What It Means
Malfunction of capacity setting (Indoor unit PCB).
Daikin Packaged Unit
Daikin Packaged Unit Error Code AJ
Troubleshooting guide for the Daikin Packaged Unit system fault AJ.
Possible Causes
- The capacity setting adaptor was not installed when replacing PCB.
- Defective indoor unit PCB.
Not sure which one it is — or if it's none of these? Try ACLogics today.
Disclaimer: This information is for general reference. Error codes can vary by model and production year. Always refer to your machine's specific manual and the information printed on the unit itself.
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Full Diagnosis
Malfunction of capacity setting (Indoor unit PCB)
All Recorded Causes
The capacity setting adaptor was not installed when replacing PCB. Defective indoor unit PCB
Verify Before Replacing Parts
- Confirm the exact Daikin model family and packaged context before acting on a generic code description.
- Start with the exact model documentation and verify the full operating sequence before replacing parts, particularly around the capacity setting adaptor was not installed when replacing PCB.
- Use the listed causes as branches to confirm or eliminate with measurements, not assumptions — defective indoor unit PCB is a reasonable second branch.
- After the correction, run the system long enough to confirm the packaged fault does not return under normal load.
Still unsure about this fault?
ACLogics walks you through Daikin Packaged Unit diagnostics step-by-step — so you confirm the cause before swapping parts.
