Air conditioning – a complex unit, consisting of a large number of elements. Even the most advanced equipment, including Daikin air conditioning, is not immune to any failure. In order to quickly identify the causes of malfunctions, manufacturers equip their models with self-diagnostic systems.

Thanks to a combination of letters with numbers and light signals, “intelligent equipment” informs about all violations in its own work. The display system displays the fault codes of the Daikin air conditioner control panel. In the event of a malfunction, the corresponding signal flashes.

This article presents the alphanumeric designations of faults, their decoding, the causes of occurrence and the methods of elimination.

Air conditioner self-diagnosis system

All Daikin air conditioners are equipped with a self-diagnostic system. With its help, they themselves diagnose their condition, and then inform about the problems encountered. You can perform this function in a special mode, but it also works automatically.

Almost all failures can be found by observing the indicators, and the mechanism of this process is very simple. In the normal state, the LEDs emit uniform light. But as soon as the violation has occurred, they begin to pulse with a subsequent repetition of flashes. An alphanumeric or alphabetical combination appears on the remote control display.

After practicing deciphering the coded fault information, you can understand that some malfunctions can be eliminated by a craftsman at home. If the failures are complex, then by informing the master of the code, the user will speed up the repair process.

The latest Daikin air conditioners are built with the latest technology. They have an elegant design, low noise, unquestionable quality. Models are economical and productive

DTC Classification

The letter at the beginning of the code indicates the structural part in which the malfunction occurred:

  • failure in the internal block – “A”, “C”;
  • power supply unit failure – “E”;
  • malfunctions of temperature sensors – “F”;
  • problems with food – “N”;
  • malfunctions in the external block – “L”;
  • the fan motors are blocked, the drain pumps are defective or the electronic board of the indoor unit is in “P”;
  • system failures – “U”, “M”.

Errors that are not critical and appear infrequently are encrypted with a combination of numbers.

Common Daikin Air Conditioning Problems

Most of the malfunctions of the Daikin air conditioner, especially its indoor unit, are not difficult. The errors displayed on the screen consist of a classification code (letter) and an error number (number), numbers and letters, two letters.

Not only for different brands, but also for different lines, the codes are slightly different. For this reason, you should read the instructions. It provides the decryption of coded violations and the methods to eliminate them.

Indoor unit errors

When the general protection device is activated, the code starts flashing AO . There are several reasons for this:

  • compressor overheating ;
  • failure of fans;
  • insufficient amount of refrigerant in the system;
  • trash in the capillary tube, another.

Among all the causes, the most difficult is the malfunction of the electronic part. To eliminate it, you need not only a professional tool, but also experience.

A faulty printed circuit board indicates an A1 code malfunction . As practice shows, the control board is often diagnosed incorrectly. Therefore, before you change it, you need to check the components that most often fail – relays, capacitors.

Among the common reasons for control board failure, there are only five:

  • voltage instability in the network;
  • improper installation of interconnection cables;
  • natural wear and tear of individual elements of the board;
  • humidity, destructive mechanical stress;
  • non-compliance with operating rules.

Often the air conditioner breaks down due to poor winter preparation. When the device is switched off, only the phase is deactivated and zero is forgotten. In this case, the electronic card, subjected to an earth on a common line, can deactivate the welding work carried out in the vicinity.

If the air conditioner does not turn on and all the LEDs on the indoor unit are flashing, it is most likely a sign of a malfunction of the software settings on the board. There is only one way out: reprogramming by codes, which can only be done in the service center.

Code A2 indicates that the fan motor is blocked. When the self-diagnosis system issues Daikin air conditioner malfunction code indicating fan motor failure, you should try to manually rotate the blades. If there is no free rotation, the cause is wear of the motor bearings, and it will need to be replaced.

The fan motor activates the rotary switch. The contacts inside corrode over time and stop passing electric current. To make sure that the rotary switch is not conducting electricity, you should use a multimeter. If the continuity of the switch is confirmed, it should be replaced.

Abnormal level in the drainage system is reported Code A3 . Excess humidity due to improper condensate drain arrangement can cause failure due to short circuit. In this case, it will be necessary to disassemble the indoor unit and thoroughly clean the drainage system.

Codes A4 and A5 indicate heat exchanger malfunction and abnormal temperature. This is due to an error in the temperature sensor.

Check if this is true, as follows:

  1. The temperature sensor is disconnected from the board.
  2. Check the resistance of the sensor using special equipment.
  3. The result of the measurement is compared with predetermined values. At a temperature of + 25⁰ on a working sensor, the resistance must be 10 kOhm. If the condition is not met, the sensor is definitely defective and must be replaced.
  4. In the event that the measurements showed that the resistance of the sensor meets the standards, it is installed in its place, connected to the board, and the unit itself to the network.
  5. Then check the connector using a multimeter. If the voltage exceeds 4.9V or is less than 0.5V, the board must be changed.
  6. If the voltage on the connector is normal, the microprocessor is defective and must be replaced.

When the fan motor is overloaded, the self-diagnostic system causes trouble code A6 . The cause could be a disconnected or broken wire, faulty contact, damage to the printed circuit board.

Error display A7 indicates a malfunction of the blind drive. The motor valve may be defective; check the connections to make sure nothing is blocking the movement of the blinds.

The most common cause is engine malfunction. In this case, simply replace it. There is also the possibility of micro switch failure, circuit board malfunction, or connector connection faults.

Such an error as a general overcurrent has code A8 . Since the compressor motor starting current is much higher than the running current, the system will output a signal three seconds after the motor is started.

Overloading can lead to a fire hazard, so you should start immediately to find out the reasons. This situation can cause a short circuit in the compressor itself.

In this case, the system decides that a fault is present, because the current rises to a significant value. A short circuit can occur outside the compressor – in the control board, on the terminals, in the power wires.

The cause of the A8 error may be an excessive increase in pressure in the discharge system. An increase in this indicator can trigger errors made during refrigerant charging.

The untimely cleaning of the heat exchanger gives the same result. Good heat transfer can be hindered even by a thin film of grease on the surface of a visually clean heat exchanger.

If an error occurs on the compressor current, it is necessary to give it access. Then the air conditioner starts in cooling mode. If the compressor has not been able to start, the compressor and the connecting wires “ring”. Defective elements or the compressor itself replace

Code A9 indicates a malfunction of the electronic expansion valve. Failure can occur due to mechanical impurities. To check its operation, the power is cut and then on again. Immediately after energizing, the expansion valve should be open for 30 s.

During this period, it is determined whether there is a voltage pulse of 12 V in the middle of the diode contacts of the expansion valve. The absence of a pulse indicates a fault in the control board.

If, when the indoor unit fan is running, the condenser fan stops, the compressor, expansion valve is turned off, the following actions are taken:

  • on the control board, the electronic contacts of the valve are disconnected;
  • check if there is a nominal voltage on the board.

If a nominal voltage is present, this indicates a malfunction of the electronic expansion valve. Lack of voltage indicates a malfunction of the control board.

Before contacting a service center, turn off the home air conditioner for a while, and then turn it on again. After reconnecting, the error may not appear. If the code flashes again, you cannot do without an assistant.

Outdoor unit errors

The instructions supplied with the air conditioner describe how to eliminate certain faults. They can be fully implemented with individual indoor unit malfunctions. External errors and system issues are more complicated, so it is better to contact the wizard.

Wink Code EO indicates the operation of a common protection device. This means that the self-diagnostic device has detected some kind of anomaly.

Work can be interrupted for several reasons:

  • the input connection of the safety device is damaged;
  • the seat belts are disconnected or broken;
  • the shut-off valve is installed in the closed position;
  • clogged refrigerant piping;
  • the external control board is defective;
  • there was an air short circuit.

Error under code E1 indicates that the split control PCB is malfunctioning. When the power is on E2PROM is not working properly.

When the high pressure sensor (HPS) is triggered, error E3 . This happens when the compressor is running while the high pressure switch is activated.


The control card processor contains the system algorithm. From there, the operation of all its elements is controlled, the information of the remote control and sensors are processed, signals are sent, the fan starts

Failure can be caused by excessively high pressure level caused by large amount of refrigerant or non-condensable gas.

Other reasons are likely:

  • high pressure switch defective;
  • disconnection or damage to the high pressure wire harness;
  • loss of contact in the high pressure connector;
  • Damage to PCBs;
  • damage to the refrigeration circuit;
  • indoor unit air filter clogged;
  • clogging of the external heat exchanger;
  • outdoor fan malfunction in cooling mode.

When the low pressure sensor (LPS) is triggered, Code E4 . The compressor is running at this time and an error occurs when the low pressure switch is activated. The reasons may lie in the malfunctions of the cooling circuit, the low pressure switch may also be defective.

The low pressure cable connection may disconnect or break. The probability of a fault in the connector, the printed circuit board can not be excluded. The shut-off valve can remain in the closed position.

If the compressor motor is overloaded, the system reports error E5 . This means that the compressor is engaged in thermal protection or that the discharge pipe is overheated.

A sign of leakage from the chiller is a greasy film on the tubes at the points of entry into the fitting and on the threaded fittings themselves.If such a phenomenon is detected and short shutdowns occur with the compressor, the chiller has left the system

The failure can be caused by a malfunction of the stop valve, lack of chiller, damage to the outdoor unit, malfunction of the 4-way valve or an electronic expansion valve.

Error E6 warns that the compressor motor is blocked by increasing the current.

At this time, the current protection is triggered due to:

  • the high pressure level is excessively high;
  • a voltage drop is observed;
  • the shut-off valve does not open;
  • compressor defective.

Error E7 – the fan motor is stuck due to overcurrent. The failure may be due to a malfunction of the fan, a disconnection of the fan motor or the circuit board from the wire harness or connector. It may simply be a matter of poor contact or foreign objects stuck in the fan.

With a general current overload, error E8 occurs . In this case, the input current of the inverter has a value greater than 28 A for 2.5 s. Among the reasons can be noted compressor failure, fault in power transistor, indoor and outdoor unit printed circuit board and short circuit.

Error E9 – damage signal on the electronic expansion valve. It appears when the chain is broken.

Error under Code EA indicates anomalies in the 4-way valve. The origin of the failure:

  • bad contact in the connector;
  • the thermistor is damaged;
  • the outdoor unit is defective;
  • Defective 4-wire valve coil;
  • the 4-wire valve is defective;
  • foreign body mixed with refrigerant.

EU code indicates abnormal water temperature due to malfunction of the outdoor unit or thermistor. In the event of an Ej error, additional protection is triggered. She – abnormal humidity in the drainage system. Ef – The heat storage unit is damaged.

All errors related to nutrition problems go under code “H” . BUT – a general sensor fault, indicates a fault in the compressor sensor system. This could be due to bad connections or to the circuit board. H1 – Air temperature sensor failure. This could be due to a faulty shock absorber or limit switch.

H2 – The system power sensor is defective. H3 – fault in the high pressure sensor. Error appears due to high pressure switch failure, wire harness disconnection, board failure, connector failure.

H4 – defective low pressure sensor. You need to make sure it is connected. If so, the switch should be checked for integrity. H5 – the compressor does not work because the overload sensor has tripped. Here you need to look for a fault in the connector or in the compressor motor overload thermistor.

H6 – compressor overload. The compressor itself or the outdoor unit may be defective. Abnormal input voltage or a closed stop valve can also cause a failure.

H7 – the fan is overloaded. Possible causes: circuit failure, connector output. When the input voltage sensor is triggered, an error will be indicated under code H8 . Here the power transistor, gearbox or outdoor unit would be faulty. Internal wiring may be faulty.

H9 – All is not well with the outside temperature sensor. Indicates that the resistance of the thermostat has exceeded the range of 60 to 600 kOhm. External thermistor, thermistor connector, circuit board may be defective. Changes in the resistance of the thermistor are inversely proportional to the change in the temperature indicators. The malfunction of the thermistor is determined using a multimeter.

If any codes appear F0 , F1 , F2 , then the protection has worked. In the first case, n ° 1 and 2, in the second – n ° 1, in the third – n ° 3. F3 appears at high temperature of the discharge pipe.

It can be caused by:

  • inappropriate cooler volume;
  • plugging the pipeline ;
  • low discharge temperature;
  • outlet of the thermistor holder;
  • disconnect the regulator coil from its body.

Error F6 – exceeding the nominal value of the heat exchanger temperature. Clogging of the filter, heat exchanger, malfunction of the fan, excessive amount of refrigerant and the inability to open the stop valve lead to such failure.

Code J0 indicates a thermistor malfunction. J1, 2, 3 – pressure sensor, current, temperature, respectively. J4 – This is a signal concerning a sensor fault in the low pressure saturation zone. J5, 6, 7, 8, 9 – malfunctions of the thermistor of the suction pipe, heat exchanger 1 and 2, liquid pipe and gas, respectively.

Errors with the code “L” indicate problems in the inverter system. This can either be the activation of protection devices that shut down the inverter, or transmission errors between the external card and the inverter card. A fault in the printed circuit board and a malfunction in the power supply unit give the same effect. You must try to restart the system.

If the cooler is insufficient, an error will be displayed P0 . Flashing code P1 speaks of power supply imbalance due to voltage inconsistency between phases. It may be due to a fault in the capacitor of the main circuit, malfunction of the magnetic relay, incorrect wiring of the main circuit.

If the temperature inside the control unit increases, a code will inform P3 . The fault is a fault in a thermistor or a printed circuit board. Need to measure resistance. P4, 5, 6 – errors indicating a failure of the sensors – power transistor, direct current, output current sensor. P7 indicates high output current.

The perfect self-diagnosis system of the Daikin unit allows you to quickly identify any malfunction. This eliminates work errors until the equipment is completely out of service.

The user not only has to decrypt the codes, but also periodically clean the air conditioner. When troubleshooting, the repair, depending on the complexity, can be done on-site or in a service environment.

Sensors are devices that allow the unit to operate automatically. They are designed to perform measurements of specific technological parameters.
A thermistor is the same thermistor, but with a negative temperature coefficient of resistance (TCR). For the manufacture of used metal oxides, ceramics, sometimes even diamond crystals