Mitsubishi Electric · R410A Systems
The 63L connector on the outdoor unit's printed circuit board (PCB) is detected as open or disconnected. This typically relates to a specific protective device or sensor circuit experiencing a loss of connection.
Click steps to track your progress.
Inspect the 63L connector on the outdoor unit PCB — verify it is securely seated and free from corrosion.
Check the continuity of the wiring connected to the 63L connector using a multimeter.