2008 AUDI S8 four wheel drive

failure. Under-inflation also reduces fue l efficiency and tire tread
life, and may affect the veh ic le's handling and stopping abi lity.
Please note that the TPMS is not a substitute for proper tire mainte­
nance, and it is the driver's responsibi lity to maintain correct tire
pressure, even if under-inflation has not reached the leve l to tr igger
illumination of the TPMS low tire pressure tellta le.
Your veh icle has a lso been equipped with a TPMS malfu nction indi­
cator to indicate when the system is not operating properly . The
TPMS malfunction indicator is combined w ith the low tire press ure
telltale . When the system detects a ma lfunction , the telltale wi ll
fl ash for approximately one minute and then remain continuously
illum inated . This sequence will continue upon subsequent vehicle
start -ups as long as the ma lfunction exists.
When the ma lfunctio n indicator is i llum inated, the system may not
be ab le to detect or signa l low tire pressure as intended . TPMS
malfunctions may occ ur for a var iety of reasons, i nclud ing the
installation of replacement or alternate tires or wheels on the
vehic le that prevent the TPMS from f unctioning proper ly . Always
check the TPMS malfunction tellta le after replac ing one or more
t ires or whee ls on yo ur ve hicle to ens ure t hat the replacement or
a lternate tires and wheels allow the T PMS to continue to function
proper ly. •
Introduction
The tire pressure monit oring system m onitors air pressure
in all four road wheels and the spare tire* while the
vehicle is movin g.
As soon as the tire pressure moni toring system se nses a signi ficant
loss of air pressure in one or severa l tires, text messages and yellow
symbo ls appear in the inst rume nt cluster d isplay to aler t t he driver .
T he
(l) warning light in the instrument c luster comes on when the
t ire is sig nificant ly underinflated
=> page 20 .
Controls and equip­
ment
Driver information di splay
The warning light U) also i lluminates in the case of a system
mal fu ncti on.
The system continuous ly receives rad io signa ls from sensors
located inside each tire .
Be aware that t ire p ressu re is also dependen t on the tempera ture of
the tire . For every
18 °F (1 O °C) increase in tire temperature, tire pres­
sure increases by about 1 .5 psi (0 .1 bar). The tire warms up wh ile the
vehicle is moving and t ire pressure rises . So you should adjust tire
pressure only when the t ires are
cold, when the temperature of the
tires is roughly the same as the ambient air temperature .
I n order to keep the tire pressure monitoring system properly cali ­
brated, tire pressure on all four tires and on the spare tire* should
be checked at regular intervals, adjusted if n ecessary and saved in
the proper setti ng (recommended
pressure) => page 44.
The tire pressure is shown on the tire pressure label. On USA vehi ­
cles, the tire pressure labe l is located on the drive r's s ide B -p ill ar. On
Canada vehicles, the tire pressure labe l is located either on the
driver's side B -pillar o r inside the fuel fi ller flap. The t ire press ure
label l ists t he recommended cold tire inflat io n pressures for t he
vehic le at its maximum capacity weight and the tires that were on
your ve hicle at the time it was manufactured . For recommended tire
pressures for normal load condit ions, please see chapter
=> page 328 .
The current temperatures and pressure of your tires can be viewed
in the M MI
=> page 43 .
& WARNING
• When the tire pre ssure monitoring system warning light i s lit ,
one or more of your tires is signifi cantly under -infl ated . You should
stop and check your tires a s soon a s po ssible , and inflate them to
the proper pre ssure a s indi cated on the vehi cle' s tire pre ssure
label
=> page 328 . Driving on a significantly under -inflated tire
ca use s the tire to o verheat and can lead to tire failure. Under -infla -
~

___ o_ n_ t_
h _e _ ro_ a_d __________________________________________________ _
Starting off with a trailer To prevent rolling back unintentionally on an incline, do
the following:
- Keep the switch pulled and depress the accelerator. The
parking brake stays applied and prevents the vehicle
from rolling backward.
- You can release the switch once you are sure that you are
developing enough forward momentum at the wheels as
you depress the accelerator.
Depending on the weight of the rig (vehicle and trailer) and the
severity of the incline, you may roll backwards as you start. You can
prevent rolling backwards by holding the parking brake switch
pulled out and accelerating -just as you would when starting on a
hill with a conventional hand brake. •
Emergency braking
In the event that the conventional brake system fails or
locks.
- Pull the switch and continue to pull it to slow your vehicle
with the parking brake in an emergency.
- As soon as you release the switch or accelerate, the
braking process stops.
If you pull the switch and hold it above a speed of about 5 mph (8
km/h), the emergency braking function is initiated . The vehicle is
braked at all four wheels by activating the hydraulic brake system.
Brake performance is similar to making an emergency
stop~ &.
So that emergency braking is not activated by mistake, an audible
warning tone (buzzer) sounds when the switch is pulled . As soon as the switch is released
, or the accelerator pedal is depressed, emer­
gency braking stops.
& WARNING
Emergency braking should only be used in an emergency, when
the normal foot brake has failed or the brake pedal is obstructed .
Using the parking brake to perform emergency braking will slow
your vehicle as if you had made a full brake application. The laws
of physics cannot be suspended even with ESP and its associated
components (ABS, ASR, EDS). In corners and when road or
weather conditions are bad, a full brake application can cause the
vehicle to skid or the rear end to break away -risking an
accident. •
Driver messages in the instrument cluster
Caution: Vehicle parked too steep
This message appears when the parking brake is applied on an
incline that exceeds about 30%.
In this case the braking power of the parking brake may
not be
adequate
to prevent the vehicle from rolling unintentionally.
Please release parking brake
This message appears, when a gear is selected and the accel erator
pedal is depressed -release the parking brake.
Press brake pedal to release parking brake
This driver message appears when the switch to release the parking
brake was pressed. The parking brake can only be released if you
press the brake or accelerator pedal and press the switch at the
same time .
~ Parking brake malfunction !
This driver message appears together with the yellow 'Jlf symbol
when there is a parking brake malfunction.
~

llll.___l_n _t _e _ll _ig=- e_n _ t_ te_ c_h _n_ o_ lo...;g'"'-=- y ___________________________________________ _
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. _,,,

Intellig ent tec hnol ogy -
------------ -=--=-= '-
& WAR NIN G (c onti nued )
acc ident canno t b e co mp ensat ed for even b y th e br ake assis tant,
s o alway s maintain a safe sp eed . •
Servotronic® - advanced power
steering system
The power steering systems uses the power of the
running engine to allow precise s teering with little effor t.
The advanced Servotronic® power steering system senses the road
speed and electronically adjusts power assistance to provide
comfortab le and safe steer ing response exactly matched to the
vehic le speed.
Power s teeri ng 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 serv ices.
0 Note
If there is an electron ic ma lfunction, servotronic will sti ll funct ion
like a conventiona l power steering system, providing a constant
steer ing suppor t force that is no longer proportionate to the vehicle
speed . This is most noticeable when turning the steering wheel at
low speeds (for examp le w hen parking), -more effor t wi ll be
required than usual.
• Be aware of the different than usua l steering response and
adjust your steering force accordingly .
• Have the problem checked and set right by an Aud i dea ler as
soon as possib le.
Controls and equip­ ment Safety first Vehicle operation
[
i ] Tip s
• When the engine is running, never hold the steer ing whee l
turned all the way to the right or to the left for longer than 15
seconds. The power steer ing pu mp wil l overheat the hydraul ic fluid
if you keep ho lding the steering whee l turned a ll the way. This is
like ly to damage the power steering system.
• I f the power steering system shou ld fail entire ly, or if the engine
is not runn ing ( for examp le, wh ile be ing towed), you w ill st ill be able
to steer the vehicle . However, considerably more effort will be
requ ired to do so.
• I f the power steering system shou ld have a leak, or is not func ­
tioning properly, contact your author ized Audi dealer im mediately.
• The power stee ring system requires a special ly formulated
hydrau lic fluid . The power steer ing reservo ir is the one located most
forward on the left side of the engine
compartment => page 308. The
correct flu id level in the reservo ir is important for proper func ­
tioning of the power steering. •
Driving with your quattro®
With All Wheel Drive, all four wheels are driven.
Genera l inf orm ati on
With All Whee l Drive, power is d istributed to all fo ur wheels. This
happens automatically depending on your driving style and the
road condi tions at the time . See
a lso => page 269, "Electronic differ ­
entia l lock ! EDU" .
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
driveabi lity and braking: these ti res must be mounted on all four
wheel s. See
also=> page 341, "Winter tires". ~
Vehicle care Do-it-yourself service Technical data

Tires and wheels -
-----------------------------
•
Sidewall
means that portion of a tire between the tread and bead.
Speed rating means the speed at which a tire is designed to be driven for
extended periods of time. The ratings range from 93 mph (150 km/h)
to 186 mph (298
km/h)=> page 338. You may not find this informa­
tion on all tires because it is not required by law.
The speed rating letter code, where applicable, is molded on the tire
sidewall and indicates the maximum permissible road
speeds=> &
in "Winter tires" on page 341.
Tire pressure monitoring system
means a system that detects when one or more of a vehicle's tires
are underinflated and illuminates a low tire pressure warning tell­
tale.
Tread
means that portion of a tire that comes into contact with the road.
Tread separation
means pulling away of the tread from the tire carcass.
Treadwear indicators (TWI)
means the projections within the principal grooves designed to give
a visual indication of the degrees of wear of the tread . See
=> page 335, "Tread Wear Indicator (TWI)" for more information on
measuring tire wear .
Uniform Tire Quality Grading
is a tire information system developed by the United States National
Highway Traffic Safety Administration (NHTSA) that is designed to
help buyers make relative comparisons among tires. The UTQG is
not a safety rating and not a guarantee that a tire will last for a
prescribed number of miles (kilometers) or perform in a certain way.
It simply gives tire buyers additional information to combine with
other considerations, such as price, brand loyalty and dealer recom- mendations
. Under UTQG, tires are graded by the tire manufac­
turers in three areas: treadwear, traction, and temperature resis­
tance . The UTQG information on the tires, molded into the
sidewalls.
U.S. DOT Tire Identification Number (TIN)
This is the tire's "serial 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
ture. For example,
DOT ... 2207 ...
means that the tire was produced in the 22th 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.
Vehicle capacity weight
means the rated cargo and luggage load plus 150 lbs. (68 kilograms)
times the vehicle's total seating capacity as listed on the label located either on the driver's side 8-pillar or on the inside of the fuel
filler flap.
Vehicle maximum load on the tire
means that load on an individual tire that is determined by dis trib­
uting to each axle its share of the maximum loaded vehicle weight
and dividing by two.
Vehicle normal load on the tire
means that load on an individual tire that is determined by dis trib­
uting to each axle its share of the curb weight, accessory weight,
and normal occupant weight (distributed in accordance with table
below => page 328) and dividing by two. ..,.
Vehicle care

Tires and wheels -
-----------------'
Tire service life
The service life of tires depends on a lot of different things
including proper installation and balancing, correct tire
pressure and driving style .
Tread Wear Ind icator (TWI)
Fig. 274 Tire tread:
tread wear indicators
(TWII
Fig . 275 Rotating tires
for more even wear
The origina l tires on your vehic le have 1/16 inch (1.6 mm) high "wear
indicators"::::, fig. 274 running across the tread. Depending on the
make, there will be six to eight of them evenly placed around the
tire. Marks on the tire sidewall (for example
"TWI" or other symbols)
indicate the positions of the tread wear indicators. Worn tires must
be rep laced. Different figures may apply in other
countries::::, &-
Tire pressure
Incorrect tire pressure causes premature wear and can cause
sudden tire blow-out. For this reason, tire pressure must be checked
at least once a
month ::::, page 331.
Driving style
Driving fast around curves, heavy accele ration and hard braking
increase tire wear .
Rotating tires for more even wear
For all four tires on your vehicle to have the same service life, we
recommend that the front and rear tires are rotated according to the
tire manufacturer's suggested tire rotation intervals. Please
remember the following:
• Tire rotation intervals may differ from the vehicle service inter­
vals outlined in your Warranty
& Maintenance booklet.
• The longer one tire is used in one location on the vehicle, the
more it wears at certain points; therefore, we recommend that you
follow the tire manufacturer 's suggested tire rotation intervals .
• Vehicles with front-wheel drive experience more tread wear on
the front wheels compared to all -wheel drive (quattro®l .
• Please rotate tires as shown
~ fig. 275.
• Extra care must be taken when rotating direction -specific tires
::::, page 357.
Wheel balancing
The wheels on new vehicles are balanced. However, various situa ­
tions during everyday driving can cause them to become unbal ­
anced, resu lting in vibrations you can usually feel through the
steering wheel.
Unbalanced wheels must be rebalanced to avoid excessive wear on
steering, suspension and tires. A whee l must also be rebalanced
when a new tire is insta lled.
...
Vehic le care I I Technical data

________________________________________________ T_ i
_ r_e _s_ a_n_ d_ w_ h_ e_e _ l_s __ l'III
•
• T he batt ery inside of the tire pressure sensor has a l imited
s er vice l ife.
• Al ways drive with the va lve stem ca ps sec ure ly m ounted. We
r ec om mend u sin g fa ctor y in sta lle d v alv e stem caps. Ask your autho­
rized Audi d ealer to replac e lost valve stem caps .
T he in stalla tio n of replacement ti res with steel cord body plies i n
th e tire s id ewal l may cause malfunct ion of the tire pressure moni ­
toring sy ste m, and is not recommended (c ord mate ria l infor mation
i n mo lded on the tire s idewa ll).
Al ways check your tir e pressure monitor ing system indicator after
r eplac ing on e o r m ore tire s on y our vehi cle. If the tire pressu re
monitorin g system indicator flashes, or is on, your system is not
w orki ng pr ope rly. You r rep lace ment tir e mi ght be in co m pati ble w ith
your t ire pr essure monitoring system, or some component of the
t ir e pr ess ure m oni to ring sys te m m ay be damaged .
& WARNING
• Using incorrect or unmatched tires and / or wheels or improper
tire and wheel combinations can lead to loss of control , collision
and serious personal injury .
• Always use tires , rims and wheel bolts that meet the specifica­
tions of original factory -installed tires or other combinations 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 . Tires that are more than 6 years old can
only be used in an emergency and then with special care and at
lower speeds .
• Never mount used tires on your vehicle if you are not sure of
their "previous history ." Old used tires may have been damaged
even though the damage cannot be seen that can lead to sudden
tire failure and loss 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
&, WARNING (continued )
with different tires reduces 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 drive with extra care . Refit the
normal road wheel as soon as safely possible.
• Never drive faster than the maximum 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 , sudden tire failure,
including a blowout and sudden deflation and loss of control.
• Temperature grades apply to tires that are properly inflated and
not over or underinflated.
• For techni cal reasons it is not always possible 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 blocked . Reduced airflow to
the brakes can them to overheat , increasing stopping distances
and causing a collision.
• Run flat tires may only be used on vehicles that were equipped
with them at the factory . The vehicle must have a chassis designed
for run flat tires and a factory-installed tire pressure monitoring
system that indicates a loss of tire pressure. Incorrect use of run
flat tires can lead to vehicle damage or accidents . Check with an
authorized Audi dealer or tire specialist to see if your vehicle can
be equipped with run flat tires . If run flat tires are used , they must
be installed on all four wheels . Mixing tire types is not permitted.
0 Note
• Fo r tec hnica l reaso ns, i t is not gene rally p oss ibl e to use the
whee l rims from other vehicles . T his can hold true for wheels of t he
sa me v ehicl e typ e.
Vehicle care

__________________________________________________ T_ ir_e_ s_ a_ n_d _ w_ h_ e_ e_l_s __ 9II
•
& WARNING
The tr action grade assigned to this tire i s ba sed on straight -ahead
braking traction tests, and does not include acceleration,
c ornering , hydroplaning or peak tra ction chara cteristic s.
& WARNING
The temperature grade for this tire is established for a tire that is
properly inflated and not overloaded. Excessive speed , underinfla ­
tion , or ex cessive loading , either separately or in combination , can
c ause heat buildup and po ssible tire failure . •
Winter tires
Winter tires c an im prove vehicle handlin g on snow and
i ce. At tem pera tures belo w 4 5 °F (7 °C ) we re commend
changi ng to w inte r tires.
In some heavy snow areas, loca l governments may require true
winter or "s now" tire s, those with very deeply cut tread. These tires
s h ou ld on ly be used in pairs and be i nstalled on all four wheels .
M ake sure you purchase snow tires that a re the same size and
co nstruct io n type as t he othe r tires on your ve hicle.
I f your vehicle is equipped with all -wheel drive *, this will improve
t raction d uring winte r dr iving , eve n wit h th e sta n dar d tir es .
However, we strongly recommend that you always equip a ll four
w hee ls on you r vehic le wi th co rrectl y fi tted w inte r tires or all-season
t ir es, w hen w inter road condi tions are expec ted . T his also improves
the vehicle 's br aking perfo rma nce a nd reduces stopping distances .
Summe r tires p rov ide less gr ip on ice a nd s now.
Wint er tires (snow tires) must a lways be fitted on all four whee ls .
Compatible ti re p ressu re m oni to ring sen so rs must be instal led on
a ll four w inte r tires for t he ti re pr essur e moni tor ing s yste m to fu nc­
tion
proper ly => page 33 8.
Ask your authorized Audi dealer or qualifi ed workshop for permitted
winter tire sizes. Use only ra di al winter tires .
W inter tires lose their eff ectiveness when the tr ead is worn down to
a depth of 0 .157 inc h (4 mm).
O nly d rive wi th winte r ti res under w inter cond itio ns. S um mer tire s
handle better when there is no snow or ice on the roads and the
te mpera ture i s abov e 45 °F ( 7 °C) .
I f you have a f lat tire, se e notes on spar e whee l
=> page 336.
Please a lways remember that winter tires may have a lower speed
r ati ng t han th e tires orig in ally ins talled o n you r ve hicle at t he time
it was manufactu red . P lease
see => page 338, "Speed rating (letter
co de)" for a l is tin g of th e sp eed ratin g letter code s an d th e
maximum speed at which the tires can b e driven .
The speed ra ti ng le tter
co de( => page 327) is on the side wa ll of the
t ire
=> page 336.
& WARNING
Winter tires have ma ximum speed limits that may be lower than
your vehicle's maximum speed . Always know the maximum speed
before driving off . Never drive faster than the speed permitted for
your specific winter tires. This will cause damage to the tires leading to an accident and serious personal injury to you and your
passengers .
& WARNING
Driving faster than the maximum speed for which the winter tires
on your vehicle were designed can cause tire failure including a
blowout and sudden deflation, loss of control , crashes and serious
per sonal injuries . Have worn or damaged tires replaced immedi­
ately.
• Winter tires have maximum speed rating that may be lower
than your vehicle's maximum speed.
Vehicle care