Okuma Alarm P-0858 – MCS Power Unit Overheat

Okuma Alarm P-0858 (MCS Power Unit Overheat) occurs when the power unit or inverter detects an abnormally high temperature and triggers an overheat protection condition. This alarm is commonly caused by cooling fan failure, clogged filters, poor airflow inside the electrical cabinet, high ambient temperature, or internal faults in the power unit temperature sensing circuit.