
GWARNING
DISTRONIC PLUS cannot always clearly iden-
tify other road users and complex traffic sit-
uations.
In such cases, DISTRONIC PLUS may:
Rgive an unnecessary warning and then
brake the vehicle
Rneither give a warning nor intervene
Raccelerate or brake unexpectedly
There is a risk of an accident.
Continue to drive carefully and be ready to
brake, in particular when warned to do so by
DISTRONIC PLUS.
GWARNING
DISTRONIC PLUS brakes your vehicle with up to 50% of the maximum possible deceleration.
If this braking force is insufficient, DISTRONIC
PLUS warns you visually and audibly. There isa risk of an accident.
In such cases, apply the brakes yourself and
try to take evasive action.
!If DISTRONIC PLUS or the HOLD function is
activated, the vehicle brakes automatically in
certain situations.
To prevent damage to the vehicle, deactivate
DISTRONIC PLUS and the HOLD function in
the following or other similar situations:
Rwhen towing the vehicle
Rin the car wash
If you fail to adapt your driving style, DISTRONIC
PLUS can neither reduce the risk of accident nor
override the laws of physics. DISTRONIC PLUS
cannot take into account the road, traffic and
weather conditions. DISTRONIC PLUS is only an
aid. You are responsible for the distance to the
vehicle in front, for vehicle speed, for braking in good time and for staying in your lane. Do not use DISTRONIC PLUS:
Rin road and traffic conditions which do not
allow you to maintain a constant speed, e.g. in
heavy traffic or on winding roads
Ron slippery road surfaces. Braking or accel-
erating could cause the drive wheels to lose
traction and the vehicle could then skid
Rwhen there is poor visibility, e.g. due to fog,
heavy rain or snow
DISTRONIC PLUS may not detect narrow vehi-
cles driving in front, e.g. motorcycles, or vehi-
cles driving on a different line.
In particular, the detection of obstacles can be
impaired if:
Rthere is dirt on the sensors or anything else
covering the sensors
Rthere is snow or heavy rain
Rthere is interference by other radar sources
Rthere are strong radar reflections, for exam-
ple, in parking garages
If DISTRONIC PLUS no longer detects a vehicle
in front, DISTRONIC PLUS may unexpected ly
a
ccelerate the vehicle to the stored speed.
This speed may:
Rbe too high if you are driving in a filter lane or an exit lane
Rbe so high in the right lane that you pass vehi-cles driving on the left (left-hand drive coun-
tries)
Rbe so high in the left lane that you pass vehi-
cles driving on the right (right-hand drive
countries)
If there is a change of drivers, advise the new
driver of the speed stored.
Cruise control lever
:To store the current speed or a higher speed
;To store the current speed or a lower speed
154Driving systems
Driving and parking

if ATTENTION ASSIST still detects typical indi-
cators of fatigue or increasing lapses in concen-
tration.
Vehicles with COMAND:if a warning is output
in the multifunction display, a service station
search is performed in the multimedia system.
You can select a service station and navigation
to this service station will then begin. This func-
tion can be activated and deactivated in the
multimedia system.
Traffic Sign Assist
General notes
Traffic Sign Assist displays the maximum speed
permitted to the driver in the instrument cluster.
The data stored in the navigation system and
general traffic regulations are used to determine
the current speed limit.
As Traffic Sign Assist is a map-based system,
traffic signs put up temporarily (e.g. near road-
works) are not detected.
If a traffic sign that is relevant to your vehicle is
passed, the display of the speed limits is upda-
ted.
Traffic signs with a restriction indicated by an
additional sign (e.g. in wet conditions) are also
shown.
The traffic signs are only displayed with the
restrictions if:
Rthe regulation must be observed with the
restriction, or
RTraffic Sign Assist is unable to determine
whether the restriction applies
If Traffic Sign Assist is unable to determine a
maximum permitted speed from any of the avail-
able sources, no speed limit is displayed in the
instrument cluster either.
Traffic Sign Assist is not available in all coun-
tries. In this case, symbol :is shown in the
assistance graphic display (
Ypage 196).
Important safety notes
Traffic Sign Assist is only an aid and is not always
able to correctly display speed limits. Traffic
signs always have priority over the Traffic Sign
Assist display.
The system may be either functionally impaired
or temporarily unavailable if the information in
the digital street map of the navigation system is
incorrect or out of date.
Instrument cluster display
Displaying the assistance graphic
XCall up the assistance graphics display func-
tion using the on-board computer
(
Ypage 196).
XSelect the Traffic Sign Assist display.
Detected traffic signs are displayed in the
instrument cluster.
Speed limit with unknown restriction
:Maximum permitted speed
;Maximum permitted speed for vehicles for
which the restriction in the additional sign is relevant
=Additional sign for unknown restriction
A maximum permitted speed of 100 mph
(100 km/h) and a speed limit of 80 km/h
(80 mph) apply with an unknown restriction.
Driving systems179
Driving and parking
Z

Switching on Blind Spot Assist
XMake sure that Blind Spot Assist
(Ypage 198) is activated in the on-board
computer.
XTurn the SmartKey to position 2in the ignition
lock.
Warning lamps :in the exterior mirrors light
up red for approximately 1.5 seconds and
then turn yellow.
Lane Keeping Assist
General notes
Lane Keeping Assist monitors the area in front of
your vehicle with camera :, which is mounted
at the top of the windshield. Active Lane Keeping
Assist detects lane markings on the road and
can warn you before you leave your lane unin-
tentionally.
This function is available in the range between
40 mph and 120 mph (60 km/h and 200 km/h).
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.
Important safety notes
GWARNING
Lane Keeping Assist may not always clearly
recognize lane markings.
In this case, Lane Keeping Assist may:
Rgive an unnecessary warning
Rnot give a warning
There is a risk of an accident.
Always pay particular attention to the traffic
situation and stay in lane, in particular if
warned by Lane Keeping Assist.
GWARNING
The Lane Keeping Assist warning does not
return the vehicle to the original lane. There is
a risk of an accident.
You should always steer, brake or accelerate
yourself, in particular if warned by Lane Keep-
ing Assist.
If you fail to adapt your driving style, Lane Keep-
ing Assist can neither reduce the risk of an acci-
dent nor override the laws of physics. Lane
Keeping Assist cannot take into account the
road, traffic and weather conditions. Lane Keep- ing Assist is merely an aid. You are responsible
for the distance to the vehicle in front, for vehi-
cle speed, for braking in good time and for stay-
ing in your lane.
The Lane Keeping Assist does not keep the vehi-
cle in the lane.
The system may be impaired or may not function
if:
Rthere is poor visibility, e.g. due to insufficient
illumination of the road, or due to snow, rain,
fog or spray
Rthere is glare, e.g. from oncoming traffic, the
sun or reflections (e.g. when the road surface
is wet)
Rthe windshield is dirty, fogged up, damaged or
covered, for instance by a sticker, in the vicin-
ity of the camera
Rthere are no, several or unclear lane markings
for a lane, e.g. in areas with road construction
work
Rthe lane markings are worn away, dark or cov-
ered up, e.g. by dirt or snow
Rthe distance to the vehicle in front is too small and the lane markings thus cannot be detec-
ted
Rthe lane markings change quickly, e.g. lanes
branch off, cross one another or merge
Rthe road is narrow and winding
Rthere are strong shadows cast on the road
Switching on Lane Keeping Assist
XSwitch on Active Lane Keeping Assist using
the on-board computer; to do so, select
Standard
or Adaptive(Ypage 198).
If you drive at speeds above 40 mph
(60 km/h) and lane markings are detected,
the lines in the assistance graphics display
182Driving systems
Driving and parking

iCanada only: This device complieswit h
RSS -210 of Industry Canada. Operation is
subject to the foll owing two conditions:
1. This device may not cause harmful inter-
ference, and
2. This device must accept any interference
receive d,inc ludin g interference that may
cause undesired operation of the device.
Removal, tampering, or altering of the device
will void any warranties, and isnot permitte d.
Do not tamper with, alter, or use inany non-
approved way.
Any unauthorized mod ification to th isdevice
could void the user's authority to operate the equipm ent.
Radar sensors
The Active BlindSpo t Assist radar sensors are
integrated into the front and rear bumpers and
behind a cover inthe radiator trim. Make sure
that the bumpers and the cover inthe radiator
grill are free of dirt, ice or slush. The rear sensors
must not becovered, for example bycyc leracks
or overhanging cargo. Fol lowing a severe impact
or inthe event of damage to the bumpers, have
the function of the radar sensors checked at a
qualif ied specialist workshop.ActiveBlindSpo t
Assist may otherwise no longer work properly.
Monitoring area
GWARNING
Active BlindSpo t Assist does not detect all
traff icsituations and road users. There isa
risk of an acc ident.
Alwa ys make sure that there issuff icientdis-
tance on the sidefor other traff icor obstacles.
The detection of obstacles can beimpaired in
the case of:
Rthere isdirt on the sensors or anything else
covering the sensors
Rpoor visibility, e.g. due to rain, snow or spray
Vehicles in the monitoring range are then not
indicated or indicated with a delay.
Active Blind Spot Assist may not detect narrow
vehicles, such as motorcycles or bicycles, or
may only detect them too late.
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 driv- ing inthe midd le of their lane. This may be the
case if there are vehicles at the edge of their
lane.
Due to the nature of the system:
Rwarnings may be issued inerror when driving
close to crash barriers or similar solid lane
borders.
Rthe warning is canceled when driving for an
extended period next to long vehicles, such as
trucks.
184Driving systems
Driving and parking

RESP®is switched off.
Ra loss of tire pressure or a defective tire is
detected.
Switching on Active Blind Spot Assist
XMake sure that Active Blind Spot Assist
(Ypage 198) is activated in the on-board
computer.
XTurn the SmartKey to position 2in the ignition
lock.
Warning lamps :in the exterior mirrors light
up red for approximately 1.5 seconds and
then turn yellow.
Active Lane Keeping Assist
General notes
Active Lane Keeping Assist monitors the area in
front of your vehicle by means of multifunction
camera :at the top of the windshield. Various
different areas to the front, rear and side of your
vehicle are also monitored with the aid of the
radar sensor system. Active Lane Keeping
Assist detects lane markings on the road and
can warn you before you leave your lane unin-
tentionally. If you do not react to the warning, a
lane-correcting application of the brakes can
bring the vehicle back into the original lane.
This function is available in the range between
40 mph and 120 mph (60 km/h and 200 km/h).
For Active Lane Keeping Assist to assist you
when driving, the radar sensor system must be
operational
Important safety notes
If you fail to adapt your driving style, Active Lane
Keeping Assist can neither reduce the risk of
accident nor override the laws of physics. Active
Lane Keeping Assist cannot take account of
road and weather conditions. It may not recog- nize traffic situations. Active Lane Keeping
Assist is only an aid. You are responsible for the
distance to the vehicle in front, for vehicle
speed, for braking in good time and for staying in
you
r lane.
Active Lane Keeping Assist cannot continuously
keep your vehicle in its lane.
GWARNING
Active Lane Keeping Assist cannot always
clearly detect lane markings.
In such cases, Active Lane Keeping Assist
can:
Rgive an unnecessary warning and then
make a course-correcting brake application
to the vehicle
Rnot give a warning or intervene
There is a risk of an accident.
Always pay particular attention to the traffic
situation and keep within the lane, especially
if Active Lane Keeping Assist alerts you. Ter-
minate the intervention in a non-critical driv-
ing situation.
The system may be impaired or may not function
if:
Rthere is poor visibility, e.g. due to insufficient
illumination of the road, or due to snow, rain,
fog or spray
Rthere is glare, e.g. from oncoming traffic, the
sun or reflections (e.g. when the road surface
is wet)
Rthe windshield is dirty, fogged up, damaged or
covered, for instance by a sticker, in the vicin-
ity of the camera
Rthe radar sensors in the front or rear bumpers
or the radiator trim are dirty, e.g. obscured by
snow
Rthere are no, several or unclear lane markings
for a lane, e.g. in areas with road construction
work
Rthe lane markings are worn away, dark or cov-
ered up, e.g. by dirt or snow
Rthe distance to the vehicle in front is too small
and the lane markings thus cannot be detec-
ted
Rthe lane markings change quickly, e.g. lanes
branch off, cross one another or merge
186Driving system s
Driving an d parking

Important safety notes
GWARNING
If you operate information systems and com-
munication equipmen tintegrate din th evehi-
cle while driving ,you will be distracte dfrom
traffic conditions. You could also lose control
of th evehicle. Ther eis aris kof an accident.
Only operate th eequipmen twhen th etraffic
situation permits. If you are no tsur ethat this
is possible ,park th evehicl epayin gattention
to traffic condition sand operate th eequip-
men twhen th evehicl eis stationary.
You must observ eth elegal requirements for th e
country in whic hyou are currentl ydriving when
operating th eon-board computer.
GWARNIN G
If th einstrumen tcluste rhas faile dor mal-
functioned, you may no trecognize function
restriction sin systems relevan tto safety. The
operating safet yof your vehicl emay be
impaired .Ther eis aris kof an accident.
Drive on carefully. Hav eth evehicl echecke d
at aqualified specialist workshop immedi-
ately.
The on-board computer only shows message sor
warning sfrom certain systems in th emultifunc-
tion display. You should therefor emak esur e
your vehicl eis operating safely at all times .
If th eoperating safet yof your vehicl eis
impaired ,pull ove ras soo nas it is saf eto do so.
Contac t aqualified specialist workshop.
Fo ran overview, see th einstrumen tpanel illus-
tration (
Ypage 33).
Displays and operation
Speedometer with segments
The segments in th espeedometer indicat e
whic hspee drange is available.
RCruis econtrol activated (Ypage 151):
The segments ligh tup from th estore dspee d
to th etype-tested maximum speed.
RDISTRONI CPLU Sactivated (Ypage 153): On
eor two segments in th eset spee drange
ligh tup.
RDISTRONI CPLU Sdetects avehicl ein front:
The segments between th espee dof th evehi-
cle in fron tand th estore dspee dligh tup.
Tachometer
!
Do no tdriv ein th eoverrevving range, as this
could damag eth eengine.
The red ban din th etachometer indicates th e
engine's overrevving range.
The fuel suppl yis interrupted to protect th e
engin ewhen th ered ban dis reached.
Outside temperature display
You should pay special attention to road condi-
tion swhen temperatures are aroun dfreezing
point.
Bea rin min dthat th eoutside temperature dis-
play indicates th etemperature measured and
does no trecord th eroad temperature.
The outside temperature display is in th emulti-
function display (
Ypage 191).
The multifunction display shows changes in th e
outside temperature wit h adelay.
Coolant temperature display
GWARNIN G
Opening th ehoo dwhen th eengin eis over-
heated or when there is afir ein th eengin e
compartmen tcould expos eyou to hot gase s
or other servic eproducts .Ther eis aris kof
injury.
Let an overheate dengin ecool down before
opening th ehood. If there is afir ein th e
engin ecompartment, keep th ehoo dclosed
and contact th efir edepartment.
!A display message is shown if th ecoolan t
temperature is to ohigh .
If th ecoolan ttemperature is ove r24 8 ‡
(12 0†), do no tcontinue driving .The engin e
will otherwise be damaged.
The coolan ttemperature gauge is in th einstru-
men tcluste ron th eleft-han dside (
Ypage 33).
Displays and operation189
On-board computer and displays
Z

Display messagesPossible causes/consequences andMSolutions
$(USA
only)
J( Canada
only)
Check Brake Fluid
Level
There is no tenough brak eflui din th ebrak efluid reservoir .
In addition ,th e$ (USAonly) or J(Canada only) warning lamp
lights up in th einstrumen tcluste rand awarning tone sounds.
GWARNIN G
The braking effec tmay be impaired.
There is aris kof an accident.
XPull ove rand stop th evehicl esafely as soo nas possible, payin g
attention to roa dand traffic conditions. Do no tcontinu edrivin g
under any circumstances.
XSecur eth evehicl eagainst rollin gaway (Ypage 144).
XConsult aqualified specialist workshop .
XDo notadd brak efluid .This does no tcorrec tth emalfunction .
#
CheckBrakePadWear
The brak epads/linings hav ereached their wear limit.
XVisit aqualified specialist workshop .
G
mbrace Inoperative
Oneor mor emain features of th embrace system are malfunctioning .
XVisitaqualified specialist workshop .
Collision Preven‐tionAssist Plu sCurrently Unavaila‐ble See Operator' sManual
COLLISION PREVENTION ASSIST PLU Sis temporarily no toperational.
Possibl ecauses are:
Rth eradar sensor system is temporarily inoperative, e.g. due to elec -
tromagneti cradiation emitted by nearby TV or radi ostation sor
other source sof electromagneti cradiation .
Rthesystem is outside th eoperating temperature range.
Rth eon-boar dvoltag eis to olow.
Whe nth ecauses state dabov eno longer apply, th edisplay message
disappears.
COLLISION PREVENTION ASSIST PLU Sis operational again .
If th edisplay message does no tdisappear :
XPull overand stop th evehicl esafely as soo nas possible, payin g
attention to roa dand traffic conditions.
XSecur eth evehicl eagainst rollin gaway (Ypage 144).
XRestart th eengine.
Collision Preven ‐tionAssist Plu sInoperative
COLLISION PREVENTION ASSIST PLU Sis temporarily inoperative due
to amalfunction .Adaptive Brake Assis tmay also hav efailed.
XVisit aqualified specialist workshop .
PRE-SAFE
Inoperative SeeOperator'sManual
Importan tfunction sof PRE-SAF E®havefailed. Al lother occupant
safet ysystems ,e.g. air bags ,remain available.
XVisit aqualified specialist workshop .
Display messages205
On-board computer and displays
Z

Display messagesPossible causes/consequences andMSolutions
PRE-SAFE
FunctionsCurrentlyLimitedSee Opera‐tor's Manual
PRE ‑S AF E®PLU Sor PRE‑SAFE®Brake is temporarily inoperative.
Possibl ecauses are:
Rfunction is impaire ddue to heav yrain or snow.
Rth eradar sensor system is temporarily inoperative, e.g. due to elec -
tromagneti cradiation emitted by nearby TV or radi ostation sor
other source sof electromagneti cradiation .
Rthesystem is outside th eoperating temperature range.
Rth eon-boar dvoltag eis to olow.
Whe nth ecauses state dabov eno longer apply, th edisplay message
disappears.
PRE ‑SAFE
®PLU Sand PRE ‑SAFE®Brake are operational again .
If th edisplay message does no tdisappear :
XPull overand stop th evehicl esafely as soo nas possible, payin g
attention to roa dand traffic conditions.
XSecur eth evehicl eagainst rollin gaway (Ypage 144).
XRestart th eengine.
PRE-SAFE
Functions Limite dSee Operator'sMan ‐ual
PRE ‑S AF E®PLU Sor PRE‑SAFE®Brake is unavailable due to amal-
function .BA SPLU Swit hCross-Traffic Assis tmay also hav efailed.
XVisit aqualified specialist workshop .
206Display messages
On-board computer and displays