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
- Turn off the air conditioner using remote or power switch
- Unplug power plug or turn off dedicated circuit breaker
- Wait about 1–2 minutes
- Restore power and attempt normal operation
Technician Only Inspect and repair thermistor and related components
- Turn off and isolate power to the unit
- Access indoor unit and locate heat exchanger liquid pipe thermistor
- Check thermistor resistance and compare against specifications
- Inspect thermistor connector and wiring for continuity and damage
- Replace faulty thermistor if confirmed defective
- 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)
- If error persists after power reset
- If thermistor or wiring inspection indicates damage requiring specialist tools
- When indoor PCB fault is suspected
Next step
Choose the next step for C4-00
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.
HVAC Control Board
Controls fan, compressor, sensor, and communication functions in the HVAC unit.
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.
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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
| note | The previous model-independent part specification was removed. Verify the full model number and diagnosis in the manufacturer's official parts catalog before ordering. |
|---|---|
| part_number | None |
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
- Daikin C4 Error Code: Ultimate Guide (community)
Data last verified: 2026-07-31
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