Daikin Air Conditioners Error Codes
Complete list of fault codes and troubleshooting guides. Use the search below to find your specific error.
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A0
Daikin indoor unit stops and displays A0; may occur after service or maintenance
External Protection Device Activated (e.g., Float Switch, External Interlock)
A1
Indoor unit does not start or stops with A1 error on Daikin controller
Indoor Unit Main PCB Failure
A3
Daikin indoor unit stops and may leak water; controller shows A3
Drain Level Error / Drain Pump Fault
A5
Indoor unit stops frequently; A5 displayed; may occur in heating or cooling
Indoor Heat Exchanger Frost / Overheat Protection
A6
Indoor fan does not run or stops; A6 error appears on Daikin controller
Indoor Fan Motor Fault
A7
Horizontal louver (flap) does not move or is stuck; A7 error displayed
Swing Flap Motor / Position Error
A8
Indoor unit stops with A8; may be related to overcurrent or overheat
Indoor Overcurrent / Overload Protection
A9
Daikin indoor unit shows A9; unit may not heat properly
Indoor EEPROM or Option Setting Error
C4
Indoor unit stops; C4 error displayed; may be associated with coil temperature sensing
Indoor Heat Exchanger Thermistor Fault
C5
Indoor unit shows C5; fan operation may be abnormal
Indoor Fan Motor Lock / Overload Detection
C9
Daikin indoor unit shows C9; poor temperature control or unit stops
Indoor Room Thermistor Fault
E0
Daikin system shows E0; unit may not start or may shut down quickly
Outdoor Unit Protection / General Error
E1
Outdoor unit does not start; E1 error logged on Daikin controller
Outdoor PCB or Power Module Failure
E3
Daikin system stops with E3; may occur during cooling or heating under heavy load
High-Pressure Protection
E4
Daikin unit stops with E4; often during heating mode
Low-Pressure Protection
E5
Daikin system stops with E5; may be associated with compressor issues
Compressor Overcurrent / Overload
E6
Outdoor fan does not run; E6 error displayed
Outdoor Fan Motor Fault
E7
Reversing valve does not switch between heating and cooling; E7 error logged
Four-Way Valve (Reversing Valve) Malfunction
E8
Daikin unit stops with E8; may be related to overload or overheat
Overload / Overheat Protection (Outdoor)
F3
Daikin system stops with F3; often in heating mode
Discharge Pipe Temperature High
F6
Daikin unit shows F6; capacity reduced or unit stops
Low Refrigerant Flow / Underload
H0
Daikin system shows H0; abnormal operation of external input/output
External I/O or Option Board Error
J3
Daikin controller shows J3; outdoor coil temperature reading abnormal
Outdoor Heat Exchanger Thermistor Fault
J6
Daikin system shows J6; compressor may not start or may stop quickly
Compressor Motor Lock / Position Detection Error
L5
Daikin unit stops with L5; often associated with inverter module protection
Inverter Overcurrent / IPM Protection
P1
Daikin controller shows P1; unit may not start or may shut down
Phase Loss / Phase Reversal (3-Phase Units)
P4
Daikin unit shows P4; compressor may not run or may stop
Inverter Heat Sink Overheat
U0
Daikin indoor unit runs but cooling is weak or stops; outdoor unit fan and compressor do not start or stop shortly after starting
Refrigerant Shortage / Undercharge Protection
U2
Daikin air conditioner stops during operation; indoor unit may show U2 and system will not restart until power is cycled
Insufficient Power Supply / Low Voltage Protection
U4
Indoor unit operates briefly then stops; remote shows communication error; some Daikin systems display U4 on wired controller
Indoor–Outdoor Communication Failure
U5
Daikin system with wired remote controller shows U5; indoor unit may not respond to remote commands
Remote Controller Communication Error
U7
Multi-split Daikin system shows U7; one or more indoor units do not operate correctly
Indoor Unit Capacity / Model Mismatch or Addressing Error
U8
Daikin system with multiple indoor units shows U8; some units may not start or may shut down unexpectedly
Indoor Unit Group Control / Central Control Communication Error
UA
Daikin multi-split outdoor unit shows UA; some indoor units may not cool or heat
Indoor–Outdoor Capacity Mismatch / Excess Connected Capacity
Symptom
Daikin air conditioner does not power on at all; no lights or display on indoor unit
No Power / Dead Indoor Unit
Symptom
Daikin air conditioner frequently turns on and off (short cycling) without reaching set temperature
Short Cycling / Control or Sizing Issue
Symptom
Daikin air conditioner makes loud rattling, buzzing, or grinding noises during operation
Mechanical Noise / Vibration Issue
Symptom
Daikin indoor unit display or LEDs are on but unit does not respond to remote control commands
Remote Control Reception / Control Lock Issue
Symptom
Daikin indoor unit display shows incorrect room temperature or temperature fluctuates wildly
Room Temperature Sensing Error
Symptom
Daikin indoor unit emits a musty, moldy, or unpleasant odor when operating
Biological Growth / Contamination in Indoor Unit
Symptom
Daikin indoor unit is running but cooling is weak or insufficient, no error code displayed
Reduced Cooling Capacity / Performance Degradation
Symptom
Daikin indoor unit runs but no air comes out or airflow is very weak even on high fan speed
Indoor Airflow Restriction / Fan Performance Issue
Symptom
Daikin outdoor unit is very noisy or vibrates strongly, especially during compressor start
Outdoor Vibration / Mounting Issue
Symptom
Daikin unit emits clicking or ticking sounds frequently during operation
Thermal Expansion / Plastic Casing Noise
Symptom
Daikin unit runs but does not heat in heating mode; blows cool or lukewarm air
Insufficient Heating Capacity
Symptom
Daikin unit trips the circuit breaker when starting or shortly after
Electrical Overcurrent / Short Circuit
Symptom
Frost or ice forming on Daikin indoor unit coil or front panel during cooling
Indoor Coil Freezing
Symptom
Water leaking from Daikin indoor unit front panel or dripping onto the floor
Indoor Condensate Drainage Failure
Symptom
Water pooling under Daikin outdoor unit or excessive dripping from base
Outdoor Condensate / Defrost Water Management Issue
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| A0 |
Daikin indoor unit stops and displays A0; may occur after service or maintenance
|
External Protection Device Activated (e.g., Float Switch, External Interlock) | View Details |
| A1 |
Indoor unit does not start or stops with A1 error on Daikin controller
|
Indoor Unit Main PCB Failure | View Details |
| A3 |
Daikin indoor unit stops and may leak water; controller shows A3
|
Drain Level Error / Drain Pump Fault | View Details |
| A5 |
Indoor unit stops frequently; A5 displayed; may occur in heating or cooling
|
Indoor Heat Exchanger Frost / Overheat Protection | View Details |
| A6 |
Indoor fan does not run or stops; A6 error appears on Daikin controller
|
Indoor Fan Motor Fault | View Details |
| A7 |
Horizontal louver (flap) does not move or is stuck; A7 error displayed
|
Swing Flap Motor / Position Error | View Details |
| A8 |
Indoor unit stops with A8; may be related to overcurrent or overheat
|
Indoor Overcurrent / Overload Protection | View Details |
| A9 |
Daikin indoor unit shows A9; unit may not heat properly
|
Indoor EEPROM or Option Setting Error | View Details |
| C4 |
Indoor unit stops; C4 error displayed; may be associated with coil temperature sensing
|
Indoor Heat Exchanger Thermistor Fault | View Details |
| C5 |
Indoor unit shows C5; fan operation may be abnormal
|
Indoor Fan Motor Lock / Overload Detection | View Details |
| C9 |
Daikin indoor unit shows C9; poor temperature control or unit stops
|
Indoor Room Thermistor Fault | View Details |
| E0 |
Daikin system shows E0; unit may not start or may shut down quickly
|
Outdoor Unit Protection / General Error | View Details |
| E1 |
Outdoor unit does not start; E1 error logged on Daikin controller
|
Outdoor PCB or Power Module Failure | View Details |
| E3 |
Daikin system stops with E3; may occur during cooling or heating under heavy load
|
High-Pressure Protection | View Details |
| E4 |
Daikin unit stops with E4; often during heating mode
|
Low-Pressure Protection | View Details |
| E5 |
Daikin system stops with E5; may be associated with compressor issues
|
Compressor Overcurrent / Overload | View Details |
| E6 |
Outdoor fan does not run; E6 error displayed
|
Outdoor Fan Motor Fault | View Details |
| E7 |
Reversing valve does not switch between heating and cooling; E7 error logged
|
Four-Way Valve (Reversing Valve) Malfunction | View Details |
| E8 |
Daikin unit stops with E8; may be related to overload or overheat
|
Overload / Overheat Protection (Outdoor) | View Details |
| F3 |
Daikin system stops with F3; often in heating mode
|
Discharge Pipe Temperature High | View Details |
| F6 |
Daikin unit shows F6; capacity reduced or unit stops
|
Low Refrigerant Flow / Underload | View Details |
| H0 |
Daikin system shows H0; abnormal operation of external input/output
|
External I/O or Option Board Error | View Details |
| J3 |
Daikin controller shows J3; outdoor coil temperature reading abnormal
|
Outdoor Heat Exchanger Thermistor Fault | View Details |
| J6 |
Daikin system shows J6; compressor may not start or may stop quickly
|
Compressor Motor Lock / Position Detection Error | View Details |
| L5 |
Daikin unit stops with L5; often associated with inverter module protection
|
Inverter Overcurrent / IPM Protection | View Details |
| P1 |
Daikin controller shows P1; unit may not start or may shut down
|
Phase Loss / Phase Reversal (3-Phase Units) | View Details |
| P4 |
Daikin unit shows P4; compressor may not run or may stop
|
Inverter Heat Sink Overheat | View Details |
| U0 |
Daikin indoor unit runs but cooling is weak or stops; outdoor unit fan and compressor do not start or stop shortly after starting
|
Refrigerant Shortage / Undercharge Protection | View Details |
| U2 |
Daikin air conditioner stops during operation; indoor unit may show U2 and system will not restart until power is cycled
|
Insufficient Power Supply / Low Voltage Protection | View Details |
| U4 |
Indoor unit operates briefly then stops; remote shows communication error; some Daikin systems display U4 on wired controller
|
Indoor–Outdoor Communication Failure | View Details |
| U5 |
Daikin system with wired remote controller shows U5; indoor unit may not respond to remote commands
|
Remote Controller Communication Error | View Details |
| U7 |
Multi-split Daikin system shows U7; one or more indoor units do not operate correctly
|
Indoor Unit Capacity / Model Mismatch or Addressing Error | View Details |
| U8 |
Daikin system with multiple indoor units shows U8; some units may not start or may shut down unexpectedly
|
Indoor Unit Group Control / Central Control Communication Error | View Details |
| UA |
Daikin multi-split outdoor unit shows UA; some indoor units may not cool or heat
|
Indoor–Outdoor Capacity Mismatch / Excess Connected Capacity | View Details |
| – |
Daikin air conditioner does not power on at all; no lights or display on indoor unit
|
No Power / Dead Indoor Unit | View Details |
| – |
Daikin air conditioner frequently turns on and off (short cycling) without reaching set temperature
|
Short Cycling / Control or Sizing Issue | View Details |
| – |
Daikin air conditioner makes loud rattling, buzzing, or grinding noises during operation
|
Mechanical Noise / Vibration Issue | View Details |
| – |
Daikin indoor unit display or LEDs are on but unit does not respond to remote control commands
|
Remote Control Reception / Control Lock Issue | View Details |
| – |
Daikin indoor unit display shows incorrect room temperature or temperature fluctuates wildly
|
Room Temperature Sensing Error | View Details |
| – |
Daikin indoor unit emits a musty, moldy, or unpleasant odor when operating
|
Biological Growth / Contamination in Indoor Unit | View Details |
| – |
Daikin indoor unit is running but cooling is weak or insufficient, no error code displayed
|
Reduced Cooling Capacity / Performance Degradation | View Details |
| – |
Daikin indoor unit runs but no air comes out or airflow is very weak even on high fan speed
|
Indoor Airflow Restriction / Fan Performance Issue | View Details |
| – |
Daikin outdoor unit is very noisy or vibrates strongly, especially during compressor start
|
Outdoor Vibration / Mounting Issue | View Details |
| – |
Daikin unit emits clicking or ticking sounds frequently during operation
|
Thermal Expansion / Plastic Casing Noise | View Details |
| – |
Daikin unit runs but does not heat in heating mode; blows cool or lukewarm air
|
Insufficient Heating Capacity | View Details |
| – |
Daikin unit trips the circuit breaker when starting or shortly after
|
Electrical Overcurrent / Short Circuit | View Details |
| – |
Frost or ice forming on Daikin indoor unit coil or front panel during cooling
|
Indoor Coil Freezing | View Details |
| – |
Water leaking from Daikin indoor unit front panel or dripping onto the floor
|
Indoor Condensate Drainage Failure | View Details |
| – |
Water pooling under Daikin outdoor unit or excessive dripping from base
|
Outdoor Condensate / Defrost Water Management Issue | View Details |
No matching codes found
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