Daikin Mini-Split Error Codes and How to Make the Unit Show One

Which Daikin systems this page covers

Coverage is per service manual, and each manual names its applied models on its own contents page. There is no such thing as "the Daikin code list" — codes and their meanings are defined per family.

Not covered by this page: every other Daikin system. That includes the FTXS-L and FDXS-L series, the FTXB and FTKB series, the Aurora and Cirra lines, the FTXM / RXM series, VRV equipment, Daikin Fit and any ducted or light-commercial unit. Those have their own service manuals with their own applied-model lists, and while some codes carry the same letters, the applicable families, decision conditions and even the retrieval procedure can differ. Read your own manual for anything not in the table above.

Getting the code out of the unit

Both manuals document the same two approaches, with only the button names differing by remote generation — the ARC452 series labels the key TIMER CANCEL, the ARC466 series labels it Timer Cancel. The important part is that the unit confirms a match with a sound rather than by displaying the code directly, so you are listening as much as looking.

FTX-N series codes (SiUS041638EA)

The table below is transcribed from "Error Codes and Description" on page 59 of SiUS041638EA, which is the complete published list for this family — twenty-nine entries including the normal state. Codes marked system-down are ones Daikin flags as displayed only when the system has actually shut down, rather than while it keeps running in a protected mode.

U4 and U7 are different faults and are easy to confuse. U4 is the indoor unit reporting that it cannot get good data from the outdoor unit; U7 is a communication failure between two microcontrollers on the outdoor board itself.

Multi-split codes (SiUS121736EA)

Transcribed from "Code Indication on Remote Controller", pages 149–150 of SiUS121736EA. This manual splits its indoor codes by indoor-unit type, which is why the same system can have two different code lists depending on which head reported the fault.

A5 is worth reading twice on a multi-split: in the RA indoor list it is freeze-up protection or heating peak-cut, and in the outdoor list it is anti-icing control for an indoor unit. UH, anti-icing control in other rooms, has no equivalent on a single-zone system at all — it exists because one outdoor unit is serving several heads.

What the code does not tell you

Both manuals follow every code with a troubleshooting chart, and those charts are written for a technician. They open the electrical compartment, check LED A on the outdoor PCB, measure between numbered terminals on the indoor terminal board, rotate the outdoor fan by hand, inspect the power supply waveform, and end at "replace the indoor unit PCB" or "replace the outdoor unit PCB". Every one of them carries the same caution: turn off the power switch before connecting or disconnecting connectors.

GridComfort publishes the code meanings and the retrieval procedure because those are the parts an owner can act on — knowing whether the unit is reporting a thermistor, a communication fault or a compressor problem changes what you tell the service company, and it changes whether the call is urgent. The diagnostic steps themselves stay with the technician, and refrigerant-circuit codes such as U0 (refrigerant shortage) are not a homeowner job under any circumstances: EPA Section 608 certification is required to service an appliance containing a regulated refrigerant.

When to call

Related pages

The most-searched code in the tables above has its own page: Daikin U4. The brand index is mini-split error codes, and the section overview is mini-split diagnostics.