2009 AUDI S8 Owners Manual

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

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& 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 .,

until the vehicle has braked to the required speed. The brake assis­
tant switches itself off as soon as you release the brake pedal.
The brake assistant will not be operative if there is a malfunction in
the 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
accident cannot be compensated for even by the brake assistant,
so always maintain a safe speed. •
Servotronic® -advanced power
steering system
The power steering systems uses the power of the
running engine to allow precise steering with little effort.
The advanced Servotronic ® power steering system senses the road
speed and electronically adjusts power assistance to provide
comfortable and safe steering response exactly matched to the
vehicle speed.
Power steering will not work if the engine is off. As a result, the
steering whee l wil l be hard to turn.
The power steering fluid level is checked during the scheduled
maintenance services.
0 Note
If there is an electronic malfunction, servotronic will sti ll function
like a conventional power steering system, providing a constant
steering support force that is no longer proportionate to the vehicle
speed. This is most noticeable when turning the steering whee l at
Controls and equip­
ment Safety first Vehicle operation
Intelligent technology
low speeds (for examp
le when parking), -more effort will be
requ ired than usual.
• Be aware of the different than usual steering response and
adjust your steering force accordingly .
• Have the problem checked and set right by an Audi dealer as
soon as possible.
[ i ] Tips
• When the engine is running, never hold the steering whee l
turned all the way to the right or to the left for longer than 15
seconds. The power steering pump will overheat the hydraulic fluid
if you keep holding the steering whee l turned a ll the way. This is
likely to damage the power steering system.
• If the power steering system shou ld fail entire ly, or if the engine
is not running (for examp le, while being towed), you will still be able
to steer the vehicle . However,
considerably more effort will be
required to do so.
• If the power steering system shou ld have a leak, or is not func ­
t ioning properly, contact your authorized Audi dealer immediately.
• The power steering system requires a special ly formulated
hydraulic fluid. The power steering reservoir is the one located most
forward on the left side of the engine compartment=>
page 310. The
correct fluid level in the reservoir is important for proper func­
tioning of the power steering .•
Driving with your q attro®
With All Wheel Drive, all four wheels are driven.
General information
With All Whee l Drive, power is distributed to all four wheels. This
happens automatically depending on your dr iving style and the
road conditions at the time. See also=>
page 271, "Electronic differ ­
entia l lock (EDU".
Vehicle care Do-it-yourself service Technical data

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Winter tires
When driving in the winter, your vehicle with All Wheel Drive has an
advantage, even with regular tires. In winter road conditions it may be advisable to mount winter tires (or all -season tires) for improved
driveability and braking: these tires must be mounted on
all four
wheels.
See also ~ page 343, "Winter tires".
Tire chains
Where tire chains are mandatory on certain roads, this normally
also applies to vehicles with All Wheel Drive~
page 344, "Snow
chains".
Replacing wheels/tires
Vehicles with All Wheel Drive must always have tires of the same
size. Also avoid tires with different tread depths . For details see
page ~
page 338, "New tires and replacing tires and wheels".
Off-Road driving?
Your Audi does not have enough ground clearance to be used as an
off-road vehicle. It is therefore best to avoid rough tracks and
uneven terrain as much as possible. Also refer to~
page 281.
& WARNING
Always adjust your driving to road and traffic conditions. Do not
let the extra safety afforded by All Wheel Drive tempt you into
taking extra risks.
• Although the All Wheel Drive is very effective, always
remember that braking capacity is limited by tire traction. You
should therefore not drive at excessive speeds on icy or slippery
road surfaces.
• On wet road surfaces, be careful not to drive too fast because
the front wheels could begin to slide on top of the water (aqua­
planing).
If this should occur, you will have no warning from a
sudden increase in engine speed as with a front-wheel drive
vehicle. Always drive at speeds which are suited to the road condi­
tions - risk of crash. •
Energy management
Starting ability is opt:m·zed
Energy management controls the distribution of electrical
energy and thus optimizes the availability of electrical
energy for starting the engine.
If a vehicle with a conventional energy system is not driven for a
long period of time, the battery is discharged by idling current
consumers (e.g . immobilizer) . In certain circumstances it can result
in there being insufficient energy available to start the engine.
Intelligent energy management in your vehicle handles the distribu­
tion of electrical energy. Starting ability is markedly improved and
the life of the battery is extended.
Basically, energy management consists of
battery diagnosis, idling
current management
and dynamic energy management.
Battery diagnosis
Battery diagnosis continuously determines the state of the battery.
Sensors determine battery voltage, battery current and battery
temperature. This determines the current state of charge and the
power of the battery .
Idling current management
Idling current management reduces energy consumption while the
vehicle is standing. With the ignition switched off, it controls the
energy supply to the various electrical components . Data from
battery diagnosis is considered.
Depending on the battery's state of charge, individual consumers
are gradually turned off to prevent excessive discharge of the
battery and thus maintain starting capability.
Dynamic energy management
While the vehicle is being driven, dynamic energy management distributes the energy generated according to the needs of the indi-•

vidual components. It regulates consumption, so that more elec­
trical energy is not being used than is being genera ted and ensures
an optimal state of charge for the battery.
[ i ] Tips
• But even energy management cannot negate the limits of
physics. Consider that the power and life of a battery are limited.
• If starting ability is threatened, you are informed by a warning
~ page 277, "Driver notification in the instrument cluster
display". •
What you should know
The highest priority is given to maintaining starting capa ­
bility.
The battery is severely taxed in short -distance driving, in city traffic
and during the cold time of year . Abundant electrical energy is
required, but only a little is generated . It is also critical if the engine
is not running and e lectrical components are turned on. In this
instance energy is being consumed but none is being generated .
It is in precisely these situations that you wi ll notice energy manage ­
ment actively regulating the distribution of energy.
Vehicle stands for an extended period
If you do not drive your vehicle over a period of several days or
weeks, electrical components are gradually cut back or switched off.
This reduces energy consumption and maintains starting capability
over a longer period.
Be aware that when you unlock your vehicle, some of the conve ­
nience functions may not operate, such as the Convenience key, the
remote control or the power seat adjustment. The convenience
functions will be available again when you turn on the ignition and start the engine.
Controls and equip­ ment Safety first Vehicle operation
Intelligent technology
With the
engine turned off
If you listen to the radio, for examp le, with the engine turned off or
use other MMI functions, the battery is being discharged.
If starting capability is jeopardized due to energy consumption, the
following warning appears in the MMI display:
Please start engine, otherwise system will switch off in 3
minutes .
The warning indicates that the system wi ll be turned off automati­
cal ly after 3 minutes. If you wish to continue using the functions,
you have to start the engine .
With the engine running
Although e lectrica l energy is generated when the vehicle is being
driven, the battery can become discharged. This happens mostly
when little energy is being generated and a great deal consumed
and the battery's state of charge is not optimal.
To bring the energy balance back into equi librium , consumers
which require especia lly large amounts of energy are temporarily
cut back or switched off. Heating systems in particular require a
great deal of energy. If you notice, for example, that the heated
seats* or the heated rear window are not heating, they have been
temporarily cut back or switched off. These systems will be available
again as soon as the energy balance has been restored.
You wil l also notice that engine idle speed has been increased
s lightly . This is norma l and not a cause for concern . By increasing
engine idle speed the additiona l energy required is generated and
the battery is charged. •
Driver notification in the instrument cluster
display
If the battery's state of charge is not in the optimal range, this driver
notification appears in the instrument cluster display:
Low battery charge: battery will be charged while driving ~
Vehicle care Do-it-yourself service Technical data

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This notification reminds you that the starting capability of the
engine may be limited . As soon as you s tart driv ing again, the
battery wi ll be recharged and the notification wi ll go out .
Driver notification appears and goes out again
If this driver notification appears after the ignition is turned on or
wh ile dr iving and i t go es out again after a w hile, the ba ttery has
been adequately recharged .
Driver notification appears and does not go out again
If this driver notification appears after the ignition is turned on or
w hile driving and d oes not go out aga in, the batte ry's s tate of
charge is not in the optimal range . Starting abi lity is restricted . Have
t he battery checke d as soon as p ossi ble at a deale rship .•