Don’t be alarmed if you notice letters and numbers appear on the unit. These more than likely are just fault codes. What is a fault code, you may ask? It’s simply a code that appears to help let you know what might be wrong with the unit. These are handy to help with diagnosing and making proper repairs. If you’re not sure what any of them mean, though, they can seem intimidating at first. That’s why Parts Town is here to help you troubleshoot Daikin air conditioner fault codes.
This article is going to cover the fault codes for both indoor and outdoor units. It’s important to keep in mind that fault codes for indoor and outdoor units incorporate different letters.
Daikin Indoor Air Conditioner Fault Codes
Indoor units have fault codes that either start with the letter A or C.
Daikin Indoor Air Conditioner A Fault Codes
Code | Issue | Causes |
A0 | External protection device is activated | - External protection device is connected to the terminal strip
- T1-T2 of indoor unit is activated
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A1 | Indoor unit PCB has malfunctioned | - Defective indoor unit PCB
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A3 | Abnormality in the drain level control system | - Clogged drain
- Defective pump drain
- Defective float switch or short circuit connector
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A4 | Freezing protection has malfunctioned | - Water volume shortage
- Low water temperature setting
- Defective water temperature thermistor
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A5 | High-pressure control in heating, freeze-up protection control in cooling | - Clogged air filter
- Defective heat exchanger thermistor
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A6 | Fan motor has malfunctioned | - Defective fan motor
- Defective indoor unit PCB
- Broken wires or disconnected connectors in the fan motor harness
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A7 | Swing flap door has malfunctioned | - Defective swing flap motor
- Defective indoor unit PCB
- Defective connection cable
- Defective air flow direction adjusting flap-cam
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A8 | Power supply has malfunctioned or AC input is overcurrent | - Defective power supply voltage
- Defective connection to signal line
- Defective wiring
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A9 | Electronic expansion valve has malfunctioned | - Defective electronic expansion valve coil
- Defective indoor unit PCB
- Defective relay cables
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AA | Heater has overheated | |
AF | Humidifier system has malfunctioned | - Humidifier unit is leaking
- Defective drain piping
- Defective indoor unit PCB
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AH | Air cleaner’s dust collector has malfunctioned | - Defective dust-collecting element
- Insulator part is stained
- Defective high voltage power supply unit
- Defective indoor unit PCB
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AJ | Capacity setting (indoor unit PCB) has malfunctioned | - Defective indoor unit PCB
- Capacity setting adaptor wasn’t installed
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Daikin Indoor Air Conditioner C Fault Codes
Code | Issue | Causes |
C1 | Transmission failure between indoor unit PCB and sub PCB | - Defective connection of the connector between indoor unit PCB
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C4 | Liquid pipe thermistor for heat exchanger has malfunctioned | - Defective thermistor for liquid pipe
- Defective indoor unit PCB
- Defective connector contact
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C5 | Gas pipe thermistor for heat exchanger has malfunctioned | - Defective thermistor for gas pipe
- Defective indoor unit PCB
- Defective connector contact
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C6 | Fan motor sensor or fan control driver has malfunctioned | - Defective fan PCB
- Defective connection of capacity setting adaptor
- Field setting error
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C7 | Faulty front panel driving motor | - Defective front panel driving motor
- Defective limit switch
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C9 | Suction air thermistor has malfunctioned | - Defective thermistor for suction air
- Defective indoor unit PCB
- Defective connector contact
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CA | Discharge air thermistor has malfunctioned | - Defective thermistor for discharge air
- Defective indoor unit PCB
- Defective connector contact
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CC | Humidity sensor system has malfunctioned | - Defective humidity sensor
- Defective connector contact
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CJ | Room temperature thermistor in the remote controller has an abnormality | - Defective room temperature thermistor in remote controller
- Defective remote controller PCB
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Daikin Outdoor Air Conditioner Fault Codes
Outdoor units have fault codes that either start with the letter E, F, H, J, L, M or P.
Daikin Outdoor Air Conditioner E Fault Codes
Code | Issue | Causes |
E0 | Protection devices are activated | - Defective protective device connector contact
- Protection device connected to outdoor unit PCB actuated
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E1 | Defective outdoor unit PCB | - Defective outdoor unit PCB
- Defective connection of inside/outside relay wires
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E3 | Actuation of high-pressure switch | - Outdoor unit heat exchanger is dirty
- Defective high-pressure switch
- Refrigerant piping is clogged
- Defective connector contact
- Water volume shortage
- Defective HPS
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E4 | Actuation of low-pressure switch | - Abnormal drop in low pressure
- Defective low-pressure sensor
- Defective outdoor unit PCB
- Defective connector contact
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E5 | Inverter compressor motor is overheated | - Defective connector contact
- UVW connection error
- Defective inverter PCB
- High differential pressure
- Inverter compressor lock
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E6 | Compressor motor overcurrent/lock or compressor overcurrent | - Defective compressor
- Defective control PCB
- Stop valve isn’t opened
- Defective electronic expansion valve
- Refrigerant shortage
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E7 | Outdoor unit fan motor system has malfunctioned | - Fan motor has failed
- Defective harness/connector connection between the fan motor and PCB
- Blockage preventing the fan motor from rotating
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E8 | Overcurrent of inverter compressor | - Defective compressor
- Defective inverter main circuit capacitor
- Defective outdoor unit PCB
- Defective power transistor
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E9 | Electronic expansion valve coil has malfunctioned | - Defective outdoor unit control PCB
- Defective electronic expansion valve coil
- Connector from electronic expansion valves are disconnected
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EA | Four-way valve or heat/cool switch has malfunctioned | - Defective four-way valve
- Gas shortage
- Defective outdoor unit PCB
- Defective thermistor
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EC | Entering water temperature exceeds upper or lower temperature limits | - Defective outdoor unit PCB
- Defective thermistor
- Cooling water temperature abnormality
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Daikin Outdoor Air Conditioner F Fault Codes
Code | Issue | Causes |
F3 | Discharge pipe temperature exceeds upper or lower temperature limits | - Defective discharge pipe thermistor
- Abnormal discharge pipe temperature
- Defective outdoor unit control PCB
- Defective connector contact
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F6 | Abnormal high-pressure or refrigerant overcharged | - Refrigerant is overcharged
- Heat exchanger deicer thermistor is disconnected
- Outdoor air thermistor is disconnected
- Liquid pipe temperature thermistor is disconnected
- Defective outdoor unit PCB
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Daikin Outdoor Air Conditioner H Fault Codes
Code | Issue | Causes |
H0 | Compressor’s sensor system has malfunctioned | - Harness is disconnected
- Defective PCB
|
H1 | Room temperature sensor or humidifier unit damper has malfunctioned | - Defective limit switch
- Defective damper
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H3 | High-pressure switch has malfunctioned | - Defective high-pressure switch
- Wire is broken
- Defective outdoor unit PCB
- Defective connector contact
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H4 | Low-pressure switch has malfunctioned | - Defective low-pressure switch
- Wire is broken
- Defective outdoor unit PCB
- Defective connector contact
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H5 | Compressor motor overload thermistor has malfunctioned | - Defective compressor motor overload thermistor
- Defective connector contact
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H6 | Position detection sensor has malfunctioned | - Defective outdoor unit PCB
- Defective compressor
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H7 | Outdoor unit fan motor signal has malfunctioned | - Abnormal signal from fan motor
- Disconnection or short circuit in fan motor leads
- Connector is disconnected
- Defective inverter PCB
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H8 | Compressor input system has malfunctioned | - Defective power transistor
- Defective reactor
- Inverter system wiring is faulty
- Defective outdoor unit PCB
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H9 | Outdoor air thermistor has malfunctioned | - Defective thermistor connection
- Defective outdoor unit PCB
- Defective outdoor air thermistor
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HC | Hot water temperature thermistor has malfunctioned | - Defective thermistor connection
- Defective outdoor unit PCB
- Defective water temperature thermistor
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HF | Alarm in thermal storage unit or storage controller | - Defective setting
- Defective wiring in thermal storage group
- Excess of thermal storage tank numbers
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HJ | Thermal storage tank water level has malfunctioned | - Low water level
- Defective switch setting
- Water level detecting sensor has failed
- Defective connector contact
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Daikin Outdoor Air Conditioner J Fault Codes
Code | Issue | Causes |
J1 | Pressure sensor has malfunctioned | - Defective pressure sensor connector contact
- Defective pressure sensor
- Defective outdoor unit PCB
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J2 | Compressor’s current sensor has malfunctioned | - Defective current sensor
- Defective compressor
- Defective outdoor unit PCB
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J3 | Discharge pipe thermistor has malfunctioned | - Defective thermistor connection
- Defective discharge pipe thermistor
- Defective outdoor unit PCB
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J4 | Low-pressure equivalent saturated temperature sensor system has malfunctioned | - Defective thermistor connection
- Defective thermistor
- Defective outdoor unit PCB
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J5 | Suction pipe thermistor has malfunctioned | - Defective thermistor connection
- Defective suction pipe thermistor
- Defective outdoor unit PCB
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J6 | Heat exchanger thermistor has malfunctioned | - Defective thermistor connection
- Defective heat exchanger thermistor
- Defective outdoor unit PCB
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J7 | Thermistor has malfunctioned (refrigerant circuit) | - Defective thermistor connection
- Defective liquid pipe thermistor
- Defective outdoor unit PCB
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J8 | Thermistor has malfunctioned (refrigerant circuit) | - Defective thermistor connection
- Defective liquid pipe thermistor
- Defective outdoor unit PCB
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J9 | Thermistor has malfunctioned (refrigerant circuit) | - Defective thermistor connection
- Defective gas pipe thermistor
- Defective outdoor unit PCB
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JA | High-pressure sensor has malfunctioned | - Defective connector contact
- Low-pressure sensor connection is mistaken for high-pressure sensor
- Defective high-pressure sensor
- Defective outdoor unit PCB
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JC | Low-pressure sensor has malfunctioned | - Defective connector contact
- High-pressure sensor connection is mistaken for low-pressure sensor
- Defective low-pressure sensor
- Defective outdoor unit PCB
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JE | Oil pressure sensor or sub-tank thermistor has malfunctioned | - Defective connector contact
- Defective sub-tank thermistor
- Defective outdoor unit PCB
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JF | Oil level sensor or heating heat exchanger thermistor has malfunctioned | - Defective connector contact
- Defective heat exchanger thermistor
- Defective outdoor unit PCB
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Daikin Outdoor Air Conditioner L Fault Codes
Code | Issue | Causes |
L0 | Inverter system has malfunctioned | - Power supply capacity shortage
- Defective power transistor
- Defective outdoor unit PCB
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L1 | Inverter PCB has malfunctioned | - Defective compressor wiring
- Defective outdoor unit fan motor
- Fuse is blown
- Defective inverter PCB
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L3 | Electrical box temperature has risen | - Short circuit has caused fin temperature to rise
- Defective outdoor unit fan motor
- Defective power transistor
- Defective outdoor unit PCB
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L4 | Inverter radiation fin temperature has risen | - Short circuit has caused fin temperature to rise
- Defective fin thermistor
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L5 | Inverter instantaneous overcurrent (DC output) | - Defective compressor coil
- Compressor startup failure
- Defective inverter PCB
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L6 | Inverter instantaneous overcurrent (AC output) | - Overcharge of refrigerant amount
- Power supply capacity shortage
- Defective compressor
- Defective inverter unit
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L8 | Overcurrent inverter compressor has malfunctioned | - Compressor is overloaded
- Compressor coil wiring is disconnected
- Compressor wiring is disconnected
- Defective inverter PCB
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L9 | Inverter compressor startup error (Stall prevention) | - Stop valve isn’t opened
- Defective compressor
- Error in wire connections to compressor
- Large differential pressure before compressor startup
- Defective inverter PCB
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LA | Power transistor has malfunctioned | - Defective power transistor
- Defective compressor
- Defective inverter PCB
|
LC | Transmission between control and inverter PCB has malfunctioned | - Defective control PCB
- Defective inverter compressor
- Defective connection between the inverter PCB and the control PCB
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Daikin Outdoor Air Conditioner M Fault Codes
Code | Issue | Causes |
M1 | Central remote controller PCB has malfunctioned | - Defective central remote controller PCB
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M8 | Transmission between optional controllers for centralized control has malfunctioned | - Disconnection of other centralized control power
- Centralized control reset switch is on
- Defective transmission wiring
- Central remote controller address change
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MA | Improper combination of optional controllers for centralized control | - Defective centralized control
- Centralized control setting is faulty
- Multiple master controllers are connected
- Improper combination of optional controllers for centralized control
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MC | Address duplication or improper setting | - Address duplication of central remote controller
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Daikin Outdoor Air Conditioner P Fault Codes
Code | Issue | Causes |
P0 | Refrigerant amount shortage (thermal storage unit) | - Refrigerant shortage
- Refrigerant piping is clogged
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P1 | Power voltage imbalance or inverter PCB | - Open phase
- Interphase voltage imbalance
- Defective capacitor or wiring in the main circuit
- Defective inverter PCB
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P2 | Automatic refrigerant charge operation has stopped | - Stop valve isn’t opened
- Refrigerant tank valve is closed
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P3 | Thermistor in the switch box has malfunctioned | - Defective thermistor connection
- Defective reactor thermistor
- Defective inverter PCB
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P4 | Radiation fin temperature sensor has malfunctioned | - Defective radiation fin temperature thermistor
- Defective inverter PCB
- Defective INV. compressor
- Defective fan motor
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P8 | Heat exchanger freezing protection occurs during automatic refrigerant charging | - Refrigerant cylinder is open
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P9 | Automatic refrigerant charge operation is completed or fan motor has malfunctioned | - Defective fan motor
- Defective outdoor unit PCB
- Relay harness is broken
- Defective connector contact
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PA | Broken heater wire or refrigerant cylinder is charging during automatic refrigerant | - Master unit’s refrigerant cylinder is empty
- Defective heater unit
- Defective thermistor
- Defective outdoor unit PCB
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PC | Refrigerant cylinder is charging during automatic refrigerant | - Slave unit 2’s refrigerant cylinder is empty
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PE | Automatic refrigerant charge operation is nearly completed | N/A |
PH | Refrigerant cylinder is charging during automatic refrigerant | - Defective heater unit
- Defective connector contact
- Defective thermistor
- Defective outdoor unit PCB
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PJ | Improper combination between inverter and fan driver or capacity setting has malfunctioned (Outdoor unit PCB) | - Capacity setting adaptor isn’t installed
- Improper capacity setting adaptor
- Defective outdoor unit PCB
- Mis-matching type of PCB
- Improper field setting after replacing outdoor unit main PCB
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For more guides on HVAC equipment, check out our full collection of Daikin manuals for assistance.
Please contact a local authorized service agent who can help with these specific units and all your HVAC equipment needs.
