
Function
Starting at aspeedofa pproximately 4mph
(7 km/h), th edistanc ewarning function warns
you ifyou rapid ly approachav ehicle in front. An
intermittentw arning tonewillthen sound, and
the · distancewarning lamp willlight up in
th ei nstrumen tcluster.
XBrake immediately inorder to increas ethe
dist ancefromt heveh icle in front.
or
XTakee vasive action,p rovide ditiss afe todo
so.
Due to th enature of th esystem, particularly
co mpli cated but non-critical driving conditions
may also caus ethe system to displayaw arning.
Witht hehelp of th eradar sensor system, the
dist ancewarning function can detect obstacles
that are inthep athofy our veh iclefor an exten-
ded period of time.
Up to aspeedofa pproximately 44 mph
(70 km/ h),t he distance warnin gfunction can
also react to stationary obstacles, such as stop-
ped or parked vehicles.
Autonomous braking function
If the driver does not react to the distance warn-
ing signal in acritical situation, Active Brake
Assis tcan assist with the autonomous braking
function.
If the autonomous brakin gfunction requires a
particularly high brakin gforce, preventative
passenger protection measures (PRE-SAFE
®)
are activated simultaneously.
Vehicles without Distance Pilot DISTRONIC:
the autonomous brakin gfunction is available in
the following speed ranges:
R4-65m ph (7-105 km/ h)for moving objects
R4-31m ph (7-50km/h)for stationary
objects
Vehicles with Distance Pilot DISTRONIC: the
autonomous braking function is available in the
following speedr anges:
R4-124 mph (7 -200 km/h )for moving
objects
R4-31m ph (7-50km/h)for stationary
objects
Due to the nature of the system ,particularly
complicated but non-critical driving conditions
may als ocaus ethe Autonomou sBraking Func-
tion to intervene. If the autonomous braking function requires a
particularly high braking force, preventative
passenger protection measures (PRE-SAFE
®)
are activated simultaneousl y(Ypage51).
Adaptive Brake Assist
General information
iObservet he "Important safety notes" sec-
tion (Ypag e54).
With the help of adaptive Brake Assist, the dis-
tance warning signa lcan detect obstacles that
are in the path of you rvehiclef or an extended
period of time.
If adaptive Brake Assist detects arisk of colli-
sion with the vehicl einfront, it calculate sthe
braking force necessary to avoi dacollision. If
you apply the brakes forcefully ,adaptive Brake
Assist wil lautomatically increas ethe braking
force to alevels uitabl efor the traffic conditions.
Adaptive Brake Assist provides braking assis-
tance in hazardouss ituations at speeds above
4m ph (7 km/h) .Itusesrada rsensor technology
to assess the traffic situation.
Up to aspeedofa pproximately 155 mph
(250 km/h) ,adaptive Brake Assist is capable of
reacting to moving objects that have already
been detected as such at least once over the
period of observation.
Up to aspeedofa pproximately 44 mph
(70 km/h), adaptive Brake Assist reacts to sta-
tionary obstacles.
If adaptive Brake Assist demands particularly
high braking force, preventative passenger pro-
tection measures (PRE-SAFE
®)a re activated
simultaneousl y(Ypage51).
XKeep the brake pedald epressed until the
emergency braking situation is over.
ABS prevents the wheels from locking.
The brakes wil lwork normally again if:
Ryou release the brake pedal.
Rthere is no longe rany dange rofacollision.
Rno obstacle is detected in front of you rvehi-
cle.
Adaptive Brake Assist is then deactivated.
Driving safety systems57
Safety
Z

Checking thebattery
XPress the &or% button.
The battery is working properl yifbattery
check lamp :lightsupb riefly.
The battery is discharged if battery check
lamp :does no tlight up briefly.
XChange th ebattery (Ypage 66).
If th eSmartKey battery is checked within the
signal reception range of th evehicle ,pressing
the & or% button:
Rlocks or
Runlock sthe vehicle
iYou can get abattery at any qualified spe-
cialist workshop.
Replacin gthe battery
You require aCR20253V cellbattery.
XTaket hemechanical ke yout of th eSmartKey
(Ypage 65).
XPress mechanical key ;intot he SmartKey
opening in th edirection of th earrow until bat-
tery compartmen tcover :opens. Do not
hold battery compartmen tcover :closed
while doings o.
XRemove battery compartmen tcover :.
XRepeatedly tap th eSmartKey against your
palm until battery =falls out.
XInsertt henewb attery witht hepositiv eter-
minal facing upwards. Use alint-free cloth to
do so.
XMakes ure that th esurface of th ebattery is
free of lint, grease and other contaminants.
XInsertt hefrontt absofb attery compartment
cover :intot he housing and then pres sto
close it.
XInsertm echanical key ;intot he SmartKey
(Ypage 65).
XCheckt hefunction of all SmartKey buttons on
th ev ehicle.
66SmartKey
Opening and closing

!When parking, pay particular attention to
objects above or below the sensors, such as
flower pots or trailer drawbars. PARKTRONIC
does not detect such objects when they are in
the immediate vicinity of the vehicle. You
could damage the vehicle or the objects.
The sensors may not detect snow and other
objects that absorb ultrasonic waves.
Ultrasonic sources such as an automatic car
wash, the compressed-air brakes on atruck
or ap neumatic drill could cause PARKTRONIC
to malfunction.
PARKTRONIC may not function correctly on
uneven terrain.
PARKTRONIC is activated automaticallyw hen
you:
Rswitch on the ignition
Rshift the transmission to position D,Ror N
Rrelease the electric parking brake
PARKTRONIC is deactivated at speeds above
11 mph (18 km/h). It is reactivated at lower
speeds.
Range of the sensors
General notes
PARKTRONIC does not take objects into con-
sideration that are:
Rbelow the detection range, e.g. people, ani-
mals or objects.
Rabove the detection range, e.g. overhanging
loads, truck overhangs or loading ramps.
:Sensors in the front bumper, left-hand side
(example)
The sensors must be free from dirt, ice or slush.
They can otherwise not function correctly. Clean
the sensors regularly, taking care not to scratch
or damage them (
Ypage 240).
Range
Front sensors
CenterApprox. 40 in (approx.
100 cm)
CornersApprox. 24 in (approx.
60 cm)
Rear sensors
CenterApprox. 48 in (approx.
120 cm)
CornersApprox. 32 in (approx.
80 cm)
Minimum distance
CenterApprox. 8in(approx. 20 cm)
CornersApprox. 6in(approx. 15 cm)
If there is an obstacle within this range, the rel-
evant warning displays light up and awarning
tone sounds. If the distance falls below the min-
imum, the distance may no longer be shown.
150Driving systems
Driving and parking

Important safety notes
GWARNING
LaneK eepin gA ssist may no talways clearly
recognize lane markings.
In this case, LaneK eepin gA ssist may:
Rgiveanu nnecessaryw arning
Rnotg iveaw arning
Thereisar iskofana cciden t.
Always pay particula rattentio ntothetraff ic
situation and stay inlane ,inp articula rif
warned byLaneK eepin gA ssist.
GWAR NING
The LaneK eepin gA ssist warning does not
return th evehicle to th eoriginal lane .Therei s
ar iskofana cciden t.
You should always steer,b rakeora ccelerate
yourself, inparticula rifwarned byLaneK eep-
ing Assist.
If you fail to adapt your driving style, LaneK eep-
ing Assist can neither reduce th eriskofana cci-
dentn oroverr idethel aws of physics .Lane
Keepin gAssist canno ttak ei ntoa ccountt he
road ,tra ffic and weather conditions. LaneK eep-
ing Assist ismerely an aid.You are responsible
for th edistanc etotheveh icle in front, for veh i-
cle speed, for braking ingood tim eand for stay-
ing inyour lane.
The LaneK eepin gAssist does no tkeept he veh i-
cle inthel ane.
The system may beimpaired or may no tfunction
if:
Rthere ispoor vis ibility, e.g .due to insuff icient
illumi nation of th eroad ,ord ue to snow, rain,
fog or spray
Rthere isglare, e.g .fro mo ncom ingt raffic, the
sun or reflections (e.g. when th eroad surface
is wet)
Rthew indshield is dirty, fogged up, damaged or
covered, for instance byasticker, inthev icin-
ity of th ecamera
Rthere are no ,several or unclear lane markings
for alane ,e.g.ina reas withroad construction
work
Rth el ane markings are worn away, dark or cov-
ere dup,e.g .byd irt orsnow
Rthed istanc etothevehicle infrontist oosmall
and th elane markings thus canno tbedetec-
ted
Rth el ane markings chang equickly, e.g. lanes
branch off ,cross onea nother or merge
Rther oad isnarrow and winding
Rthere are stron gshadows cas tontheroad
Switching on Lane Keeping Assist
XSwit ch on Activ eLaneK eepingA ssist using
th eo n-bo ard computer; to do so, select
Standard
or Adaptive(Ypage 171).
If you driv eatspeeds above4 0mph
(60 km/ h)and lane markings are detected,
th el ine sint heassistance graphicsd isplay
(
Ypage 171) are showning reen. LaneKeep-
ing Assist is ready for use.
Standard
If Standardis selected, no warning vibration
occurs if:
Ryou switch on th eturns ignals. In this event,
th ew arning sare suppressedf orac ertain
period of time.
Rad riving safety system intervenes, sucha s
ABS, BA SorESP®.
Adaptive
When Adaptiveis selected, no warning vibra-
tio no ccurs if:
Ryou switch on th eturns ignals. In this event,
th ew arning sare suppressedf orac ertain
period of time.
Rad riving safety system intervenes, e.g .ABS ,
BA SorE SP®.
Ryou accelerate hard,e .g.k ickdown.
Ryou brak ehard.
Ryou steer actively, e.g .swerve to avoid an
obstacle or chang elane squickly.
Ryou cut th ecorner on asharpb end.
In orde rtha ty ou are warned only when neces-
sary and in good tim eifyou cross th elane mark-
ing ,the system recognize scertain conditions
and warn syou accordingly.
The warning vibratio noccurs earlieri f:
Ryou approach th eouter lane markin gona
bend.
Rth er oad has ver ywide lanes, e.g .ahighway.
Rthes ystem recognize ssolid lane markings.
Driving systems161
Driving and parking
Z

Safety systems
Display messagesPossible causes/consequences andMSolutions
!÷
Currently Unavaila‐ble See Operator'sManual
ABS (Anti-lock Braking System) and ESP®(Electronic Stability Pro-
gram) are temporarily not available.
Other driving systems and driving safety systems may also malfunc-
tion.
In addition, the ÷,åand! warning lamps light up in the
instrumentc luster.
Possible causes are:
Rself-diagnosis is not yet complete.
Rthe on-board voltage may be insufficient.
GWARNING
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.
XCarefullyd riveasuitable distance, making slight steering move-
mentsatas peed above 12 mph (20 km/h).
If the display message disappears, the functions mentioned above are available again.
If the multifunction display still shows the display message:
XDrive on carefully.
XVisit aqualified specialist workshop immediately.
!÷
Inoperative SeeOperator's Manual
ABS and ESP®are malfunctioning.
Other driving systems and driving safety systems may also malfunc-
tion.
The $ (USA only) or J(Canada only), ÷,åand!
warning lamps in the instrumentc luster also light up.
GWARNING
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.
XDrive on carefully.
XVisit aqualified specialist workshop immediately.
Display messages179
On-board computer and displays
Z

Safety systems
Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
$JN$ (USA only) or J(Canada only): the red brake system warning lamp is
lit while the engine is running. Awarning tone also sounds.
GWARNING
There is not enough brake fluid in the brake fluid reservoir.
The braking effect may be impaired.
There is arisk of an accident.
XPull over and stop the vehicle safely as soon as possible, paying attention to road
and traffic conditions. Do not continue driving under any circumstances.
XSecure the vehicle against rolling away (Ypage 131).
XDo not add brake fluid. Adding more will not correct the malfunction.
XConsult aqualified specialist workshop.
XObserve the additional display messages in the multifunction display.
$NUSA only: the red brake system warning lamp is lit while the engine is running.
The multifunction display also shows adisplay message with the #symbol.
The brake pads/linings have reached their wear limit.
XVisit aqualified specialist workshop.
!NThe yellow ABS warning lamp is lit while the engine is running.
ABS (anti-lock braking system) is malfunctioning.
If there is an additional warning tone, the EBD (electronic brake force distribution)
is malfunctioning.
Other driving systems and driving safety systems may also malfunction.
GWARNING
The brake system continues to function normally, but without the functions listed
above. The front and rear wheels could therefore lock if you brake hard, for exam-
ple.
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.
XObserve the additional display messages in the multifunction display.
XDrive on carefully.
XVisit aqualified specialist workshop immediately.
If the ABS control unit is faulty, there is also apossibility that other systems, such
as the navigation system or the automatic transmission, will not be available.
204Warning and indicator lamps
On-board computer and displays

Warning/
indicator
lampNSignal type
Possiblec auses/consequences and M
Solutions
$J
֌
!N$ (USA only), J(Canada only): the red brake warning lamp and the yellow
ESP®,E SP®OFF and ABS warning lamp sare lit while the engine is running.
ABS and ESP®are malfunctioning.
Other driving systems and driving safety systems may als omalfunction.
GWARNING
The brake system continues to function normally, but without the functions listed
above. The front and rear wheels coul dtherefore lock if you brake hard ,for exam-
ple.
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.
XObserve the additiona ldisplay messages in the multifunction display.
XDrive on carefully.
XVisi taq ualified specialist worksho pimmediately.
÷N The yellow ESP®warning lamp flashes while the vehicleisinm otion.
ESP®or traction control has intervened because there is arisk of skidding or at
least one whee lhas started to spin.
Cruise control or Distance Pilot DISTRONIC is deactivated.
XWhen pulling away, only depress the accelerator pedalasf ar as necessary.
XEase off the accelerator pedalwhile the vehicleisinmotion.
XAdapt yourdriving style to sui tthe road and weather conditions.
XDo not deactivate ESP®.
In rare cases (
Ypag e60) it may be best to deactivate ESP®.
Observe the important safety notes on ESP®(Ypag e58).
÷åNThe yellow ESP®and ESP®OFF warning lamp sare lit while the engine is running.
ESP®is malfunctioning.
Other driving systems and driving safety systems may als omalfunction.
GWARNING
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.
XObserve the additiona ldisplay messages in the multifunction display.
XDrive on carefully.
XVisi taq ualified specialist worksho pimmediately.
Warning and indicator lamps205
On-board computer and displays
Z

XPull the tire sealant bottle out of the tire infla-
tion compressor.
The filler hose remains attached to the tire
sealant bottle.
XDrive to the nearest qualified specialist work-
shop and have the tire changed there.
XHave the tire sealant bottle and the filler hosereplaced as soon as possible at aqualified
specialist workshop.
XHave the tire sealant bottle replaced every
four years at aqualified specialist workshop.
Battery (vehicle)
Important safety notes
Special tools and expert knowledge are required
when working on the battery, e.g. removal and
installation .You should therefore have all work
involvin gthe battery carried out at aqualified
specialist workshop.
GWARNING
Work carried out incorrectly on the battery
can lead, for example, to ashort circuit and
thus damage the vehicle electronics. This can
lead to function restriction sapplying to
safety-relevant systems, e.g the lighting sys-
tem, the ABS (anti-loc kbraking system) or the
ESP
®(Electronic Stability Program). The oper-
ating safety of your vehicle may be restricted.
You could lose control of the vehicle, for
example:
Rwhen braking
Rin the event of abrupt steerin gmaneuvers
and/or when the vehicle's speed is not
adapted to the road conditions
There is arisk of an accident.
In the event of ashort circuit or asimilar inci-
dent, contact aqualified specialist workshop
immediately. Do not drive any further .You
should have all work involvin gthe battery car-
ried out at aqualified specialist workshop.
For further information about ABS and ESP
®,
see (Ypage 55) and (Ypage 58).
GWARNING
Electrostatic build-up can lead to the creation of sparks, which could ignite the highly explo-
sive gases of abattery. There is arisk of an
explosion.
Before handling the battery, touch the vehicle
body to remove any existin gelectrostatic
build-up.
The highly flammable gas mixture forms when
charging the battery as well as when jump-start-
ing.
Always make sure that neither you nor the bat-
tery is electrostatically charged. Abuild-up of
electrostatic charge can be caused, for exam-
ple:
Rby wearing clothin gmade from synthetic
fibers
Rdue to friction between clothin gand seats
Rif you push or pull the battery across the car-
pet or other synthetic materials
Rif you wipe the battery with acloth
GWARNING
During the charging process, abattery produ-
ces hydrogen gas. If ashort circuit occurs or
sparks are created, the hydrogen gas can
ignite. There is arisk of an explosion.
RMake sure that the positive terminal of a
connected battery does not come into con-
tact with vehicle parts.
RNever place metal object sortools on abat-
tery.
RIt is importan tthat you observe the descri-
bed order of the battery terminals when
connectin gand disconnectin gabattery.
RWhen jump-starting, make sure that the
battery poles with identical polarity are
connected.
RIt is particularly importan ttoobserve the
described order when connectin gand dis-
connectin gthe jumper cables.
RNever connect or disconnect the battery
terminals while the engine is running.
GWARNING
Battery acid is caustic. There is arisk of injury.
246Battery (vehicle)
Breakdown assistance