Mitsubishi Electric · City Multi Air Conditioning Systems
This fault signifies an instantaneous overcurrent or a sustained overcurrent (effective value) detected by the system's software. It points to a severe electrical issue often linked to the Inverter Power Module (IPM).
Click steps to track your progress.
Turn off the power to the outdoor unit at the main circuit breaker immediately.
Do not attempt to restart the unit to prevent further damage.
Contact a qualified HVAC technician or electrician to thoroughly inspect the inverter, compressor, and IGBT components.
The technician will verify the settings of the model selection switch (Dipswitches SW5-3 to SW5-8) on the outdoor unit control board.
Professional diagnosis is essential for this serious electrical fault.