
The brightness of the indicator/warning
lamps is adjusted automatically according to
the ambient light.
Visual and acoustic collision warning
If you switch on the turn signals to change
lanes and a vehicle is detected in the side
monitoring range, you receive a visual and
acoustic collision warning. You then hear a
double warning tone and red warning
lamp 0002flashes. If the turn signal remains on,
detected vehicles are indicated by the
flashing of red warning lamp 0002.There are no
further warning tones.
Course-correcting brake application G
WARNING
Ac ourse-correcting brake application cannot
always prevent a collision. There is a risk of
an accident.
Always steer, brake or accelerate yourself,
especially if Active Blind Spot Assist warns
you or makes a course-correcting brake
application. Always maintain a safe distance
at the sides. If Active Blind Spot Assist detects a risk of a
lateral collision in the monitoring range, a
course-correcting brake application is carried
out. This is meant to assist you in avoiding a
collision.
If a course-correcting brake application
occurs, red warning lamp
0002flashes in the
exterior mirror and a dual warning tone
sounds. In addition, 0003appears in the
multifunction display.
In very rare cases, the system may make an
inappropriate brake application. An
inappropriate course-correcting brake
application may be interrupted at any time if
you steer slightly in the opposite direction or
accelerate, for example.
The course-correcting brake application is
available in the speed range between
20 mph (30 km/h) and 120 mph (200 km/h).
Either no braking application, or a course-
correcting brake application adapted to the
driving situation occurs 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 Assist
X Make sure that Active Blind Spot Assist
(Y page 242) is activated in the on-board
computer.
X Turn the SmartKey to position 2in the
ignition lock.
Warning lamps 0002in the exterior mirrors
light up red for approximately
1.5 seconds and then turn yellow. Driving systems
227Driving and parking Z

If no vehicle is detected in the adjacent lane
and there are broken lane markings detected,
no lane-correcting brake application is made.
Warning vibration in the steering wheel
A warning may be given if a front wheel
passes over a lane marking. It will warn you
by means of intermittent vibration in the
steering wheel for up to 1.5 seconds.
Lane-correcting brake application G
WARNING
A lane-correcting brake application cannot
always bring the vehicle back into the original
lane. There is a risk of an accident.
Always steer, brake or accelerate yourself,
especially if Active Lane Keeping Assist warns
you or makes a lane-correcting brake
application. G
WARNING
Active Lane Keeping Assist only detects
traffic conditions or road users to a limited
extent. In very rare cases, the system may
make an inappropriate brake application, e.g.
after intentionally driving over a solid lane
marking. There is arisk of an accident.
An inappropriate brake application may be
interrupted at any time if you steer slightly in
the opposite direction .Always make sure that
there is sufficient distance on the side for
other traffic or obstacles. If you leave your lane, under certain
circumstances the vehicle will brake briefly on one side. This is mean
tto assist you in
bringing the vehicle back to the original lane.
If a lane-correcting brake application occurs,
display 0002appears in the multifunction
display.
A lane-correcting brake application can be
made after driving over a lane marking
recognize as being solid or broken .Before
this, a warning must be given by means of
intermittentv ibration in the steering wheel.
In addition, a lane with lane markings on both
sides must be recognized.
In the case of a broken lane marking being
detected, a lane-correcting brake application
can only be made if a vehicle has been
detected in the adjacent lane. The following
vehicles can have an influence on brake
application: oncoming traffic, vehicles that
are overtaking and vehicles that are driving
parallel to your vehicle.
i A further lane-correcting brake
application can only occur after your
vehicle has returned to the original lane.
No lane-correcting brak eapplication occurs
if:
R you clearly and actively steer, brake or
accelerate.
R you cut the corner on a sharp bend.
R you have adopted a sporty driving style with
high cornering speeds or high rates of
acceleration.
R you have switched on the turn signals.
R a driving safety system intervenes, e.g.
ESP ®
, PRE-SAFE ®
Brake or Active Blind
Spot Assist.
R ESP ®
is switched off.
R the transmission is not in position D.
R an obstacle has been detected in the lane
in which you are driving.
R a loss of tire pressure or a defective tire has
been detected and displayed.
There is a possibility that the Active Lane
Assistant could misjudge the given traffic Driving systems
229Driving and parking Z

situation. An inappropriate brake application
may be interrupted at any time if you:
R steer slightly in the opposite direction
R switch on the turn signal
R clearly brake or accelerate
Al ane-correcting brake applicatio nis
interrupted automatically if:
R a driving safety system intervenes, e.g.
ESP ®
, PRE-SAFE ®
Brake or Active Blind
Spot Assist.
R lane markings can no longer be recognized.
Switching on Active Lane Keeping Assist
X Switch on Active Lane Keeping Assist using
the on-board computer; to do so, select
Standard or
Adaptive (Y
page 242).
If you drive at speeds above 40 mph
(60 km/h) and lane markings are detected,
the lines in the assistance graphics display
(Y page 240) are shown in green. Active
Lane Keeping Assist is ready for use.
If Standard is selected, no warning
vibration occurs if:
R you have switched on the tur nsignals .In
this event, the warnings are suppressed
for a certain period of time.
R a driving safety syste mintervenes, such
as ABS, BAS or ESP ®
.
When Adaptive is selected, no warning
vibration occurs if:
R you have switched on the tur nsignals .In
this event, the warnings are suppressed
for a certain period of time.
R a driving safety syste mintervenes, e.g.
ABS, BAS or ESP ®
.
R you accelerate hard, e.g .kickdown.
R you brake hard.
R you steer actively, e.g. swerve to avoid
an obstacle or change lanes quickly.
R you cut the corner on a sharp bend.
In order that you are warned only when
necessary and in good tim eifyou cross the
lane marking, the system recognizes certain
conditions and warns you accordingly. The warning vibration occurs earlier if:
R
you approach the outer lane marking on a
bend.
R the road has very wide lanes, e.g. a
highway.
R the system recognizes solid lane markings.
The warning vibration occurs later if:
R the road has narrow lanes.
R you cut the corner on a bend. 230
Driving systemsDriving and parking

The assistance graphic can display the status
of and information from other driving systems
or driving safety systems.
The assistance graphic shows:
R the 0002 symbol when ATTENTION ASSIST
(Y page 220) is deactivated.
R the lane markings as bright lines when Lane
Keeping Assist (Y page 223) or Active Lane
Keeping Assist (Y page 228) is activated.
R the 0001 symbol when the distance
warning function (Y page 71) is
deactivated.
R the 0001 symbol when PRE-SAFE ®
Brake
(Y page 76) is deactivated.
Deactivating/activating ESP ®i
Observe the "Importan tsafety notes"
section in the description of ESP
(Y page 74). G
WARNING
If you deactivate ESP ®
, ESP ®
no longer
stabilizes the vehicle .There is an increased
risk of skidding and an accident.
Only deactivate ESP ®
in the situations
described in the following.
It may be best to deactivate ESP ®
in the
following situations:
R when using snow chains
R in deep snow
R on sand or gravel
For further information about ESP ®
, see
(Y page 74).
X Start the engine.
X Press the 0002or0005 button on the
steering wheel to select the DriveAssistmenu.
X Press the 0003or0004 button to select
ESP . X
Press the 000Bbutton.
The current selection is displayed.
X To activate/deactivate: press the000B
button again.
ESP ®
is deactivated if the 0015warning lamp
in the instrumentc luster lights up
continuously when the engine is running.
If the 000C warning lamp and the 0015
warning lamp are lit continuously, ESP ®
is not
available due to a malfunction.
Observe the information on warning lamps
(Y page 279).
Observe the information on display messages
(Y page 249).
Activating/deactivating PRE-SAFE ®
Brake PRE-SAFE
®
Brake is only available in vehicles
with DISTRONIC PLUS.
X Press 0002or0005 on the steering wheel
to selec tthe DriveAssist menu.
X Press the 0003or0004 button to select
PRE-SAFE Brake .
X Press the 000Bbutton.
The current selection is displayed.
X To activate/deactivate: press the000B
button again.
When PRE-SAFE ®
Brake is deactivated, the
assistance graphic shows the 0001symbol
in the multifunction display.
For more information on PRE-SAFE ®
Brake,
see (Y page 76).
Activating/deactivating the distance
warning function X
Press the 0002or0005 button on the
steering wheel to select the DriveAssist menu.
X Press 0003or0004 to select Distance Warning . Menus and submenus
241On-board computer and displays Z

Safety systems
Display messages Possible causes/consequences and
0001 Solutions
0017000C
Currently
Unavailable See
Operator's Manual ABS (Anti-lock Braking System), ESP
®
(Electronic Stability
Program), BAS (Brake Assist), PRE-SAFE ®
,t he HOLD function and
hill start assist are temporarily unavailable.
BAS PLUS, COLLISION PREVENTION ASSIST and
PRE-SAFE ®
Brake may also have failed.
In addition, the 000C,0015and0017 warning lamps light up in
the instrument cluster.
ATTENTION ASSIST is deactivated.
For example, the on-board voltage may be insufficient.
G WARNING
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
The steerability and braking characteristics may be severely
affected. The braking distance in an emergency braking situation
can increase.
If ESP ®
is not operational, ESP ®
is unable to stabilize the vehicle.
There is an increased risk of skidding and an accident.
X Drive on carefully.
If the display message disappears, the functions mentioned
above are available again.
If the display message continues to be displayed:
X Drive on carefully.
X Visit a qualified specialist workshop. 0017000C
Inoperative See
Operator's Manual ABS, ESP
®
, BAS, PRE-SAFE ®
, the HOLD function and hill start
assist are unavailable due to a malfunction.
BAS PLUS, COLLISION PREVENTION ASSIST and
PRE-SAFE ®
Brake may also have failed.
The 000B (USA only)/0005 (Canada only),000C,0015and0017
warning lamps in the instrumentc luster also light up.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
The steerability and braking characteristics may be severely
affected. The braking distance in an emergency braking situation
can increase. Display messages
249On-board computer and displays Z

Display messages Possible causes/consequences and
0001 Solutions
If ESP
®
is no toperational, ESP ®
is unable to stabilize the vehicle.
There is an increased risk of skidding and an accident.
X Drive on carefully.
X Visit a qualified specialist workshop immediately. 000C
Inoperative See
Operator's Manual ESP
®
,B AS, PRE-SAFE ®
, the HOLD functio nand hill start assist are
unavailable due to a malfunction.
BAS PLUS, COLLISION PREVENTION ASSIST and
PRE-SAFE ®
Brake may also have failed.
In addition, the 000Cand0015 warning lamps light up in the
instrument cluster.
The self-diagnosis functio nmight not be complete, for example.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the
functions listed above.
The braking distance in an emergency braking situation can thus
increase.
If ESP ®
is not operational, ESP ®
is unable to stabilize the vehicle.
There is an increased risk of skidding and an accident.
X Drive on carefully.
X Visit a qualified specialist workshop. 250
Display messagesOn-board computer and displays

Display messages Possible causes/consequences and
0001 Solutions
000B(USA
only)
0005(Canada
only)
Check Brake Fluid Level There is no
tenough brake fluid in the brake fluid reservoir.
In addition, the 000B(USA only)/0005 (Canada only) warning
lamp lights up in the instrument cluster and a warning tone
sounds.
G WARNING
The braking effect may be impaired.
There is a ris kofanaccident.
X Pull ove rand stop the vehicle safely as soo nas possible, paying
attention to road and traffic conditions. Do not continue driving
under any circumstances.
X Secure the vehicle against rolling away (Y page 182).
X Consult a qualified specialist workshop.
X Do not add brake fluid. This does not correct the malfunction. 0006
Check Brake Pad
Wear The brake pads/linings have reached their wear limit.
X
Visit a qualified specialist workshop. 0008
mbrace Inoperative One or more main features of the mbrace system are
malfunctioning.
X
Have the mbrace system checked immediately at a qualified
specialist workshop. PRE-SAFE
Inoperative See
Operator's Manual Important functionso
f PRE-SAFE®
have failed .All other occupant
safety systems, e.g. air bags, remain available.
X Visit a qualified specialist workshop immediately. 252
Display messagesOn-board computer and displays

Display messages Possible causes/consequences and
0001 Solutions
PRE-SAFE
Functions
Currently Limited
See Operator's
Manual PRE-SAFE
®
brake or Adaptive Brake Assist of COLLISION
PREVENTION ASSIST is temporarily not operational.
Possible causes are:
R function is impaired due to heavy rain or snow.
R the sensors in the radiato rgrill and the bumper are dirty.
R the rada rsensor 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.
When the causes stated above no longer apply, the display
message disappears.
PRE-SAFE ®
Brake is operational again.
If the display message does not disappear:
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Secure the vehicle against rolling away (Y page 182).
X Clean the sensors in the radiator grill and the bumper
(Y page 323).
X Restart the engine. PRE-SAFE
Functions Limited
See Operator's
Manual PRE-SAFE
®
brake or Adaptive Brake Assist of COLLISION
PREVENTION ASSIST is not available due to a malfunction. BAS
PLUS or the distance warning signal may also have failed.
X Visit a qualified specialist workshop. 0013
Malfunction
Service Required G
Risk of injury
Cabriolet: the roll bars are defective.
X Visit a qualified specialist workshop immediately. 001D
SRS Malfunction
Service Required There is a malfunction in the SRS (Supplemental Restraint
System). The
001Dwarning lamp also lights up in the instrument
cluster.
G WARNING
The air bags or Emergency Tensioning Devices may either be
triggered unintentionally or, in the event of an accident, may not
be triggered.
There is an increased risk of injury.
X Visit a qualified specialist workshop.
For further information about SRS, see (Y page 43). Display messages
253On-board computer and displays Z