System self-test
The 42 indicator lamp illuminates when you:
• turn the SmartKey to position 1 or 2 in the
ignition lock
• on vehicles with KEYLESS-GO, press the
Start/Stop button once or twice
The 
indicator lamp goes out
again after approximately six seconds.
If the indicator lamp does not
illuminate or is lit continuously, the system is
malfunctioning. Have the BabySmart™
system checked at an authorized Mercedes-
Benz Center before transporting a child on
the front-passenger seat.
For further information, see "Problems with air bag deactivation system".
WARNING 
Do not place powered-on laptops, mobile
phones, electronic tags such as those used in
skipasses or similar electronic devices on the
front passenger seat. Signals from such
devices may interfere with the BabySmart™
air bag deactivation system. Such signal
interference may cause the
indicator lamp not to come on during self-test.
The + SRS indicator lamp and/or the
indicator lamp could be
continuously lit, indicating that the system is
not functioning. The front-passenger front air
bag could deploy inadvertently or fail to
deploy in an accident.
See also:
Important safety notes
Your vehicle may be equipped with a sliding
sunroof or a panorama roof with power tilt/
sliding panel. In the following section, the
term "sliding sunroof" refers to both types of
sl ...
Qualified specialist workshop
An authorized Mercedes-Benz Center is a
qualified specialist workshop. It has the
necessary specialist knowledge, tools and
qualifications to correctly carry out the work
required on your vehi ...
Switching to MUSIC REGISTER
Select Audio in the main function bar by
sliding and turning
the COMAND
controller and press to confirm.
If MUSIC REGISTER was the last mode
selected, it is now switched on.
If another au ...