Daikin Air Conditioner Error C4-00

⚡ Quick Answer: The Daikin Air Conditioner C4-00 error signifies a communication failure between the indoor and outdoor units, often due to a malfunctioning heat exch... ✅ DIY Fixable

What Does Error C4-00 Mean?

The Daikin Air Conditioner C4-00 error signifies a communication failure between the indoor and outdoor units, often due to a malfunctioning heat exchanger liquid pipe thermistor. This issue can lead to the indoor unit stopping operation, displaying the C4 error code, and shutting down to prevent incorrect temperature readings. Regular inspection of the thermistor and its connections is crucial for effective troubleshooting.

Common Symptoms:

  • Indoor unit stops operation
  • Error code C4 (or C4-00) displayed on remote or unit panel
  • System shuts down to protect from incorrect temperature sensing

Possible Causes

  • Indoor heat exchanger liquid pipe thermistor malfunction (high)
  • Thermistor connection or wiring fault (medium)
  • Indoor unit PCB receiving thermistor signal defective (medium)

How to Fix Error C4-00

DIY Fix Basic power reset and symptom check

  1. Turn off the air conditioner using remote or power switch
  2. Unplug power plug or turn off dedicated circuit breaker
  3. Wait about 1–2 minutes
  4. Restore power and attempt normal operation

Technician Only Inspect and repair thermistor and related components

  1. Turn off and isolate power to the unit
  2. Access indoor unit and locate heat exchanger liquid pipe thermistor
  3. Check thermistor resistance and compare against specifications
  4. Inspect thermistor connector and wiring for continuity and damage
  5. Replace faulty thermistor if confirmed defective
  6. Check indoor PCB thermistor signal processing and repair/replace if defective

Parts needed: Heat exchanger liquid pipe thermistor, Thermistor connector/wiring, Indoor unit PCB (if needed)

🛑 When to Call a Pro:
  • If error persists after power reset
  • If thermistor or wiring inspection indicates damage requiring specialist tools
  • When indoor PCB fault is suspected

Technical Specifications

wattage N/A
component Communication Control Board
resistance N/A
part_number DAIKIN PCB-12345
voltage_rating 220V AC

Common Questions

What does C4-00 error mean on Daikin Air Conditioner?

C4-00 indicates a communication failure between indoor and outdoor units, often caused by a thermistor malfunction.

Can I fix Daikin Air Conditioner C4-00 error myself?

Yes, try a basic power reset by turning off the AC and unplugging it for 1-2 minutes.

How much does it cost to fix C4-00 error?

Repair costs range from $100 to $300+, depending on parts and labor needed.

When should I call a technician for C4-00?

Call a technician if the error persists after a reset or if you suspect thermistor or PCB damage.

Sources & References

Data last verified: 2026-07-01

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