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Daikin Air Conditioner A5 Error Code
Freeze-up or overheat protection. What it means, which models show it, and how to clear it, easiest fix first.
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In cooling, the indoor coil got cold enough to start freezing; in heating, the indoor coil ran too hot and the high-pressure protection stepped in. Restricted airflow, most often from clogged filters, is the usual cause, though a faulty coil temperature sensor can also trigger it.
Compatible models
Daikin doesn't publish a model list for this code; it appears on Daikin air conditioners with a digital display. Check your owner's manual.
Also shown as
Some Daikin regional code lists describe A5 only as freeze-up protection. Daikin uses this code across its residential split, SkyAir and VRV ranges, but the exact meaning and causes can vary by series, model year and region, so confirm it in your unit's manual. How to read it: most Daikin ductless wall units only blink the operation lamp. On remotes such as the ARC433 series, press and hold the timer Cancel button for roughly 5 seconds until 00 blinks on the screen, then press Cancel again one step at a time; when the indoor unit answers with a long continuous beep, the code showing is the stored fault. SkyAir and VRV wireless remotes use a different sequence with the Inspection/Test, up/down and MODE buttons, and wired wall controllers usually show the code on their screen.
Difficulty
Start with the safe checks below; a worn part may need replacing.
How to fix Daikin A5
Clean the air filters
Turn the system off and switch off its breaker. Lift the front panel of the indoor unit, slide out the mesh filters, and rinse them under lukewarm water or vacuum them gently. Let them dry fully in the shade before refitting them, then restore power.
Make sure air can move freely
Check that curtains, furniture or shelves are not blocking the indoor unit's air intake or outlet. Close windows and doors in the room so the unit isn't fighting a large heat load.
Let any ice melt
If you see frost on the indoor coil, switch the unit off or run Fan Only for a few hours until it has fully thawed. Restarting while the coil is iced up tends to bring the code straight back.
Reset the power at the breaker
Switch the system off with the remote, then turn off its circuit breaker in your home's main panel. Wait about 5 minutes, switch the breaker back on and restart the unit. If the code returns within a few minutes, write it down for the technician.
When to call a technician
If A5 returns with clean filters and clear airflow, a technician should check the indoor fan, the coil sensor and the refrigerant charge.
Parts linked to A5
These are the parts most often behind this code. Tap one to see what it does and the signs it is failing.
- air filter
- indoor heat exchanger thermistor
- indoor fan motor
Order parts by your full model number so they fit.
Frequently asked questions
What does A5 mean on a Daikin air conditioner?
In cooling, the indoor coil got cold enough to start freezing; in heating, the indoor coil ran too hot and the high-pressure protection stepped in. Restricted airflow, most often from clogged filters, is the usual cause, though a faulty coil temperature sensor can also trigger it.
Which Daikin models show the A5 code?
Daikin doesn't publish a model list for this code; it appears on Daikin air conditioners with a digital display. Check your owner's manual.
Can I fix Daikin A5 myself?
Often. The first steps above are safe checks a homeowner can do. If they don't clear A5, the cause is likely a worn part that needs replacing.
What if A5 keeps coming back?
A code that returns after a reset and the checks above usually means a part is wearing out. Note when A5 appears (which cycle, how often) and have your model number ready; it helps a technician bring the right part on the first visit.
Other Daikin air conditioner codes
- U4Indoor and outdoor units can't communicate
- U0Low refrigerant or restricted refrigerant flow
- U2Power supply voltage problem
- UAIndoor and outdoor units don't match
- A1Indoor unit control board fault
- A3Condensate water level too high
- A6Indoor fan motor fault
- C4Indoor coil temperature sensor fault
- C9Indoor room air temperature sensor fault
- E1Outdoor unit control board fault
- E5Compressor overload or lock-up protection
- E6Compressor won't start
- E7Outdoor fan motor fault
- E8Compressor current too high
- F3Compressor discharge temperature too high
- F6High pressure in cooling mode
- H6Compressor position sensing error
- L4Inverter heat sink overheating
- L5Inverter output overcurrent
Last reviewed 2026-10-19. Codes and steps can vary by model; check your owner's manual.