Monitoring area
Active Blind Spot Assist monitors the area
shown in the figure up to 10 ft (3 m) behind
and immediately adjacent to your vehicle. For
this purpose, Active Blind Spot Assist uses
radar sensors in the rear bumper.
Example: Coupe
GWARNING
Active Blind Spot Assist monitors certain
areas in the immediate vicinity of your vehicle.
Vehicles that approach and drive past at high
speeds are not detected. No visual nor
audible warnings are emitted and the system
does not brake the vehicle to correct your
course.
If the lanes are very wide, it may not be
possible to monitor the complete width of the
neighboring lane. For this reason, vehicles in
the next lane may not be detected, especially
if they are driving in a staggered formation.
This may be the case if vehicles are driving at
that edge of their lane which is furthest away
from your vehicle.
Always pay attention to traffic conditions and
your surroundings. Otherwise, you may fail to
recognize dangers in time, cause an accident
and injure yourself and others.
If the lanes are narrow, vehicles driving in the
lane beyond the lane next to your vehicle may
be indicated, especially if the vehicles are not
driving in the middle of their lane. This may
be the case if there are vehicles driving at the
inner edge of their lanes.
Due to the nature of the system:
R warnings may be issued in error when
driving close to crash barriers or similar
solid lane borders.
R warnings may be interrupted when driving
alongside long vehicles, such as trucks, for
a prolonged time.
Two Active Blind Spot Assist radar sensors
are integrated into the front and rear bumpers
respectively. An additional radar sensor is
located behind the cover in the radiator grill.
Make sure that the sensor areas on the
bumpers and the sensor cover in the radiator
grill are free of dirt, ice and slush. The rear
sensors must not be covered, for example by
cycle racks or overhanging cargo. Following
a severe impact or in the event of damage to
the bumpers, have the function of the radar
sensors checked at a qualified specialist
workshop. Blind Spot Assist may otherwise
not work properly.
Indicator and warning display:Yellow indicator lamp/red warning lamp
When Active Blind Spot Assist is activated,
indicator lamp : lights up yellow in the
exterior mirrors up to a vehicle speed of
20 mph (30 km/h). When the vehicle speed
exceeds 20 mph (30 km/h), the indicator
lamp goes out and Active Blind Spot Assist is
ready for use.
190Driving systemsDriving and parking
There will be either no or only a weak course-
correcting brake application if:
R there are vehicles or obstacles, e.g. crash
barriers, located on both sides of your
vehicle.
R a vehicle approaches you too closely at the
side.
R you have adopted a sporty driving style with
high cornering speeds.
R you clearly brake or accelerate.
R a driving safety system intervenes, e.g.
ESP ®
or PRE-SAFE ®
Brake.
R ESP ®
is switched off.
R a loss of tire pressure or a defective tire is
detected.
Switching on Active Blind Spot AssistXMake sure that the radar sensor system
( Y page 210) and Active Blind Spot Assist
( Y page 207) are activated in the on-board
computer.XTurn the SmartKey to position 2 in the
ignition lock.
Warning lamps : light up red in the
exterior mirrors for approximately 1.5
seconds and then turn yellow.
Active Lane Keeping Assist
Important safety notes
Active Lane Keeping Assist monitors the area
in front of your vehicle by means of a camera
at the top of the windshield. Active Lane
Keeping Assist detects lane markings on the
road and warns you before you leave your
lane unintentionally. If you do not react to the
warning, a lane-correcting application of the
brakes can bring the vehicle back into the
original lane.
:Active Lane Keeping Assist camera
If you have selected the Display Unit
Speed-/Odometer (Y page 208) function in
the on-board computer and select km as the
unit of measurement, Active Lane Keeping
Assist is active from speeds of 60 km/h. If
the miles display unit is selected, the
assistance range begins at 40 mph.
GWARNING
Active Lane Keeping Assist does not keep
your vehicle in its lane. It is only an aid and
may detect the lane markings on the road
incorrectly or not at all.
The system may be impaired or may not
function if:
R several or no lane markings for a single lane
are present.
R there is poor visibility, e.g. due to
insufficient illumination of the road, or due
to snow, rain, fog or spray.
R there is glare, e.g. from oncoming traffic,
the sun, or reflection from other vehicles.
R the windshield is dirty, fogged up or
covered, for instance by a sticker, in the
vicinity of the camera.
R the lane markings are worn away, dark or
covered up, e.g. by dirt or snow.
R the distance to the vehicle in front is too
small and the lane markings thus cannot be
detected.
R the lane markings on the road are unclear,
e.g. near roadworks.
192Driving systemsDriving and parking
Deactivating delayed switch-off of the
exterior lighting temporarily:XBefore leaving the vehicle, turn the
SmartKey to position 0 in the ignition lock.XTurn the SmartKey to position 2 in the
ignition lock and back to position 0.
The exterior lighting delayed switch-off is
deactivated.
Delayed switch-off of the exterior lighting is
reactivated the next time you start the
engine.
Activating/deactivating the interior
lighting delayed switch-off
If you activate the Light. delay function,
the interior lighting remains on for 20
seconds after you remove the SmartKey from
the ignition lock.
XPress the = or ; button on the
steering wheel to select the Settings
menu.XPress the : or 9 button to select the
Lights submenu.XPress the a button to confirm.XPress the : or 9 button to select the
Light. Delay function.
When the Light. Delay function is
activated, the vehicle interior is displayed
in red in the multifunction display.XPress the a button to save the setting.
Vehicle
Activating/deactivating the automatic
door locking feature
If you select the Auto. Door Locks
function, the vehicle is centrally locked above
a speed of around 9 mph (15 km/h).
i For further information on the automatic
locking feature, see ( Y page 78).
XPress the = or ; button on the
steering wheel to select the Settings
menu.XPress the : or 9 button to select the
Vehicle submenu.XPress the a button to confirm.XPress the : or 9 button to select the
Auto. Door Locks function.
When the Auto. Door Locks function is
activated, the vehicle doors are displayed
in red in the multifunction display.XPress the a button to save the setting.
Activating/deactivating the acoustic
locking verification signal
If you activate the Acoustic Lock function,
an audible signal sounds depending on the
vehicle's date of manufacture:
R when locking
or
R once when unlocking and three times when
locking
XPress the = or ; button on the
steering wheel to select the Settings
menu.XPress the : or 9 button to select the
Vehicle submenu.XPress the a button to confirm.XPress the : or 9 button to select the
Acoustic Lock function.
If the Acoustic Lock function is activated,
the & symbol in the multifunction
display lights up red.XPress the a button to save the setting.
Activating/deactivating the radar sensor
system
The following systems are switched off when
the radar sensor system is deactivated:
R DISTRONIC PLUS ( Y page 166)
R BAS PLUS ( Y page 62)
R PRE-SAFE ®
Brake ( Y page 65)
210Menus and submenusOn-board computer and displays
RBlind Spot Assist ( Y page 186)
R Active Blind Spot Assist ( Y page 189)
i USA only: This device has been approved
by the FCC as a "Vehicular Radar System".
The radar sensor is intended for use in an
automotive radar system only. Removal,
tampering, or altering of the device will void
any warranties, and is not permitted by the
FCC. Do not tamper with, alter, or use in
any non-approved way.
Any unauthorized modification to this
device could void the user's authority to
operate the equipment.
i Canada only:
This device complies with RSS-210 of
Industry Canada. Operation is subject to
the following two conditions:
1. This device may not cause harmful
interference, and
2. this device must accept any interference
received, including interference that may
cause undesired operation.
Any unauthorized modification to this
device could void the user's authority to
operate the equipment.XPress the = or ; button on the
steering wheel to select the Settings
menu.XPress the : or 9 button to select the
Vehicle submenu.XPress the a button to confirm.XPress the 9 or : button to select
Radar Sensor (See Oper. Manual): .
You will see the selected setting: Enabled
or Disabled .XPress the a button to save the setting.
Convenience
Activating/deactivating the EASY-
ENTRY/EXIT feature
You can use the Easy Entry/Exit: function
to activate or deactivate the EASY ENTRY/
EXIT feature ( Y page 109).
GWARNING
You must make sure no one can become
trapped or injured by the moving steering
wheel when the easy-entry/exit feature is
activated.
To stop steering wheel movement, move
steering wheel adjustment lever or press one
of the memory position buttons.
Do not leave children unattended in the
vehicle, or with access to an unlocked vehicle.
Children could open the driver's door and
unintentionally activate the easy-entry/exit
feature, which could result in an accident
and/or serious personal injury.
XPress the = or ; button on the
steering wheel to select the Sett. menu.XPress the : or 9 button to select the
Convenience submenu.XPress the a button to confirm.XPress the : or 9 button to select the
Easy Entry/Exit function.
If the Easy Entry/Exit function is
activated, the vehicle steering wheel is
displayed in red in the multifunction
display.XPress the a button to save the setting.
Switching the belt adjustment on/off
For further information on belt adjustment
( Y page 53).
XPress the = or ; button on the
steering wheel to select the Settings
menu.XPress the : or 9 button to select the
Convenience submenu.XPress the a button to confirm.XPress the : or 9 button to select the
Belt Adjustment function.
When the Belt Adjustment function is
activated, the vehicle seat belt is displayed
in red in the multifunction display.XPress the a button to save the setting.Menus and submenus211On-board computer and displaysZ
Display messagesPossible causes/consequences and M SolutionsG
Tele Aid
InoperativeUSA only: one or more of the main functions in the mbrace system
are malfunctioning.
Canada only: one or more of the main functions of the TELEAID
system are malfunctioning.XUSA only: have the mbrace system checked at a qualified
specialist workshop.XCanada only: have the TELEAID system checked at a qualified
specialist workshop.PRE-SAFE
Inoperative See
Operator's ManualGRisk of injury
Important functions of PRE-SAFE ®
have failed. All other occupant
safety systems, e.g. air bags, remain available.
XVisit a qualified specialist workshop immediately.PRE-SAFE
Function Currently
Limited See Oper.
ManualGRisk of accident
PRE-SAFE ®
Brake is temporarily inoperative if:
R the DISTRONIC PLUS cover in the radiator grill is dirty.
R the sensors in the bumpers are dirty.
R its function is impaired due to heavy rain or snow.
R the radar sensor system is temporarily inoperative, e.g. due to
electromagnetic radiation emitted by nearby TV or radio
stations or other sources of electromagnetic radiation.
R the system is outside the operating temperature range.
R the on-board voltage is too low.
PRE-SAFE ®
Brake is operational again and the display message
disappears if:
R the dirt (e.g. slush) drops away while the vehicle is in motion.
R the system detects that the sensors are fully available again.
R the system is within the operating temperature range.
If the display message continues to be displayed:
XClean the DISTRONIC PLUS cover in the radiator grill
( Y page 284).XClean the bumpers ( Y page 284).XRestart the engine.XWait until the battery is sufficiently charged.Display messages217On-board computer and displaysZ
Display messagesPossible causes/consequences and M Solutionsb
AUTO Lamp Function
InoperativeThe light sensor is defective.XVisit a qualified specialist workshop.b
Switch Off LightsThe lights are still switched on when you leave the vehicle. A
warning tone also sounds.XTurn the light switch to c or à .Adaptive Highbeam
Assist InoperativeAdaptive Highbeam Assist is faulty.XVisit a qualified specialist workshop.Adaptive Highbeam
Assist Currently
Unavailable See
Operator's ManualAdaptive Highbeam Assist is deactivated and temporarily
inoperative. Possible causes are:
R the windshield in the camera's field of vision is dirty.
R visibility is impaired due to heavy rain, snow or fog.XClean the windshield.
If the system detects that the camera is fully functional again, the
Adaptive Highbeam Assist Now Available display message
is shown.
Adaptive Highbeam Assist is operational again.
Engine
Display messagesPossible causes/consequences and M Solutions+
Check Coolant
Level See
Operator's ManualThe coolant level is too low.XAdd coolant, observing the warning notes when doing so
( Y page 276).XIf coolant needs to be added more often than usual, have the
engine coolant system checked at a qualified specialist
workshop.GWARNING
Do not spill antifreeze on hot engine parts. Antifreeze contains ethylene glycol which may burn
if it comes into contact with hot engine parts. You could be seriously burned.
! The coolant level is too low. Avoid making long journeys with too little coolant in the cooling
system. The engine will otherwise be damaged.
The display messages and the corresponding symbol that indicate that the coolant level is
too low must not be ignored.
Display messages225On-board computer and displaysZ
Display messagesPossible causes/consequences and M SolutionsRadar Sensors
Deactivated See
Operator's ManualThe radar sensor system is deactivated.XSwitch on the radar sensor system ( Y page 210).Lane Keeping
Assist Currently
Unavailable. See
Operator's Manual
or Lane Keeping
Assist Currently
Unavailable. See
Operator's ManualLane Keeping Assist or Active Lane Keeping Assist is deactivated
and temporarily inoperative if:
R the windshield is dirty in the camera's field of vision.
R visibility is impaired due to heavy rain, snow or fog.
R there are no lane markings for a longer period.
R the lane markings are worn, dark or covered, for example by dirt
or snow.
Lane Keeping Assist or Active Lane Keeping Assist is operational
again and the display message disappears if:
R the dirt (e.g. slush) drops away while the vehicle is in motion.
R the system recognizes that the camera is fully operational again.
If the display message continues to be displayed:XClean the windshield.Lane Keeping
Assist Inoperative
or Active Lane
Keeping Assist
InoperativeLane Keeping Assist or Active Lane Keeping Assist is defective.XVisit a qualified specialist workshop.Display messages229On-board computer and displaysZ
Display messagesPossible causes/consequences and M SolutionsBlind Spot Assist
Currently
Unavailable See
Operator's
ManualBlind Spot
Assist Currently
Unavailable See
Operator's Manual
or Active Blind
Spot Assist
Currently
Unavailable See
Operator's ManualBlind Spot Assist or Active Blind Spot Assist is temporarily
inoperative if:
R the sensors are dirty.
R its function is impaired due to heavy rain or snow.
R the radar sensor system is outside the operating temperature
range.
R the radar sensor system is temporarily inoperative, e.g. due to
electromagnetic radiation emitted by nearby TV or radio
stations or other sources of electromagnetic radiation.
The yellow 9 indicator lamps also light up in the exterior
mirrors.
Blind Spot Assist or Active Blind Spot Assist is operational again
and the display message disappears if:
R the dirt (e.g. slush) drops away while the vehicle is in motion.
R the system detects that the sensors are fully available again.
R the radar sensor system is back within the operating
temperature range.
If the display message continues to be displayed:XClean the sensors ( Y page 284).XRestart the engine.Blind Spot Assist
Inoperative or
Active Blind Spot
Assist InoperativeBlind Spot Assist or Active Blind Spot Assist is defective.
The yellow 9 indicator lamps also light up in the exterior
mirrors.XVisit a qualified specialist workshop.Parking Guidance
InoperativeParking Guidance is malfunctioning ( Y page 181).XRestart the engine.
If the display message continues to be displayed:
XVisit a qualified specialist workshop.230Display messagesOn-board computer and displays