Page 65 of 441

BAS (Brak
eAssis tSystem)
i Observet he "Imp ortant safety notes "sec-
tion (Y page 61). G
WARNING
If BAS is malfunctioning, the braking distance
in an emergency braking situation is
increased .There is arisk of accident.
In an emergenc ybraking situa tion, depress
the bra kepedal with full force. AB Sprevents
th ew heels fr om locking.
BAS operate sinemergency brakin gsitua-
tions. If you depress the brake pedal quickly,
BAS automatically boosts the brakin gforce,
thus shortening the stoppin gdistance.
The brakes will func tion as usual onc eyou
release the brake pedal. BA Sisd eactivated. BAS PLUS (Brake Assist Syste
mPlus)
i Observe the "Importan tsafety notes" sec-
tion (Y page 61).
BAS PLUS is only available on vehicles with
DISTRONIC PLUS.
BAS PLUS provides braking assistance in haz-
ardous situations at speeds greater than
7k m/h and uses rad ar sensortechnology to
assess the traffic situation.
With the help of the rada rsensor system ,BAS
PLU Scan detect obstacles that are in the
path of your vehicle for an extended period of
time.
At speeds up to approximately 70 km/ h,BAS
PLUS may also det ects tationar yobstacles,
for example, stopped or parked vehicles.
To prevent afront-en dcollision, BA SPLUS
calculate sthe brake force necessary if:
R you approach an obstacle, and
R BA SP LUS ha sdetected arisk of collision
If you ar edriving at aspeed over
30 km/h:ify ou depress the brake sharply,
BA SP LUS automatically raise sthe brake
pressur etoavalue adapted to the traffic sit-
uation. If you are driving at
aspeed under
30 km/h:ify ou depress the brake, BA SPLUS
is activated. Braking will be carried ou tatthe
last possible moment.
If BA SPLUS demand sparticularly high brak-
ing force, preventative passenger protection
measures (PRE-SAFE ®
)a re activate dsimul-
taneously.
X Keep the brake pedal depressed until the
emergenc ybraking situatio niso ver.
ABS prevents th ewheels from locking.
BA SP LUS is deactivate dand the brakes func-
tion as usual ,if:
R you release th ebrake pedal.
R there is no longe rany danger of arear-end
collision.
R no obstacl eisdetected in front of your
vehicle.
If you have activated DSR (Y page 251), BAS
PLU Sisa lso deactivated.
The radar sensor system is switched off auto-
matically in the vicinit yofradio telescope
facilities in the following vehicles:
R vehicles with COMAND Online and naviga-
tion
R vehicles with Audio 20 and Becker ®
MAP
PILOT
Becker ®
MAP PILOT must be connected;
see the separate operating instructions.
The radar senso rsystem must be switched off
using the on-board computer in the vicinit yof
radio telescop efacilities in the following vehi-
cles:
R vehicles without COMAND Online and nav-
igation
R vehicles without Audio 20 and Becker ®
MAP PILOT
R vehicles for Australia
For information on switching off the radar
senso rsystem using the on-board computer,
see (Y page 283). 62
Driving safety systemsSafety
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For BAS PLUS to assis
tyou whe ndriving, the
rad ar se nsorsystem must:
R be switched on (Y page 283)
R be operational (Y page 298)
If the radar sensor syste mism alfunctioning,
BA SP LUS wi llnot be available. The brake
system is stil lavailable wit hcomplete brake
boostin geffect and BAS. G
WARNING
BAS PLUS canno talways clearly identify
objects and complex traffic situations. BAS
PLU Scannot intervene in these cases. There
is ar isk of an accident.
Always pay careful attention to the traffic sit-
uation and be ready to brake.
In partic ular,the detection of obstacles can
be im paired if there is:
R dirt on the sensors or anything else cov er-
ing the sensors
R snow or heavy rain
R interference by othe rradar sources
R the possibility of stron gradar reflections,
for example, in multi-storey car parks
R an arrow vehicle travellin ginfront,e.g. a
motorcycle
R av ehicle travel lingin fron tonad ifferent
line G
WARNING
BA SP LUSd oes no treact:
R to peopl eoranimals
R to oncomin gvehicles
R to crossin gtraffic
R when corneri ng
As aresult, BAS PLU Smay not intervene in all
critical situations. There is arisk of an acci-
dent.
Always pay careful attention to the traf fics it-
uation and be ready to brake.
Following damage to the fron tend of the vehi-
cle ,havet he configuration and operation of
the radar sensors checked at aqualified spe- cialist workshop. This also applie
stoc olli-
sions at slow speeds where ther eisnovisible
damage to the fron tofthe vehicle. COLLISION PREVENTION ASSIST
Genera lnotes COLLISION PREVENTION ASSIST consist
sof
Adaptive Brake Assist and the distance warn-
ing function, which are described in the fol-
lowing.
Distance warnin gfunction Important safety notes
i
Observe th e"Importan tsafety notes" sec-
tion (Y page 61). G
WARNING
The distance warning function does not react:
R to people or animals
R to oncomin gvehicles
R to crossing traffic
R when cornering
Thus, the distanc ewarning function cannot
provide awarning in all critical situations.
There is arisk of an accident.
Always pay careful attention to the traffic sit-
uation and be ready to brake.
The distance warnin gfunction cannot always
clearly identify objects and complex traffic
situations.
In such cases, the distance warning signal
may:
R give an unnecessary warning
R not give awarning
Always pay careful attention to the traffic sit-
uation, do not rely on the distance warning
function alone.
Function
X To activate/deactivate: activate or deac-
tivate the distance warning function in the
on-board computer (Y page 278). Driving safety systems
63Safety Z
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When the distan
cewarning function is acti-
vated, the multifunction display shows the
Ä symbol as long as the HOLD function is
not activated (Y page 211). On vehicles with
Active Parking Assist, the Äsymbol is dis-
played when position Pis engaged or you are
driving faster than 35 km/h.
The distanc ewarning function can help you
to minimise the risk of acollision with the
vehicle in fron torreduce the effects of such
ac ollision .Ifthe distanc ewarning function
detect sthat ther eisar isk of acollision ,you
will be warned visually and acoustically .The
distanc ewarning function cannot preven ta
collision without your inte rvention.
The distan cewarning function will issue a
warning at speed sofaround 30 km/h or
more if:
R thed istanc etothe vehicle in fron tist oo
short for the speed you ar edriving at for
severa lseconds. The ·distan cewarn-
ing lamp then lights up in the instrument
cluster.
R you are rapidly approaching the vehicle in
front. An intermittent warning ton ewill
then sound and the ·distanc ewarning
lamp will light up in the instrument cluster.
X Brak eimmediatel yinordertoi ncreas ethe
distanc efrom th evehicle in front.
or
X Take evasiv eactio nprovide ditiss afe to do
so.
For the distanc ewarning function to assist
you when driving, the function must be acti-
vated in the on-board computer and be opera-
tional (Y page 278).
Due to the nature of the system, particularly
complicated driving conditions may cause the
system to display an unnecessary warning.
With the help of the radar senso rsystem, the
distanc ewarning function can detect obsta-
cles that are in the path of your vehicle for an
extended period of time.
At speeds up to approximately 70 km/h, the
distance warning fun ction may also detect stationary obstacles, for example, stopped or
parked vehicles.
If you approach an obstacle and the distance
warnin gfunction detects arisk of acollision,
the system will initially aler tyou both visually
and acoustically.
In particular ,the detection of obstacles can
be impaired if ther eis:
R dir tont he sensors or anythin gelse cover-
ing the sensors
R snow or heavy rain
R interferenc ebyother radar sources
R the possibility of strong radar reflections,
for example, in multi-storey car parks
R an arro wvehicle travelling in front, e.g. a
motorcycle
R av ehicle travelling in fron tonadifferent
line
Following damage to the fron tend of the vehi-
cle ,havet he configuration and operation of
the radar sensor checked at aqualified spe-
cialist workshop. This also applie stoc olli-
sions at slow speeds where ther eisnovisible
damage to the fron tofthe vehicle.
Adaptive Brake Assist i
Observ ethe "Importan tsafety notes" sec-
tion (Y page 61). G
WARNING
Adaptive Brake Assist cannot always clearly
identify objects and complex traffic situa-
tions. In these cases, Adaptive Brake Assist
may not intervene. There is arisk of an acci-
dent.
Always pay careful attention to the traffic sit-
uation and be ready to brake. G
WARNING
Adaptive Brak eAssist does not react:
R to people or animals
R to oncomi ng vehicles
R to crossing traffic 64
Driving safety systemsSafety
Page 68 of 441

R
to stationary obstacles
R when cornering
As aresult, Adaptive Br akeA ssist may not
int ervene in al lcritica lconditions .There is a
risk of an accident.
Always pay carefu lattention to the traffic sit-
uation and be ready to brake.
Adaptive Brake Assist aids you in braking dur-
ing hazardous situations at speeds above
30 km/h and uses the radar sensor system
to evaluate the traffic situation.
With the hel pofthe adaptive Brake Assist ,the
distanc ewarning signal can detect obstacles
that are in the path of your vehicle for an
extended period of time.
Should you approach an obstacle and the
adaptive Brake Assis thas detected arisk of
collision, the adaptive Brake Assist calculates
the brakin gforc enecessar ytoavoidac olli-
sion with the vehicle in front .Should you
apply the brakes forcefully ,the adaptive
Brake Assist will automatically increase the
brakin gforc etoal evel suitable for the traffic
conditions.
X Keep the brak epedal depressed until the
emergency braking situation is over.
ABS prevents the wheels from locking.
The brakes will work normally again if:
R you release the brak epedal.
R there is no longer any danger of arear-end
collision.
R no obstacl eisdetected in front of your
vehicle.
Adaptive Brake Assist is then deactivated.
If adaptive Brake Assist demands particularly
high braking force, preventative passenger
protec tion measure s(PRE-SAFE ®
)a re activa-
ted simultaneousl y.
Up to vehicl espeeds of around 25 0km/h,
th ea daptiv eBrake Assist is capable of react-
ing to moving objects that have alread ybeen
recognised as such at least once over the
period of observation .Adaptiv eBrake Assist
does not react to stationary obstacles. If th
eadaptiv eBrake Assist is not available
du et oam alfunction in the radar senso rsys-
tem, the brake syste mremains available with
ful lbrake boostin geffect and BAS.
In particular, th edetection of obstacles can
be impaired if there is:
R dirt on the sensors or anything else cover-
ing the sensors
R snow or heavy rain
R interference by other rada rsources
R the possibility of stron gradar reflections,
for example, in multi-storey car parks
R an arrow vehicle travelling in front ,e.g. a
motorcycle
R av ehicle travelling in front on adifferent
line
Following damage to the front end of the vehi-
cle, have the configuration and operation of
the radar sensor checked at aqualified spe-
cialist workshop. This also applies to colli-
sions at slow speeds where there is no visible
damage to the front of the vehicle. Adaptive brake lamps
If you brake sharply from aspeed of more
than 50 km/ horifbraking is assisted by BAS
or BAS PLUS, th ebrake lamp sflash rapidly.
In this way, traffic travelling behind you is
warned in an even more noticeable manner.
If you brake sharply from aspeed of more
than 70 km/ htoastandstill, the hazard warn-
ing lamps are activated automatically .Ifthe
brakes ar eapplied again, the brak elamps
light up continuously .The hazard warning
lamps switc hoff automatically if you travel
faster than 10 km/h .You can also switc hoff
th eh azard warning lamps using the hazard
warning button (Y page 122). Driving safety systems
65Safety Z
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ESP
®
(Electronic Stability Program)
Important safety notes i
Observ ethe "Important safety notes "sec-
tio n(Ypage 61). G
WARNING
If ESP ®
is mal functioning, ESP ®
is unable to
stabilis ethe vehicle. In addition, othe rdriving
safety systems are switche doff. This increa-
se st he risk of skiddi ngand an accident.
Driv eonc arefully. Have ESP ®
checked at a
qualified specialis tworkshop.
! Only operat ethe vehicle for amaximum
of ten seconds on abrake dynamometer.
Switch off th eignition.
Application of the brakes by ESP ®
ma yoth-
erwise destroy the brake system.
! Afunction or performanc etest should
only be carried out on atwin-axle dyna-
mometer .Before you operate th evehicle
on such adynamometer, pleas econsult a
qualified workshop. You coul dotherwise
damage the drive train or the brake system.
ESP ®
is deactivated if the åwarning lamp
in the instrument cluster lights up continu-
ousl ywhen the engin eisrunning.
If the ÷ warning lamp and the åwarn-
ing lamp are lit continuously, ESP ®
is not
available due to amalfunction.
Observe the information on warning lamps
(Y page 329 )and display message swhich
ma ybes hown in the inst rument cluster
(Y page 291).
If ESP ®
detects that th evehicle is deviating
from the direction desired by the driver, one
or mor ewheels ar ebrake dtos tabilise the
vehicle .The engin eoutput is also modified to
keep the vehicle on the desired course within
physical limits. ESP ®
assists the driver when
pulling away on wet or slippery roads. ESP ®
can also stabilise the vehicle during braking.
If ESP ®
intervenes, the ÷ESP®
warning
lamp flashes in the instrument cluster. If ESP
®
intervenes:
X Do not deactivate ESP ®
under any circum-
stances.
X When pulling away ,only depress the accel-
erator pedal as far as is necessary.
X Adapt your driving style to suit the prevail-
ing road and weather condi tions.
i Only use wheels with the recommended
tyr es izes. Only then will ESP ®
func tion
properly.
4ETS (Electronic Traction System) Traction con
trol is par tofESP®
.
Tractio ncontrol brakes the drive wheels indi-
vidually if they spin. This enables you to pull
away and accelerate on slipper ysurfaces, for
example if the road surface is slippery on one
side .Ina ddition, mor edrive torqu eistrans-
ferre dtot he wheel or wheels with traction.
Traction con trol remains active if you deacti-
vate ESP ®
.
In appropriate drivin gsituations, activate the
off-road program:
X Vehicles without the ON&OFFROAD pack-
age (Y page 252)
X Vehicles with the ON&OFFROAD package
(Y page 253)
Off- road 4ETS (Electronic Traction Sys-
tem) A4
ETS syste mspecifically suited to off -road
ter rain is activated automatically onc ethe off-
roa dprogram is acti vated on:
R Vehicle swithout the ON&OFFROA Dpack-
age (Y page 252)
R Vehicles with the ON&OFFROAD package
(Y page 253) 66
Driving safety systemsSafety
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Deactivating/activating ESP
®G
WARNING
If you deactivat eESP®
,E SP ®
no longer sta-
bilises the vehicle. There is an increased risk
of skidding and an accident.
Only deactivat eESP®
in th esituation sdescri-
bed in th efollowing. X
To switch off: press button:.
The å ESP®
OF Fw arnin glamp in the
instrumen tcluster lights up.
X To switch on: press button:.
The å ESP®
OFF warnin glamp in the
instrumen tcluster goes out.
ESP ®
is activated automatically when the
engin eisstarted.
The ECO start/stop fun ction switches the
engin eoff automaticall yifthe vehi cles tops
moving. When pulling away again, the engine
start sautomatically. ESP ®
remain sinits pre-
viousl yselected status. Example: if ESP ®
was
deactiva tedb efor ethe engine was switched
off ,ESP ®
remains deactivated when the
engine is switched on again.
If ESP ®
is deactivated and one or more wheels
start to spin, the ÷ESP®
warning lamp in
th ei nstrumen tcluster flashes. In such situa-
tions, ESP ®
will not stabilise th evehicle. It may be best to deact
ivateESP®
in the fol-
lowing situations:
R when using sno wchains
R in deep snow
R on sand or gravel
If you deactivate ESP ®
:
R ESP ®
no longe rimproves driving stab ility.
R traction control is still activated.
R ESP ®
still provides support when you
brake.
R engine torque is not limited and the drive
wheels are abl etospin. The spinnin gofthe
wheels resu ltsinac utting action for better
traction.
Off-roa dESP® An ESP
®
syste mspecif icall ys uited to off-road
terrain is activated automatically once the off-
road progra misactivate don:
R Vehicles without the ON&OFFROAD pack-
age (Y page252)
R Vehicles wit hthe ON&OFFROAD package
(Y page 253)
Off-road ESP ®
intervenes with adelay if there
is oversteerin gorundersteering ,thus improv-
ing traction.
ESP ®
trailer stabilisation G
WARNING
If roa dand weather conditions are poor,
trailer stabilis ation will not be able to prevent
the vehicle/trailer combination from swerv-
ing. Trailers with ahigh centre of gravit ycan
tip over before ESP ®
can detect this. There is
ar isk of an accident.
Always adap tyour driving style to the prevail-
ing road and weather conditions.
If your vehicle/trailer combination begins to
lurch, you can only stabilise the vehicle/
trailer combination by depressin gthe brake
firmly. Driving safety systems
67Safety Z
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In this situation, ESP
®
assist syou and can
detec tifthe vehicle/trailer combination
begins to lurch. ESP ®
slows the vehicle down
by brakin gand limiting the engine outp ut until
the vehicle/trailer combinatio nhas stabi-
lised.
Trailer stabilisation is active above speeds of
about 60 km/h.
Trailer stabilisation does not work if ESP ®
is
deactivated or disabled because of amal-
function.
Crosswin dAssist Strong crosswinds can cause your vehicle to
deviate from astraight course. The crosswind
driving assistance function integrated into
ESP ®
significantly reduces thes eeffects.
ESP ®
intervene sautomatically according to
the direction and intensity of the crosswinds
affecting your vehicle.
When driving on straight roads or gentle
bends ,your vehicle is kept safel yonc ourse
by astabilising brake intervention.
Crosswind driving assistance is active above
av ehicle speed of 80 km /h.
Crosswind driving assistance does not work
if ESP ®
is deactivated or disabled because of
am alfunction. EBD (electronic brake force distribu-
tion)
i Observe the "Importan tsafety notes" sec-
tion (Y page 61). G
WARNING
If EBD has malfunctioned, the rear wheels can
still lock, e.g. under full braking. This increa-
ses the risk of skidding and an accident.
You should therefor eadapt your driving style
to the different handling characteristics. Have
the brak esystem checked at aqualified spe-
cialist workshop. Observe information regarding indicator and
warning lamps (Y
page 327) as well as dis-
play messages (Y page 293).
EBD monitors and controls the brake pres-
sure on the rear wheels to improve driving
stability while braking. ADAPTIVE BRAKE
ADAPTIVE BRAKE enhances braking safety
and offers increased braking comfort. In addi-
tion to the braking function, ADAPTIVE BRAKE
also has the HOLD function (Y page 211) and
hill start assist (Y page 162). PRE-SAFE
®
Brake
i Observe the "Important safety notes" sec-
tion (Y page 61).
PRE-SAFE ®
Brake is only available in vehicles
with DISTRONIC PLUS.
PRE-SAFE ®
Brake can help you to minimise
the risk of acollision with avehicle in front or
reduc ethe effect sofsuchacollision .IfPRE-
SAFE ®
Brake has detected arisk of collision,
you will be warned visually and acoustically
as well as by automatic braking. PRE-SAFE ®
Brake cannot prevent acollision withou tyour
interven tion.
This func tion will issue awarning if:
R at speeds of around 30 km/ horm ore over
several seconds, the distance maintained
to the vehicle travellin ginfront is insuffi-
cient.
The · distance warning lamp then lights
up in th einstrument cluster.
R at as peed of approximately 7km/h or
high er,y ou ver yquickly approach avehicle
in front.
An intermittent warning tone will then
sound and the ·distance warning lamp
will light up in the instrumen tcluster. 68
Driving safety systemsSafety
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X
Brake immediatel yinorder to increas ethe
distanc efrom th evehicle in front.
or
X Take evasive actio nprovided it is safe to do
so.
From aspeed of approxim ately 7km/h ,ifthe
driver and passengers hav efastened their
seat belts, PRE-SAFE ®
Brake can brake the
vehicl eautom atically at speeds up to approx-
imatel y200 km/h.
Due to the nature of the sy stem, particu larly
comp licate ddriving conditions may cause
unneces sary warnings or th eunneces sary
interventi onof PRE-SAFE ®
Brake.
You can stop PRE-SAFE ®
Brake interventi on
at any time by:
R depressing the accelerato rpedal further
R activa ting kickdown
R releasing the brake pedal.
The braking action of PRE-SAFE ®
Brak eis
ended automatically if:
R you manoeuvr etoavoidthe obstacle.
R ther eisnol onger any danger of arear-end
collision.
R ther eisnol onger an obstacle detected in
fron tofy our vehicle.
If you have activa tedD SR (Y page 25 1)PRE-
SAFE ®
Brak eisa lso deactiva ted.
With the help of the rada rsensor system,
PRE- SAFE ®
Brake can detect obstacles that
are in front of your vehicle for an extended
period of time.
At speed suptoapproximately 70 km/h, PRE-
SAFE ®
Brak ecan also detect stationary
obstacles such as stopped or parked vehi-
cles.
If you approach an obstacle and PRE-SAFE ®
Brak edetects arisk of acollision ,the system
will aler tyou both visually and acoustically .If
you do not brake or take evasive action, the
syste mwill warn you by automatically braking
the vehicle gently. If ther eisanincreased risk
of collision, preventativ epassenger protec-
tion measures (PRE-SAFE ®
)a re activated (Y
page 45). If, at speeds ove r30km/h, arisk
of collision remains and you do not brake,
take evasive action or significantly acceler-
ate, automatic brakin gmay be performed up
to alevel of automatic emergency braking.
Automatic emergency brakin gisnot per-
formed until immediately prior to an accident
that can no longer be avoided. G
WARNING
PRE- SAFE®
Brake wil linitiall ybrake your vehi-
cle by apartial application of the brakes if a
danger of collisio nisd etected. There may be
ac ollision unless you also brake. Automatic
emergency brakin gcannot preven tacolli-
sion. There is arisk of an accident.
Always apply the brakes yourself and try to
take evasive action. G
WARNING
PRE-SAFE ®
Brak ecannot alway sclearly iden-
tify objects and complex traf ficc onditions.
In these cases, PRE- SAFE®
Brake may:
R give an unnecessary warning and then
brake the vehicle
R neithe rgive awarning nor intervene
There is arisk of an accident.
Always pay particular attention to the traf fic
situation and be ready to brake, especiall yif
PRE- SAFE®
Brake warns you. Terminate the
intervention in anon-critical driving situation.
In particular, the detection of obstacles can
be impaired if ther eis:
R dir tont he sensor soranything els ecover-
ing the sensors
R snow or heav yrain
R interference by other radar sources
R the possibility of strong radar reflections,
for example, in multi-storey car parks
R an arrow vehicle travellin ginfront, e.g .a
motorcycle
R av ehicle travellin ginfront on adifferent
line Drivin
gsafety systems
69Safety Z