2008 AUDI S8 brakes

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Ap plie s to vehic les: with Adaptive Cru ise Co nt rol
Messages
The text messages and symbols shown in this area of the
display are not displayed perm anently .
Time interval s
Fig . 16 1 Informa tion
lin e
The different symbols for the time intervals appear if you change the
settings. In addition, there is a display if the gong (audible warning
signa l) is turned off.
The text message ... (three white dots) appears if a setting cannot be
implemented with the operat ing lever. The fol lowing are possible
reasons
• If you pu ll the control lever forward to resume speed but no
requested speed was set.
• I f you push the lever up to increase (or down to reduce) speed
when no speed has been set previously.
• I f you push the lever up (down) to increase (reduce) speed and
this speed is outside the range from 20 to 95 mph !Canada models:
30 to 150 km/h) .
Controls a nd eq uip­
ment
A CC not a vailab le
The text message ACC not av ailabl e appears, for example, if the
temperature of the brakes is excessive . Adaptive Cruise Control is
t emporarily not availab le . A warning tone sounds as a rem inder.
A CC not available !
The text message ACC not av ailabl e! appears in the event of a
malfunction. Adaptive Cruise Control is turned off . A warning tone
sounds as a reminder. Have the system inspected by a qua lified
dea lersh ip.
ACC senso r blocked
The text message AC C s en so r blo 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
cont rolled . The ACC system is not switched off, so increased alert ­
ness is required. The following may be reasons for the text message
ACC sensor blocked:
• The ACC sensor is dirty. The ACC system is not react ing, or is not
reacting correctly, to vehic les traveling ahead.
• It is possible that you are driving on a road with very light traffic
without any thing 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 again,
it returns to its control range and the text message d isappears .
The ACC sensor is located in the area under the front license plate .
I f there is a loss of operation due to heavy contamination, this area
should cleaned to restore proper operation.
AC C senso r bl ock ed!
The text message ACC sensor blocked! appears when the ACC
System can no longer guarantee safe detection of objects . Adaptive
cruise control is turned off . A chime sounds as a reminder.
To decide whether it is necessary to switch off t he ACC (ACC sensor
blocked!) or if it is only a temporary condition (ACC sensor blocked),
the system wi ll a lso takes into cons ideration the outside tempera -
ture and/or the windshield wiper operation .
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Vehicle care I I irechnical data

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[ i J Tip s
Settings in the Adapt ive Crui se C ontrol menu are possib le only with
the engine running and the vehicle stationary .•
Special driving situations
Applies to vehic les: with Adaptive Cru ise Control
General
Some driving situations which affect the function of the
radar sensor are described below.
There are l imits to what Adap tive Cruise Control can do as the
vehicle is driven. So be especially attentive :
• when driving around curves => page
149.
• when driving in staggered lanes of traffic~ page 150.
• when other vehicles are changing lanes::> page 150.
• when other vehicles are difficu lt to detect ~ page 150.
& WARNING
The radar s en sor 's visi on can b e re du ced by rain , snow and h eav y
sp ray. Thi s can re sult in ve h ic les driving ahe ad be ing inade quately
detect ed or , in some cir cum stan ce s, not det ected a t all . •
Contro ls a nd eq uip­
ment
Ap plie s to vehicles: with Adapt ive Cru ise Co nt rol
When driving around curves
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j
Entering a curve
Fig . 16 3 Ve hicle
e nt erin g a c urv e
F ig . 164 Vehicle
l eav ing a cu rve
When entering a curve, the radar sensor may react to a vehic le in the
next lane and apply the brakes in your
vehicle ~ fig. 163. The
braking action can be stopped by depressing the accelerator pedal.
Lea ving a curve
At the exit from very long curves the pred ictive lane reading can
cause the radar sensor to react to another vehicle in the next lane
and apply the brakes in your
vehic le => fig. 164 . The braking act ion
can be stopped by depressing the accelerator pedal. •
Vehicle care I I irechnical data

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_ ra_ n_s_ m __ is_s_ io_ n _ ___.1111
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 763 .
Before you move the selector lever to R, press both the button in the
handle of the selector lever
and the brake peda l 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 165.
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 167.
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.
Contro ls a nd eq uip­
ment
& WARNING
Read and follow all WARNINGS => & in "Driving the automatic
transmission " on
page 163.
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 . 185 Shift gate
selector lever lock
positions and interlock
button highlighted
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. 185 with your thumb until you have moved the
selector lever to the desired position.
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Vehicle care I I Technical data

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T he direction in which the driver wishes to travel is determined with
t he aid of the steering angle and vehicle speed and is con tinua 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 stabi lized by the forces act ing 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 whee l that is on
the outside of the curve. In the case of a vehicle that is
understeering
(tendency to s lide out of the curve), t he brakes are applied a t the
rear wheel that is on the inside of the curve. An acoustic signal indi ­
cates when ESP brake app lication cuts in
=> & .
The system operates across t he entire speed range in comb inat ion
with the ABS system
=> page 272 . If the Anti -Lock Brake System
(ABS) malfunctions, the ESP wi ll be out of act ion as well.
Ac tivation
When you turn on the eng ine, ESP will automatically be activated
and wil l perform a self -test.
The system can be activated or deactivated by pressing the but ton
=> page 268, fig. 254 . The warning light comes on when the system
is switched off
=> page 18.
Normally, the ESP s hould 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 des ired such as:
• when driving with snow chains
• whe n driving in deep snow or on a loose surface (to allow the
whee ls to dig in to reach firm ground)
• whe n trying to
"rock" the vehicle free whe n it has become 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
& WARNING
The Ele
ctron ic Stabiliz ation Pr ogram i s ne verthele ss subje ct to the
laws of phy sic s. It is p articularl y important to pay attention to this
fa ct on wet and slipper y ro ad s. It i s therefore important th at you
alway s adapt your dr iving to the condit ion of the road and traffic
c ondition s. Do not allo w the in crea sed safety pro vided by the Ele c­
tronic Stabilization Program system to lull you into a ccepting
a ddition al safety ri sk s.
•
Electronic differential lock (EDL)
The elec tronic d ifferen tial lock moni tors the rotation al
s p eed of the drive wheels.
G en era l not es
The elect ronic d ifferential lock (EDU helps the ca r to start mov ing,
accelerate and c limb a grad ient on surfaces providing poor or
a lmost no grip . Without EDL, this would be difficult, if not impos ­
s ib le.
How the syst em works
The EDL operates automatical ly. It monitors the rotationa l speed of
t he drive wheels on an ax le with the he lp of the ABS senso rs
=> page 272. If a not iceable 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 bra ked, thereby transferring power
to the other drive wheel or wheels (a ll -whee l drive) . This is done up
t o a speed of ab out 60 mph (100 km/h). N oises from the brake
system signal that wheel spin is being control led .
Dri ving off
When driving off, always be sure to keep road conditions in mind as
you accelerate. I f one drive wheel spins because it is on a sur face
with less grip, gradual ly increase the pressure on the accelerator
pedal unt il the car star ts to move . The whee l less able to t ra nsfer
power spins.
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Vehicle care Do-it-yourself service Technical data

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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
stabili zation 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 272, 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 336, "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 which are driven mostly in stop-and-go city traffic or
which are driven hard, the brake pads should be checked by your
authorized Audi dealer more often than specified in the
Warranty &
Maintenance booklet. _,,,

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•
On steep slo pes, you shou ld use th e braking effect of the engine .
This way, yo u preve nt u nn ecessary wear on the bra ke sys te m. If you
must use your brakes, do not hold the brakes down cont inuous ly .
Pu mp the brakes at in terval s.
Moisture or road salt
U nder ce rtain cond itions, for e xa m ple, w hen drivi ng thro ug h w ate r
or v ery h eavy rain, or even after washing your vehicle, the braking
e ff ect can be red uce d du e to mo is tu re ( or in fr eezin g c ond it ions ice)
on t he b rake pads . A few carefu l brake applicatio ns should dry off
t h e br ake pads o r rem ove a ny ice coatings .
The e ffective ness of t he b ra kes ca n b e red uced wh en th e ve hicle is
driven o n a salt -covered road and t he brakes are not used. Here too,
yo u should cle an off acc umulate d sa lt co atin g from b rake di scs a nd
pads w ith a few careful app lications of th e
brake=>&.
Corrosion
T here may be a tendency for dirt to build up on t he bra ke pads and
c o rr os ion t o form on th e dis cs if t he car is not driven reg ular ly or
only for short trips with little use of the bra kes .
If th e bra ke s are not us ed fr equ ent ly , or if corro sion h as form ed on
th e discs, it is adv isab le to cl ean off the pa ds and discs by braking
firm ly a few times from a moderate ly h igh
speed =>& .
Faults in the brake system
If y ou s ho uld n oti ce a
sud d en inc rea se in b rake pe dal trave l, then
one of the two b rake c ircuits may h ave
fai led =>& .
Low brake fluid level
M alfunctions can occur in the brake system if the b ra ke fluid leve l is
t oo low. Th e br ake fluid level is monitor ed ele ctr onic a lly .
& WARNING
• You should perform braking maneuvers for the purpose of
cleaning the brake system only if road conditions permit. Other
road users must not be put at risk -you may cause an accident!
& WARNING (continued )
• Before descending a steep grade , reduce speed and shift trans­
mission 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
cause 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 climatic and operating conditions such as
passing through water, driving in heavy rain or after washing the
vehicle , 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 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 flow to the front brakes is not obstructed.
Otherwise the brake system could overheat reducing the effective­
ness of the entire brake system.
• Failure of one brake circuit will impair the braking capability
resulting in an increased stopping distance. Avoid driv ing the
vehicle and have it towed to the nearest Audi dealer or qualified
workshop. •
Brake booster
Th e brake boo ster adds ex tra braking po wer.
The b ra ke booster works wit h vacuu m press ure which is created
on ly wh en th e e ngi ne is
r un ning => & .

-Intelligent technology
P:V:1--------=-- --=-=-------------
& WARNING
• Never let the vehi cle roll to a stop with the engine shut off .
• If the brake boo ster i s not working, for example when towing
your vehicle , or because the brake booster has so mehow been
damaged, the brake pedal must be pres sed considerably harder to
make up for the la ck of booster as sistan ce . •
Functioning of Anti-Lock Brake System (ABS)
AB S pre vent s th e wh eels fr o m lo ckin g up un der braking .
The ABS contributes effective ly to ve hicle control s ince it prevents
th e whee ls from
lo cking w hen t he brakes are a ppl 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 . Just hold the brake
pedal down.
H owever, do not expect the ABS to shorten braking distance under
all cir cum stances. W hen drivin g on g ravel o r on new ly fallen s now
on top of icy surfac es, bra king distance may be even longer, there ­
fo re, unde r th ese circum stances, i t is especially i mporta nt th a t yo u
drive slow ly and with great care .
How the ABS system works
An automatic check is made when a speed of about 4 mph (6 km/h)
is reac hed . When this ha p pens, a pumping n oise can be hea rd.
If an indiv idua l wheel begins to rotate too s lowly in relation to
vehic le speed and tends to lock, the ABS automatica lly reduces
brake pressure to prevent that whee l from loc king .
T his automat ic adjustment process wil l cause a
slight vibration of
th e br ak e pe dal a nd some noises to ale rt you th at ve hic le sp eed
must be adapted to existing road and traffic conditions.
& WARNING
Although the ABS is very effe ctive , always remember that braking
capability is limited by tire traction. Alway s adjust your driving
speed a ccording to the road and traffi c conditions . Do not let the
extra safety afforded by the ABS tempt you into taking extra risks.
The ABS cannot overcome the laws of physics.
[ i ] Tips
• I f ABS is not funct io ni ng properl y, a wa rn ing li ght will co me o n.
See ~ page 21.
• I f a fault occurs in the A BS, the EDL is also not functioning. This
i s indica ted by the ABS wa rn ing l igh t.•
Brake assistant
The brake assis tant is desig ned to ach ieve the o ptim um
brakin g eff ec t.
The br ake assistan t helps to in cr eas e the effec tive b raki ng pow er
and thus to achieve a shorter stopping distance . If the driver
p re sses the b rake pe dal very q uick ly, the brake assistan t auto mati ­
ca lly boosts the brakin g force to the maximum level, up to th e point
whe re the a nti-lock b rake functi on (AB S) int ervenes to sto p the
w hee ls from loc king . You s hou ld t hen k eep th e br ake pedal pressed
until t he vehicle ha s braked to the required speed . The brake a ssis ­
t ant s witches itse lf off as soo n as you re lease t he bra ke pedal.
T he b rake assistant will not be ope rative if there is a malfunction in
th e ABS .
& WARNING
Please remember that the accident risk always increases if you
drive too fast , especially in corners or on a slippery road , or if you
follow the vehicle ahead of you too closely . Increased risk of an
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New brake pads
Remember that new brake pads do not have a full braking
effec t during the first 250 miles (400 kilometers) after they
are installed .
New brake pads have to be "burnished in" before they have optimal
grab =>& .
During the break -in period, you s hou ld avoid putting severe loads
on the brakes . Severe loads include, for examp le, sudden hard
braking, in particular at very high speeds or, for example, on moun ­
t ain passes.
& WARNING
N ew brake p ad s don 't h ave the be st stopping po wer and mu st be
"broken -in " during the initial 100 to 150 mile s (150 to 200 kil ome ­
t e rs) of norm al c ity dri ving . You can comp en sa te for thi s by
pr ess ing the brake ped al more firmly . Thi s al so appli es later when
ne w pad s a re in sta lled. •
Catalytic converter
It is very important tha t your emission control sys tem
(catalytic converter) is functioning properly to e nsure that
y o ur vehicle is running in an environmentally sound
manner.
-Always use lead-f ree gasoli ne :=> page 301, "Fuel supply".
-Never run the tank down a ll the way to empty.
-Never put too much motor o il in your engine :=> page 312,
"Adding eng ine oil 'l=;r111
•
-Never try to push -or tow -s ta rt yo ur vehic le.
T he catalytic converter is an efficient "clean -up" device built into the
exhaust system of the vehicle. The catalytic converter burns ma ny
of the po llutants in the exhaust gas before they are released into the
atmosphere.
The exclusive use o f un leaded fue l is critica lly important for the l ife
of the cata lytic converter and proper functioning of the engine.
& WARNING
• Do not park or operate th e veh icle in ar ea s where the hot
e x hau st sys tem m ay come in cont act w ith dr y grass, brush , fuel
s pill or other material which can cau se a fire .
• Do not appl y additi ona l u ndercoating or ru stpr oofing on or
near the exhau st manifol d, exhau st pipe s, ca tal ytic converter or
h ea t shield s. Du ring dri ving , the sub sta nce u sed f or under coating
c ould overhe at and cau se a fir e.
0 Note
• Be aware that just one tank filling with leaded fue l wi ll already
seriously degrade the performance of the catalyt ic converter.
• Do not exceed the correct engine oil
level => page 312 .
• Do not drive until the fuel tank becomes comp letely empty . The
engine cou ld misfire. Unburned fuel could also get into the exhaust
system and this could cause the catalytic converter to overheat .
• Do not turn off t he ignition wh ile the vehicle is moving.
• Do not continue to operate your vehicle under these conditions,
as otherwise fuel can reach the cata lyt ic converter . This cou ld result
in overheating of the converter, requiring its rep lacement .
• To assure eff ic ient operat ion of the Emiss ion Contro l System:
- Have your vehicle maintained properly and in accordance with
the service recommendations in your Warranty
& Maintenance
booklet. _,.