What It Means
Malfunction of radiation fin temperature sensor.
Daikin Packaged Unit
Daikin Packaged Unit Error Code P4
Troubleshooting guide for the Daikin Packaged Unit system fault P4.
Possible Causes
- Defective radiation fin temperature thermistor.
- Defective inverter PCB.
- Defective INV.
- compressor.
- Defective fan motor.
Not sure which one it is — or if it's none of these? Try ACLogics today.
Disclaimer: This information is for general reference. Error codes can vary by model and production year. Always refer to your machine's specific manual and the information printed on the unit itself.
New to this code? Click to see why this happens
Full Diagnosis
Malfunction of radiation fin temperature sensor
All Recorded Causes
Defective radiation fin temperature thermistor Defective inverter PCB Defective INV. compressor Defective fan motor
Verify Before Replacing Parts
- Confirm the exact Daikin model family and packaged context before acting on a generic code description.
- Confirm board LEDs, wiring polarity, and model compatibility before replacing control boards — this Daikin fault points at defective radiation fin temperature thermistor.
- Check for intermittent communication faults caused by connectors, moisture, or damaged harnesses, and rule out defective inverter PCB.
- After the correction, run the system long enough to confirm the packaged fault does not return under normal load.
Still unsure about this fault?
ACLogics walks you through Daikin Packaged Unit diagnostics step-by-step — so you confirm the cause before swapping parts.
