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:
Problems with PARKTRONIC
Problem
Possible causes/consequences and - Solutions
Only the red segments
in the PARKTRONIC
warning displays are lit.
You also hear a warning
tone for approximately ...
Windshield washer system and headlamp cleaning system
The washer fluid reservoir is used for both the windshield washer system and
the headlamp cleaning system.
Vehicle components and their service products must match. You should, therefore,
only ...
Socket in the front-compartment centerconsole
If accessories are connected, make sure
that a maximum current draw of 15 A is not
exceeded. Otherwise, you will overload the
fuse.
The socket is not suitable for operating
the tire inflati ...