CJ means the temperature sensor in a wired/remote controller is not being read normally on systems that use that input.
Urgency
advisory
This is not usually an immediate safety hazard, but do not keep resetting it. Try the safe homeowner check below; if the code comes back, schedule service.
Likely causes
Brief power event, brownout, or unstable supply voltage
Loose power connection, reactor, or outdoor electrical component problem
Inverter/IPM protection or current-detection fault
Compressor winding, drive, or outdoor board fault after power checks pass
Homeowner fix
Reset power once if you can do so safely and make sure the controller is not in direct sun, over a heat source, or blocked by furniture. If CJ returns, stop there.
When to call a pro
Call a licensed HVAC technician if CJ returns. Tell them the code is remote controller thermistor abnormality.
This code points to compressor and electrical or inverter work - get repair quotes from contractors in your area.
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Repair vs replace
Sensor and communication faults are usually repairable. Compare repair with replacement only if the system is older, out of warranty, or multiple boards or sensors are being quoted together.
Technician note: confirm controller sensor setting/location, controller thermistor reading, wiring, and indoor-controller communication. Page context: Daikin maps this display to the AURORA R-32 line; source: Daikin Nineteen, ATMOSPHERA, Entra, and MXM/MXT/MXTH local service manuals; display convention: match the letter C and letter J marker exactly before comparing neighboring codes.
Which systems show it
Daikin current US residential R-32 ductless single-zone systems, including AURORA R-32, ATMOSPHERA R-32, Entra R32, OTERRA R-32, and Nineteen-series style high-wall diagnostics where the same Daikin A/C/E/F/H/J/L/P/U code family is used.
Daikin concealed-duct/FDMQ indoor units where the Nineteen service manual explicitly lists the same indoor drain, fan PCB, remote-controller, and FDMQ-only C/U codes.
Daikin AURORA Multi R-32 and Standard Multi R-32 MXT/MXTH/MXM systems where the MXM engineering manual lists the same homeowner code table.
MXM/MXT/MXTH multi-zone systems for the additional multi-zone U-series and inverter/control codes specifically called out from the MXM manual.
Related troubleshooting
Use the symptom guide alongside the exact display code if the unit is flashing, cycling, or showing comfort symptoms.
Reset power once if you can do so safely and make sure the controller is not in direct sun, over a heat source, or blocked by furniture. If CJ returns, stop there.
Manual trigger
CJ means the temperature sensor in a wired/remote controller is not being read normally on systems that use that input.