See also:

Vehicle remote opening
If you have unintentionally locked your vehicle (e.g. the SmartKey is still in the vehicle) and a replacement SmartKey is not available, the vehicle can be opened by a Mercedes-Benz Customer Assis ...

Problems with the SmartKey
Problem Possible causes/consequences and Solutions You cannot lock or unlock the vehicle using the SmartKey. The SmartKey battery is discharged or nearly discharged. - ...

Activating AUX mode
AUX drive Select AUX in the menu using the buttons on the remote control and press the button to confirm. The AUX menu appears. Select Source from the AUX menu and press the button to ...