Daikin Air Conditioner Error P4
⚡ Quick Answer: The Daikin air conditioner P4 error code indicates a communication failure between the indoor and outdoor units, primarily due to an abnormality in th... ✅ DIY Fixable
What Does Error P4 Mean?
The Daikin air conditioner P4 error code indicates a communication failure between the indoor and outdoor units, primarily due to an abnormality in the outdoor unit's temperature sensor (radiation/heat sink fin thermistor). This can lead to the outdoor unit stopping operation, error displays on the indoor remote, and possible cooling inefficiencies.
Common Symptoms:
- Outdoor unit stops operation
- Error displayed on indoor remote/display
- Possible cooling inefficiency or shutdown
Possible Causes
- Faulty radiation/heat sink fin thermistor (temperature sensor) (high)
- Loose or defective thermistor connector/wiring (medium)
- Outdoor unit control/PCB abnormality affecting temperature reading (medium)
- Outdoor fan motor or heat dissipation issue (especially during cooling) (medium)
How to Fix Error P4
DIY Fix Basic power cycle
- Turn off the air conditioner using the remote or unit switch
- Disconnect power at plug or breaker
- Wait ~1 minute
- Restore power and restart the unit
Technician Only Inspect and test outdoor thermistor and connections
- Access outdoor unit
- Test the radiation/heat sink fin thermistor resistance and temperature response
- Inspect and secure thermistor connectors and wiring harness
- Replace thermistor if faulty
Parts needed: thermistor (radiation/heat sink fin), connector harness
Technician Only Evaluate outdoor control board and fan operation
- Diagnose outdoor inverter/control PCB for faults
- Test outdoor fan motor and verify proper heat dissipation
- Repair or replace defective components
Parts needed: outdoor control/PCB, fan motor
- If error persists after basic power cycle
- If outdoor unit fan isn’t running or odd noises are present
- If thermistor readings are out of specification
Next step
Choose the next step for P4
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.
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 | N/A |
|---|---|
| component | Communication Cable |
| resistance | N/A |
| part_number | DAIKIN 4P-1.5MM |
| voltage_rating | 230V AC |
Common Questions
What does P4 error mean on daikin air conditioner?
The P4 error indicates a communication failure, often due to a faulty outdoor temperature sensor.
Can I fix daikin air conditioner P4 error myself?
You can try a basic power cycle by turning off the unit and disconnecting power for about a minute.
How much does it cost to fix P4 error?
Repair costs range from ¥5,000 to ¥20,000 for parts, plus additional labor charges.
When should I call a technician for P4?
Call a technician if the error persists after a power cycle or if you hear odd noises from the outdoor unit.
Sources & References
- Daikin NZ P4 fault definition (official)
- Daikin AC P4 error details (Japanese) (community)
- Daikin error code P4 explanation (airconland.jp) (community)
Data last verified: 2026-07-25
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