This bulletin applies to Mercedes-Benz vehicles equipped with electric power steering, such as the 2016 C300.
A rattling/humming noise may be heard from the electric steering system when steering. The issue may not impact the ability to steer or control the vehicle.
The ball screw drive (KGT) of the electric steering unit may be damaged by external force, including hitting curbs with the front wheels, driving over obstacle such as potholes at an inappropriate speed, corrosion/water ingress through a damaged boot.
Inspect the boots for cracks, holes caused by a high pressure cleaner, animal bites, etc. The fix involves replacing the electric steering assembly.
ART: BENZ (courtesy Mitchell1)
CAPTION: Inspect steering boots for damage.