ErrorCodeDoctor
Daikin Air Conditioner UJ error code
The UJ error means your Daikin air conditioner detected a transmission fault with an accessory device connected to the system. This can be caused by a defect in the accessory device itself or faulty wiring to it. Contact a qualified technician to inspect the accessory device and its wiring.
Common causes
- Defect of an accessory device connected to the system
- Faulty wiring to the accessory device
How to fix it
-
1
Contact a qualified technician to inspect the accessory device and its wiring connections
Related Daikin Air Conditioner error codes
A0
An external protection device connected to the indoor unit has been activated
A1
A fault was detected in the indoor unit PCB (control board)
A3
The drain level control system has detected an abnormality — drain may be clogged
A5
Freeze-up protection (cooling) or high pressure control (heating) has activated — check the air filter
UJ error — frequently asked questions
What does the UJ error mean on a Daikin air conditioner?
A communication fault was detected with an accessory device
What causes the UJ error?
The UJ error is usually caused by: Defect of an accessory device connected to the system; Faulty wiring to the accessory device.
Can I fix the UJ error myself?
This is rated a hard fix — it often requires tools, parts, or experience, and may be safer left to a professional technician.
How much does it cost to fix the UJ error?
Fixing the UJ error on a Daikin air conditioner typically costs $80–$300, depending on parts and whether you do it yourself or hire a technician.
Is it safe to keep using my air conditioner with the UJ error?
We'd recommend addressing the UJ error before continuing to use the air conditioner, since hard-rated issues often involve a real fault rather than a minor glitch.