Daikin R71FUV1 Service Manual page 340

Troubleshooting by Remote Controller
Remote Controller Display
P4
Applicable Models
CMSQ
Method of Error Detection
Resistance of radiation fin thermistor is detected when
the compressor is not operating.
Error Decision Conditions
When the resistance value of thermistor becomes a value
equivalent to open or short circuited status.
∗ Error is not decided while the unit operation is
continued.
"P4" will be displayed by pressing the inspection
button.
Supposed Causes
Defective radiation fin temperature thermistor
Defective inverter PCB
Si20-701_B
333