Daikin VRV IV RXTQ-TA / RXTQ-TB error code JC
Low pressure sensor abnormality
Which models this applies to. Outdoor unit
Quick answer
On Daikin VRV IV RXTQ-TA / RXTQ-TB, JC is a fault. It means low pressure sensor abnormality. A first thing to check: A failed low pressure sensor.
- Applies to
- Daikin VRV IV RXTQ-TA / RXTQ-TB
- Daikin VRV IV RXTQ heat pump codes · Heat Pump
- Type of code
- Fault
- Urgency: Needs attention soon
- First safe check
- Compare the reported pressure against an independent gauge reading before concluding that the system has lost its charge.
What JC means on this model
The low pressure sensor has reported a fault or is reading implausibly. This is the sensor behind the low pressure protection, so a failure can stop the system from starting, and an implausible reading produces a refrigerant leak that is not there. Verify against a real gauge before searching for a leak.
Symptoms you will notice
- Outdoor unit shows JC and the system stops
- The system will not start
- The system reports low pressure with no real leak
- The fault appeared after work on the outdoor unit
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 low pressure sensor
- A loose or corroded connector at the sensor
- A failed input on the outdoor main PCB
- A damaged or disconnected pressure port or capillary
- A wiring fault in the sensor circuit
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 reported pressure against an independent gauge reading before concluding that the system has lost its charge.
- Check the connector at the sensor.
Do not do these
- ×Do not search for a refrigerant leak on a JC code until the sensor has been verified. An implausible sensor reading produces a leak that is not there.
- ×Do not work on the sensor connector with the power switch on.
When to call a technician
Book a technician, do not keep resetting it
This fault will not clear on its own. Every power cycle gives the control one more failed attempt, and repeated attempts are what turn a cheap part replacement into a seized or contaminated system.
- 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
Low pressure sensor $60 to $180.
Labor
One to two hours to test 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.