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Daikin Mini-Split Error Codes

Daikin ductless and heat pump units show a letter and number code such as U4, A5 or E7 on the remote controller or thermostat. Below are 26 Daikin codes across 1 model series. Each one says what it means, which series it applies to, what you can safely check, and when to call a licensed pro, with a link to the Daikin document it comes from.

The same code can mean different things on different series, so match the series column to your unit. Your unit's manual is the final word. Reviewed October 2026.

26 codes

Daikin A1Indoor unit PCB abnormalityDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)Daikin A5Freeze-up or heating peak-cut protectionDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)Daikin A6Indoor fan motor abnormalityDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)Daikin C4Indoor heat exchanger thermistor abnormalityDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)Daikin C9Room temperature thermistor abnormalityDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)Daikin U0Refrigerant shortageDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)Daikin U2Low-voltage or over-voltage detectionDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)Daikin U4Signal error between indoor and outdoor unitDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)Daikin UAUnspecified voltage between indoor and outdoor unitDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)Daikin E1Outdoor unit PCB abnormalityDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)Daikin E5Compressor overload (OL) activationDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)Daikin E6Compressor lockDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)Daikin E7Outdoor DC fan lockDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)Daikin E8Input overcurrent detectionDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)Daikin EAFour-way valve abnormalityDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)Daikin F3Discharge pipe temperature controlDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)Daikin F6High pressure control in coolingDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)Daikin H0Compressor system sensor abnormalityDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)Daikin H6Compressor position sensor abnormalityDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)Daikin H9Outdoor temperature thermistor abnormalityDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)Daikin J3Discharge pipe thermistor abnormalityDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)Daikin J6Outdoor heat exchanger thermistor abnormalityDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)Daikin L3Electrical box temperature riseDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)Daikin L4Radiation fin temperature riseDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)Daikin L5Output overcurrent detectionDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)Daikin P4Radiation fin thermistor abnormalityDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)

All Daikin error codes

CodeMeaningApplies toSafety
A1
Shown on the remote controller (and as blinking lamps on the indoor unit)
Indoor unit PCB abnormalityDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)🛑 Call a pro
A5
Shown on the remote controller (and as blinking lamps on the indoor unit)
Freeze-up or heating peak-cut protectionDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)🧭 Check first
A6
Shown on the remote controller (and as blinking lamps on the indoor unit)
Indoor fan motor abnormalityDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)🛑 Call a pro
C4
Shown on the remote controller (and as blinking lamps on the indoor unit)
Indoor heat exchanger thermistor abnormalityDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)🛑 Call a pro
C9
Shown on the remote controller (and as blinking lamps on the indoor unit)
Room temperature thermistor abnormalityDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)🛑 Call a pro
U0
Shown on the remote controller (and as blinking lamps on the indoor unit)
Refrigerant shortageDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)🛑 Call a pro
U2
Shown on the remote controller (and as blinking lamps on the indoor unit)
Low-voltage or over-voltage detectionDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)🧭 Check first
U4
Shown on the remote controller (and as blinking lamps on the indoor unit)
Signal error between indoor and outdoor unitDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)🧭 Check first
UA
Shown on the remote controller (and as blinking lamps on the indoor unit)
Unspecified voltage between indoor and outdoor unitDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)🛑 Call a pro
E1
Shown on the remote controller (and as blinking lamps on the indoor unit)
Outdoor unit PCB abnormalityDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)🛑 Call a pro
E5
Shown on the remote controller (and as blinking lamps on the indoor unit)
Compressor overload (OL) activationDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)🛑 Call a pro
E6
Shown on the remote controller (and as blinking lamps on the indoor unit)
Compressor lockDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)🛑 Call a pro
E7
Shown on the remote controller (and as blinking lamps on the indoor unit)
Outdoor DC fan lockDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)🧭 Check first
E8
Shown on the remote controller (and as blinking lamps on the indoor unit)
Input overcurrent detectionDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)🛑 Call a pro
EA
Shown on the remote controller (and as blinking lamps on the indoor unit)
Four-way valve abnormalityDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)🛑 Call a pro
F3
Shown on the remote controller (and as blinking lamps on the indoor unit)
Discharge pipe temperature controlDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)🛑 Call a pro
F6
Shown on the remote controller (and as blinking lamps on the indoor unit)
High pressure control in coolingDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)🧭 Check first
H0
Shown on the remote controller (and as blinking lamps on the indoor unit)
Compressor system sensor abnormalityDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)🛑 Call a pro
H6
Shown on the remote controller (and as blinking lamps on the indoor unit)
Compressor position sensor abnormalityDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)🛑 Call a pro
H9
Shown on the remote controller (and as blinking lamps on the indoor unit)
Outdoor temperature thermistor abnormalityDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)🛑 Call a pro
J3
Shown on the remote controller (and as blinking lamps on the indoor unit)
Discharge pipe thermistor abnormalityDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)🛑 Call a pro
J6
Shown on the remote controller (and as blinking lamps on the indoor unit)
Outdoor heat exchanger thermistor abnormalityDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)🛑 Call a pro
L3
Shown on the remote controller (and as blinking lamps on the indoor unit)
Electrical box temperature riseDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)🛑 Call a pro
L4
Shown on the remote controller (and as blinking lamps on the indoor unit)
Radiation fin temperature riseDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)🧭 Check first
L5
Shown on the remote controller (and as blinking lamps on the indoor unit)
Output overcurrent detectionDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)🛑 Call a pro
P4
Shown on the remote controller (and as blinking lamps on the indoor unit)
Radiation fin thermistor abnormalityDaikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)🛑 Call a pro

✅ Usually fine to keep running · 🧭 Check a few things first · 🛑 Turn it off and call a licensed pro

Find your Daikin model series

The codes Daikin documents for each series we have checked. If your series is not listed, the code may mean something different on your unit, so check its manual.

Daikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU)

More Daikin codes

Daikin A1: Indoor unit PCB abnormality

🛑 Turn it off and call a licensed pro

Applies to: Daikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU). Shows as: Shown on the remote controller (and as blinking lamps on the indoor unit)

The system checks if the circuit works properly within the microcomputer of the indoor unit, and cannot set the internal settings. The manual lists wrong models interconnected, a disconnected connector or reduced supply voltage among the possible causes.

When to call a pro: The indoor control board needs checking by a licensed technician, including confirming the indoor and outdoor units are a compatible pair.

Source: Daikin Service Manual SiUS091133 - FTXS-L / FDXS-L Series, Troubleshooting p.95

Daikin A6: Indoor fan motor abnormality

🛑 Turn it off and call a licensed pro

Applies to: Daikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU). Shows as: Shown on the remote controller (and as blinking lamps on the indoor unit)

The indoor fan motor rotation speed detected during operation does not reach the demanded speed (less than 50% of maximum). The manual lists a faulty fan motor, broken motor wiring or a defective indoor board among the causes.

When to call a pro: The indoor fan motor or board needs diagnosing by a licensed technician.

Source: Daikin Service Manual SiUS091133 - FTXS-L / FDXS-L Series, Troubleshooting p.99

Daikin C9: Room temperature thermistor abnormality

🛑 Turn it off and call a licensed pro

Applies to: Daikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU). Shows as: Shown on the remote controller (and as blinking lamps on the indoor unit)

The room temperature sensor in the indoor unit reads outside its valid range during compressor operation. The manual lists a disconnected connector, a defective thermistor or a defective indoor board.

When to call a pro: A technician needs to check the sensor and its connector.

Source: Daikin Service Manual SiUS091133 - FTXS-L / FDXS-L Series, Troubleshooting p.103

Daikin E1: Outdoor unit PCB abnormality

🛑 Turn it off and call a licensed pro

Applies to: Daikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU). Shows as: Shown on the remote controller (and as blinking lamps on the indoor unit)

The system checks if the microprocessor on the outdoor board is working and if the zero-cross signal comes in properly. The manual lists a defective outdoor board, a broken harness between boards, noise or a momentary power failure.

When to call a pro: The outdoor board needs diagnosing by a licensed technician.

Source: Daikin Service Manual SiUS091133 - FTXS-L / FDXS-L Series, Troubleshooting p.113

Daikin E6: Compressor lock

🛑 Turn it off and call a licensed pro

Applies to: Daikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU). Shows as: Shown on the remote controller (and as blinking lamps on the indoor unit)

A compressor lock is detected by checking the compressor running condition. If the error repeats, the system is shut down.

When to call a pro: A licensed technician must diagnose the compressor.

Source: Daikin Service Manual SiUS091133 - FTXS-L / FDXS-L Series, Troubleshooting p.116

Daikin E8: Input overcurrent detection

🛑 Turn it off and call a licensed pro

Applies to: Daikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU). Shows as: Shown on the remote controller (and as blinking lamps on the indoor unit)

An input overcurrent is detected with the compressor running. The manual lists outdoor temperature outside the operating range, a defective compressor, power module or board, or a short circuit.

When to call a pro: Electrical and compressor faults need a licensed technician.

Source: Daikin Service Manual SiUS091133 - FTXS-L / FDXS-L Series, Troubleshooting p.118

Daikin EA: Four-way valve abnormality

🛑 Turn it off and call a licensed pro

Applies to: Daikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU). Shows as: Shown on the remote controller (and as blinking lamps on the indoor unit)

The room temperature thermistor and the indoor heat exchanger thermistor are checked in each operation mode, and the readings do not match the expected mode. If the error repeats, the system is shut down.

When to call a pro: The reversing (four-way) valve circuit needs a licensed technician.

Source: Daikin Service Manual SiUS091133 - FTXS-L / FDXS-L Series, Troubleshooting p.119

Daikin H0: Compressor system sensor abnormality

🛑 Turn it off and call a licensed pro

Applies to: Daikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU). Shows as: Shown on the remote controller (and as blinking lamps on the indoor unit)

The system checks the DC current and voltage before the compressor starts and found them out of range. The manual lists a broken or disconnected harness or a defective outdoor board.

When to call a pro: Outdoor board and sensor faults need a licensed technician.

Source: Daikin Service Manual SiUS091133 - FTXS-L / FDXS-L Series, Troubleshooting p.125

Daikin H9: Outdoor temperature thermistor abnormality

🛑 Turn it off and call a licensed pro

Applies to: Daikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU). Shows as: Shown on the remote controller (and as blinking lamps on the indoor unit)

The outdoor air temperature sensor reads outside its valid range. The manual lists a disconnected connector, a defective thermistor or a defective outdoor board.

When to call a pro: A technician needs to check the sensor and its connector.

Source: Daikin Service Manual SiUS091133 - FTXS-L / FDXS-L Series, Troubleshooting p.134

Daikin J6: Outdoor heat exchanger thermistor abnormality

🛑 Turn it off and call a licensed pro

Applies to: Daikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU). Shows as: Shown on the remote controller (and as blinking lamps on the indoor unit)

The outdoor heat exchanger thermistor reads outside its valid range. The manual lists a disconnected connector, a defective thermistor or a defective outdoor board.

When to call a pro: A technician needs to check the sensor and its connector.

Source: Daikin Service Manual SiUS091133 - FTXS-L / FDXS-L Series, Troubleshooting p.134

Daikin L3: Electrical box temperature rise

🛑 Turn it off and call a licensed pro

Applies to: Daikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU). Shows as: Shown on the remote controller (and as blinking lamps on the indoor unit)

A temperature rise in the outdoor electrical box was detected by the radiation fin thermistor with the compressor off. The outdoor fan runs to cool the electrical parts.

When to call a pro: Electrical box cooling and board faults need a licensed technician.

Source: Daikin Service Manual SiUS091133 - FTXS-L / FDXS-L Series, Troubleshooting p.136

Daikin L4: Radiation fin temperature rise

🧭 Check a few things first

Applies to: Daikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU). Shows as: Shown on the remote controller (and as blinking lamps on the indoor unit)

The outdoor board radiation fin temperature rose above the limit with the compressor on. If the error repeats, the system is shut down. The manual lists a defective outdoor fan motor among the causes.

When to call a pro: If the code comes back after a power reset, have a licensed HVAC technician diagnose it.

Source: Daikin Service Manual SiUS091133 - FTXS-L / FDXS-L Series, Troubleshooting p.138

Daikin P4: Radiation fin thermistor abnormality

🛑 Turn it off and call a licensed pro

Applies to: Daikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU). Shows as: Shown on the remote controller (and as blinking lamps on the indoor unit)

The radiation fin thermistor on the outdoor board reads outside its valid range. The manual lists a disconnected connector, a defective thermistor or a defective outdoor board.

When to call a pro: A technician needs to check the sensor and outdoor board.

Source: Daikin Service Manual SiUS091133 - FTXS-L / FDXS-L Series, Troubleshooting p.134

Safe first steps for any code

  1. Write down the exact code and how it shows (remote display or number of lamp blinks). Similar codes mean different things on different series.
  2. Turn the system off at the remote, switch off the breaker or disconnect for the unit, wait a few minutes, then turn it back on.
  3. Clean or replace the indoor unit air filters, and make sure nothing blocks the indoor or outdoor unit.
  4. Check that the condensate drain line is not blocked or kinked where you can see it.
  5. Replace the remote controller batteries if the display is dim or the unit does not respond.

🛑 Stop and call a licensed pro if

  • Any code pointing to refrigerant, the compressor, high pressure or the outdoor unit board. Refrigerant work legally needs a certified technician.
  • Burning smell, sparks, or a breaker that trips again after a reset.
  • Water leaking from the indoor unit that does not stop after the drain is clear.

Tell us the brand, model and code, and what you have already tried. Describing it is free, and a chat with a verified HVAC technician costs $1.

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