Daikin Air Conditioner Error Code JC

Error code JC on a Daikin air conditioner indicates a low pressure sensor abnormality in the outdoor unit. The system has detected either a short-circuit or an open-circuit condition in the sensor circuit connected to X18A on the outdoor PCB (A1P). This causes the unit to shut down to protect the compressor from operating without valid pressure data.

No, you should not attempt to run the unit while the JC fault is active. The low pressure sensor provides critical data that protects the compressor from operating under unsafe pressure conditions. Running the system without a valid sensor signal risks serious compressor damage, which is a much costlier repair.

Repair costs vary depending on what component has failed. A service call to diagnose and reseat a connector is typically the least expensive outcome. Replacing the low pressure sensor or its wiring harness generally falls into a moderate cost range, while replacing the outdoor PCB (A1P) can be significantly more expensive. Total costs including labor typically range from around $150 to $600 or more depending on the specific fault and local labor rates.

Some basic checks, such as verifying the sensor connector at X18A is firmly seated and inspecting the wiring harness for visible damage, can be done by a knowledgeable DIYer. However, measuring sensor signal voltage, testing the sensor, and handling refrigerant-side work require proper tools and in many regions a certified technician. If the sensor or PCB needs replacement, professional service is strongly recommended.

A power reset may temporarily clear the fault display, but the JC code will return if the underlying wiring or sensor problem has not been corrected. The fault is generated by a detected electrical condition in the sensor circuit, so the root cause must be diagnosed and repaired before the system will operate normally.