Technical Service Bulletin LI15.40-P-078041 — 2024 MERCEDES-BENZ S 580 E

Complaint Whistling and/or howling noises in the area of the engine compartment when idling at low rpm. Cause The high-voltage belt-driven starter alternator (HV-BSA) charges the high-voltage battery whenever its state of charge (SOC) is less than 20% and the speed is lower than 15 km/h. The displayed SOC refers to the value shown in the display (AMG Dynamics). When auxiliary consumers such as the air conditioning system are activated and the on-board electrical system load increases, the idling speed is not sufficient for the HV-BSA to provide enough current to the high-voltage battery. As a consequence, the idle speed is increased in stages. The noises may vary in intensity and frequency depending on the idle speed and load. This causes the noises mentioned above. Remedy Replacing the HV-BSA will not remedy the issue. Charge the high-voltage battery to 100% SOC before handing it over to the customer.