The electronic throttle potentiometer is operated by a cable.
The actual engine throttle body is drive by wire.
MB has been using this kind of set-up since ASR and Electric Throttles came out in the early 90's.
DR.D

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Dr.Diesel -
Shop Foreman
Master Guild Mercedes-Benz Technician.

Think the dealer is expensive? Do you know how much it costs to train a dealer tech? Or buy the required MB special tools to have on hand?