See also:

"Coupling up a trailer" function
This function is only available on vehicles with a trailer tow hitch. 1 Center of the vehicle on the red guide line approximately 10 in (0.25 m) away from the rear area 2 Center of the vehic ...

Mercedes-Benz M-Class Owners Manual
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Important safety notes
WARNING Do not adjust the steering wheel while driving. Adjusting the steering wheel while driving, or driving without the steering wheel adjustment feature locked could cause the driver to los ...