Deactivating the key functions
If you do not use the vehicle or a key for an extended period of time, you can reduce the energy consumption of the respective key. To do so, deactivate the key functions.
To deactivate:
press the 
button on the key twice in quick succession. The battery check lamp of the key flashes twice briefly and lights up once.
To activate:
press any button on the key. When the vehicle is started with the key in the stowage compartment of the centre console, the key functions are automatically activated More.
Overview of the Mercedes-Benz emergency call system
The Mercedes-Benz emergency call system can help to decisively reduce the time between an accident and the arrival of emergency services at the site of the accident. It helps locate an accident site in places that are difficult to access.
The emergency call can be made automatically More or manually More. Only make emergency calls if you or others are in need of rescue. Do not make an emergency call in the event of a breakdown or a similar situation.
Displays in the media display:
SOS READY: emergency call available
SOS NOT READY: the ignition is not on or there is a malfunction with the emergency call system.
During an active emergency call, 
appears in the display.
You can find more information on the regional availability of the Mercedes-Benz emergency call system at: Mercedes-Benz emergency call system.
If there is a malfunction in the emergency call system (e.g. a fault with the speaker, microphone, airbag, SOS button), a corresponding message appears in the multifunction display of the instrument cluster.
Emergency guide
In the event of an accident or breakdown, the emergency guide shows safety notes in the multimedia system display.
These include, for example:
Recommended actions when leaving the vehicle
Procedure for safely removing seat belts in the event of an accident whereby the vehicle comes to rest on its roof
The emergency guide is activated in the following situations:
a protection system is triggered
an emergency call is made
certain breakdown situations
The availability as well as the scope of the emergency guide can vary depending in the country and vehicle equipment.