Your Daikin aircon is flashing a code, or you suspect there’s an error but can’t see one displayed. You need to know three things: how to display the code on your specific remote, what the code means, and whether you can fix it yourself or need to call a technician.
This guide answers all three. At Lion City Aircon, we’ve serviced over 22,000 Daikin units across Singapore since 2016. This page is based on Daikin’s official service manual (SM-TS3) cross-checked against what we actually see in real Singapore homes.
Jump to your section:
- How to Display and Read Your Daikin Error Code
- Quick Reference Table
- Detailed Error Code Sections
- Repair Cost in Singapore
- Frequently Asked Questions
- Official Daikin Reference PDFs
How to Display and Read Your Daikin Error Code
Daikin uses different remote controllers depending on whether your unit is a residential split (HDB and condo), a SkyAir cassette or ducted, or a VRV commercial system. The procedure to display the error code differs for each. Find your remote below and follow the steps.
Wireless Remote ARC455A, ARC452A, ARC433B, ARC423A, ARC417A
These are the small wireless remotes that come with most Daikin split aircons in Singapore homes. If you’re using a typical Daikin in an HDB flat or condo, this is probably your remote.
Check Method 1 (most models):
- Hold the Timer Cancel button for 5 seconds. A “00” indication will flash on the temperature display.
- Press the Timer Cancel button repeatedly to cycle through codes. The display will change with each press.
- Listen for a continuous long beep from the indoor unit. The code displayed when you hear that long beep is your error code.
- To cancel the code display, hold the Timer Cancel button for 5 seconds again. The display also clears itself if no button is pressed for 1 minute.
Check Method 2 (ARC433B67, 68, 69, 76 only):
- Press the 3 buttons simultaneously: TEMP up, TEMP down, and MODE to enter diagnosis mode.
- The tens digit will blink. If it doesn’t blink, try again from the start.
- Press TEMP up or down to cycle through digits. Listen for the sound:
- 1 short beep: Tens digit doesn’t match the code
- 2 short beeps: Tens digit matches, ones digit doesn’t
- 1 long beep: Both digits match (this is your code)
- Press MODE. The ones digit will now blink.
- Press TEMP up or down again, listening for the long beep that confirms the full code.
- Press MODE to exit. Press ON/OFF twice to return to normal mode.
Wireless Remote ARC447A
- Hold the Timer Cancel button for 5 seconds with the remote pointed at the indoor unit.
- The temperature display changes to show the error code, and a long beep confirms the change.
- To cancel, hold Timer Cancel for 5 seconds again, or wait 1 minute for the display to clear automatically.
Wired Remote Controller BRC1E62 (modern wired)
The larger LCD wired controller often used for ceiling cassette and ducted units.
- When the unit stops due to a malfunction, the operation indicator on the remote blinks. The message “Error: Press Menu Button” appears at the bottom of the screen.
- Press the Menu/Enter button. The malfunction code displays on screen.
- To see malfunction history, press Menu/Enter again from the basic screen to enter the Main Menu, then navigate to Service Contact or Model Info.
- To clear malfunction history while in code display mode, hold the ON/OFF button for 4 seconds or more.
Wired Remote Controller BRC1C62 (older wired)
Smaller wired controller common on older SkyAir installations in Singapore offices and shops.
- When operation stops due to malfunction, the LED blinks and a code is shown.
- If no code is showing but you suspect an error, press the Inspection/Test button once to enter inspection mode. The mode cycles: Normal → Test → Inspection → Malfunction code display → Indoor model code → Outdoor model code → back to Normal.
- To clear malfunction history, hold the ON/OFF button for 4 seconds or more while in check mode.
Wireless Remote (Cassette and Ducted Units)
If your ceiling cassette or ducted indoor unit has its own wireless remote, this is the procedure. When operation stops due to malfunction, the operation indicator LED on the indoor unit’s light reception section flashes.
- Press the Inspection/Test button to select “Inspection.” The unit enters inspection mode. The “Unit” indicator lights up and Unit No. display shows a flashing “0”.
- Set the Unit No. using UP or DOWN buttons. Cycle through until you hear a beep:
- 3 short beeps: Continue with all following steps
- 1 short beep: Continue with steps 3 to 6 (keep pressing buttons until you hear a continuous beep)
- Continuous beep: No abnormality detected on this unit
- Press the MODE button. The left “0” (upper digit) of the malfunction code flashes.
- Find the upper digit. Press UP or DOWN to cycle through. The upper digit sequence is: 0 → A → C → E → H → J → L → P → U → 9 → 8 → 7 → 6 → 5 → 4 → 3 → 2 → 1 → 0. Listen for:
- Continuous beep: Both digits match (code confirmed)
- 2 short beeps: Upper digit matches
- 1 short beep: Lower digit matches
- Press MODE again. The right “0” (lower digit) flashes.
- Find the lower digit. Use UP or DOWN. Lower digit sequence: 0 → 1 → 2 → 3 → 4 → 5 → 6 → 7 → 8 → 9 → A → C → E → F. Stop when you hear the continuous beep.
If You Can’t Get a Code to Display
Common troubleshooting:
- Change the remote batteries. Weak batteries can prevent the beep response from the indoor unit.
- Point the remote directly at the indoor unit’s sensor (usually behind the front panel, near the display LEDs).
- Reduce ambient noise. The beeps from the indoor unit are quiet, easily missed.
- If still no response, the indoor PCB or remote receiver may be faulty. Time to call us.
Need the official Daikin procedure document? Download Daikin’s Official “How to Check Error Code” Guide (PDF).
How to Read a Daikin Error Code
Daikin codes are made up of one letter and one or two characters. The letter tells you which part of the system is affected:
- A codes: Indoor unit faults (fan motors, drainage, swing flaps, freezing protection)
- C codes: Sensor and thermistor problems (temperature, humidity, communication between PCBs)
- E codes: Outdoor unit and compressor protection
- F codes: Discharge pipe temperature and refrigerant pressure
- H codes: Sensor systems for compressor, pressure switches, motor overload
- J codes: Refrigerant circuit thermistors and pressure sensors
- L codes: Inverter system faults (PCB, power transistors, compressor startup)
- P codes: Power supply, voltage imbalance, automatic refrigerant charging
- U codes: System-wide issues (refrigerant shortage, transmission errors, power)
If you see two codes flashing at once, address the lower-letter one first (an A code before a U code, for example). It’s usually the root cause.
Quick Reference Table: Daikin Error Codes
| Code | What it Means | Severity |
|---|---|---|
| A0 | External protection device activated | High |
| A1 | Indoor unit PCB fault | High |
| A3 | Drainage system abnormality | Medium |
| A4 | Freezing protection malfunction | Medium |
| A5 | High pressure or freeze-up protection | Medium |
| A6 | Indoor fan motor malfunction | High |
| A7 | Swing flap motor malfunction | Low |
| A8 | Power supply or AC input overcurrent | High |
| A9 | Electronic expansion valve malfunction | High |
| AA | Heater overheat | High |
| AF | Humidifier system malfunction | Low |
| AH | Dust collector or air cleaner malfunction | Low |
| AJ | Capacity setting malfunction (PCB) | High |
| C1 | Transmission failure between indoor PCBs | High |
| C4 | Liquid pipe thermistor (heat exchanger) fault | Medium |
| C5 | Gas pipe thermistor (heat exchanger) fault | Medium |
| C6 | Fan motor sensor or control driver fault | High |
| C7 | Front panel driving motor fault | Low |
| C9 | Suction air thermistor fault | Medium |
| CA | Discharge air thermistor fault | Medium |
| CC | Humidity sensor system malfunction | Low |
| CJ | Remote controller room thermistor fault | Low |
| E0 | Protection device activated (unified) | High |
| E1 | Outdoor unit PCB fault | High |
| E3 | High pressure switch (HPS) activated | High |
| E4 | Low pressure switch (LPS) activated | High |
| E5 | Inverter compressor motor overheat | High |
| E6 | Standard compressor motor overcurrent or lock | High |
| E7 | Outdoor fan motor system malfunction | High |
| E8 | Inverter compressor overcurrent | High |
| E9 | Electronic expansion valve coil fault | High |
| EA | Four-way valve or cool/heat switching fault | High |
| F3 | Discharge pipe temperature malfunction | High |
| F6 | Abnormal high pressure or refrigerant overcharge | High |
| H0 | Compressor sensor system malfunction | High |
| H3 | High pressure switch (HPS) malfunction | High |
| H4 | Low pressure switch (LPS) malfunction | High |
| H5 | Compressor motor overload thermistor fault | High |
| H6 | Position detection sensor fault | High |
| H7 | Outdoor fan motor signal fault | High |
| H8 | Compressor input (CT) system fault | High |
| H9 | Outdoor air thermistor fault | Medium |
| HC | Water temperature thermistor fault | Medium |
| J1 | Pressure sensor malfunction | High |
| J2 | Compressor current sensor fault | High |
| J3 | Discharge pipe thermistor fault | Medium |
| J5 | Suction pipe thermistor fault | Medium |
| J6 | Heat exchanger thermistor fault | Medium |
| J7 | Liquid pipe thermistor fault (refrigerant circuit) | Medium |
| J8 | Liquid pipe thermistor fault (refrigerant circuit) | Medium |
| J9 | Gas pipe thermistor fault (refrigerant circuit) | Medium |
| JA | High pressure sensor malfunction | High |
| JC | Low pressure sensor malfunction | High |
| L0 | Inverter system malfunction | High |
| L1 | Inverter PCB malfunction | High |
| L3 | Electrical box temperature rise | High |
| L4 | Inverter radiation fin temperature rise | High |
| L5 | Inverter instantaneous overcurrent (DC output) | High |
| L6 | Inverter instantaneous overcurrent (AC output) | High |
| L8 | Overcurrent inverter compressor | High |
| L9 | Inverter compressor startup error (stall prevention) | High |
| LA | Power transistor malfunction | High |
| LC | Transmission fault between control and inverter PCB | High |
| P0 | Refrigerant shortage (thermal storage unit) | High |
| P1 | Power voltage imbalance or inverter PCB | High |
| P3 | Switch box thermistor fault | Medium |
| P4 | Radiation fin temperature sensor fault | Medium |
| PJ | Capacity setting malfunction (outdoor PCB) | High |
| U0 | Shortage of refrigerant | High |
| U1 | Reverse phase or open phase | High |
| U2 | Power supply fault or instantaneous power failure | High |
| U3 | Check operation not executed or transmission error | Medium |
| U4 | Transmission error between indoor and outdoor unit | High |
| U5 | Transmission error between indoor unit and remote controller | Medium |
| U6 | Transmission error between indoor units | Medium |
| U7 | Transmission error between outdoor units | High |
| U8 | Transmission error between remote controllers | Low |
| U9 | Transmission error (other system) | High |
| UA | Improper combination of indoor and outdoor units | High |
| UC | Centralized control address setting malfunction | Medium |
| UE | Transmission error with centralized control | Medium |
| UF | System not yet set | High |
| UH | System malfunction | High |
| UJ | Accessory device transmission error | Medium |
Need the full official Daikin reference? Download Daikin’s Official Error Code List (PDF).
Indoor Unit Errors (A Codes)
A0: External Protection Device Activated
An external protection device connected to the indoor unit terminal has been triggered. Usually this means a connected accessory (humidifier, additional sensor, etc.) is signalling a fault. Check any connected external devices first. If none are connected and you still see A0, the indoor PCB needs inspection.
A1: Malfunction of Indoor Unit PCB
The indoor unit’s printed circuit board is faulty or has been affected by external interference (often electrical noise from nearby equipment). In Singapore HDB flats, we sometimes see A1 after power surges from thunderstorms. Reset the unit by switching off at the wall for 5 minutes, then back on. If A1 returns, the PCB likely needs replacement. Expect $250 to $450 for a Daikin PCB replacement depending on model.
A3: Drain Level Control System Abnormality
The drain system isn’t clearing properly. Most common cause we see: a clogged drain pipe (Singapore’s humidity creates sludge in drain pipes fast). Less commonly: a defective drain pump or float switch. This is fixable. A proper drain pipe vacuum during servicing usually clears A3 on the spot. See our water leak guide for the full breakdown.
A4: Malfunction of Freezing Protection
The freezing protection system has activated. Typically caused by low water volume (for water-cooled systems), a low water temperature setting, or a defective water temperature thermistor. Less common in standard residential Singapore split units; more common in commercial chiller systems.
A5: High Pressure Control or Freeze-up Protection
The unit detected high pressure during heating mode, or freeze-up risk during cooling. Most often we see this from a clogged air filter restricting airflow, or a defective heat exchanger thermistor. Clean your filters first. If A5 persists after a clean filter, the thermistor or coil needs attention.
A6: Malfunction of Fan Motor
The indoor fan motor isn’t responding correctly. Causes include broken wires in the motor harness, a defective fan motor, or a faulty indoor PCB. Fan motor replacement on a Daikin typically runs $200 to $350 in Singapore.
A7: Malfunction of Swing Flap Motor
The horizontal swing flap motor is faulty. The unit still cools but the louvre won’t move properly. Cosmetic-level fault, not urgent. Often caused by a stuck flap (debris or physical damage). Manually check the flap moves freely. If still showing A7, replace the swing motor.
A8: Malfunction of Power Supply or AC Input Overcurrent
Indicates either defective power supply voltage or faulty wiring. Check that nothing else has shifted in your electrical setup (renovations, added appliances). If unchanged, this needs an electrician to verify supply integrity, then a technician for any aircon-side wiring issues.
A9: Malfunction of Electronic Expansion Valve
The electronic expansion valve coil isn’t operating correctly. Causes: defective valve coil, defective indoor PCB, or defective relay cables. Technician-only fix. Expansion valve replacement is moderate cost (typically $300 to $500 including labour).
AA: Heater Overheat
The internal heater (in models with heating function or thermal storage units) has overheated. Switch off immediately and call for service. Don’t continue to operate.
AF: Malfunction of Humidifier System
For models with humidifier units (uncommon in standard Singapore residential). Usually a humidifier accessory leak or upward-sloping drain piping.
AH: Malfunction of Dust Collector or Air Cleaner
Air cleaner module fault, applicable to models with built-in air purifiers. Causes include defective dust collecting element, stained insulator part, or high voltage power supply fault. Cosmetic to medium-severity.
AJ: Malfunction of Capacity Setting (Indoor Unit PCB)
The capacity setting adapter wasn’t installed correctly when the PCB was replaced. Installer or technician error from a previous service. Needs the correct capacity adapter installed.
Sensor and Thermistor Errors (C Codes)
C1: Failure of Transmission Between Indoor PCBs
The main PCB and sub PCB inside the indoor unit aren’t communicating. Usually a defective connector. Technician fix.
C4: Liquid Pipe Thermistor for Heat Exchanger
The thermistor reading temperature on the liquid refrigerant pipe is faulty or has lost connection. Common causes: defective thermistor, faulty PCB, or loose connector. The unit may still cool but will run inefficiently. Replacement is straightforward (parts under $50, labour adds about $100).
C5: Gas Pipe Thermistor for Heat Exchanger
Same as C4 but on the gas-side pipe instead of the liquid side. Same fix approach.
C6: Malfunction of Fan Motor Sensor or Fan Control Driver
The fan motor’s internal sensor or control driver isn’t responding. Often related to the fan PCB rather than the motor itself. Diagnosis required.
C7: Front Panel Driving Motor Fault
The motor that opens and closes the front panel (in models with auto-opening panels) is faulty. Cosmetic-level. Manual override usually possible.
C9: Malfunction of Suction Air Thermistor
The thermistor that reads air temperature at the suction side is faulty. The unit may not cool effectively because it can’t accurately read room temperature. Common in older units. Cheap fix.
CA: Malfunction of Discharge Air Thermistor
Similar to C9 but on the air-discharge side. Same fix approach.
CC: Malfunction of Humidity Sensor System
The humidity sensor (in models with humidity reading) is faulty. The unit will still cool but may not manage humidity correctly in dry mode.
CJ: Room Temperature Thermistor in Remote Controller
The remote controller’s built-in temperature sensor is faulty. In some Daikin models, the remote reads room temperature and tells the unit. If this fails, the unit may behave strangely. Sometimes fixed by replacing the remote, sometimes the PCB. External factors (noise, interference) can also trigger this temporarily.
Outdoor Unit Errors (E Codes)
E0: Protection Devices Activated (Unified)
A protection device connected to the outdoor unit PCB has triggered. Multiple possible sources. Technician needs to diagnose which protection circuit fired.
E1: Defective Outdoor Unit PCB
The outdoor unit’s main control board is faulty or has poor connections to the indoor PCB. Common after voltage surges in Singapore’s monsoon season. PCB replacement runs $300 to $600.
E3: Actuation of High Pressure Switch (HPS)
The high pressure protection switch has triggered. The most common cause we see is a dirty outdoor unit heat exchanger restricting heat dissipation. Other causes: defective HPS itself, clogged refrigerant piping, or faulty connector. First check we do: how clean is your outdoor unit? If it’s dirty, a condenser cleaning often resolves E3 immediately.
E4: Actuation of Low Pressure Switch (LPS)
The low pressure protection switch has triggered. Usually means refrigerant pressure has dropped abnormally, often from a leak. Defective sensors and PCB can also cause it. Needs technician diagnosis with pressure gauges.
E5: Inverter Compressor Motor Overheat
The inverter compressor is overheating. Causes: compressor lock, high differential pressure across the system, defective inverter PCB, or wrong UVW connection. Serious. Don’t keep running the aircon. Call for diagnosis.
E6: Standard Compressor Motor Overcurrent or Lock
The standard (non-inverter) compressor is drawing too much current or has mechanically seized. Most common cause we see: the outdoor unit’s stop valve wasn’t opened after a recent installation or repair. Less common: actual compressor failure. Check the stop valve first if E6 appeared after recent work.
E7: Outdoor Fan Motor System Malfunction
The outdoor unit’s fan motor isn’t responding. Causes include fan motor failure, harness disconnection, or foreign object caught in the fan blades. In Singapore, we sometimes find leaves or plastic debris jamming the outdoor fan. Visual inspection first, then electrical diagnosis if no obstruction.
E8: Overcurrent of Inverter Compressor
The inverter compressor is drawing too much current. Causes: defective compressor, defective inverter main circuit capacitor, faulty outdoor PCB, or defective power transistor. Serious electrical fault.
E9: Malfunction of Electronic Expansion Valve Coil
The expansion valve coil on the outdoor unit isn’t operating. Connector disconnection, defective coil, or defective control PCB.
EA: Malfunction of Four-Way Valve
The four-way reversing valve (used for switching between cool and heat modes on heat pump models) is faulty. Less common in Singapore where cooling-only models dominate, but possible on multi-function models.
Refrigerant and Pressure Errors (F Codes)
F3: Malfunction of Discharge Pipe Temperature
The discharge pipe temperature is reading abnormally, or the thermistor is faulty. Most often a thermistor problem (cheap fix). Can also indicate genuine high discharge temperature from a deeper issue.
F6: Abnormal High Pressure or Refrigerant Overcharge
System has excessive high pressure. The most common cause we see is refrigerant overcharging from a previous service where someone topped up gas without measuring properly. Also possible: disconnected heat exchanger thermistor, outdoor air thermistor, or liquid pipe thermistor. This is why we never just “top up” gas without proper gauges. Refrigerant levels need to be exact.
Sensor System Errors (H Codes)
H0: Malfunction of Sensor System of Compressor
The compressor’s sensor harness is disconnected or the PCB is defective. Technician diagnosis.
H3: Malfunction of High Pressure Switch (HPS)
The high pressure switch itself is faulty (not the same as E3, which is the switch activating correctly because of high pressure). H3 means the switch is broken. Replacement needed.
H4: Malfunction of Low Pressure Switch (LPS)
Same as H3 but for the low pressure switch.
H5: Malfunction of Compressor Motor Overload Thermistor
The thermistor that monitors compressor temperature has failed. Important because it prevents catastrophic compressor damage. Replace immediately to prevent compressor failure.
H6: Malfunction of Position Detection Sensor
The sensor that detects compressor rotor position is faulty. Often a contact issue at the compressor cable. Can also indicate compressor failure.
H7: Malfunction of Outdoor Fan Motor Signal
Abnormal signal from the outdoor fan motor. Disconnection or short circuit in the fan motor leads, or defective inverter PCB.
H8: Malfunction of Compressor Input (CT) System
The current transformer monitoring the compressor input is faulty. Diagnosis required for power transistor, reactor, or PCB.
H9: Malfunction of Outdoor Air Thermistor
The outdoor temperature sensor is faulty. Cheap fix. Common in older units.
HC: Malfunction of Water Temperature Thermistor
For water-cooled or heat pump water heater models. The water temperature thermistor needs replacement.
Refrigerant Circuit Thermistor Errors (J Codes)
J1: Malfunction of Pressure Sensor
The system pressure sensor is faulty or its connector has poor contact. Replacement.
J2: Malfunction of Current Sensor of Compressor
The compressor current sensor is faulty. Replacement.
J3: Malfunction of Discharge Pipe Thermistor
The thermistor on the discharge pipe is faulty or disconnected. Replacement.
J5: Malfunction of Suction Pipe Thermistor
Same as J3 but on the suction side. Replacement.
J6: Malfunction of Heat Exchanger Thermistor
The heat exchanger thermistor is faulty. Replacement.
J7, J8, J9: Refrigerant Circuit Thermistor Faults
These are all variations of refrigerant circuit thermistor failures (liquid pipe, gas pipe). All are diagnosis and replacement jobs. None are DIY.
JA: Malfunction of High Pressure Sensor
The high pressure sensor itself is faulty. Could also be a sensor wired into the wrong port (we’ve seen this on previous installations from other companies).
JC: Malfunction of Low Pressure Sensor
Same as JA but for the low pressure sensor.
Inverter System Errors (L Codes)
L codes are serious. They usually mean expensive components are about to fail or have failed. Don’t keep operating the unit if you see an L code.
L0: Malfunction of Inverter System
General inverter system fault. Causes: shortage of power supply capacity, defective power transistor, defective outdoor PCB.
L1: Malfunction of Inverter PCB
The inverter PCB itself is faulty. Often from defective compressor wiring, defective outdoor fan motor, blown fuse, or the PCB itself.
L3: Electrical Component Box Temperature Rise
The electrical control box is overheating. Cooling fin issues, fan motor problems, or power transistor faults.
L4: Malfunction of Inverter Radiation Fin Temperature Rise
The inverter’s cooling fin is overheating. Usually airflow problem (short circuit, fan motor issue) or thermistor fault.
L5: Inverter Instantaneous Overcurrent (DC Output)
The inverter detected a sudden overcurrent on the DC output side. Causes include defective compressor coil (wiring disconnection or insulation failure), compressor startup failure (mechanical lock), or defective inverter PCB. This often means the compressor is failing.
L6: Inverter Instantaneous Overcurrent (AC Output)
Same as L5 but on the AC output side. Causes: refrigerant overcharge, shortage of power supply capacity, defective compressor or inverter unit.
L8: Malfunction of Overcurrent Inverter Compressor
Compressor is drawing too much current. Compressor overload or wiring disconnection. Serious.
L9: Inverter Compressor Startup Error (Stall Prevention)
The compressor failed to start properly. Most common cause: the stop valve wasn’t opened. Other causes: defective compressor, wiring errors, large differential pressure before startup, defective inverter PCB.
LA: Malfunction of Power Transistor
Power transistor failure. Diagnose and replace.
LC: Malfunction of Transmission Between Control and Inverter PCB
The control PCB and inverter PCB aren’t communicating. Defective connection, external electrical noise, defective compressor, or defective control PCB.
Power and PCB Errors (P Codes)
P0: Shortage of Refrigerant (Thermal Storage Unit)
For thermal storage models. Refrigerant shortage or clogged refrigerant piping.
P1: Power Voltage Imbalance or Inverter PCB
Open phase, interphase voltage imbalance, defective main circuit capacitor, defective main circuit wiring, or defective inverter PCB. Electrical fault.
P3: Malfunction of Thermistor in Switch Box
The thermistor in the switch box is faulty. Replacement.
P4: Malfunction of Radiation Fin Temperature Sensor
Radiation fin thermistor failure. Replacement.
PJ: Malfunction of Capacity Setting (Outdoor PCB)
The outdoor PCB’s capacity setting adapter is missing, improper, or the PCB is defective. Installer or technician error.
System-Wide Errors (U Codes)
U codes are some of the most common Daikin errors customers ask us about.
U0: Shortage of Refrigerant
Refrigerant is low. Most often from a slow leak in the copper piping. Less commonly: defective thermistor, defective low pressure sensor, or PCB issue. Just topping up gas doesn’t fix the underlying leak. Pressure-test the system, find the leak, repair, then recharge. See our gas top-up guide.
U1: Reverse Phase, Open Phase
The power supply has reverse phase wiring, T-phase open phase, or the outdoor PCB is defective. Common after electrical work in your flat (renovations, panel changes). Needs licensed electrician to verify phase wiring.
U2: Malfunction of Power Supply or Instantaneous Power Failure
Abnormal supply voltage, brief power failure, or defective main circuit wiring. Common in Singapore after thunderstorms or grid disturbances. Sometimes resolves itself; if persistent, electrical diagnosis needed.
U3: Check Operation Not Executed or Transmission Error
The system needs a check operation to be run (typically after installation or major service). Run the check operation procedure or have the installer return to complete it.
U4: Malfunction of Transmission Between Indoor and Outdoor Unit
The most common U code we see in Singapore. Communication between indoor and outdoor units is failing. Causes: short circuit in F1 or F2 transmission wiring, wrong wiring, outdoor power off, system address mismatch, or defective PCBs. First check: is the outdoor unit isolator switched on? Sounds basic, but we attend U4 jobs where the answer was simply that the outdoor power had tripped.
U5: Malfunction of Transmission Between Indoor Unit and Remote Controller
The remote controller and indoor unit can’t communicate. Often from connecting two main remote controllers (when using a dual remote setup, only one should be main). Sometimes electrical noise interference. Replacement remote or PCB diagnosis.
U6: Malfunction of Transmission Between Indoor Units
For multi-split systems where indoor units talk to each other. Faulty wiring or external noise interference.
U7: Malfunction of Transmission Between Outdoor Units
Connection error between outdoor units, or outdoor unit and external control adapter. Wiring or PCB issue.
U8: Malfunction of Transmission Between Remote Controllers
Transmission error between main and sub remote controllers in dual-remote setups. Connection issue.
U9: Malfunction of Transmission (Other System)
Transmission error from another indoor or outdoor unit on the same system. Defective expansion valve in another indoor unit, defective PCB, or improper wiring.
UA: Improper Combination of Indoor and Outdoor Units
The indoor and outdoor units don’t match (excess connected indoor units, mismatched refrigerant types, wrong PCB after replacement). Usually an installer error or aftermarket configuration problem.
UC: Malfunction of Centralized Control Equipment Address Setting
Address duplication in centralized control system or defective indoor PCB. More common in commercial or VRV installations than residential.
UE: Malfunction of Transmission Between Indoor Unit and Centralized Control Equipment
Communication failure with centralized control. Connector disconnection or PCB fault.
UF: System Is Not Set Yet
Wiring between indoor-outdoor or outdoor-outdoor units isn’t proper, check operation hasn’t been executed, or the stop valve isn’t opened. Installer needs to complete setup properly.
UH: Malfunction of System
Improper wiring between indoor-outdoor or outdoor-outdoor units, or defective PCBs.
UJ: Malfunction of Transmission (Accessory Device)
An accessory device (additional sensor, controller, etc.) is faulty or wired incorrectly.
What to Do When You See a Daikin Error Code
- Note the exact code. Even letter case matters. JC is different from J C.
- Check the severity. Use the table above. Low severity codes can wait a day or two; High severity codes should not.
- For Low severity codes (A7, AF, AH, C7, CC, U8): Try a power reset first. Switch off at the wall for 5 minutes, then back on. If the code clears, monitor for return.
- For Medium severity codes: Book a service within the next few days. The unit will likely still work but may underperform.
- For High severity codes: Switch the aircon off and call a technician. Running through these codes risks damaging expensive components.
- WhatsApp +65 8818 5781 with a photo of the error code and your unit’s outdoor nameplate. We can usually identify the likely cause and price the visit before sending a team.
How Much Does Fixing a Daikin Error Code Cost in Singapore?
Lion City Aircon pricing across Singapore (HDB, condo, landed, same rate):
- Diagnostic visit: $35 to $50 per unit
- Thermistor replacement (C, J codes): from $130 (parts and labour)
- Capacitor replacement: from $130
- Indoor PCB replacement: $250 to $450 (depends on model)
- Outdoor PCB replacement: $300 to $600 (depends on model)
- Fan motor replacement: $200 to $350
- Electronic expansion valve replacement: $300 to $500
- Gas leak repair plus recharge (U0 code): from $180
- Compressor replacement (E5, E6, E8, L codes): from $750
If you’re on our annual maintenance contract, diagnostic visits are free and most thermistor and capacitor replacements are included between scheduled visits.
Frequently Asked Questions About Daikin Error Codes
What’s the most common Daikin error code in Singapore?
U4 (transmission error between indoor and outdoor unit) is the one we attend most often, followed by A3 (drainage issues) and E3 (high pressure switch activation, usually from a dirty outdoor unit). All three are diagnosable in one visit.
Can I clear a Daikin error code by switching off the aircon?
Sometimes yes for low-severity codes (A7, C7, AF, AH, U8). For medium and high severity codes, the underlying fault remains even if the code temporarily clears. The code will return, and continuing to operate the unit can worsen the underlying problem.
Are Daikin error codes the same across all models in Singapore?
Yes, the core code system is standardised across Daikin residential models (RA series, SkyAir, and VRV). Some commercial-specific codes (7x, 8x, 9x series) only appear on chiller and heat reclaim ventilator models. Standard split aircons in Singapore homes use the A, C, E, F, H, J, L, P, U codes covered above.
My Daikin is showing two error codes at once. Which do I fix first?
Usually the lower-letter code is the root cause. A code before C code, C before E, E before U. Fix the upstream cause and the downstream code often clears automatically. If unsure, send us both codes via WhatsApp and we’ll prioritise.
Why did the error code appear after a power outage?
Daikin units run a self-check on startup. A power outage or surge can trip protection circuits, leading to U2 (power supply fault), A1 (indoor PCB), or E1 (outdoor PCB) codes. Sometimes a clean 5-minute power reset clears these. If they persist, voltage damage may have occurred and a technician needs to verify.
Should I try to fix Daikin codes myself?
Filter cleaning, drain pipe checking, and power resets are safe DIY. Anything involving refrigerant (U0, F6), inverter components (L codes), or compressor protection (E5, E6, E8) needs a licensed technician. Refrigerant handling especially is regulated in Singapore.
Will running my aircon with an error code damage it?
Depends on the severity. Low severity codes won’t cause additional damage if you keep running the unit short-term. Medium severity codes will worsen over time. High severity codes can cause catastrophic damage if ignored. When in doubt, switch off and ask us.
My Daikin display shows just a single letter, like “A” or “U”. What does that mean?
Most Daikin units flash the full code (letter plus character) in sequence. If you’re only seeing the first character, watch the display for the next few seconds. The second character should follow. If only the letter ever appears, this can itself indicate a remote controller fault. Take a video and send to us via WhatsApp.
Official Daikin Reference PDFs
For the original Daikin documentation, we’ve made both PDFs available for download:
- How to Check Daikin Error Codes (PDF). Official Daikin guide showing the diagnosis procedure for all wired and wireless remote controller types.
- Daikin Full Error Code List SM-TS3 (PDF). Official Daikin service manual listing every error code across RA, SkyAir, VRV, Package, Heat Reclaim Ventilator, Chiller, and Fan Coil systems.
These documents are produced by Daikin Industries Ltd. and are made available here for the convenience of Singapore aircon owners. For the most current Daikin documentation, visit daikin.com.
Get Your Daikin Aircon Fixed Today
Most Daikin error codes are diagnosable in a single visit. The longer you wait with an active error, the more likely cascading damage develops.
WhatsApp +65 8818 5781 with a photo of the error code and your outdoor unit’s nameplate. We diagnose remotely where possible and dispatch a team. Same-day service in most cases across Singapore. 22,000+ jobs done since 2016, 5.0★ across 1,500+ Google reviews, BizSafe Level 3 certified.
No scare tactics. No upselling. If your fix is a $130 thermistor, we’ll tell you that and price it accordingly. If it’s a serious inverter or compressor issue, we’ll show you what we found and give you honest repair-versus-replace numbers before doing anything.
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