Daikin mini_split Error Code C4

What does C4 mean?

Outdoor coil temperature sensor reading out of range or has failed.

Common causes

• Failed outdoor coil thermistor
• Loose thermistor connector
• Liquid or moisture damage to sensor
• Thermistor lead wire damaged

Diagnostic & testing steps

1. 1. Check thermistor resistance at 77°F: should be ~10K ohms
2. 2. Resistance decreases as temperature increases
3. 3. Inspect thermistor connector for corrosion
4. 4. Compare thermistor reading to actual coil temperature
5. 5. Replace thermistor if reading is erratic or open/shorted

Tools required

• Multimeter
• Thermometer

OEM parts & part numbers

Outdoor Coil Thermistor

Part numbers: 2503193