U5
Daikin
Remote Controller Communication Error
Daikin system with wired remote controller shows U5; indoor unit may not respond to remote commands
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Open or short in remote controller wiring, Incorrect wiring between remote and indoor unit terminals, Faulty wired remote controller, Faulty indoor unit main PCB remote interface
How to Fix / Troubleshooting
Safety first: Turn off power to the indoor unit before removing the remote controller or indoor front panel.
Checks:
- If you have a wired controller, remove its front cover and ensure the communication cable is firmly connected and not corroded.
- Trace the cable from the controller to the indoor unit; look for damage or splices that may have failed.
- If the system also has an IR remote, try operating with the IR remote to confirm that the indoor unit itself can run.
Technician steps:
- Measure continuity of the remote controller cable; replace if open or shorted.
- Verify correct terminal connections at the indoor PCB (per Daikin wiring diagram).
- Substitute a known-good wired controller to rule out a defective controller.
- If wiring and controller are good, replace or repair the indoor main PCB.
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Repair Difficulty
Medium
3/5
Required Part
Wired Remote Controller
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