Daikin Air Conditioner Error C9-00
⚡ Quick Answer: The Daikin Air Conditioner C9-00 error indicates a communication failure with the compressor, typically caused by an abnormality in the indoor unit's ... ✅ DIY Fixable
What Does Error C9-00 Mean?
The Daikin Air Conditioner C9-00 error indicates a communication failure with the compressor, typically caused by an abnormality in the indoor unit's suction air temperature thermistor (sensor). This malfunction leads to the unit stopping operation and may prevent the indoor fan or cooling from functioning, resulting in an error message on the remote or control panel.
Common Symptoms:
- Unit stops operation when code appears
- Indoor fan or cooling operation may stop
- Error displayed via remote or control panel
Possible Causes
- Faulty suction air temperature thermistor (sensor) (high)
- Thermistor wiring or connector issues (medium)
- Indoor unit PCB processing/signal fault (medium)
How to Fix Error C9-00
DIY Fix Basic checks and power reset
- Stop unit operation
- Turn off AC and disconnect power (unplug or breaker)
- Wait ~1 minute
- Restore power and attempt restart
Technician Only Inspection and repair of thermistor circuit
- Inspect the suction air thermistor for proper function using diagnostic tools
- Check wiring harness, connectors for continuity and secure attachment
- Test/replace the thermistor if defective
- Inspect indoor unit PCB for signal processing faults and repair/replace as needed
Parts needed: Suction air thermistor (indoor air temperature sensor), Connecting wires and connectors, Indoor unit PCB (if required)
- After basic power reset and error persists
- If you are uncomfortable performing electrical or internal checks
Technical Specifications
| wattage | 3000W |
|---|---|
| component | Compressor Control Board |
| resistance | 3-5 ohms |
| part_number | DAIKIN 4E0B0A |
| voltage_rating | 220V AC |
Common Questions
What does C9-00 error mean on Daikin Air Conditioner?
C9-00 indicates a communication failure with the compressor due to a thermistor fault.
Can I fix Daikin Air Conditioner C9-00 error myself?
Yes, perform a basic power reset by turning off the AC and disconnecting power for a minute.
How much does it cost to fix C9-00 error?
Repair costs range from $100 to $400+, depending on parts and labor.
When should I call a technician for C9-00?
Call a technician if the error persists after a power reset or if you're uncomfortable with electrical checks.
Sources & References
Data last verified: 2026-07-01
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