When a Daikin system stops on a fault, it rarely shows the code on its own. A ductless unit just blinks its operation lamp until you ask the remote for the code, a Sky Air or VRV system puts a message on its wired remote, and a Daikin Fit or a system with the Daikin One+ thermostat shows a number on the thermostat. This guide lists the Daikin error codes for each of those systems, what each one means, which displays aren’t faults at all, how to reset the unit and what repairs usually cost.
The meanings come from Daikin’s own documents: the US operation manuals for Daikin wall-mounted units, Daikin’s global malfunction code list, the Daikin Fit installation and service manual and Daikin’s One+ fault code tables. Daikin uses several code systems, and the same characters can mean different things in each one, so start by working out which system you have.
Table of Contents
First, which kind of Daikin system do you have?
| Your system | What the codes look like | Where you see them |
|---|---|---|
| Ductless mini split (wall, floor or ceiling units, single or multi-zone) | A letter and a digit or letter, such as U4, A5 or E7 | On the wireless remote, using the check method below |
| Sky Air, VRV and ducted units with a wired remote | The same letter codes, sometimes with a two-digit sub-code, such as AH09 | On the wired remote’s screen |
| Daikin Fit (DX17VSS / DZ17VSA) | E plus two digits on the outdoor board, such as E13, and the same number on the thermostat | Outdoor control board and the thermostat |
| Ducted systems with the Daikin One+ thermostat | Two-character codes, such as 13, 41 or b0, with a short message | On the One+ screen |
Daikin’s ducted fault numbers can look like ductless codes but mean something else. On a One+ system, furnace code E3 is an open high-limit switch, while ductless E3 is high-pressure protection. Always identify the equipment first.
How to read the code on a ductless remote
On Daikin’s current US wireless remotes, the check works like this:
- Point the remote at the indoor unit and hold the TIMER CANCEL button (or ON TIMER CANCEL / OFF TIMER CANCEL) for about 5 seconds. “00” flashes in the temperature display.
- Press TIMER CANCEL again and again. The code on the display changes with each press.
- When the indoor unit gives a long, continuous beep, the code on the display is the stored fault. A short beep followed by two beeps means “not this one”.
- Hold TIMER CANCEL for 5 seconds to exit. The display also clears itself after a minute with no button press.
Some older Daikin remotes use a different button sequence, so check your remote’s manual if TIMER CANCEL does nothing.
On a wired remote
Daikin’s Navigation Remote Controller separates errors from warnings. If the green operation lamp flashes and the screen says “Error: Push Menu button”, the unit has stopped: press Menu to see the code and the service contact. If the lamp stays lit and the screen says “Warning: Push Menu button”, the unit keeps running and the code is a heads-up, such as AH09 when the auto-cleaning filter couldn’t finish.
Displays that aren’t faults
- 00 in the remote check means no fault is stored.
- A delay of about 3 minutes before the unit restarts after it stops, after a mode change or after a power cut is normal protection.
- No heat for several minutes in winter usually means defrost. Daikin’s US manual says it takes about 4 to 12 minutes, and the outdoor unit may give off water or steam while it runs.
- A slow start in heat mode of 1 to 4 minutes is the warm-up, which stops the unit blowing cold air.
- The outdoor fan running for about a minute after the unit stops is normal.
- E11 on a new Daikin Fit means the start-up test hasn’t been run yet. It isn’t a failure.
Daikin ductless system codes (U)
U codes cover the whole system rather than one unit.
| Code | What it means |
|---|---|
| U0 | Refrigerant shortage, usually from a leak; a blockage or a faulty sensor can also cause it |
| U2 | Supply voltage out of range or a brief power failure |
| U4 | Indoor and outdoor units not communicating (see our Daikin U4 guide) |
| U5 | Wired remote and indoor unit not communicating |
| U7 | Communication error inside the outdoor unit, between its control board and inverter board |
| UA | Installation error, such as indoor and outdoor units that don’t match |
| UF | Piping and wiring mismatch on a multi-zone system, wrong wiring or low refrigerant |
| UH | Freeze protection running in another room’s indoor unit (multi-zone) |
On large VRV systems, U7, UF and UH have different meanings: U7 points to communication between outdoor units, UF means the system hasn’t been set up, and UH is a system or wiring fault. The meanings in the table are the ones in Daikin’s US manuals for home units.
Daikin indoor unit codes (A and C)
| Code | What it means |
|---|---|
| A1 | Indoor control board fault |
| A3 | Drain pump or drain level problem (units with a pump, such as cassettes and ducted units) |
| A5 | Indoor coil too cold in cooling (freeze protection) or too hot in heating. A clogged filter is a common cause |
| A6 | Indoor fan motor fault |
| AH | Air cleaner or auto-cleaning filter fault |
| C4 | Indoor coil temperature sensor open or shorted |
| C5 | Second indoor coil temperature sensor open or shorted |
| C7 | Louver or front-panel motor fault |
| C9 | Room temperature sensor open or shorted |
| CC | Humidity sensor fault (models with one) |
Daikin outdoor unit codes (E, F, H, J, L and P)
| Code | What it means |
|---|---|
| E1 | Outdoor control board fault |
| E3 | High-pressure protection tripped |
| E4 | Low-pressure protection tripped |
| E5 | Compressor locked or overloaded |
| E6 | Compressor failed to start |
| E7 | Outdoor fan motor locked or failed; ice or debris can jam it |
| E8 | Input overcurrent |
| E9 | Electronic expansion valve fault |
| EA | Four-way (reversing) valve or heating/cooling switching fault |
| F3 | Discharge pipe too hot, often linked to low refrigerant |
| F6 | Outdoor coil overheating, high pressure or too much refrigerant |
| H0 | Compressor sensor system fault |
| H3 | High-pressure switch fault |
| H6 | Compressor position sensing fault (start failure) |
| H7 | Outdoor fan motor overload or signal fault |
| H8 | Current sensor fault |
| H9 | Outdoor air temperature sensor open or shorted |
| J1 | Pressure sensor fault |
| J3 | Discharge pipe sensor open, shorted or out of place |
| J5 | Suction pipe sensor open or shorted |
| J6 | Outdoor coil sensor open or shorted |
| L1 | Outdoor inverter board fault |
| L3 | Outdoor electrical box overheating |
| L4 | Inverter heat sink overheating |
| L5 | Inverter or compressor overcurrent |
| L8 | Inverter compressor overcurrent |
| L9 | Compressor start-up protection (stall prevention) |
| LC | Communication error between the outdoor control board and inverter board |
| P1 | Open phase or voltage imbalance |
| P4 | Heat sink temperature sensor open or shorted |
| PJ | Capacity setting error, often after a board replacement |
Daikin Fit error codes
The Daikin Fit (DX17VSS air conditioner and DZ17VSA heat pump) shows serious faults twice: as an E-code on the outdoor control board and as the same number on the thermostat. Minor faults appear on the thermostat only, and Daikin says continued operation is acceptable while they’re active.
| Thermostat | Outdoor board | What it means |
|---|---|---|
| 12 | E12 | Memory error on the control board |
| 13 | E13 | Frequent high-pressure faults (critical) |
| 14 | none | Frequent high-pressure faults (minor) |
| 15 | E15 | Frequent low-pressure faults (critical) |
| 16 | none | Frequent low-pressure faults (minor) |
| 17 | E17 | Frequent compressor faults |
| 18 | E18 | Outdoor fan motor connection or control board fault |
| 19 | E19 | Outdoor control board or fan motor fault |
| 20 | E20 | Outdoor expansion valve coil not connected |
| 21 | E21 | Frequent low discharge superheat faults |
| 22 | E22 | Frequent high discharge temperature faults |
| 23 | E23 | Discharge temperature sensor out of range |
| 24 | E24 | High-pressure switch open |
| 25 | E25 | Outdoor air temperature sensor open or shorted |
| 26 | E26 | Pressure sensor not responding properly |
| 27 | E27 | Outdoor coil defrost sensor out of range |
| 28 | E28 | Outdoor coil temperature sensor out of range |
| 29 | E29 | Liquid temperature sensor out of range |
| 30 | E30 | Wiring to the control board disconnected, or a board fault |
| 32 | E32 | High temperature on the outdoor control board (critical) |
| 33 | none | High temperature on the outdoor control board (minor) |
Daikin One+ thermostat codes
Ducted Daikin systems that talk to the One+ thermostat use ClimateTalk codes. Each one comes with a short consumer message on the screen. These are the main codes for the outdoor air conditioner or heat pump:
| Code | Message on screen | What it means |
|---|---|---|
| 13 | Pressure error | Frequent high-pressure faults |
| 15 | Pressure error | Frequent low-pressure faults |
| 17 | System error | Frequent compressor faults |
| 18 | System error | Outdoor control board error |
| 19 | System error | Outdoor board or fan failure |
| 22 | Sensor error | High discharge temperature |
| 24 | Pressure error | High-pressure switch open |
| 31 | Safety error | High current leak |
| 41 | System error | Low refrigerant |
| 51 | Communication error | Outdoor board has detected communication problems |
| 60 | System error | Heat pump recovering from a sudden loss of power |
The same number can mean something different on the thermostat itself, the air handler or the furnace. For example, 22 is a high discharge temperature on the heat pump but “furnace communication loss” when it comes from the thermostat. Read the message and the equipment name on the One+ screen, not just the number.
How to reset a Daikin
Daikin’s US operation manual says that when the operation lamp flashes and the unit stops, you should clean the air filters, clear anything blocking the air inlets and outlets, switch the unit’s breaker off and back on, and try again. Daikin’s global troubleshooting page adds a waiting time: switch the breaker off and wait about 20 minutes before turning it back on.
If the lamp flashes again after a reset, Daikin treats it as a malfunction. Repeated resets won’t fix it, so write down the code and call a technician. Switch the unit off at the breaker and call for service straight away if you notice a burning smell, a hot or damaged power cord, unusual noises, water leaking from the indoor unit or a breaker that keeps tripping.
What you can safely check yourself
- Clean the filters. A clogged filter is one of the causes Daikin lists for A5, and it’s the easiest fix.
- Clear the outdoor unit. Remove leaves, snow and ice from around it. For E7, check with the power off that nothing is blocking the fan blades.
- Look for a storm or power cut. U2 can follow a brief power failure. If it clears after a reset and doesn’t come back, the unit is fine.
- Note the code and the model number before you reset anything, so the technician knows where to start.
Leave refrigerant codes such as U0, F3 and E3, compressor and inverter codes (E5, E6, L5) and anything inside the panels to a licensed technician. Daikin’s manual tells owners not to repair or modify the unit themselves. If your system cycles on and off without a code, see our guide to heat pump short cycling. If it’s running but blowing cold air, see why a heat pump blows cold air in heat mode.
What Daikin repairs usually cost
| Repair | Codes that can lead to it | Typical cost |
|---|---|---|
| Diagnostic visit | Any | $75–$250 |
| Control or inverter board | A1, E1, L1, PJ, U7, LC | $150–$700 |
| Fan motor (indoor or outdoor) | A6, E7, H7 | $200–$700 |
| Refrigerant leak repair and recharge | U0, F3, sometimes E3 or E4 | $300–$1,200 |
| Reversing valve | EA | $200–$650 |
| Compressor | E5, E6, H6, L5 (once other causes are ruled out) | $650–$2,400 or more |
Ranges come from Angi’s heat pump repair data (October 2026), and the diagnostic visit from Fixr (January 2026). Which codes lead to which repair is our grouping, based on the causes Daikin lists for each code. Sensor replacements aren’t priced by the main cost guides. The part is usually inexpensive, so most of the bill is the service call. Under warranty you mostly pay for labor, because Daikin’s parts warranty doesn’t cover it.
Is it covered by the warranty?
| Daikin product | Not registered | Registered within 60 days |
|---|---|---|
| Main ductless lines (FTXS, FTX, FTXM, Emura, multi-zone MX and others) | 5 years parts | 12 years parts |
| Value ductless (FTXC / RXC and similar) | 5 years parts | 10 years parts |
| Ducted DX/DZ SE models | 5 years parts | 12 years parts, plus a one-time unit replacement if the compressor fails within 6 years (with conditions) |
The warranties cover parts only. Labor, freight and other costs aren’t included, and units bought online without a licensed installer have no warranty. In California, Florida, Georgia and Quebec, the law says coverage can’t depend on registration. The compressor replacement on the DX/DZ SE models also requires yearly maintenance by a licensed contractor, with written records, and a matched indoor coil or air handler. Terms vary by model and year, so check the certificate for your unit on Daikin’s website.
Frequently asked questions
Why is the light on my Daikin flashing?
A flashing operation lamp on a Daikin ductless unit means it has stopped on a fault. Hold TIMER CANCEL on the remote for 5 seconds and step through the codes until the unit gives a long beep. That code is the fault.
What does U4 mean on a Daikin?
U4 means the indoor and outdoor units have stopped communicating. Wiring, power to the outdoor unit and the control boards are the usual causes. Our Daikin U4 guide covers it in detail.
What does A5 mean on a Daikin?
A5 is freeze protection in cooling or overheating protection in heating. Daikin lists a clogged air filter as a common cause, so clean the filters first.
What does 00 mean on a Daikin remote?
00 is the starting point of the code check and means “normal”. Keep pressing TIMER CANCEL to step through the other codes.
How do I reset a Daikin mini split?
Switch off its breaker, wait about 20 minutes as Daikin’s troubleshooting page suggests, then switch it back on. If the lamp flashes again, the fault is still there and needs a technician.
Sources
- Daikin, Operating Manual, wireless remote BRC52B for FTK(X)B wall-mounted units (OM-BRC52B)
- Daikin, Operation Manual, FTXS30HVJU / FTXS36HVJU
- Daikin Global, Error Codes, After Sales Service (malfunction code list and how to check error codes)
- Daikin, Service Manual, Navigation Remote Controller BRC1E73 (SiUS721424EB)
- Daikin, Installation Instructions and Service Reference, outdoor unit DX17VSS / DZ17VSA (Daikin Fit), part no. 3P515859-5S
- Daikin One+, unitary error codes
- Daikin Global, Troubleshooting (FAQ), split and multi-split
- Daikin, Limited Warranty PWDDMSTWZS, ductless (July 2026)
- Daikin, Limited Warranty PWDDSSTJ, value ductless (October 2026)
- Daikin, Limited Warranty PWDACHPTWSL, DX/DZ SE (October 2026)
- Daikin, Warranty Information (updated January 2026)
- Angi, Heat Pump Repair Cost (October 2026)
- Fixr, Heat Pump Repair Cost (January 2026)