MERCEDES-BENZ, MERCEDES-MAYBACH · 2026-05-20
Complaint 48V battery (A66) part numbers A 000 982 78 24, A 000 982 57 30, A 000 982 88 31, A 000 982 50 32, A 000 982 87 32) may trigger a fault message ("48 V Service Required" with fault codes P0ADA91, P0ADE91, P0AA100, P0ADD00 or P0AA000) in the instrument cluster. This fault message may prevent the 48 V battery contactors from opening automatically if the 12 V power supply is interrupted. In this case, the 48 V on-board electrical system, including connected components, remain energized. Cause The contactors of the 48 V battery do not open, resulting in residual voltage (> 3V) even when the 12 V battery is disconnected. Remedy When working on the 48 V on-board electrical system or connected components, ensure the component being repaired is de-energized in the 48 V system after…