U4Daikin
Daikin U4 Error Code
Transmission disruption between indoor and outdoor unit
Get instant help with Daikin U4
Stop searching through PDFs. Our AI assistant on WhatsApp is trained on official Daikin documentation and can diagnose this fault code and guide you through the repair in minutes.
5-day free trial — no credit card required.
Other Daikin Error Codes
A1
Indoor unit PCB malfunction
A3
Drain level control system malfunction
A5
High pressure / freeze-up protection activated
A6
Fan motor locked, overloaded, or overcurrent
C4
Liquid pipe thermistor malfunction
C5
Gas pipe thermistor malfunction
C9
Suction air thermistor malfunction
E1
Outdoor unit PCB defect
E3
High pressure switch actuation
E4
Low pressure switch actuation
E5
Inverter compressor motor overheat/lock
E7
Outdoor unit fan motor malfunction