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

  1. Turn off the unit using the remote control or power switch
  2. Switch off the circuit breaker supplying the air conditioner
  3. Wait ~1 minute
  4. Restore power and attempt restart

Technician Only Inspect and service communication and power converter components

  1. Inspect wiring and connectors between the main control board and optional modules/multilevel converter
  2. Measure and verify thermistor and converter component functionality
  3. Check for signs of overheating or physical damage
  4. Replace defective components as needed

Parts needed: multilevel converter, thermistor sensors, communication wiring/connectors

🛑 When to Call a Pro:
  • If the error persists after basic reset
  • If there are signs of overheating, burning smell or unusual noises

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: 2026-07-01

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