor unit boards | Check wiring between outdoor main board and driver board |
| EE | EEPROM fault | EEPROM chip on main PCB corrupted or not seated | Check EEPROM chip seating, replace indoor or outdoor PCB board |
| EF | Outdoor fan motor fault (DC) | Outdoor DC fan motor failure or speed signal abnormal | Check fan motor wiring, hall sensor, blade obstruction, replace motor |
| EH | Intake temperature sensor fault | Suction/intake air thermistor open or short circuit | Inspect sensor wiring, check resistance, replace sensor if faulty |
| EP | Compressor top temperature switch fault | Temperature switch on compressor top open or faulty | Check switch wiring to CN3 on outdoor board, replace switch if needed |
| EU | Voltage sensor fault | Voltage sensing circuit failure on outdoor power board | Check voltage sensor circuit, replace outdoor power source board |
| P0 | IPM protection (hardware) | Hardware-level overcurrent in inverter power module | Check compressor insulation, wiring, and inverter board components |
| P1 | Over-voltage / under-voltage protection | Input power supply voltage out of acceptable range | Check incoming voltage with multimeter, verify power supply stability |
| P2 | Overcurrent protection | Compressor or system drawing excessive current | Check compressor windings, power supply, and refrigerant charge |
| P4 | Exhaust over-temperature protection | Compressor discharge temperature exceeds safe limit | Check refrigerant charge, superheat, condenser cleanliness |
| P5 | Subcooling protection in cooling mode | Subcooling value below minimum in cooling operation | Check refrigerant charge, expansion valve, and condenser airflow |
| P6 | Overheating protection in cooling mode | Evaporator coil temperature too high during cooling | Check indoor airflow, air filter, fan motor, and refrigerant charge |
| P7 | Overheating protection in heating mode | Indoor coil temperature too high during heating | Check indoor airflow, air filter, fan motor operation |
| P8 | Outdoor over/under-temperature protection | Outdoor ambient temperature outside operating range | Check outdoor ambient sensor, verify operating conditions are within spec |
| P9 | IPM protection (software) | Software-level drive protection in inverter module | Check compressor, inverter board, and reset power to clear fault |
Browse by Brand
Daikin
Japan
30 codes
Mitsubishi Electric
Japan
29 codes
LG
South Korea
24 codes
Samsung
South Korea
19 codes
Gree
China
20 codes
Panasonic
Japan
24 codes
Hitachi
Japan
36 codes
Mitsubishi Heavy Industries
Japan
32 codes
Carrier
USA
23 codes
Fujitsu General
Japan
27 codes
Trane
USA
20 codes
York
USA
20 codes
Midea
China
22 codes
Haier
China
19 codes
Toshiba
Japan
22 codes
Hisense
China
20 codes
Lennox
USA
32 codes
Bosch
Germany
29 codes
Rheem
USA
28 codes
TCL
China
26 codes
Troubleshooting Tips
- • Record the exact error code - Some brands use letters, numbers, or both
- • Check for multiple errors - Some systems store error history in service mode
- • Note when the error occurs - Startup, during operation, or after running
- • Check both indoor and outdoor units - Errors may be displayed on either unit
- • Reset after repair - Clear error codes after fixing the issue
- • Some codes are informational - Not all codes indicate a fault (e.g., defrost mode)