2009 AUDI S8 brakes

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• "°" ""° D riv ing in traffi c: The warning light "°"""° shows that a
vehic le moving in your lane of travel has been de tected up front in
your lane of travel. Your speed is adjusted according to the speed of
the vehicle up front. ACC accelerates and brakes automatical ly
within the system's capabilities.
• "°" ""°
Reque st f or driver to a ssume control: The red flashing
warning light
G'.'.::> 1,.,<:Q means R equ est fo r d riv er to assume control.
You as the driver must slow the vehicle with the foot brake. The
symbo l "°""G'.'.::l tells you that the Adaptive Cruise Control is not able
to slow the vehicle down enough to keep a enough distance to the
vehicle in front of you . A warning tone signal wi ll also sound when
the symbol appears .
& WARNING
Improper use of the Adaptive Cruis e Control f eatures and inatten ­
ti on c an lead to an cra sh a nd s erio us per sonal injury .
• Never allo w the c losing speed between you and other v ehicles
to be so high t hat th e Adap tive Cru is e Control ma y not be abl e to
slow your vehi cle safel y. If closing speed i s too high , you must
apply the brake s yourself to r ed uc e the ri sk of a r ear-end cra sh .
• Alway s sele ct a greater follow ing di stance to th e vehi cle up
a he ad on w et ro ad s th an on dr y roa ds.
• Alway s read and he ed the inf ormation and WARNINGS~
& in
" De scription " on
pag e 139 .
[ i J Tips
• If the Adaptive Cruise Control initiates braking, the hydraulic
brake system is under pressure . Therefore, the brake peda l distance
is shorter and the pedal feels "harder".
• If you use the accelerator to go faster than the speed of the
vehicle ahead of you, the driver intervention prompt wi ll not be
accompanied by a warning tone.
• If the speed you previously set is exceeded, the indicator light in
the speedometer wi ll switch o ff.•
Con tro ls and eq uip­
ment
Ap plies to vehi cle s: wi th Ad apt ive Crui se Co ntro l
Display in the instrument cluster
You should hove the supplementary information
displayed here, p articularly on your first trips.
Fig. 160 D ispla y in th e
i n strum ent cl uste r
Scroll th rough the available information displays by briefly tapping
the ( RESET] button at the end of the windshield wiper lever . You can
se lect and information from the trip computer, naviga tion syste m or
Adaptive Cruise Control.
@ Veh icle symbol
@ Status
© Distance
@ V ehi cle sym bol
The vehicle symbol indicates whether the system has detected a
moving vehicle up front in your lane of travel.
• When no moving vehic le is detected up front, on ly the
outline of
the vehicle
is displayed.
• A
gra y vehicle will appear when a moving vehic le is detected up
ahead.
• A
red vehicle will appear i f the situation detected will soon lead
to a request for the driver to assume control. .,,_
Vehicle care I I irechnical data

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A CC no t avai la bl e
The text message ACC n ot av aila bl e appears, for examp le, if the
temperature of the brakes is excessive. Adaptive Cruise Contro l is
temporari ly not available . A warning tone sounds as a reminder.
A CC no t avai lable!
The text message ACC not avai la ble! appears in the event of a
malfunction. Adaptive Cruise Control is turned off. A warning tone
sounds as a rem inder. Have the system inspected by a qua lified
dea lership.
A CC sen sor bloc ked
The text message AC C se nsor b lo cked appears when the ACC
System does not detect any objects over an extended time period .
For the time being, the distance to vehicles up ahead is not being
controlled. The ACC system is not switched off, so increased a lert­
ness is required. The following may be reasons for the text message
ACC sensor blocked:
• The ACC sensor is d irty. The ACC system is not reacting, or is not
reacting correctly, to vehicles trave ling ahead .
• It is possible that you are dr iving on a road with very light traffic
without anything at the side of the road (e.g. guard rai ls, traffic
s igns, trees) . As soon as a vehicle is detected by the system aga in,
it returns to its control range and the text message disappears .
The ACC sensor is located in the area under the front license plate .
If there is a loss of operation due to heavy contamination, this area
should cleaned to restore proper operation.
A CC se nso r blo cked !
The text message ACC sen sor blocked! appears when the ACC
System can no longer accurately detect vehic les moving up ahead
in your lane of travel. Adapt ive Cruise Cont rol is tu rned off . A
warning tone a lso sounds as a reminder.
T o decide whether it is necessary to switch off the ACC (ACC sensor
b locked!) o r if it is on ly a temporary condition (ACC sensor blocked),
Controls and equip ­
ment
the system will also takes into consideration the outside tempera ­
t ure and/or the windshield wiper operation.
The ACC sensor is dirty or blocked (e.g. leaves, snow).
The ACC sensor is located in the area under the front license plate .
I f the ACC sensor is d irty or blocked, clean the area to restore system
operation .
EPB acti vation
The text message EPB a cti vation appears if emergency braking was
initiated with the Electromechan ical Parking Brake (EPB) . Adaptive
Cruise Control is turned off. A gong sounds as a reminder.
ESP activ at ion
The text message E S P activ ation appears if the Electronic Stabiliza ­
tion Program (ESP) has intervened to take control in a critica l driving
situation. In this case Adaptive Cruise Control is automatically
turned o ff. A gong sounds as a reminder .
Speed r ange
The text message Sp eed r ange appea rs if the current speed is too
low
to set or to hold the requested speed.
When se tting a desired speed, it must be a t leas t 20 m ph (30 km/h).
At speeds below 17 mph (25 km/h), the cruise control is turned off.
Shift le ver po sition!
The text message Shift lever po sition! appears when the shift se lect
leve r is m oved to position
N. In this position, Adaptive Cruise
Control is not avai lable .•
I • •

Adaptive Crui se Control -
---------------=-------'
Applies to vehicles: with Adaptive Cru ise Co nt rol
When driving around curves
k;;;:;::;;;;~==========; ~
o5
J
Entering a curve
Fig . 1 63 V eh ic le
enterin g a c urve
F ig . 164 Vehicle
l ea ving a curv e
When entering a curve, the Adaptive cruise control may react to a
vehicle in the next lane and apply the brakes in your vehicle
=> fig . 163 . The braking action can be overridden by depressing the
accelerator pedal.
L e avi ng a cu rve
At the end of very long curves, ACC 's predictive lane reading can
cause ACC to react to a nother vehicle in the next lane and app ly the
brakes on your vehicle=> fig. 164 . T he braking action can be over ­
ridden by depressing the accelera tor pedal. •
Contro ls and eq uip­
ment
Ap plies to veh icles: with Adapt ive Crui se Contro l
Vehicles offset to one side
Fig . 165 V ehi cle tra v­
e ling ahe ad outsid e th e
d etec tion r ange of the
ra dar se nsor
Vehic les moving up ahead but offset in the lane cannot be detected
by ACC until they are in sensor range. •
Applies to veh ic les: with Adaptive Cruise Co nt ro l
Lane changes by other vehicles
Fig . 166 A veh ic le
c han ges la ne s
Vehicles that cut into your lane a short distance in front of you
cannot be detected by ACC until they are in sensor range. •
Vehicle care I I irechnical data

• ..__A_ u_ t _o_ m_ a_ t_ i_ c _ t_r _a _n_ s_ m_ is_ s_io _ n ________________________________________________ _
Select R only when the vehicle is at a full stop and the engine is
running at idle speed=>
& in "Driving the automatic transmission"
on
page 166.
Before you move the selector lever to R, press both the button in the
handle of the selector lever
and the brake pedal at the same time.
When the ignition is on, the backup lights illuminate when the
selector lever is moved into
R.
N -Neutral
The transmission is in neutral in this position. Shift to this position
for standing with the brakes applied =>
page 168 .
When the vehicle is stationary or at speeds below 3 mph (5 km/h),
you must always apply the footbrake before and while moving the
lever out of
N.
D -Normal position for driving forward
Position Dis for normal city and highway driving. It ranges from zero
to top speed and all six gears shift automatically, depending on
engine load, driving speed and automatically selected shift
programs.
When the vehicle is stationary or at speeds below 3 mph (5 km/h),
you must always apply the foot brake before and while moving the
lever to
D out of N.
In certain circumstances it may be advantageous to temporarily
switch to the manual shift program to manually select gear ratios to
match specific driving conditions=>
page 170.
S -Sport position
Select this position for sportier performance. In this position, the
transmission will not upshift as soon, allowing the vehicle to use the increased power available at higher engine speeds to achieve live ­
lier acceleration.
When the vehicle is stationary or at speeds below 3 mph (5 km/h),
you must always apply the foot brake before and while moving the lever to
S out of N.
& WARNING
Read and follow all WARNINGS => & in "Driving the automatic
transmission" on
page 166.
0 Note
Coasting downhill with the transmission in N and the engine not
running will result in damage to the automatic transmission and
possibly the catalytic converter. •
Automatic Shift Lock (ASL)
Automatic shift lock prevents you from accidentally
shifting into a forward gear or into reverse, thus causing the vehicle to move unintentionally.
Fig. 187 Shift gate
selector lever lock
positions and interlock
button highl ighted
The selector lever lock is released as follows:
- Turn the ignition on.
Step on the brake pedal.
At the same time press and hold
the lock button on the side of the gear selector knob
=> fig. 187 with your thumb until you have moved the
selector lever to the desired position.
~

The direction in which the driver wishes to travel is determined with
t he aid of the steering angle and vehicle speed and is continua lly
compared with the actual behavior of the vehicle. If the two do not
match, for example, when the vehic le starts hydrop laning on a wet
road, ESP will automatically brake the appropriate whee l to correct
the prob lem.
The vehicle is then stab ilized by the forces acting on the whee l
during braking. If the vehicle is oversteering (rear tends to skid out
of the turn), the brakes are mainly app lied on the wheel that is on
the outside of the curve. In the case of a vehicle that is understeering
(tendency to sl ide out of the curve), the brakes are applied at the
rear wheel that is on the inside of the curve . An acoustic signal indi­
cates when ESP brake application cuts in
~ & .
The system operates across the entire speed range in combination
with the ABS system
~ page 274 . If the Anti -Lock Brake System
(ABS) malfunctions, the ESP wi ll be out of action as well.
Ac tivat ion
When you turn on the eng ine, ESP will automatically be activated
and will perform a self -test.
The system can be activated or deactiva ted by pressing the button
~ page 270, fig. 256. The warning light comes on when the system
is switched off
~ page 18.
Normally , the ESP should always be on, however, it may be advanta­
geous to turn off the system in certain special cases when some
degree of wheel spin is desired such as :
• when driving with snow chains
• when driving in deep snow or on a loose surface (to allow the
wheels to dig in to reach firm ground)
• when trying to "rock" the vehicle free when it has beco me stuck.
T he system should be reactivated once you are no longer in such
situations .
Both the ABS and EDS systems are still functioning even if the ESP
is switched off .
Controls and equip­
ment Safety first Vehicle operation
In
te llig ent tec hn olo gy
& WARNING
The Ele ctron ic St abiliz ation Progr am i s ne ve rt h el ess s ubject to the
laws of ph ysics. It i s particularl y important t o pay attention t o th is
f ac t on wet an d slipp ery road s. It i s th ere fore important that you
alway s adapt your driving to the condition of the road and traffic
c onditio ns. Do n ot allow the in crease d sa fety p ro vi ded by t he El ec­
tronic Stabiliz ation Program sy stem to lu ll you into a ccepting
a dditional safety ri sk s.
c
Electronic differential lock (EDL)
The electronic differential lock monitors the rotation al
s p eed of the drive wheels.
G en era l not es
The elect ronic differential lock (EDU helps the car to start moving,
accelerate and c limb a gradient on surfaces providing poor or
a lmost no grip . Without EDL , this would be difficult, if not impos ­
s ib le.
How the system works
The EDL operates automatical ly. It monitors the rotational speed of
the drive wheels on an axle with the he lp of the ABS sensors
~ page 274. If a noticeable difference in rotational speed between
the drive wheels on one axle is detected (e.g. on slippery ground on
one side), the spinning w heel is braked, thereby transferring power
to the other drive wheel or wheels (all -whee l drivel. This is done up
to a speed of about 60 mph (100 km/h) . Noises from the brake
system signal that wheel spin is being control led .
Dri ving off
When driving off, always be sur e to ke ep road conditions in mind as
you accelerate. I f one drive wheel spins because it is on a surface
with less grip, gradual ly increase the pressure on the accelera tor
pedal unt il the car star ts to
move . The whee l less able to t ra nsfer
power spins. _.,
Vehicle care Do-it-yourself service Technical data

-Intelligent technology --=---=-=-------------
Overheating
of brakes
To prevent the disc brake of the braked wheel from overheating if
subjected to excessive loads, the EDL cuts out temporarily . The
vehicle remains operational and behaves in the same way as a
vehicle without EDL.
As soon as the brake has cooled down, EDL switches on again auto ­
matically.
& WARNING
• When accelerating on slippery surfaces, such as on ice or snow,
always be careful when depressing the accelerator pedal. Even
with the EDL working, the drive wheels can spin and reduce your ability to control your car. Risk of crash!
• The increased safety afforded by EDL does not mean that you
can take safety risks . Always adapt your driving style to the road
conditions and traffic situation.
[ i] Tips
If a fault occurs in the ABS, the EDL is also not functioning. This is
indicated by the ABS warning light=>
page 21. •
Anti-Slip Regulation System (ASR)
The Anti-Slip Regulation System prevents the driven
wheels from spinning when the car is accelerating.
General notes
The Anti-Slip Regulation System (ASR) is integrated in the electronic
stabilization program (ESP). When the vehicle starts up and acceler­
ates, the wheels are prevented from spinning by adjusting the
engine power to match the amount of grip available from the road
surface.
How the system works
ASR performs automatically, i.e. without the driver's intervention.
With the aid of the ABS sensors=>
page 274, ASR monitors the
speed of the driven wheels. If the wheels start to spin, the engine
power is reduced automatically until the tires find enough grip to
lock onto the road surface. The system is active across the entire
speed range.
The ASR works in conjunction with the ABS. If a malfunction should
occur in the ABS, the ASR will also be out of action.
& WARNING
The increased safety afforded by ASR does not mean that you can
take safety risks. Always adapt your driving style to the road
conditions and traffic situation.
[ i] Tips
To ensure that the ASR works properly, all four wheels must be fitted
with identical tires Any differences in rolling radius of the tires can
cause the system to reduce engine power when this is not desired.
See also=>
page 338, "New tires and replacing tires and wheels".
Braking
General information
What affects braking efficiency?
Operating conditions and driving habits
The brakes on today's automobiles are still subject to wear,
depending largely on operating conditions and driving habits=>& .
On vehicles that are either driven mostly in stop-and-go city traffic
or are driven hard, the brake pads should be checked by your autho ­
rized Audi dealer more often than specified in the
Warranty & Main- ~

tenance boo klet. Failure to have your brake pads inspected can
r esult i n reduce d brake pe rfor mance .
On steep slopes , you s hou ld use the braking effect of the engine .
T his way, you prevent unnecessary wear on the bra ke system . If you
must use your brakes, do not hold the brakes down con tinuo usly.
P ump the brakes at intervals.
Moisture or road salt
U nder ce rtain conditions, for example, when driving through water
or very heavy rain, or even after washing your vehicle, the brak ing
effect can be reduced due to moisture (or in freezing conditions ice)
on the b rake pads. A few carefu l brake appl icat io n s sh ould d ry o ff
the brake pads or remove any ice coatings.
Th e eff ectiveness of the b rakes ca n b e re d uce d whe n the ve hicle is
driven on a salt -covered road and the brakes are not used . Here too,
you sh ould clean off acc umulated sa lt coat ing from brake d iscs and
pads with a few careful app lications of the brake~&.
Corrosion
T here may be a tendency for dirt to build up on the brake pads and
co rrosion to form o n the discs if the car is not d rive n regu lar ly or
only for short trips with little use of the brakes .
I f the brakes are not used frequently, or if corrosion has fo rmed on
t he d iscs, i t is a dv isab le to clea n off th e pads an d discs by braking
firmly a few times from a moderate ly high speed~& .
Faults in the brake system
I f you shou ld notice a sudden increase in brake pedal trave l, then
one of the two brak e circu its may have failed~ &.
Low brake fluid level
Ma lfunctions can occur in the brake system if the brake fluid leve l is
t oo low. T he b rake fl uid level is mon ito red e lect ro nica lly .
Controls and equip­ ment Safety first
Vehicle operation
Intelligent technology
Brake lining wear status
Brake l ini ng w ear may be checke d by visua l ins pec tion of the co nd i­
tion of the brake pads throu gh the open ings in the wheel. If neces ­
sa ry, the wheel may be removed for this i nspectio n
~ page 353,
"Changin g a whee l".
& WARNING
• You should perform braking maneuvers for the purpose of
cleaning the brake system only if road conditions permit . Other
road use rs must not be put at r isk -you may cause an accident !
• Before descending a steep grade , reduce speed and shift trans ­
mi ssion into a lower gear or lower driving range . Do not ride the
brakes or hold the pedal down too long or too often . This could
cau se the brakes to get hot and diminish braking efficiency .
• 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 climati c and operating conditions such as
passing through water , driving in heavy rain or after washing the
vehi cle , the effectiveness of the brakes can be reduced. In winter ,
ice can accumulate on the brake pads , linings , discs and drums .
Carefully apply brakes for a test. Brakes will dry and ice coatings
will be cleaned off after a few careful brake applications .
• Driving for an extended period of time on salt -covered roads
without using your brakes can also affect braking efficiency. Clean off accumulated salt coating from brake disc s and pads with a few
careful brake applications .
• If you damage the front spo iler , or if you install a different
spoiler, be sure the air flow to the front brakes is not obstructed.
Otherwise the brake sy stem could overheat reducing the effective ­
ness of the entire brake system.
• Failure of one brake cir cuit will impair the braking capability
resulting in an increased stopping distance. Avoid driving the
Vehicle care Do-it-yourself service Technical data

___ ln_ t _e_ ll-'"ig ...,_ e_ n_t _t_ e_ c_ h _ n_o _ l_o _,.g= y,_ __________________________________________ _
& WARN ING (continued )
vehicle and have it towed to the nearest Aud i dealer or qualified
workshop.
;:a
Brake booster
The brake booster a dds ex tra braking power.
The bra ke booster works wit h vacuu m pressure w hich is created
only when the engine is running =>& .
& WARNING
• Never let the vehicle roll to a stop with the engine shut off .
• If the brake boo ster i s not wor king , for e xample when towing
your vehicle, or because the brake booster has somehow been
damaged , the brake pedal must be pre ssed considerably harder to
make up for the lack of booster as sistance. •
Functioning of Anti-Lock Brake System {ABS)
A BS prevents the wheels from l ocking up under braking.
The ABS contributes effective ly to vehicle contr ol since i t preven ts
t he whee ls from
locking whe n the brakes are appl ied. This mea ns
that the vehicle remains steerable and is less likely to skid .
With ABS you do not need to pump the brake. Ju st hold the brake
pedal down .
However, do no t ex pect the ABS to sho rten braking distance u nder
all circumstances. When drivin g on gravel or on new ly fallen snow
on top of icy surfaces, bra king distance may be even longer, there­
f ore, under these c ircu msta nces, it is especially importa nt that you
drive slow ly and with great care.
How the ABS system works
An au toma tic c heck is made when a s peed of about 4 mph (6 km/h)
is reached. When this happens, a pumping no ise can be heard.
I f an individual wheel begins to rotate too slowly in relation to
veh ic le speed and tends to lock, the ABS au tomat ically reduces
brake pressure to prevent that whee l from locking.
Th is au tomatic a djust ment pr oces s wi ll cause a
slight vibration o f
the brake peda l and some noises to alert you that vehicle speed
m ust be ada pted to e xisting road and traff ic conditio ns.
& WARNING
Although the ABS is very effective , alway s remember that braking
capability is limited by tire traction . Always adjust your driving
speed according to the road and traffi c conditions. Do not let the
extra safety afforded by the ABS tempt you into tak ing extra risks.
The ABS cannot overcome the laws of physics.
[ i ] Tips
• I f ABS is not functioning properly, a wa rning light will come on .
See=>
page 27.
• I f a faul t occurs in t he ABS, t he EDL is also n ot fu nctio ning . Th is
is indicated by the ABS warning light. •
Brake assistant
T he brak e assi stant i s designe d to ac hie ve th e optimu m
bra kin g eff ec t.
The bra ke assistant helps to increase the effective braking power
an d th us to achieve a shorter s top ping dis tan ce. If the dr iver
presses the brake pedal very quic kly, the brake assistant automati ­
c a lly bo osts t he braking force to the max imum level, up to th e point
where the anti -lock brake function (ABS) intervenes to stop the
whee ls from locking. You shou ld then keep the brake peda l pressed .,