Daikin Mini-Split Code C5
Warning
Indoor heat exchanger thermistor 2 or related abnormality. The second indoor coil sensor is reading open or shorted (voltage at or above 4.96 V, or at or below 0.04 V, during compressor operation).
Manual wording: “C5 Indoor heat exchanger thermistor 2 or related abnormality”
Documented for: Indoor units with a second coil thermistor on RMXS multi-split systems
Likely causes, most common first
- Disconnection of connector
- Thermistor corresponding to the error code is defective
- Defective indoor unit PCB
What you can safely check yourself
- Turn the system off at the breaker or disconnect switch and back on once
When to call a technician
Same as C4 - a technician needs to check the sensor connector and resistance inside the indoor unit.
A Daikin mini-split throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Source
- Service Manual - Multi-Split Type Air Conditioners RMXS-L Series (SiUS181631EA) (Daikin, RMXS48LVJU outdoor, BPMKS048A2U/049A3U branch provider, CTXG/CTXS/FTXS/CDXS/FDXS/FVXS/FFQ indoor units) · checked 2026-08-25