2011 AUDI S8 brakes

Adaptive cruis e control and bra kin g guard
vehicles such as motorcycles and bicy­
cles.
- The adaptive cruise control system can­
not detect people, animals and cannot
detect objects or traffic that crosses your
lane of travel.
- Never drive at speeds that are too fast for traffic, road and weather conditions.
- Never use adaptive cruise control when
you cannot drive safely at a steady speed, including on wind ing roads or
when road conditions are poor (for exam ­
ple, in construction sites, on ice , gravel,
in fog, heavy ra in or on wet roads that in­
crease the risk of hydroplan ing).
- Never follow a veh icle so closely that you
cannot stop your vehicle safely. The
adaptive cruise cont ro l cannot slow or
brake the veh icle safely when you follow
another veh icle too closely. Always re ­
member that the automatic braking
function cannot bring the vehicle to a
sudden or emergency stop under these
condit ions.
- Never rest your foot on the acce lerator
pedal, especially when the adaptive
cruise control is being used. Pressure on
the accelerator w ill override the adaptive
cruise control braking function and pre­
vent the brakes from being applied whe n
adaptive cruise cont ro l detects a situa­
t io n when the brakes must be applied.
- Never use adaptive cruise control whe n
the radar sensors cannot accurately de­
t ect vehicles moving in t raff ic. The rad ar
sensor's vision can be reduced by heavy
rain, ice, snow, heavy road spray and re­
flect ions from guard rails, t unnel ent ran­
ces, etc. These and simi lar conditions can
prevent vehicles from being accurately
detected and in some cases they may not
be detected at all .
- Always turn off adaptive cru ise contro l
when entering turn lanes, exit lanes and
constr uction zones or in similar sit ua­
t ions because the vehicle will automati­
ca lly accelerate to the sto red speed when
the roa d ahead is clear. -
To prevent unintended operation, a lways
sw itch ACC off when it is not being used .
(D Note
The sensors can be moved by impac ts or
damage to the bumper, wheel housing and underbody . Damage in these areas could
change the way the adaptive cru ise control
system and Aud i brak ing guard work to­
gether . Have your authorized Audi deale r
check to make s ure that the adaptive
cruise control system is wor king p roperly if
your vehicle had a m ino r frontal impact or
was damaged in the area of the sensors.
In curves
Applies to vehicles: wi th adaptive cruise control
Fi g. 86 Exa mpl e: dri vin g into a curve
When dr iving into a curve¢ fig. 86 and out of
a curve, the adaptive c ruise control may react
to a vehicle in the next lane and app ly the
brakes . You c an override or preven t the brak­
ing by pressing the accelerator pedal b riefly .
Stationary objects
Applies to vehicles: wit h adaptive cruise control
Fig. 87 E xam ple: object c hanging l anes a nd s tationa ry
o ~ect
~
8 7

Adaptive cru ise co ntrol and b rakin g guar d 89
You must also press the b rake pedal when
the vehicle is stopped.
Sw itching adapti ve cruis e co ntrol off
~ Push the lever away from you into position
@ until it clic ks into p lace. The message
A CC off appears.
I ndicator lamps and messages in the instru­
ment cluster display inform you about the c ur­
rent system status and settings.
@ Indic ator light s
fl-adaptive cruise control is sw itched on . No
veh icles are detected up ahead . The stored
speed is ma inta ined.
I -A moving vehicle is detected up ahead .
The adaptive cruise control system regulates
the speed and distance to the moving veh icle
ahead and accelerates/brakes automat ically.
f:i -adaptive cru ise control is switched on. A
mov ing vehicle up ahead was detected. Your
veh icle remains stopped and will not start
driving automatically.
I -When automat ic braking is not able to
keep enough distance to a previously detected
mov ing vehicle up ahead, you must take con­
trol and brake¢
page 90, Prompt for driver
intervention.
© Di splay
If adaptive cruise control is not shown in the
d isplay, you can call it up with the multifunc­
tion steering wheel buttons
¢ page 23 .
Based on the symbols in the display, you can
determine if the system is maintaining a dis­
tance to the vehicle ahead and what that d is­
tance is .
No v ehicle -No vehicle ahead was detected.
White vehicle -A vehicle ahead was detected .
Red ve hicl e -Prompt for the d river to take ac­
tion
¢ page 90.
Both arr ow s on the scal e© indicate the dis­
tance to the vehicle ahead . No ar row appears
when the vehicle is on an open road and there is no object ahead.
If an object is detected
ahead, the arrow moves on the scale .
T he green zone on the sca le shows the stored
distance. For informat ion on changing the
stored distance ¢
page 91. If the distance
selected is too close or may soon become too
close, the arrows move into the red zone on
the scale .
A WARNING
Improper use of the adaptive cruise con­
trol can cause collisions, other accidents
and serious personal injur ies .
- Pressing the
!SET ! button when driv ing at
speeds below
20 mph (30 km/h), w ill au­
tomatically accelerate the vehicle to
20
mph (30 km/h), wh ich is the minimum
speed that can be set .
(D Tips
- If you switch the ignit ion or the adaptive
cruise control off, the set speed is e rased
from the system memory.
- You cannot switch the Electron ic Stabili­
zation Program (ESP) to the SPORT mode
when adaptive c ruise control is sw itched
on.
Driving in stop-and-go traffic
Appl ies to vehicles: wi th adap tive c ruise control
T he adaptive cru ise contro l system also as­
sists yo u in stop-and-go traffic. If a previous
detected vehicle ahead stops, your vehicle wi ll
brake to a stop, within the limits of the sys­
tem.
~ To resume driving with adaptive cruise con­
trol, tap the acce lerator pedal or
~ Pull the lever toward you into position @
¢ page 88, fig. 89.
(D Tips
- If adaptive cruise control is act ive and
your vehicle does not start driving as ex­ pected after pu lling the lever once, you
can start out again by tapping the acce l-
erator peda l. ..,.

Adaptive cruise control and braking guard 91
Setting the distance and driving
program
Applies to vehicles: with adaptive cruise co ntrol
Fig. 93 Operating leve r: sett ing the distance
The distance at which the adaptive cruise con­
trol follows a vehicle in front is determined by
time interva ls. A time interval to a vehicle in
front is estab lished and maintained. This pro ­
duces a speed-dependent inte rval. The higher
the speed, the greater the safety interval in
yards (meters)¢ ,&.
Setting the distance
~ Tap the switch to d isplay the current set dis­
tance
¢fig. 93.
~ To increase or reduce the distance by incre­
ments, tap the switch again to the left or
right. The distance between the two vehicles
will change in the instrument cluster dis­
play.
Setting the driving program
~ Select in the MMI: !CAR ! function button >
Car Systems control button > Driver assist >
adaptive cruise control > Driving program .
Setting the distance
When approaching a movi ng veh icle up ahead,
the adaptive cruise contro l system automati­
cally brakes to match that object's speed and
then maintains the stored distance. When this happens, the actual distance may briefly be
less than the stored distance. If the veh icle
ahead accelerates, adaptive cruise control will
also accelerate up to the stored speed.
The higher the speed, the greater the distance
in yards (meters) ¢&. . The
Distance 3 setting
is recommended. The distances
provided are specified va lues.
Depending on the driving situation and the
how the vehicle ahead is driving, the actual
distance may be more or less than these tar­
get distances.
,;:::::;, _c::::, ___ Distance 1: This setting corre-
sponds to a distance of 92 feet/28 meters
when traveling at 62 mph (100 km/h), or a
time interval of 1 second.
,;:::::;, __ c::::, __ Distance 2: This setting corre­
sponds to a distance of 118 feet/36 meters
when traveling at 62 mph (100 km/h), or a
t ime interval of 1.3 seconds.
,;:::::;, ___ ,;:::::;,_ Distance 3: This setting corre-
sponds to a distance of 164 feet/SO meters
when traveling at 62 mph (100 km/h), or a
time interval of 1.8 seconds.
,;:::::;, ____ c::::, Distance 4: This setting corre-
sponds to a distance of 210 feet/64 meters
when traveling at 62 mph (100 km/h), or a
t ime interval of 2.3 seconds.
Setting the driving program
You can select Dynamic, Standard or Comfort
driving programs. Depending on the selected
driving program and distance, driving behav­
ior when accelerating will vary from dynamic
to comfortable.
.&_ WARNING
Following other vehicles too closely in­
creases the risk of coll is ions and ser ious
personal injury.
- Sett ing short d istances to the traffic
ahead reduces the time and distance
availab le to bring your vehicle to a safe
stop and makes it even more necessary
to pay close attention to traffic.
-
-Always obey applicable traffic laws, use
good judgment, and select a safe follow­
ing d istance for the traff ic, road and
weather conditions .
(0 Tips
-Distance 3 is set automat ically ea ch time
you switch the ignition on. ..,.

92 Adaptive cruise control and braking guard
-Your standard settings are automatically
stored and assigned to the remote con­
trol key being used .
Audi braking guard
Description
Applies to vehicles: wit h adapt ive c ru ise control
Fig. 94 Instrument cluster: approach warn ing
Audi brak ing guard uses radar sensors and a
video camera . It is active at speeds above
about 6.2 mph (10 km/h) and also works
within system limits when adaptive cruise control is switched off.
On vehicles with aAdaptive cruise control and
Audi side assist (Audi pre sense plus), system
functions also engage when a co llision is im­
minent
¢page 188.
What can Audi braking guard do?
When detected in time, the system can assess
situations when a vehicle ahead brakes sud­
denly or if your own veh icle is traveling at a
h igh speed and approaching a vehicle up
ahead that is moving more slowly. Audi brak­
ing guard does not react if it cannot detect
the situation.
The system advises you of various kinds situa­ tions :
- The
distance warning is given if you are too
close to the vehicle ahead for a long time. If
the vehicle ahead brakes sharply, you will not be able to avoid a coll is ion. The ind icator
light
I i n the d isplay comes on. Take imme ­
diate action to avoid the coll is ion and in­
crease the distance to the vehicle up ahead. -
The
approach warning is given when a de­
tected vehicle up ahead in your lane is mov­
ing much more slowly that you are or if it
brakes sharp ly. When this warning is given,
it may only be possible to avoid a collision
by swerving or braking sharp ly . The indicator
light
I and the symbol in the disp lay will
warn you about the danger
c:> fig. 94 . You
w ill also hear an acoustic signal.
If you do not react fast enough or do not react
at all to the situation, Aud i braking guard w ill
intervene by braking and the message
braking
guard intervention
w ill appear.
- If a coll is ion is imminent, the system will
first provide an
acute warning by brak ing
sharply .
- If you do not react to the acute warning, Au­
di braking guard will brake w ith increased
force in severa l stages to reduce the speed
in a possible collisio n. On ve hicles w ith
adaptive cruise contro l and Audi side assist
(Audi pre sense plus), the system can brake
with increasing force up to maximum decel­
eration shortly before a sensed collision
¢ page 188.
- If
the Audi braking g uard senses that you
are not braking hard enough when a colli­
sion is imminent, it can increase the braking
force.
Audi braking guard takes the driver's reaction
time into consideration in order to provide
timely warnings. The system reaction time de­ creases automatically in some situations, for
example when it detects accelerator pedal use
or steering input . The Audi braking guard in­
tervent ion stops in certa in situations, for ex­
amp le if you press the accelerato r pedal to
pass the vehicle moving ahead of you in your
lane.
Which functions can be controlled?
You can switch Audi braking guard and the
distance/approach warning on or off in the
M M I c:> page 93, Settings in the MMI.

Adaptive cru ise co ntrol and b rakin g guar d 93
A WARNING ,~
The Audi braking guard is an assist system
and cannot prevent a collis ion by itself.
The driver must always intervene. The driv­ er is always responsible for braking at the
co rrect time.
- Always pay close attention to traffic,
even when the Aud i brak ing guard is
switched on. Be ready to intervene and
be ready to take complete control whe n­
ever necessary. Always keep the safe and
legal distance between your vehicle and
vehicles up ahead.
-Audi braking guard works within limits and wi ll not respond outside the system
limits, for examp le when approaching a
stopped vehicle or stationary obstacle
(end of a traff ic jam or vehicle that has
broken down in traffic).
- Always remember that the radar sensor
for the Audi braking guard works only
within defined detect ion and range limits
that may prevent the proper detection of
other vehicles.
- The radar sensor's function and range
can be reduced by rain, snow and heavy
spray. moving vehicles up ahead may not
be promptly detected or may not be de ­
tected at al l.
- Reflective surfaces includ ing c rash ba rr i­
ers or tunnel en trances may impair the
function of the radar sensor .
(D Tips
Innattention can cause collisions, other ac­
cide nts and serious persona l injuries.
- You can stop the Audi b raking guard in­
te rvention w ith increas ing braking force
by applying the brakes yourse lf or by a c­
ce le rat ing rapidly.
- Audi braking guard error messages
¢page 93.
Settings in the MMI
App lies to vehicles : wi th adap tive c ruise contro l
.,. Select: !CAR ! function button> Car sy ste m s
cont ro l butto n > Driv er a ssist> Audi brak ­
ing gua rd .
S ys tem -
Switch Audi b raking guard On and
Off . When you switch the ign it ion on, the
message
Audi br aking guard off appears in
the instr ument cluster d isp lay if the system is
switched off.
E arly warning -The distance and approach
warnings in the d isplay can be switched
On/
Off.
(D Tips
- Yo ur settings are automatically stored
and assigned to the remote cont ro l key
being used at the times the settings are
made.
- If you switch the ESP to sport mode, A u­
di braking guard switches off a utomati ­
cally
¢page 192.
Messages
App lies to vehicles : wi th adap tive c ruise control
ACC una vailable
ACC and braking guard: unavailabl e
The system cannot detect moving vehicles up
ahead co rrectly and is switched off . The sen­
sors have been d isplaced or are not worki ng
proper ly. The Audi pre sense functions may a l­
so be affected.
ACC: unavailabl e at this time. No sensor vi ­
s ion
ACC and b rak ing gu ide: una vailable at this
time . No s enso r vision
This message appears if the sensor view is ob­
structed, for examp le by leaves, snow, heavy
spray or d irt . Clean the sensors¢
page 86,
fig. 85.
ACC: unav ailable at this time. Incline too
steep

ESP includes and/or works together with the
anti-lock brake assist system (ABS), brake as­
sist system, anti -slip regulation (ASR), elec­
tronic differential lock (EDL), dynamic steer­
ing* and electronic interaxle differential lock*.
ESP is switched on all the t ime . In certa in sit­
uations when you need less traction, you can
sw itch
off ASR by pressing the button above
the selector lever. Be sure to switch ASR on
again when you no longer need less traction.
Anti-lock braking system (ABS)
ABS prevents the wheels from locking up
when braking. The vehicle can still be steered even during hard braking . Apply steady pres­
sure to the brake pedal. Do not pump the ped­
al. A puls ing in the brake pedal indicates that
the system is he lping you to brake the vehicle.
Brake assist system
The brake assist system can decrease brak ing
distance.
It increases braking power when the
driver presses the brake pedal quickly in emer­
gency situations. You must press and hold the
brake pedal until the situation is over. In vehi­
cles with adaptive cruise control*, the brake
assist system is more sensitive if the distance
detected to the vehicle ahead is too small.
Anti-slip regulation (ASR)
ASR reduces engine power when the drive
wheels begin to spin and adapts the force to
the road conditions. This makes it easier to
start, accelerate and drive up hills .
Electronic differential lock (EDL)
The EDL brakes wheels that are spinning and
transfers the drive power to the other drive
wheel or whee ls if the vehicle is equipped with
a ll whee l drive *. This function is available up
to about 75 mph (120 km/h).
I n extreme cases, EDL automatically switches
off to help keep the brake on the braked wheel
from overheating . EDL will switch on again au­
tomatically when conditions have returned to
normal.
Intelligent technology 191
Dynamic steering*
On vehicles with dynamic steering, ESP helps
stabilize the steering in certain situations.
Electronic interaxle differential lock
function*
T he electronic interaxle differential lock func­
tion activates when driving th ro ug h curves.
Braking is targeted toward the wheels on the
inside of the curve as needed. This he lps to
minimize front whee l skid, improves traction
and allows for more precise driving through
curves .
A WARNING
- ESP, ABS, ASR, EDL, dynamic steering*
a nd the electronic interaxle differential
loc k fu nction* cannot overcome the laws
of physics. This is especially impo rtant
on slippery or wet roads.
If the systems
begin acting to stabilize your vehicle, you
should immediately change yo ur speed
to match the road and traffic conditions .
Do not let the increased safety provided
by these systems tempt you to take risks.
Doing so will increase the risk of a loss of
veh icle contro l, collision and ser ious per­
sonal injur ies.
- Always adapt your speed to road, traffic
and weather conditions. The risk of los­
ing con trol of the vehicle increases when
driving too fast, espe cially through
curves and on slippery or wet roads, and
when dr iving too close to vehicles up
ahead. ESP, ABS, the brake assist system,
EDL, ASR, dynam ic steer ing* and the
electronic interaxle differentia l lock func­
tion* cannot prevent collisions.
- Always accelerate with special care on
even, smooth surfaces such as those that
are wet or covered with ice and snow.
The drive wheels can spin even with
these assistance systems that cannot al­
ways he lp to reduce the risk of loss of ve­
hicle contro l.
-
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192 Intelligent technology
-ABS and ASR on ly work correctly when
a ll four wh eels are eq uipped w ith ident i­
ca l tires. Different tire s iz es can lead to a
reduct ion in engine power.
- You may hear no ises when the systems
described are working.
- If the indicator light
DJ or m (USA
models) ;tl] (Canada models) appea rs,
there may be a malfunct ion
c::;, page 19,
c::;, page
18 .
Switching on and off
ESP turns on au toma tically when you s tar t
the engine .
Fig . 170 Cen ter con sole w it h ESP OF F button
Switching ASR off (sport mode)
In ce rtain situat io ns, yo u can switch ASR and
E SP into sport mode by pressing the button
l!I
c::;, fig. 170. The indicato r light fl comes on
and the mess age
C aution! Limit ed driving
s tability
appears . ASR deact ivates comp lete ly
and the assistance prov ided by the ESP sys ­
tem is limited. Switch to sport mod e onl y
when your d riv ing sk ills, traffic and weather
conditions permit.
In some situations, it may be useful to switc h
ASR off to let the wh eels slip. Example:
- Rocking the vehicle bac k and forth when it is
stuck
- Driv ing in deep snow or on loose ground
- Driving with snow cha ins
Sw itching ASR on
Press the button I!] aga in. The message ESP /
ASR: on appears .
A WARNING
-Drive whee ls can sp in and you can lose
control of the vehicle more eas ily when
ASR and ESP are in sport mode, especial­
ly whe n the road is slippery .
- Sw itch to sport mode only when your
d riving skills, traff ic and weather condi­
tions perm it.
@ Tips
You cannot sw itch sport mode on whe n
adaptive c ruise co ntrol* is worki ng.
Braking
General information
Wha t affe cts braking effi cien cy?
-
Operating conditions and driving habits
The brakes o n today's automobiles are still
s u bjec t to wear, depending largely on operat­
ing cond it ions and driving hab its
c::;, &. . On ve­
hicles that a re e it h er dr iven most ly in stop­
and-go city t ra ffi c or are dr iven hard, the
brake pads should be checked by yo ur au thor­
ized Audi dea ler mo re often than specified in
t h e
Warranty & Maintenance booklet. Failure
to have your brake pads inspected can result in reduced brake performance.
On steep slopes , you sho uld use the braking
effect of the engine. This way, you prevent un­
necessary wear on the brake system . If you
must use your b rakes, do not hold t he brakes
down continuous ly. Pump the brakes at in ter­
vals .
Moisture or road salt
U nd er certain conditions, for example, when
driving through water or very heavy rain, or
even after washing your veh icle, the braking
effect can be reduced due to moisture (or in
freez ing cond itions ice) on the brake pads . A
few caref ul brake applicat ions should dry off
t h e b rake pads or remove a ny ice coatings .
The effectiveness of the brakes ca n be reduced
when the vehicle is d riven on a sa lt-covered
ll>

road and the brakes are not used. Here too,
you shou ld clean off accumu lated salt coating
from brake discs and pads with a few carefu l
applications of the brake
c> ,&. .
Cor rosion
There may be a tendency for dirt to build up
on the brake pads and corrosion to form on
the discs if the car is not driven regularly or
only for short trips with little use of the brakes.
If the brakes are not used frequently, or if cor­ rosion has formed on the discs, it is advisable
to clean off the pads and discs by brak ing
f irmly a few times from a moderately high
speed
c> &, .
Fau lts in th e bra ke s ystem
If you should notice a sudden increase in
brake peda l travel, then one of the two brake
ci rcu its may have failed
c> ,&. .
Low brak e fluid l evel
Malfunct ions can occur in the brake system if
the brake fluid level is too low. The brake fluid
leve l is monitored electronically.
Brake lining w ear statu s
Brake lining wear may be checked by visual in­
spection of the condition of the brake pads
through the openings in the whee l. If neces­
sary, the wheel may be removed for this in­
spection
c> page 262, Changing a wheel .
8_ WARNING
-You should perform braking maneuvers
for the purpose of clean ing the brake
system on ly if road condit ions permit.
Other road users must not be put at r isk -
you may cause an acc ident!
- Before descending a steep grade, reduce
speed and shift transmiss ion into a lower
gear or lower driving range . Do not ride
the brakes or hold the pedal down too lo ng or too often. This cou ld cause the
brakes to get hot and dimin ish b raking
effi ciency.
Int ellig ent technolog y 193
-Do not "ride the brakes" by resting your
foot on the pedal when you do not intend
to brake. This may cause the brakes to
overheat, premature wear and increased
stopping distance .
- Under certain cl imatic and operat ing
conditions such as passing through wa­
ter, dr iv ing in heavy rain or after washing
the vehicle, the effectiveness of the
b rakes can be reduced. In winte r, ice can
accumulate on the brake pads , lin ings,
discs and drums . Carefu lly app ly brakes
for a test . Brakes will dry and ice coat­
ings wi ll be cleaned off after a few care­
fu l brake applications.
- Driving for an extended period of time on
salt-covered roads without using your
brakes can a lso affect braking efficiency.
Clean off accumu lated salt coating from
brake discs and pads with a few careful
brake applications .
- If you damage the front spoiler, or if you
install a different spoiler, be sure the air
f low to the front brakes is not obstruct­
ed. Otherw ise the brake system could
overheat reduc ing the effectiveness of
the entire brake system.
- Failure of one b rake circuit will impai r
the braking capab ility result ing in an in­
creased stopping distance. Avoid driving
the vehicle and have it towed to the near­
est A udi dealer or qualified workshop .
Brake booster
The brake booster adds extra braking power.
The brake booster works with vacuum pres­
su re which is created only whe n the engine is
runn ing
c> &, .
A WARNING
-Never let the vehicle roll to a stop with
the engine shut off.
-
- If the b rake booster is no t working, for
examp le when towing you r vehicle, or
because the brake booster has somehow
Ill>
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