Mitsubishi Air Conditioner Error Code CP

The CP code on a Mitsubishi inverter air conditioner is a parameter copy warning. It appears when parameter data has been copied from one inverter unit to another unit with a different capacity rating. The system flags this mismatch to prevent the inverter from running on incorrect settings. It is a warning, not a hardware fault, and can be resolved through parameter correction.

The CP warning is a protective measure built into the inverter to prevent operation under mismatched settings, which could cause improper motor protection thresholds or incorrect current limiting. Running the system with unresolved capacity-mismatched parameters could lead to inadequate motor protection or performance issues. The system intentionally restricts operation until the parameters are corrected, so the warning itself is the safety mechanism working as intended.

Because the CP warning typically requires only a parameter programming correction rather than parts replacement, repair costs are primarily labor-based. A technician service visit to diagnose and correct the parameters could range from roughly $80 to $200 depending on your location and the technician's rates. If the CP warning resulted from a failed or incorrect inverter replacement and the correct replacement inverter is also needed, total costs would be higher, generally in the range of $300 to $800 or more depending on the unit capacity.

To clear the CP warning, a technician must first identify and reset the capacity-specific parameters that were incorrectly copied. At minimum, parameters Pr.9, Pr.30, and Pr.51 should be reviewed and set to values appropriate for the destination inverter's capacity. Once those parameters are corrected, setting Pr.989 to the parameter copy alarm release value will clear the CP warning and allow normal operation to resume.

A simple power reset will not clear the CP warning on a Mitsubishi inverter unit. The warning is tied to specific stored parameter values that remain in memory even after a power cycle. Clearing it requires manually correcting the affected parameters, including Pr.9, Pr.30, Pr.51, and others as applicable, and then setting Pr.989 to the alarm release value. Until those steps are completed, the warning will persist.