Fujitsu Error Code Custom code A/B/C/D: Wireless remote custom code display (Heat Pump)

Updated October 16, 2026 · by Aurora Star Tech Inc.

Fujitsu error code Custom code A/B/C/D on a heat pump means: Wireless remote custom code display. It is also called Fujitsu diagnostic code Custom code A/B/C/D.

Low severityHeat PumpFujitsu wall-mounted 7-15 (NA ASU/AOU type) · Fujitsu slim duct ARU 7-18 (LL type)

Homeowner? What Fujitsu code Custom code A/B/C/D means for you

Usually minor Your heat pump is reporting: Wireless remote custom code display. This code is usually informational or minor. The safe checks below often clear it; call us if it keeps showing up.

Safe things you can check yourself

Check the thermostat: right mode (Heat or Cool), set a few degrees past room temperature, and fresh batteries if it uses them.
Check both breakers and the outdoor disconnect box beside the outdoor unit; all should be ON.
Look at the air filter. If it is grey and clogged, replace it; a blocked filter causes many shutdowns.
In winter, keep snow and ice off and away from the outdoor unit. A short defrost cycle with steam is normal.
Try one reset: turn the power off for 30 seconds, then back on. If the code comes back, stop resetting and call a technician.

Call (647) 657-2977 Book a service call

Licensed technicians serving Vaughan, Toronto and the GTA.

What does Fujitsu error code Custom code A/B/C/D mean?

The wireless remote can be set to one of four custom codes, A to D, and the indoor unit only answers to the same code. The remote shows the current code when you hold MODE for 5 seconds or more. Shipping default is A, and the remote returns to A when its batteries are replaced.

Applies to: Fujitsu ductless heat pumps: Fujitsu wall-mounted 7-15 (NA ASU/AOU type); Fujitsu ductless heat pumps: Fujitsu slim duct ARU 7-18 (LL type)

Safety: Gas, electrical and refrigerant work must be done by a licensed technician. Turn off power and gas before servicing, never bypass a safety control, and always follow the manufacturer's manual for your exact model.

Other Fujitsu Heat Pump codes

Code	Meaning
98	Outdoor fan motor 2 error
99	4-way valve error
A1	High discharge temperature
A3	High compressor temperature
A4	High pressure error
A5	Low pressure error
Error memory recall	Show the stored error on the indoor lamps
J1	VRF branch box error
J2	Branch box error (flexible multi)
MANUAL AUTO 10 s	Start test run / forced cooling from the indoor unit
OPERATION + TIMER lamps flash together	Test run / forced cooling running
Outdoor LED1 1 flash	Serial comms error, outdoor to indoor unit A (outdoor board LED)

All Fujitsu Heat Pump error codes →

Fujitsu code Custom code A/B/C/D: homeowner questions

What does Fujitsu code Custom code A/B/C/D mean?

Wireless remote custom code display. The wireless remote can be set to one of four custom codes, A to D, and the indoor unit only answers to the same code. The remote shows the current code when you hold MODE for 5 seconds or more. Shipping default is A, and the remote…

Is it safe to keep using my heat pump with code Custom code A/B/C/D?

Usually yes. Code Custom code A/B/C/D is normally minor, but if it keeps coming back have it checked.

Can I reset Fujitsu code Custom code A/B/C/D myself?

You can try one reset (power off for 30 seconds, then on). If Fujitsu code Custom code A/B/C/D comes back, the cause is still there and a licensed technician should check it.

Who can fix Fujitsu code Custom code A/B/C/D near me?

Aurora Star Tech Inc. repairs Fujitsu heat pumps in Vaughan, Toronto and across the GTA. Call (647) 657-2977 or book a service call online.

Homeowner help: AC Running But Not Cooling: What to Check · Heat Pump Not Heating or Blowing Cold Air

Troubleshooting guides

2 flashes: HPS open ≥6 s; 3: discharge >263°F; 4: discharge <90°F after 1 h; 5: defrost failure; 6: discharge sensor short; 7: outdoor sensor open/short; 9: bonnet sensor fail All brands · Heat Pump
Excess ice on outdoor coil All brands · Heat Pump
Extremely high head pressure in heating (dual fuel) All brands · Heat Pump
Insufficient heat in cold weather All brands · Heat Pump
Liquid slugging / compressor damage in heating All brands · Heat Pump
No mode change / wrong mode All brands · Heat Pump
Odour at registers (dirty sock) All brands · Heat Pump
Poor heating but OK cooling (or vice-versa) All brands · Heat Pump
Service problem analysis (Amana chart excerpt) All brands · Heat Pump
Subcooling too high All brands · Heat Pump
Subcooling too low vs mfr target All brands · Heat Pump
TXV bulb/diaphragm failure All brands · Heat Pump
Water-source: coil freezing All brands · Heat Pump
Won't change mode / both coils same temperature All brands · Heat Pump
Wrong superheat after line-set change; poor capacity All brands · Heat Pump
Change the wireless remote custom code (A/B/C/D) Fujitsu · Heat Pump
Enter the indoor function setting mode (wireless remote) Fujitsu · Heat Pump
Recall the stored error on the indoor lamps Fujitsu · Heat Pump
Start a forced cooling test run from the indoor unit Fujitsu · Heat Pump
Start a test run from the wired remote Fujitsu · Heat Pump

Source: Fujitsu Wall-mounted 7-9-12-15 (North American trilingual, UTY-RNNUM remotes; e.g. ASU9-12-15 RLF1-RLS familie.pdf - section 11 Function setting, step 1 and remote controller custom code setting; Fujitsu Slim duct AR07-09-12-14-18 (ARU-ARYG LL-type equivalent) installation P-N 9381858064.pdf - section 13 Customer guidance. Written in our own words as a summary; always check the original manual.

General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.