See also:

Mercedes-Benz M-Class Owners Manual
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Function restrictions
You will not be able to use the telephone, will no longer be able to use the telephone, or you may have to wait before using it, in the following situations: • when the mobile phone is switch ...

Panic alarm
To activate: press button 1 for at least one second. An alarm sounds and the exterior lighting flashes. To deactivate: press button 1 again. or Insert the SmartKey into the ignition ...