Daikin Aircon AJ Error Code
Confirm the listed meaning of Daikin AJ, note the unit that shows the code and its model, and match the service manual before diagnosis. Match the model first; same-looking codes can point to different rows.
What does Daikin AJ mean?
Daikin AJ is listed as malfunction of capacity setting on indoor unit PCB, defective capacity setting, and indoor capacity-setting malfunction in fault lists for more than one model family, including VRV X RXQ-A(N)R cooling only, VRV 5-S RXYSA R32, VRV 5 Heat Recovery REMA / REYA R32, VRV 5 Heat Pump RYMA / RXYA R32, EKVDX / VAM R32 ventilation, Sky Air FNA R32 - indoor error overview, and EKEA / EKEXVA AHU control box. This meaning comes from the manufacturer's own diagnostic material. Do not collapse this code across model families; use the model, series, or system type to choose the right row. Confirm the exact model, series, or signal row before accepting a parts quote.
Choose the listing that matches your unit
The same code has more than one listed meaning. Match the model family, the system type and the unit that shows the code before approving parts.
| Code | What it means | What to check first |
|---|---|---|
| SkyAir | Malfunction of capacity setting on indoor unit PCB | Match this meaning to your installed model and the unit that shows the code, then use the checks below. |
| VRV X RXQ-A(N)R cooling only | Defective capacity setting | Match this meaning to your installed model and the unit that shows the code, then use the checks below. |
| VRV 5-S R32 - AJ / VRV 5 Heat Recovery R32 - AJ / VRV 5 Heat Pump R32 - AJ | Indoor capacity-setting malfunction | Record the displayed code, unit type, and serial number for qualified diagnosis. |
| EKVDX / VAM R32 ventilation - AJ | Indoor-unit PCB capacity-setting malfunction | Match the EKVDX and paired VAM model, then use the project service manual for diagnosis. |
| Sky Air FNA R32 - AJ (indoor error overview) | Indoor PCB capacity-setting abnormality | Confirm the indoor model is FNA25~60A2VEB(9), record the reporting controller, and follow the matching Daikin service procedure. |
| EKEA / EKEXVA AHU control box | Capacity-setting error | Match this meaning to your installed model and the unit that shows the code, then use the checks below. |
- Code
- SkyAir
- What it means
- Malfunction of capacity setting on indoor unit PCB
- What to check first
- Match this meaning to your installed model and the unit that shows the code, then use the checks below.
- Code
- VRV X RXQ-A(N)R cooling only
- What it means
- Defective capacity setting
- What to check first
- Match this meaning to your installed model and the unit that shows the code, then use the checks below.
- Code
- VRV 5-S R32 - AJ / VRV 5 Heat Recovery R32 - AJ / VRV 5 Heat Pump R32 - AJ
- What it means
- Indoor capacity-setting malfunction
- What to check first
- Record the displayed code, unit type, and serial number for qualified diagnosis.
- Code
- EKVDX / VAM R32 ventilation - AJ
- What it means
- Indoor-unit PCB capacity-setting malfunction
- What to check first
- Match the EKVDX and paired VAM model, then use the project service manual for diagnosis.
- Code
- Sky Air FNA R32 - AJ (indoor error overview)
- What it means
- Indoor PCB capacity-setting abnormality
- What to check first
- Confirm the indoor model is FNA25~60A2VEB(9), record the reporting controller, and follow the matching Daikin service procedure.
- Code
- EKEA / EKEXVA AHU control box
- What it means
- Capacity-setting error
- What to check first
- Match this meaning to your installed model and the unit that shows the code, then use the checks below.
What to do now
Use these steps to record evidence and match the installed model to its service manual before diagnosis or a repair quote.
Record AJ and match the service manual
Record AJ and stop there; the manufacturer gives no customer reset procedure. Arrange diagnosis with the matching service manual.
No manufacturer reset steps listed for AJ
Capture the complete AJ error code and model stickers first. The manufacturer lists the meaning but no customer reset procedure; do not treat a generic power-cycle as manufacturer guidance.
Send these to us
AJ error code, a clear display photo, Daikin indoor and outdoor model stickers, the controller, gateway, or unit that reported the code, operating mode and affected area, and any power or setting changes made after the code appeared
Guidance for your model
Notes that match the code to your exact model. Electrical, refrigerant, wiring, resistance and component checks are for a technician.
| Detail | What it says |
|---|---|
| Singapore / model note | Official Daikin SM-TS3 self-diagnosis row. Manual causes: Capacity setting adaptor missing after PCB replacement; Defective indoor unit PCB. |
| Singapore / model note | Official Daikin RXQ6-48A(N)R cooling-only service-manual row. Confirm the installed model and matching regional manual before diagnosis; this source is not claimed as universal across every Daikin VRV generation. |
| Singapore / model note | Official Daikin 4P600330-1F row for the RXYSA4~6A7V/Y1B VRV 5-S R32 family. Confirm the exact model and displayed punctuation before using this interpretation. |
- Detail
- Singapore / model note
- What it says
- Official Daikin SM-TS3 self-diagnosis row. Manual causes: Capacity setting adaptor missing after PCB replacement; Defective indoor unit PCB.
- Detail
- Singapore / model note
- What it says
- Official Daikin RXQ6-48A(N)R cooling-only service-manual row. Confirm the installed model and matching regional manual before diagnosis; this source is not claimed as universal across every Daikin VRV generation.
- Detail
- Singapore / model note
- What it says
- Official Daikin 4P600330-1F row for the RXYSA4~6A7V/Y1B VRV 5-S R32 family. Confirm the exact model and displayed punctuation before using this interpretation.
What to check before repair
The manufacturer's fault table gives the code's meaning, not a repair procedure. Capture evidence first; model-specific tests belong to the matching service manual.
| You can check | Technician should confirm |
|---|---|
| Photograph the complete AJ error code before taking any action. | Confirm AJ exactly and record which controller, gateway, or unit reported it. |
| Capture the Daikin indoor and outdoor model stickers and identify which controller or unit reported it. | Match the indoor and outdoor model stickers, installed family, and reporting equipment to the source scope. |
| The manufacturer provides no customer reset procedure. Preserve the evidence and use the matching service manual for any system action. | Follow the matching service-manual procedure and keep measured test evidence before naming a failed part. |
- You can check
- Photograph the complete AJ error code before taking any action.
- Technician should confirm
- Confirm AJ exactly and record which controller, gateway, or unit reported it.
- You can check
- Capture the Daikin indoor and outdoor model stickers and identify which controller or unit reported it.
- Technician should confirm
- Match the indoor and outdoor model stickers, installed family, and reporting equipment to the source scope.
- You can check
- The manufacturer provides no customer reset procedure. Preserve the evidence and use the matching service manual for any system action.
- Technician should confirm
- Follow the matching service-manual procedure and keep measured test evidence before naming a failed part.
Source-bounded repair decision
Daikin AJ confirms the fault label the manufacturer lists, not a failed part or repair procedure. Match the installed model to its service manual and require measured diagnostic evidence before approving parts, settings, or refrigerant work.
Whether the reporting controller or unit and exact installed model are confirmed.
What the matching service-manual procedure and measured tests show.
Whether the proposed repair names the evidence for the failed part or condition.
Daikin AJ questions
What does the Daikin AJ error mean?
Can I fix a Daikin AJ error myself?
Is it safe to keep running the aircon with an AJ error?
What causes a Daikin AJ error?
Will a Daikin AJ error need a repair or a full replacement?
What should I send a technician about a Daikin AJ error?
Confirm the fault
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Use this quote-check guide only after the matching service manual identifies the diagnostic path.