2009 AUDI S8 sensor

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Intelligent technology
Notice about data recorded by
vehicle control modu les
Your vehicle is not equipped with an Event Data Recorder (EDR),
installed by some manufacturers for the express purpose of
capturing data for retrieval after an accident or crash event . EDR's
are sometimes called "crash recorders" .
Some state laws restrict the retrieva l or downloading of data stored
by EDR's that were insta lled in a vehicle for the express purpose of
retrieving data after an accident or crash event without the owner's
consent.
Although your vehicle is not equipped with an EDR, it is equipped
with a number of electronic control modules for various vehicle systems such as, for example, engine function, emission control, as
well as for the airbags and safety belts.
These electronic control modules also record vehicle-related data during norma l vehicle operation for diagnost ic and repair purposes .
The recording capacity of the electronic control modules is limited
to data (no sound is recorded) and only a small amount of data is
actually recorded over a very limited period of time and stored when
a system fault or other condition is sensed by a control unit. Some
of the data then stored may relate to vehicle speed, direction, braking as well as restraint system use and performance in the
event of a crash or other condition . Stored data can only be read and
down loaded with special equipment .•
Electron ic Stabilizat ion Program (ESP)
General =nformation
The ESP improves the vehicle stability.
I~
"' " "'
- -
( ra I 5£ IA I -3, )
Fi g. 256 C ente r
co nso le w it h ES P
swi tch
ESP is designed to he lp you maintain vehic le control in situations
where the car approaches the limits of "grip", especia lly when
accelerating and cornering. ESP reduces the risk of skidding and
improves stabil ity under all road conditions .
T he system operates across the entire speed range in combination
with the ABS system. If the Anti-Lock Brake System (ABS) malfunc­
tions, the ESP wil l also shut down .
How th e sys te m w ork s
The Anti -Lock Brake System (ABS) , Electronic Differential Lock (EDU
and the Anti-Slip Regulation System (ASR) are integrated in the e lec­
tronic stabi lization program . In addition to the data provided by
these functions, the ESP control unit requires additional measure­ ment data provided by high performance sensors . The rotational
speed of the vehic le about its vertical axis, the lateral acce leration
acting on the vehicle, the brake pressure and the steering angle are
a ll measured .

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- ~

ll}Jl __ ln_ t _e_ ll-'"ig ...,_ e_ n_t _t_ e_ c_ h _ n_o _ l_o _,.g= y,_ __________________________________________ _
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-•

Checking and filling -
------------------------------------------- -=----- =------
0 Note
• Before winter sets in, have the coolant checked to see if the
coolant additive in your vehicle is sufficient to meet the climate
conditions. This is especially important if you live in a region where
the winter is extremely cold. If necessary, increase the proportion of
coolant additive to 60%.
• When adding coolant additive to your cooling system,
remember:
-We recommend using only coolant additive G12+ + (check the
label) for your vehicle. This coolant additive is available at autho­
rized Audi dealers. Other types of antifreeze can significantly
reduce corrosion protection . The resulting corrosion can cause a
loss of coolant and serious engine damage .
• Do not add any type of radiator leak sealant to your vehicle's
engine coolant. Adding radiator repair fluid may adversely affect the
function and performance of your cooling system and cou ld result
in damage not covered by your New Vehicle Limited Warranty .•
Checking the engine coolant level
The engine coolant level can be checked with a quick
glance.
Fig . 269 Engine
compartment : Coolant
expansion tank
Before you check anything in the engine compartment,
always read and heed all WARNINGS==> & in "Working in
the engine compartment" on
page 309.
Turn off the ignition .
Read the engine coolant level from the coolant expan­
sion tank==> fig. 269. With a cold engine, the coolant level
should be between the "min" and "max" markings. When
the engine is warm, the level may be slightly above the
" max" marking .
The location of the coolant expansion tank can be seen in the
engine compartment illustration=>
page 310.
To obtain an accurate reading, the engine must be switched off .
The expansion tank in your vehicle is equipped with an electric
coolant level sensor.
When the coolant level is too low, the warning light in the Auto­
Check System =>
page 31 will blink until you add coolant and the
level has been restored to normal. Even though there is an electric
coolant level sensor, we still recommend you check the coolant level
from time to time.
Coolant loss
Coolant loss may indicate a leak in the cooling system. In the event
of coolant loss, the cooling system should be inspected immedi­
ately by your authorized Audi dealer. It is not enough merely to add
coolant.
In a
sealed system, losses can occur only if the boiling point of the
coolant is exceeded as a result of overheating.
& WARNING
The cooling system is under pressure and can get very hot. Reduce
the risk of scalding from hot coolant
by following these steps. ~
Vehic le care I I Technical data

-~_T_ ir_e_ s_ a_ n_d _ w_ h_ e_e _l_s _________________________________________________ _
Tire manuf acturin g date
The manufacturing date is a lso indicated on the tire sidewall
(possibly only on the
inner side of the wheel):
"DOT ... 2207 ... " means, for example, the tire was produced in th e
22nd week of 2007.
Sp eed rating (l ett er code )
The speed rating letter code on the wheels indicates the maximum
permissible road speeds=>
& in "Winter tires" on page 343.
P up to 93 mph (150 km/h)
Q up to 99 mph (158 km/h)
R upto 106mph(170km /h)
S upto110mph(180km/h)
T upto118mph(190km/h)
U up to 124 mph (200 km /h)
H up to 130 mph (2 10 km/h)
V up to 149 mph (240 km/h)3>
Z over 149 mph (240 km/h)3>
W up to 168 mph (270 km/h)3
l
Y up to 186 mph (298 km/h)3>
Your vehicle is normally factory equipped with tires, which possess
excellent driving characteristics and give your Audi optimum
driving comfort . An e lectronic speed limiter=>
page 28will normally
prevent your vehicle from going faster than the t ire speed rating
=> & .
U.S . D OT T ire Identifi cation Number (TIN ) an d tire
m anuf actur e date
This is the tire's "seria l number" . It begins with the letters "DOT"
and indicates that the tire meets all federal standards . The next two
numbers or letters indicate the plant where it was manufactured,
and the last four numbers represent the week and year of manufac-
31 F or tires with a maximum speed capab il ity over 149 mph (240 km/h), t ire
manufactur ers som etimes use the lett ers "ZR."
ture. For example, the numbers 2207 mean the tire was produced in
the 22nd week of 2007. The other numbers are marketing codes that
may or may not be used by the tire manufacturer. This information
is used to contact consumers if a tire defect requires a recall.
T ire ply co mpositio n a nd m ate ria ls used
The number of p lies indicates the number of layers of rubber -coated
fabric in the tire. In genera l, the greater the number of p lies, the
more weight a tire can support. Tire manu facturers also must indi ­
cate the materials in the tire, which include steel, ny lon, polyester,
and others.
M ax im um Load R ating
This number indicates the maximum load in kilograms and pounds
that can be carried by the tire.
Tire quali ty grading f or tr eadwe ar, trac tion , and
t e mp era tu re resis ta nce
Tread wear, traction and temperature grades=> page 342.
Max imum P ermi ssibl e Infl ation Press ure
This number is the greatest amount of air pressure that should ever
be put in the tire under norma l driving conditions.
Repl acin g tir es o r rim s on vehicles e quippe d with t ire
pr ess ure m onit orin g syste m*
The wheels on your vehicle are equipped with a sensor which
constantly monitors the a ir pressure inside the tire, and then trans ­
m its this in formation to the tire pressure mon itoring system*. If you
are going to replace the wheel rims on your vehicle , make sure the
new rims also have these sensors. The sensors must be compa tib le
with the tire pressure monitoring system * on your vehic le.
If you install rims, which do not have the sensors, or have sensors
which are not compatible, then the tire pressure monitoring system* will not work prope rly. In this case, the tire pressure moni ­
tor ing system * would not be able to monitor the tire pressu re or
warn you if it is necessary . .,_

__________________________________________________ T_ ir_e_ s_ a_ n_d _ w_ h_ e_ e_l_s __ _
•
• T he battery inside of the tire pressure sensor has a limited
service life.
• Always drive with the va lve stem caps securely mounted. We
recommend using fac tory insta lled valve stem caps . Ask your autho­
rized Audi dealer to replace lost valve stem caps .
T he installation of replacement tires with steel cord body plies in
the tire sidewall may cause malfunction of the tire pressure moni ­
toring system *, and is not recommended (cord material info rmation
i n molded on the t ire sidewa ll).
A lways check your tire pressure monitoring system * indicator after
replac ing one or more tires on you r veh ic le . If t he tir e pressure
monitoring system * indicator f lashes, or is on, your system is not
wo rking pr ope rly. Your re place ment tire might be i nco m patible wit h
your tire pr essure monitoring system *, or some component of the
t ir e pr ess ure moni toring system * m ay be da maged.
& WARNING
• Using incorrect or unmatched tires and / or wheels or improper
tire and wheel combinations can lead to los s of control , collision
and serious personal injury .
• Alway s use tires , rims and wheel bolts that meet the specifica ­
tions of original fa ctory -installed tires or other combination s that
have been specifically approved by the vehi cle manufacturer .
• Tires age even if they are not being used and can fail suddenly,
espe cially at high speeds . Tire s that a re more than 6 years old can
only be used in an emergency and then with special care and at
lo wer speeds .
• Never mount used tire s on your vehicle if you are not sure of
their "previous history ." Old used tires may have been dam aged
even though the damage cannot be seen that can lead to sudden
ti re failure and lo ss of vehicle control.
• All four wheels must be fitted with radial tires of the same type ,
size (rolling cir cumference ) and the same tread pattern . Driving
& W ARNING (continued )
with different tires redu ces vehicle handling and can lead to a loss
of control.
• If the spare tire is not the same as the tires that are mounted
on the vehicle -for example with winter tires -only use the spare
tire for a short period of time and dri ve with extra care . Refit the
normal road wheel as soon a s safely pos sible.
• Never drive faster than the ma ximum speed for which the tires
on your vehicle are rated because tires that are driven faster than
their rated speed can fail suddenly .
• Overloading tires cause heat build -up , su dden tire failure ,
includ ing a blowout and sudden deflation and loss of control.
• Temperature grades apply to tires that are properly inflated and
not over or underinflated .
• For te chni cal reasons it is not always po ssible to use wheels
from other vehicles -in some cases not even wheels from the
same vehicle model.
• If you install wheel trim discs on the vehicle wheels , make sure
that the air flow to the brakes is not blo cked . Redu ced airflow to
the brake s can them to overheat , increa sing stopping distances
and causing a collision.
• Run flat tires may only be used on vehicles that were equipped
with them at the fa ctory . The vehicle mu st have a cha ssi s designed
for run flat tires and a factory -installed tire pressure monitoring
s ystem* that indicates a lo ss of tire pressure . Incorrect use of run
flat tires can lead to vehicle damage or accident s. Check with an
authorized Audi dealer or tire specialist to see if your vehicle can
be equipped with run fl at tires . If run flat tires are used , they must
be installed on all four wheels . Mi xing tire types is not permitted.
0 Note
• Fo r techn ica l reaso ns, i t is no t genera lly p oss ibl e to use the
whee l rims from other vehicles . T his can hold true for wheels of the
sa me vehicle type. ..,.
Vehicle care
I t •

-~_T_ ir_e_ s_ a_ n_d _ w_ h_ e_e _l_s _________________________________________________ _
• If the spare tire is different from the tires that you have mounted
o n your vehi cle (for e xample winter tires or wide profile tires), then
use the spare tire for a short period of time on ly and drive with extra
care . Replace the f lat tire with the tire matching the others on your
vehicle as soon as possible.
• If you should put different wheels and tires on your vehicle (e.g.
winter wheels and tires), you must be certain that the wheels and
tires are compatible with the tire pressure monitoring system* .
Otherwise the system will register a ma lfunction and a fault
message will be displayed . For more information, contact your Audi
dea ler.
0 Note
• When installing new tires, be careful not to damage the valves or
tire pressure monitoring system* sensors.
• Never drive without the va lve stem cap. The valves could get
damaged.
• If the sensors must be replaced, then the valve must also be
replaced at the same time.
c£> For the sake of the environment
Dispose of old tires in accordance with the loca l requirements. •
Uniform tire quality grading
• Tread wear
• Traction AA A B C
• Temperature A B C
Qua lity grades can be found where applicable on the tire side wal l
between tread shoulder and maximum section width
=> page 338,
fig. 278.
For e xample: Tread wear 200 , Traction AA, Temperature A.
All passenger car tires must conform to Federal Safety Require­
ments in addit ion to these grades.
Tread w ea r
The tread wear grade is a comparative rating based on the wear rate
of the tire when tested under contro lled conditions on a specified
government test course.
For example, a tire graded 150 wou ld wear one and one half (1 1/2)
times as well on the government course as a tire graded 100.
The relative performance of tires depends upo n the actua l condi­
tions of their use, however, and may depart significantly from the
n orm due to variations in d riving habi ts, service practices and differ­
ences in road characteristics and climate.
Tra ction
The traction grades, from highest to lowest, are AA, A, Band C.
Those grades represent the tire's ability to stop on wet pavement as
measured under contro lled conditions on specified government
t est surfaces of asphalt and concrete . A tire marked C may have
poor traction performance => & .
Temperature
The temperature grades are A (the highest), 8, and C, representing
the tire's resistance to the generation o f heat and its abi lity to dissi ­
pate heat when tested under control led conditions on a specified
indoor laboratory test wheel.
Sustained high temperature can cause the mater ial of the tire to
degenerate and reduce tire life, and excessive temperature can lead
to sudden tire failure=>&.
T he grade C corresponds to a leve l of performance which a ll
passenger car tires must meet under the Federal Motor Vehicle
Safety Standard No. 109. Grades Band A represent higher levels of
p er formance on the la b ora tory test whee l than t he mi nimum
required by law.
~