Daikin Air Conditioner Error UJ
⚡ Quick Answer: The Daikin air conditioner UJ error indicates a communication failure between the main unit and the compressor, preventing the unit from cooling effec... ✅ DIY Fixable
What Does Error UJ Mean?
The Daikin air conditioner UJ error indicates a communication failure between the main unit and the compressor, preventing the unit from cooling effectively. This malfunction can arise from issues with optional or auxiliary components, such as the multilevel converter or its thermistor. The system will not resume normal operation without intervention, and unusual display behavior may occur.
Common Symptoms:
- Unit stops operation and displays UJ code
- System does not resume normal run without intervention
Possible Causes
- Communication fault between unit and optional/auxiliary components (e.g., multilevel converter) (medium)
- Faulty multilevel converter component (thermistor or converter itself) or overheating of converter (medium)
How to Fix Error UJ
DIY Fix Basic system reset and check external connections
- Turn off the unit using the remote control or power switch
- Switch off the circuit breaker supplying the air conditioner
- Wait ~1 minute
- Restore power and attempt restart
Technician Only Inspect and service communication and power converter components
- Inspect wiring and connectors between the main control board and optional modules/multilevel converter
- Measure and verify thermistor and converter component functionality
- Check for signs of overheating or physical damage
- Replace defective components as needed
Parts needed: multilevel converter, thermistor sensors, communication wiring/connectors
- If the error persists after basic reset
- If there are signs of overheating, burning smell or unusual noises
Next step
Choose the next step for UJ
Confirm the diagnosis before ordering. An error code can identify the system involved, but it does not prove that a specific part has failed.
Most relevant component to inspect
Thermistor
Measures precise temperature changes and sends resistance feedback to the control board.
- Typical part-only price
- $15 - $35
- DIY difficulty
- Easy
- Estimated time
- 15-30 mins
Where can I find the model number?
Check the rating label around the door, lid, frame, rear panel, or inside the appliance cabinet. Use the complete model number, including suffixes.
Verify the complete model and part number on the retailer's compatibility page before ordering.
Other parts options
Check related components first; use model search as a fallback.
Wiring Harness
Connects controls, sensors, motors, and other electrical components inside the appliance.
Model-compatible Air Conditioner parts
Enter the complete model number to browse compatible replacement parts. This is a model-based parts search, not a diagnosis that a specific component failed.
Affiliate disclosure: As an Amazon Associate I earn from qualifying purchases. We may earn a commission from other qualifying purchases or service requests made through links on this page, at no additional cost to you. Recommendations are based on repair relevance, not commission rate.
Optional routine care
Maintenance supplies
These products support cleaning or routine upkeep. They are separate from the possible repair components above and are not claimed to fix this error code or symptom.
Air Conditioner Fin Cleaner
For routine cleaning of accessible coil fins when permitted by the manufacturer. Disconnect power and follow product and appliance instructions.
Model-Compatible Washable AC Filter
A reusable filter option only where the appliance supports one. Match the full model, dimensions, and filter specification.
Compatibility check required: use the complete appliance model and compare the existing filter, bag, or specification before ordering.
Affiliate disclosure: As an Amazon Associate I earn from qualifying purchases. Recommendations are based on routine-care relevance, not commission rate.
Technical Specifications
| wattage | 2000W |
|---|---|
| component | Compressor Control Board |
| resistance | 3-5 ohms |
| part_number | DAIKIN 4E134A |
| voltage_rating | 230V AC |
Common Questions
What does UJ error mean on daikin air conditioner?
The UJ error indicates a communication failure with the compressor, causing the unit to stop cooling.
Can I fix daikin air conditioner UJ error myself?
Yes, you can try a basic reset by turning off the unit and circuit breaker, then waiting a minute.
How much does it cost to fix UJ error?
Repair costs for the UJ error range from ¥15,000 to ¥60,000, depending on parts and labor.
When should I call a technician for UJ?
Call a technician if the error persists after a reset or if you notice overheating or unusual noises.
Data last verified: 2026-07-25
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