See also:

Mercedes-Benz M-Class Owners Manual
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Lap evaluation
This function is only available if you have stored at least two laps and have stopped the RACETIMER. Press or on the steering wheel to select the AMG menu. Press the button repeatedly ...

Setting a speed
WARNING Keep in mind that it may take a brief moment until the vehicle has made the necessary adjustments. Increase or decrease the set vehicle speed to a value that the prevailing road cond ...