Daikin self-diagnostic by error code

Do you have a Daikin air-to-water heat pump or a Daikin air-to-air heat pump? Find the problem using the error code on Daikin’s self-diagnostic chart

Download the Daikin self-diagnostic chart by error code

Indoor unit

Code malfunction		Nature of the malfunction	Suspected causes	Models
Code malfunction		Nature of the malfunction	Suspected causes	RA	SkyAir	*VRV*	Monobloc	Energy recovery ventilator (HRV)	Chiller unit	Fan coil unit
	A0	External protection device activated	The external protection device connected to the T1-T2 terminal block of the indoor unit is activated.		✔	✔	✔
	A1	Malfunction caused by the indoor unit’s electronic board	Faulty indoor unit electronic board External factor (noise, etc.)	✔	✔	✔	✔	✔	✔
	A3	Malfunction caused by the drain level control system	Drain blockage, upward slope, etc. Faulty drain pump Faulty float switch or short-circuited connector	✔	✔	✔		✔		✔
	A4	Malfunction caused by freeze protection	Insufficient water supply Low water temperature setting Faulty water temperature thermistor	✔	✔	✔	✔		✔	✔
	A5	High pressure control in heating mode, freeze protection control in cooling mode	Clogged indoor unit air filter and short circuit Faulty indoor unit heat exchanger thermistor	✔	✔	✔	✔
	A6	Malfunction caused by the fan motor	Broken wires, short circuit, or disconnected connectors on the fan motor harness Faulty fan motor Faulty indoor unit electronic board	✔	✔	✔	✔	✔
	A7	Malfunction caused by the swing flap motor	Faulty swing flap motor Faulty indoor unit electronic board Faulty connection cable Faulty airflow direction adjustment flap cam		✔	✔
	A8	Malfunction caused by overcurrent at the AC input or power supply	Abnormal supply voltage Faulty connection on the signal line Faulty wiring		✔	✔		✔
	A9	Malfunction caused by the electronic expansion valve	Faulty electronic expansion valve coil Faulty indoor unit electronic board Faulty relay wires		✔	✔	✔	✔	✔
	AA	Overheating of the heating device	26WH activation				✔		✔
	AF	Malfunction caused by a humidification system	Leak in the humidifier unit (optional accessory) Faulty drain pipe (upward slope, etc.) Faulty indoor unit electronic board		✔	✔		✔
	AH	Malfunction caused by the air filter dust collector	Faulty dust collection element Dirty insulation component Faulty high-voltage power unit Faulty indoor unit electronic board	✔	✔	✔				✔
	AJ	Malfunction caused by the power setting (indoor unit electronic board)	The power setting adapter was not installed when the electronic board was replaced. Faulty indoor unit electronic board		✔	✔	✔
	C1	Transmission failure (between the indoor unit’s electronic board and the secondary electronic board)	Faulty connector connection on the indoor unit’s electronic board		✔	✔
	C4	Malfunction caused by the heat exchanger liquid pipe thermistor	Faulty liquid pipe thermistor Faulty indoor unit electronic board Faulty connector contact	✔	✔	✔	✔	✔	✔	✔
	C5	Malfunction caused by the heat exchanger gas pipe thermistor	Faulty gas pipe thermistor Faulty indoor unit electronic board Faulty connector contact	✔		✔	✔	✔	✔
	C6	Malfunction caused by the fan motor sensor or fan control motor	Faulty fan electronic board Faulty power setting adapter connection On-site setting error		✔	✔
	C7	Fault in the front panel drive motor	Faulty front panel drive motor Faulty limit switch	✔
	C9	Malfunction caused by the intake air thermistor	Faulty intake pipe thermistor Faulty indoor unit electronic board Faulty connector contact	✔	✔	✔	✔	✔	✔
	CA	Malfunction caused by the discharge air thermistor	Faulty discharge air thermistor Faulty indoor unit electronic board Faulty connector contact	✔		✔	✔	✔
		Malfunction caused by the humidity sensor circuit	Faulty humidity sensor Faulty connector contact	✔	✔		✔
	CJ	Room temperature thermistor fault in the remote control	Faulty room temperature thermistor in the remote control Faulty remote control electronic board External factor (noise, etc.)	✔	✔	✔	✔			✔

Outdoor unit

Code malfunction		Nature of the malfunction	Suspected causes	Models
Code malfunction		Nature of the malfunction	Suspected causes	RA	SkyAir	*VRV*	Monobloc	Energy recovery ventilator (HRV)	Chiller unit	Fan coil unit
Outdoor unit	E0	Protection devices activated (unified)	The protection device connected to the outdoor unit’s electronic board is activated. Faulty contact on the protection device connector		✔	✔			✔
	E1	Faulty outdoor unit electronic board	Faulty outdoor unit electronic board Faulty connection of indoor/outdoor relay wires	✔	✔	✔	✔		✔
	E3	High pressure switch activated	Dirty outdoor unit heat exchanger Faulty high pressure switch Blocked refrigerant piping Faulty connector contact	✔	✔	✔	✔
	E3	Circuit No. 1 High pressure switch activated	Dirty outdoor unit heat exchanger Insufficient water supply Blocked refrigerant piping Faulty connector contact Faulty high pressure sensor						✔
	E4	Low pressure switch activated	Abnormal low pressure drop Faulty low pressure sensor Faulty outdoor unit electronic board Faulty connector contact		✔	✔	✔		✔
	E5	Inverter compressor motor or overheating	Inverter compressor lockup High differential pressure Faulty Inverter electronic board UVW connection error Faulty connector contact	✔	✔	✔	✔		✔
	E6	STD compressor motor lockup/overcurrent	Faulty compressor Faulty control electronic board The shutoff valve is not open	✔	✔	✔	✔
	E6	Circuit No. 1 – Compressor overcurrent	Faulty electronic expansion valve Insufficient refrigerant amount Faulty compressor						✔
	E7	Malfunction caused by the outdoor unit fan motor circuit	Faulty fan motor Missing or incorrect connection of the wiring harness/connector between the fan motor and the electronic board Foreign objects blocking the fan are preventing it from operating.	✔	✔	✔	✔		✔
	E8	Inverter compressor overcurrent	Faulty compressor Faulty Inverter main circuit capacitor Faulty outdoor unit electronic board Faulty power transistor	✔					✔
	E9	Malfunction caused by the electronic expansion valve coil	Disconnected electronic expansion valve connectors Faulty electronic expansion valve coil Faulty outdoor unit electronic board		✔	✔	✔		✔
	EA	Malfunction caused by the four-way valve or cooling/heating switchover	Faulty four-way valve Insufficient gas Faulty outdoor unit electronic board Faulty thermistor	✔
	EC	Malfunction caused by the inlet water temperature	Cooling water temperature abnormality Faulty outdoor unit electronic board Faulty thermistor			✔
	F3	Malfunction caused by the discharge pipe temperature	Faulty discharge pipe thermistor Abnormal discharge pipe temperature Faulty outdoor unit electronic board Faulty connector contact	✔	✔	✔	✔		✔
	F6	Abnormally high pressure or refrigerant overcharge	Refrigerant overcharge Disconnected heat exchanger defrost thermistor Disconnected outdoor air thermistor Disconnected liquid pipe temperature thermistor Faulty outdoor unit electronic board	✔	✔	✔	✔
	H0	Malfunction caused by the compressor sensor circuit	Disconnected wiring harness, or connection fault Faulty electronic board	✔					✔
	H1	Malfunction caused by the room temperature sensor or the humidifier unit damper	Faulty limit switch Faulty damper	✔					✔
	H3	Malfunction caused by the high-pressure switch	Faulty high-pressure switch Broken cable Faulty outdoor unit electronic board Faulty connector contact	✔	✔	✔	✔		✔
	H4	Malfunction caused by the low-pressure switch	Faulty low-pressure switch Broken cable Faulty outdoor unit electronic board Faulty connector contact		✔	✔			✔

Code error code		Nature of the malfunction	Suspected causes	Units
Code error code		Nature of the malfunction	Suspected causes	RA	SkyAir	*VRV*	Monobloc	Heat recovery ventilator (HRV)	Chiller unit	Fan coil unit
Outdoor unit	H5	Malfunction caused by the compressor motor overload thermistor	Faulty compressor motor overload thermistor Faulty connector contact	✔					✔
	H6	Malfunction caused by the position detection sensor	Faulty compressor contact or cable Faulty compressor Faulty outdoor unit electronic board	✔			✔		✔
	H7	Malfunction caused by the outdoor unit fan motor signal	Abnormal signal from the fan motor (circuit failure) Disconnection/short circuit in the fan motor cables or connector unplugged Faulty Inverter electronic board		✔	✔	✔		✔
	H8	Malfunction caused by the compressor input circuit (CT)	Faulty power transistor Faulty reactor Inverter system wiring fault Faulty outdoor unit electronic board	✔					✔
	H9	Malfunction caused by the outdoor air thermistor	Thermistor connection fault Faulty outdoor unit electronic board Faulty outdoor air thermistor	✔	✔	✔	✔		✔
	C	Malfunction caused by the (hot) water temperature thermistor	Thermistor connection fault Faulty outdoor unit electronic board Faulty water temperature thermistor		✔	✔			✔
	HF	Alarm at the thermal storage unit or thermal storage controller	Thermal storage unit wiring fault Incorrect setting Excessive number of thermal storage tanks			✔
	HJ	Malfunction caused by the water level in the thermal storage tank	Low water level Faulty switch setting Faulty water level sensor Faulty connector contact	✔	✔	✔	✔
	J1	Malfunction caused by the pressure sensor	Faulty contact at the pressure sensor connector Faulty pressure sensor Faulty outdoor unit electronic board		✔	✔	✔		✔
	J2	Malfunction caused by the compressor current sensor	Faulty current sensor Faulty compressor Faulty outdoor unit electronic board	✔	✔	✔	✔		✔
	J3	Malfunction caused by the discharge pipe thermistor	Thermistor connection fault Faulty discharge pipe thermistor Faulty outdoor unit electronic board	✔	✔	✔	✔		✔
	J4	Malfunction caused by the low-pressure equivalent saturation temperature sensor circuit	Thermistor connection fault Faulty thermistor Faulty outdoor unit electronic board			✔			✔
	J5	Malfunction caused by the suction pipe thermistor	Thermistor connection fault Faulty suction pipe thermistor Faulty outdoor unit electronic board		✔	✔	✔		✔
	J6	Malfunction caused by the heat exchanger thermistor	Thermistor connection fault Faulty heat exchanger thermistor Faulty outdoor unit electronic board	✔	✔	✔	✔		✔
	J7	Malfunction caused by the thermistor (refrigerant circuit)	Thermistor connection fault Faulty liquid pipe thermistor Faulty outdoor unit electronic board		✔	✔	✔		✔
	J8	Malfunction caused by the thermistor (refrigerant circuit)	Thermistor connection fault Faulty liquid pipe thermistor Faulty outdoor unit electronic board	✔	✔	✔	✔		✔
	J9	Malfunction caused by the thermistor (refrigerant circuit)	Thermistor connection fault Faulty gas pipe thermistor Faulty outdoor unit electronic board	✔	✔	✔	✔		✔
	JA	Malfunction caused by the high-pressure sensor	Faulty connector contact Low-pressure sensor incorrectly connected in place of the high-pressure sensor Faulty high-pressure sensor Faulty outdoor unit electronic board		✔	✔	✔		✔
	JC	Malfunction caused by the low-pressure sensor	Faulty connector contact High-pressure sensor incorrectly connected in place of the low-pressure sensor Faulty low-pressure sensor Faulty outdoor unit electronic board		✔	✔	✔		✔

Code error code		Nature of the malfunction	Suspected causes	Units
Code error code		Nature of the malfunction	Suspected causes	RA	SkyAir	*VRV*	Monobloc	Heat recovery ventilator (HRV)	Chiller unit	Fan coil unit
Outdoor unit	JE	Malfunction caused by the oil pressure sensor or the sub-tank thermistor	Faulty connector contact Faulty sub-tank thermistor Faulty outdoor unit electronic board			✔
	JF	Malfunction caused by the oil level sensor or the heat exchanger heater thermistor	Faulty connector contact Faulty heat exchanger thermistor Faulty outdoor unit electronic board			✔
	L0	Malfunction caused by the Inverter circuit	Insufficient power supply Faulty power transistor Faulty outdoor unit electronic board			✔			✔
	L1	Malfunction caused by the Inverter electronic board	Compressor wiring fault Faulty outdoor unit fan motor Blown fuse Faulty Inverter electronic board		✔	✔	✔		✔
	L3	Electrical box temperature rise	Rise in fin temperature due to a short circuit Faulty outdoor unit fan motor Faulty power transistor Faulty outdoor unit electronic board	✔	✔	✔			✔
	L4	Malfunction caused by the rise in Inverter radiator fin temperature	Rise in fin temperature due to a short circuit Faulty fin thermistor	✔	✔	✔	✔		✔
	L5	Instantaneous Inverter overcurrent (DC output)	Faulty compressor coil (such as a disconnected cable or insulation issue) Compressor startup failure (mechanical lock) Faulty Inverter electronic board	✔	✔	✔	✔		✔
	L6	Instantaneous Inverter overcurrent (AC output)	Refrigerant overcharge Insufficient power supply Faulty compressor Faulty Inverter unit			✔			✔
	L8	Malfunction caused by an Inverter compressor overcurrent	Compressor overload Disconnected cable at the compressor coil Disconnected compressor wiring Faulty Inverter electronic board	✔	✔	✔	✔		✔
	L9	Malfunction caused by an Inverter compressor startup error (stall prevention)	The shutoff valve is not open Faulty compressor Incorrect cable connection on the compressor High differential pressure before compressor startup Faulty Inverter electronic board		✔	✔	✔		✔
	LA	Malfunction caused by the power transistor	Defective power transistor Defective compressor Defective Inverter circuit board			✔			✔
	LC	Malfunction caused by transmission issues between the control circuit board and the Inverter board	Faulty connection between the inverter circuit board and the main circuit board External factors (noise, etc.) Defective Inverter compressor Fault in the control circuit board (transmission block)	✔	✔	✔	✔		✔
	M1	Malfunction of the central remote control circuit board	Fault in the centralized remote control circuit board	✔	✔	✔	✔			✔
	M8	Transmission malfunction between the optional controls and the centralized control	Electrical disconnection of another centralized control Activation of the centralized control’s reset switch Faulty transmission wiring Change of the centralized remote control’s address	✔	✔	✔	✔			✔
	MA	Incorrect combination of the centralized control’s optional controls	Incorrect combination of the centralized control’s optional controls Several master remote controls are connected. Faulty centralized control setting Centralized control fault	✔	✔	✔	✔			✔
	MC	Duplicate address, incorrect setting	Duplicate address of the centralized remote control	✔	✔	✔	✔			✔
	P0	Insufficient refrigerant level (thermal storage unit)	Insufficient refrigerant level Blocked refrigerant piping			✔			✔
	P1	Power supply voltage imbalance or Inverter circuit board issue	Open phase Phase-to-phase voltage imbalance Defective capacitor in the main circuit Faulty wiring in the main circuit Defective Inverter circuit board		✔	✔	✔		✔