Daikin AC – Error Codes and Fixes



The Daikin air conditioner’s mechanism is a bit complex. So, besides cleaning the filters, users cannot address any other fault.

All faults require you to contact the Daikin AC service center online by booking a service call. However, we suggest users note the error code to help the technician accurately diagnose the problem. So, let us now discuss the error codes displayed in Daikin ACs and their fixes.

How do you find out the error code?

Many Daikin ACs do not have a display on the IDU. So, users should know where to see the error code and how.

  1. Hold the “Cancel” button on the remote controller for around five seconds.
  2. You will get the error code blinking in the temperature display section.
  3. Press the “Cancel” option repeatedly until you hear a long beep.

Here are the Daikin AC error codes and their resolutions.

System Error Codes

00 – Everything is normal

The 00 code signifies that the Daikin AC is in perfect working condition and has no problems with its functioning. So, you need not do anything about the 00 code.

UA – Indoor and Outdoor unit combination fault

The UA error code signifies a combination fault between the indoor and the outdoor unit. The solution is to replace the faulty unit by installing the correct combination. Therefore, it is an installation fault.

U0 – Refrigerant Shortage

Refrigerant shortage produces the U0 error code. There could be a gas leak somewhere, resulting in the loss of pressure. So, the ideal remedy is to seek professional attention and get the leak identified and repaired. Subsequently, the technician will refill the gas and check the pressure. The error code should vanish now.

U2 – Voltage drop or over-voltage in the main circuit

Usually, Daikin ACs can handle voltage fluctuations between 160V and 260V. If the input voltage is beyond this operational range, the appliance displays the U2 error code. You can check the input voltage and fix a voltage stabilizer. Your local electrician can do this job. You need not book a service complaint with the Daikin service center.

U4 – Transmission failure between the indoor and the outdoor unit

The U4 error code suggests a lack of communication between the indoor and the outdoor unit. The connecting wires could have snapped. Instead of joining the snapped portions, we recommend fixing a new wire. The AC technician is the right person for the job. If the pipes have snapped, they require replacement.

Indoor Unit Faults

A1 – Indoor PCB Defective

A defective indoor PCB displays an A1 error code. The remedy is replacing the PCB or repairing it if possible. Usually, the PCBs are under warranty. Under such circumstances, you should summon the authorized service technician to attend to the problem.

A5 – Freeze-up protector

The A5 error code signifies a freeze-up protector issue in the cooling mode and high-pressure control in the heating mode. A clogged air filter or a short circuit can trigger this problem. An indoor unit heat exchange thermistor defect can activate the A5 error code. There can be insulation problems. So, the ideal solution is to summon a qualified technician from Daikin.

A6 – Indoor fan motor fault

An indoor fan motor defect can activate the A6 error code. The fault could be a damaged capacitor or loose winding. Accordingly, the Daikin AC technician will rectify the problem.

C4 – Heat exchange temperature sensor fault

A faulty heat exchange temperature sensor can result in the C4 error code. We advise you to lodge a service complaint and summon the Daikin service technician. The sensor might have disconnected or malfunctioned. So, it will require reconnection or replacement accordingly.

C9 – Suction air temperature sensor fault

The C9 error code flashes when the diagnosis system detects a fault with the suction air temperature sensor. The solution is reconnecting the sensor or replacing it if faulty. The service technician is the ideal person to handle this issue.

Outdoor Unit Faults

E1 – Circuit Board Fault

A defect in the outdoor unit (ODU) printed circuit board (PCB) results in the E1 error code. The Daikin AC technician is the ideal person to handle this problem. Usually, PCBs are under warranty. The remedy is to repair the circuit or repair it, depending on the extent of the damage.

E5 – OL Started

Overheating of the compressor can result in the remote controller displaying the E5 error code. It can happen due to a clogged refrigerant piping system. There can be a shortage of refrigerant, or there might be a fault in the overload protector or connection. The remedy is to repair the system. Users should book a service call and summon the technician to handle the matter. 

E6 – Faulty compressor start

The E6 error code flashes when there is a fault with the compressor start-up. The compressor does not start, so the AC does not function. The solution is to replace the faulty capacitor. The authorized Daikin service technician is the right person for the job.

E7 – DC Fan motor fault

A faulty DC fan motor or a defective capacitor can result in the E7 error code. The solution is to repair the fan motor by replacing the defective part. Users should book a service appointment with the authorized Daikin representative to resolve the issue.

E8 – Input over-current

An input overcurrent of the inverter compressor can result in the E8 error code. The reason could be a defective compressor, defective inverter main circuit capacitor, outdoor unit PCB defect, or a power transistor defect. The remedy is to call the Daikin AC technician to handle the matter. Users should not reset the circuit breaker without checking for other problems because it can cause extensive damage to the equipment.

F3 – High-temperature discharge pipe control

The discharge pipe temperature control malfunction can result in the F3 error code. Under such circumstances, the molded case circuit breakers can trip. Users should not reset the circuit breakers without investigating other reasons. So, summoning the Daikin AC technician is the right course of action.

F6 – High-pressure control when cooling

Abnormal high pressure or overcharging of the refrigerant can cause the F6 error code. It can lead to disconnection of the heat exchange thermistor, liquid pipe temperature thermistor, or a defective outdoor PCB. But, again, the solution is to let the qualified Daikin AC technician handle the job.

H0 – Sensor Fault

H0 is an outdoor unit sensor fault because of a disconnected harness, a defective connection, or a damaged PCB. The solution is to repair the loose connection or replace the sensor if damaged. The AC technician will decide if there is a loose connection or total damage. Refixing the sensor can also resolve the issue.

H6 – Detection sensor faulty position, resulting in a halt in operations

The malfunctioning of the position detection sensor can trigger the H6 error code. The reason could be a faulty connection or cable, a defective compressor, or a faulty PCB. The AC technician is the ideal person to rectify the damage.

H8 – DC sensor fault

A DC sensor fault or the malfunctioning of the compressor input system can activate the H8 error code. A defective power transistor, reactor, outdoor PCB, or faulty wiring of the inverter system can cause the DC sensor to fail. The remedy is replacing the sensor. The AC technician is the right person to handle the job. Users should not restore the circuit breaker position if it has tripped without checking for other problems.

H9 – Suction air temperature sensor fault

The malfunctioning of the suction air temperature sensor or the outdoor air thermistor causes the H9 error code in a Daikin AC. The defective sensor could be because of a defect in the outdoor unit PCB or a loose connection. Accordingly, the Daikin AC technician will replace or repair the sensor. 

J3 – Discharge pipe temperature sensor fault

The J3 error code flashes when there is a discharge pipe temperature sensor fault. The reasons could be a defective pipe thermistor, a loose connection, or a faulty outdoor unit PCB. Users should contact the Daikin service center and raise a complaint. The authorized AC technician repairs or replaces the discharge pipe temperature sensor accordingly.

J6 – Heat exchanger temperature sensor fault

A defective thermistor connection or a faulty outdoor PCB can cause the heat exchanger temperature sensor fault and the J6 error code. The solution is replacing or repairing the sensor if there is a loose connection. But, again, the Daikin AC technician is the right person for the job.

L3 – Electrical parts heat fault

A short circuit, a defective power transistor, or an outdoor PCB can result in the overheating of the electrical component box. It can result in the L3 error code. The circuit breaker trips under such circumstances. However, the user should not restore the connection without determining the other faults because it can cause extensive damage. It is advisable to lodge a complaint and summon the Daikin AC service technician to handle the matter. 

L4 – High-temperature at inverter circuit heat sink

A defective fin thermistor or a short circuit can cause the inverter radiation fin temperature to malfunction and cause it to rise. Consequently, the circuit breaker trips and flashes the L4 error code. Under such circumstances, users should not restore the power supply but seek professional help to set the matter right. The correct action is to lodge a service complaint and call the AC technician.

L5 – Output over-current

The L5 error code signifies an inverter instantaneous overcurrent situation. The reason can be a defective compressor coil, a wiring fault, or an insulation failure. Users should summon the Daikin AC technician to rectify the error. For example, the compressor coil can need replacement, or the wiring changed.

P4 – Inverter circuit heat sink temperature sensor fault

The P4 error is similar to the L4 error. The radiation fin temperature sensor malfunction can be because of a defective inverter compressor, fan motor, radiation fin temperature sensor, or inverter PCB. Users should seek professional assistance and call the AC technician to look into the matter and resolve it.

Important points to note

Users should not try to repair the Daikin AC independently because the circuits are complicated. The only repair job users can do is to clean the filters. Anyone can remove the cover and remove the filters to clean them. We recommend cleaning the filters every fortnight to remove dust deposits. It helps the AC perform efficiently and makes it durable. All other faults require the intervention of a qualified AC technician. It is better to lodge a complaint online and book a service call.

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