Daikin VRV IV RXTQ-TA / RXTQ-TB error code CC
Humidity sensor system abnormality, warning
Which models this applies to. Indoor unit
Quick answer
On Daikin VRV IV RXTQ-TA / RXTQ-TB, CC is a fault. It means humidity sensor system abnormality, warning. A first thing to check: A failed humidity sensor.
- Applies to
- Daikin VRV IV RXTQ-TA / RXTQ-TB
- Daikin VRV IV RXTQ heat pump codes · Heat Pump
- Type of code
- Fault
- Urgency: Worth keeping an eye on
- First safe check
- Compare the humidity the unit reports against a separate hygrometer in the same room, since a drifting sensor and a failed sensor look similar from the controller.
What CC means on this model
The humidity sensing circuit has reported a fault. The operation lamp stays lit and the system keeps running, so the practical effect is that the unit still controls temperature but has lost control of humidity. Daikin still asks for it to be checked and repaired.
Symptoms you will notice
- Indoor unit shows CC with the operation lamp lit
- The unit heats and cools normally
- Humidity control is poor or the unit runs continuously
- Short cycling in humid weather
Common causes
The code tells you what the control detected, not which part failed. These are the causes we see most often, roughly in order of likelihood:
- A failed humidity sensor
- A wiring or connector fault in the humidity circuit
- A failed indoor unit PCB input for the sensor
What you can safely check
These are homeowner-level checks. None of them need you to open a live electrical compartment or work on gas.
- Compare the humidity the unit reports against a separate hygrometer in the same room, since a drifting sensor and a failed sensor look similar from the controller.
- Check the connector at the humidity sensor.
Do not do these
- ×Do not treat a CC warning as a stop. The lamp stays lit because the unit can keep running, and there is no benefit to shutting a working unit down for a humidity fault.
- ×Do not work on the sensor connector with the power switch on.
When to call a technician
No call needed yet, but write it down
Note the date and the exact code, and watch whether it comes back. If it turns into a repeat fault or starts affecting performance, that is when it becomes worth a technician.
- The refrigerant circuit is sealed and legally requires licensed handling. Opening it without certification releases refrigerant and can put the whole system in violation of regulation, so a low-pressure or high-pressure fault on this equipment is a call-out, not a weekend job.
- If the appliance has stopped mid-cycle, is making a noise you have not heard before, or smells burnt, stop reading here and call. Those are symptoms of something the fault code does not describe well enough.
A technician job.
What it costs to fix
Parts
Humidity sensor $60 to $180. Indoor unit PCB $200 to $450 if the input has failed.
Labor
One to two hours to diagnose and replace.
DIY or technician
A technician job.
Typical US part and labor ranges, 2026. They vary by region, model and contractor, so treat them as a planning figure, not a quote.
Scope of this code
- Code table
- Daikin VRV IV RXTQ heat pump codes
- Models in scope
- Daikin VRV IV RXTQ-TA / RXTQ-TB
- Checked
- Confirm on your own unit
- Find the model number on the data plate, then check this code in the service manual for that model. Manufacturers revise code tables between model years, and a revised board can renumber a fault.