The short answer
A Daikin ductless mini split in Northern Virginia doesn’t show its error code on the wall unit. It blinks the green light, and the remote reads the code out: hold TIMER CANCEL about 5 seconds until 00 blinks, then keep pressing it until the unit answers with a long beep. The code on the remote at that beep is the error. U4 is a signal problem between the indoor and outdoor units, A5 is freeze or high pressure protection, and E7 is the outdoor fan. Check the breaker and the filters first. A visit starts with a $99 diagnostic.
How to read the code on the remote
This is for the ARC480 remote that comes with most current Daikin wall units, and the ARC452 on the FTXS30 and 36. Point it at the indoor unit.
- Hold the TIMER CANCEL button for about 5 seconds, until 00 blinks in the temperature spot.
- Press TIMER CANCEL again, once at a time. Each press shows the next code and the unit beeps back.
- A short beep means no match. Keep going.
- A long or continuous beep means that’s the code. Write it down.
- Hold TIMER CANCEL 5 seconds to get out, or leave it and the remote goes back on its own in a minute.
Daikin notes that not every error shows this way, so a tech’s tool may still be needed. Steps are from the FTX owner’s manual and FTXS30 and 36 owner’s manual.
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What the codes mean
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| Code | Daikin’s name for it | What it usually means for you |
|---|---|---|
| 00 | Normal | No error stored |
| U0 | Refrigerant shortage | Low on refrigerant, which means a leak somewhere |
| U2 | Voltage problem | Power dropping or surging at the outdoor unit |
| U4 | Signal transmission, indoor to outdoor | The two units stopped talking: wiring, power or a board |
| UA | Wrong combination | Indoor and outdoor units that don’t match, usually after a part swap |
| A1 | Indoor board | The indoor unit’s control board |
| A5 | Freeze-up or high pressure protection | Iced coil in cooling, or too much pressure in heating |
| A6 | Indoor fan motor | The fan inside the wall unit isn’t turning right |
| C4, C9 | Indoor sensor | A temperature sensor in the wall unit |
| E1 | Outdoor board | The outdoor unit’s control board |
| E5 | Compressor overload | The compressor got too hot and shut itself off |
| E6 | Compressor won’t start | Locked or failed start |
| E7 | Outdoor fan lock | The outdoor fan is blocked, iced or failed |
| E8 | Input overcurrent | Drawing too much power |
| EA | Cooling and heating switching | The reversing valve between heat and cool |
| F3, F6, F8 | Discharge, pressure or compressor temperature | Running too hot: airflow, charge or a dirty coil |
| H0, H6, H8 | Compressor sensors | The inverter can’t read the compressor |
| H9, J3, J6, P4 | Outdoor sensors | A temperature sensor in the outdoor unit |
| L3, L4, L5 | Electrical box, heat sink, output current | The inverter board is overheating or overloaded |
From the FTX and RXL service manual, the LV series service manual and the FTX owner’s manual. These cover the FTX, FTXS and RXL lines; the 17 Series, Aurora and Emura can differ.
What you can check yourself
Daikin tells owners not to repair or modify the unit themselves. These are on the outside and safe:
- Power. Turn the breaker off, wait a minute, turn it back on and restart from the remote. If the light blinks again, read the code.
- The remote. Two fresh AAA batteries, and no bright sun on the unit’s receiver.
- The filters. Daikin says every 2 weeks. A clogged filter is behind a lot of A5 and F codes.
- The outdoor unit. Clear snow, ice and leaves from around it and off the fan.
- The settings. The right mode, a reasonable temperature, the timer off.
Things that look like a problem and aren’t
- It waits about 3 minutes after you turn it on or off.
- In heat it blows nothing for a few minutes while the coil warms up.
- In winter it stops heating for several minutes, hisses or steams outside. That’s defrost.
- The outdoor fan keeps going about a minute after it shuts off.
More on that in our blinking light guide.
When to stop and call
- The breaker, fuse or GFCI keeps tripping.
- You smell something burning.
- Water is dripping from the indoor unit.
Water dripping from the wall unit has its own guide: mini split leaking water.
What it costs
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| Cause | How you’d know | What fixing it costs |
|---|---|---|
| Dirty filters or a blocked outdoor unit | A5, F codes, weak heat or cooling | Nothing if you clean them |
| Communication wiring or power | U4, U2, the light blinks after storms | Priced in writing before any work starts |
| A sensor | C, H, J or P codes | Priced in writing before any work starts |
| Refrigerant leak | U0, ice on the lines, weak output | Priced in writing before any work starts |
| A fan motor | A6 or E7 | Priced in writing before any work starts |
| A board or the compressor | A1, E1, E5, E6, L codes | Priced in writing before any work starts |
The tech starts with the $99 diagnostic, reads the code on Daikin’s service tools, checks voltage, wiring and pressures, and gives you the price in writing. When an older system needs a compressor or a board, a new one-zone ductless system is $7,000 to $10,000. From about $117 a month at 0% APR for 60 months, the whole price financed, on approved credit.
We fix Daikin systems across Northern Virginia, in Ashburn, Leesburg, Sterling, Herndon, Chantilly, Fairfax, Arlington and Manassas, ducted and ductless.
More Daikin: a blinking green light on a Daikin mini split; Daikin One thermostat alerts; the Daikin One Touch thermostat; Daikin mini split troubleshooting. Daikin owns Goodman and Amana, so their furnace codes are in our Goodman furnace codes chart, and other brands are in our error codes and warning lights guide.
Get it fixed
Call (703) 997-9757 and we’ll get a tech out to read your Daikin mini split’s code. We answer day or night. Rather book online? Pick a time here and a box of warm cookies comes with the visit. A repair visit starts with our $99 diagnostic, and you get the price in writing before any work starts. Already have a quote? We’ll give you a free second opinion. Rated 5.0 stars across 1,138 reviews on Google, Angi, Yelp, the BBB and Facebook, Virginia Class A license 2705192276.
Questions people ask
How do I check the error code on my Daikin mini split?
Hold TIMER CANCEL on the remote about 5 seconds until 00 blinks, then press it again and again. When the unit gives a long beep, the code on the remote is the error.
What does U4 mean on a Daikin mini split?
The indoor and outdoor units stopped talking. It’s usually the wiring between them, a power problem or a board. Try the breaker first; if it comes back, call.
What does A5 mean on a Daikin mini split?
Freeze-up protection in cooling or high pressure protection in heating. Dirty filters and poor airflow are the usual cause, so clean them first.
How do I reset a Daikin mini split?
Turn it off at the breaker, wait a minute, turn it back on and restart it from the remote. If the light blinks again, read the code and call.
