2012 AUDI A8 wheel

regulations must be observed. Your au­
thorized Audi dealer is familiar with these requirements and we recommend that you
have your dealer perform this service for
you.
Other things that can affect Advanced
Airbag performance
Changing the vehicle's suspension system can
change the way that the Advanced Airbag Sys­
tem performs in a crash. For example, using
tire-rim combinations not approved by Audi, lower ing the vehicle, changing the stiffness of
the suspension, including the springs, suspen­ sion struts, shock absorbers etc. can change
the forces that are measured by the airbag
sensors and sent to the electronic control
un it . Some suspension changes can, for exam­
ple, increase the force levels measured by the
sensors and make the airbag system deploy in
crashes in which it would not dep loy if the
changes had not been made. Other kinds of
changes may reduce the force Levels meas­
ured by the sensors and prevent the airbag
from deploying when it should.
The sensors in the safety belt buckle for the
driver and front passenger seat tell the elec­
tronic control module if the safety belt is
latched or not. If the safety belt is being used,
the front airbag will deploy at a slightly high­
er rate of vehicle deceleration than if the safe­
ty belt is not being used. Therefore, in a par­
ticular collision, it is poss ible that an airbag
will not deploy at a seating position where the
safety belt is being used but will inflate at the
position where the safety belt is not being
used. It is important that nothing interfere
with the safety belt buckles so that the sen­
sors can send the correct information about
safety belt use to the electronic control unit.
A WARNING
Changing the vehicle's suspension includ­
ing use of unapproved tire-rim combina­
tions can change Advanced Airbag per­
formance and increase the risk of serious personal injury in a crash.
Airbag system 157
-Never install suspension components
that do not have the same performance
characteristics as the components origi­
nally installed on your vehicle .
- Never use tire-rim combinations that
have not been approved by Audi.
A WARNING
-
Items stored between the safety belt
buckle and the center console can cause
the sensors in the buckle to send the
wrong information to the electronic con­
trol module and prevent the Advanced Air­
bag System from working properly.
- Always make sure that nothing can inter­
fere with the safety belt buckles and that they are not obstructed.
Knee airbags
Description of knee airbags
The knee airbag system con provide supple­
mental protection to properly restrained
front seat occupants.
Fig. 149 Driver 's airbag
The driver knee airbag is in the instrument
panel underneath the steering wheel
¢ fig . 149, the airbag for the passenger is at
about the same height in the instrument pan­
el underneath the glove compartment.
The knee airbag offers additional protection
to the driver's and passenger's knees and up ­
per and Lower thigh areas and supplements
the protection provided by the safety belts.
If the front airbags deploy, the knee airbags
also deploy in frontal col lisions when the de­
ployment threshold stored in the control unit .,,.

The knee airbag system has been designed so
that the airbags for the driver and front pas­
senger deploy in certain but not all frontal
collis ions .
I f the front airbags deploy , the knee airbags
also deploy in fronta l collis ions when the de ­
p loyment threshold stored in the control unit
is met .
When the system dep loys, the airbags fill
with a prope llant gas, and inflate between the
l ower part of the instrument panel and the
driver and the lower part of the instrument panel and the fron t passenger
c> page 151 ,
fig . 14 7.
Although they are not a soft pillow, they can
"cush ion" the impact and in this way they can
help to reduce the r isk of injury to the lower
extremities .
All of this takes place in the blink of an eye, so
fast that many people don't even reali ze that
t he airbags have deployed . The airbags also
inflate w it h a great deal of force and it is im ­
portant for occupant safety that not hing
should be in the ir way when they dep loy .
Fully infla ted airbags in comb ination with
properly worn safety belts slow down and lim ­
it the occupant's forward movement and help
to reduce the r isk of injury .
Important safety instructions on the
knee airbag system
Airbags are only supplemental restraints. Al­
ways wear safety belts correctly and ride in a
proper seating position .
There is a lot that you and your passengers
must know and do to help the safety belts and
airbags to provide supp lemen tal protection .
& WARNING
An inflating knee airbag can cause ser ious
injury. Wearing safety belts incorrectly and
improper seating positions increase the
r isk of serious personal injury and death
whenever a vehicle is being used.
A irbag system 159
-The knee a irbag system cannot protect
you proper ly if you a re seated too close
to any of the airbag locat ions. When ad­
justing their seat pos itions, it is impor­
tant that both the driver and the front passenger keep the ir upper bod ies and
knees at the following m inimum safe
distances :
- at least 10 inches (25 cm) between the
chest and the steering wheel/instru­
ment panel.
- at least 4 inches (10 cm) between the knees and the lower part of the instru­
ment panel.
- The risk of personal in jury increases if
you lean forward or to the s ide, or if the
seat is improperly positioned and you are
not wearing yo ur safety belt . The risk i n­
creases even more should the ai rbag de­
ploy .
- Always make sure that the knee a irbag
can inflate without inte rfe rence. Objects
between yo u and the airbag can inc rease
the risk of in jury in an accident by inte r­
fering w ith the way the a irbag deploys or
by being p ushed into you as the airbag
deploys.
- Never let anybody, especia lly children
or anima ls ride in the footwell in front
of the passenge r seat. If the airbag de­
ploys, th is can result in serious or fa tal
i njur ies.
- Never carry obje cts of any kind in the
footwe ll area in front of the dr iver's or
passenger 's sea t. Bulky objects (shop ­
ping bags , fo r example) can interfere
with o r prevent proper deployment of
the airbag. Small objects can be
thrown through the ve hicle if the air­
bag deploys and injure you or your pas­
sengers .
- Make sure there are no cracks, deep
scratches or other damage in the area of
the instrument panel where the knee air­
bags are located.
- If ch ildren are incorrectly seated, their
risk of injury increases in a collision
c> page 166, Child Safety .
•
•

-Always install rear-facing child safety
seats on the rear seat.
- If you must install a rearward facing
child safety seat on the front passenger
seat in exceptional circumstances and
the
PASSENGER AIR BAG OFF light does
not come on and stay on, immediately
install the rear-facing child safety seat in
a rear seating position and have the air­
bag system inspected immediately by
your Audi dealer.
_& WARNING
If, in exceptional circumstances, you must
install a forward-facing child restraint on
the front passenger's seat:
- Always make sure the forward-facing
seat has been designed and certified by its manufacturer for use on a front seat
with a passenger front and side airbag.
- Always follow the manufacturer's in­
structions provided with the child safety
seat or carrier.
- Always move the passenger seat into its
rearmost position in the seat's fore and
aft adjustment range, as far away from
the airbag as possible before installing
the child restraint. The backrest must be
adjusted to an upright position .
- Always make sure that the
PASSENGER
AIR BAG OFF
light comes on and stays
on all the time whenever the ignition is
switched on.
(D Tips
Always replace child restraints that were
installed in a vehicle during a crash. Dam­
age to a child restraint that is not visible
could cause it to fail in another collision
situation.
Advanced front airbag system and children
Your vehicle is equipped with a front "Ad­
vanced Airbag System" in compliance with United States Federal Motor Vehicle Safety
Child Safety 167
Standard (FMVSS) 208 as applicable at the
time your vehicle was manufactured.
The Advanced Airbag system in your vehicle
has been certified to meet the "low-risk" re­
quirements for 3- and 6-year old children on
the passenger side and small adults on the driver side. The low risk deployment criteria
are intended to reduce the risk of injury
through interaction with the airbag that can
occur, for example, by being too close to the
steering wheel and instrument panel when
the airbag inflates . In addition, the system
has been certified to comply with the "sup­
pression" requirements of the Safety Stand­
ard, to turn off the front airbag for infants up
to 12 months who are restrained on the front
passenger seat in child restraints that are list­
ed in the Standard.
Even though your vehicle is equipped with an
Advanced Airbag system, all children, espe­ cially those 12 years and younger, should al­
ways ride in the back seat properly restrained
for their age and size. The airbag on the pas­
senger side makes the front seat a potentially dangerous place for a child to ride . The front
seat is not the safest place for a child in a for­
ward-facing child safety seat. It can be a very
dangerous place for an infant or a larger child
in a rearward-facing seat .
Advanced Airbags and the weight­
sensing mat in the front seat
The Advanced Airbag System in your vehicle
detects the presence of an infant or child in a
child restraint on the front passenger seat us­
ing the weight -sensing mat in the seat cush­
ion and the sensor below the safety belt latch
on the front passenger seat that measures the
tension on the safety belt.
The weight -sensing mat measures total
weight of the child and the child safety seat
and a child blanket on the front passenger seat. The weight on the front passenger seat
is related to the design of the child restraint
and its "footprint", the size and shape of the
bottom of the child restraint as it sits on the ..,.
•
•

Intelligent technology Notice about data
recorded by vehicle
control modules
Your vehicle is not equipped with an Event Da­
ta Recorder (EDR), installed by some manu­
facturers for the express purpose of capturing
data for retrieval after an accident or crash
event. EDR's are sometimes called "crash re­
corders".
Some state laws restrict the retr ieval or down­
loading of data stored by EDR's that were in­
stalled 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 electron­
ic control modules for various vehicle systems
such as, for examp le, engine function, emis­
sion control, as well as for the airbags and
safety belts.
These electronic control modules also record
vehicle-related data during norma l vehicle op­
eration for diagnostic and repair purposes.
The recording capacity of the electronic con­
trol modules is limited to data (no sound is re­
corded) and only a small amount of data is ac­
tually 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 we ll as restraint
system use and performance in the event of a
crash or other condition. Stored data can only be read and downloaded with special equip­
ment.
Electronic Stability
Control (ESC)
Description
ESC helps to improve road holding and vehicle
dynamics to help reduce the probability of
skidding and loss of veh icle control. It works
only when the engine is running. ESC detects
Intelligent technology 187
certain difficult driving situations, including
when the vehicle is beginning to spin (yaw)
out of control and helps you to get the veh icle
back under control by se lectively braking the
wheels, and/or reducing engine power and
providing steering ass istance to help hold the
vehicle on the driver's intended course. The in­
dicator light
Ip.] in the instrument cluster
blinks when ESC is taking action to help you
control the vehicle.
ESC has limitations .
It is important to remem­
ber that ESC cannot overcome the laws of
physics.
It will not always be able to help out
under all conditions you may come up against.
For example, ESC may not always be able to
help you master situations where there is a
sudden change in the coefficient of friction of
the road surface. When there is a section of
dry road that is suddenly covered with water,
slush or snow, ESC cannot perform the same
way it would on the dry surface . If the vehicle
hydroplanes (rides on a cushion of water in­
stead of the road surface), ESC will not be
able to help you steer the vehicle because con­
tact with the pavement has been interrupted
and the vehicle cannot be braked or steered .
During fast cornering, particularly on winding
roads, ESC cannot always deal as effectively
with difficult driving situations than at lower
speeds. When towing a trailer, ESC is not able
to help you regain control as it would if you
were not tow ing a trailer.
Always adjust your speed and driving style to road, traffi<; and weather conditions. ESC can­
not override the vehicle's physical limits, in­
crease the available traction, or keep a veh icle
on the road if road departure is a result of
driver inattention. Instead, ESC improves the
poss ibility of keeping the vehicle under con­
trol and on the road dur ing extreme maneu­
vers by using the driver's steering inputs to
help keep the vehicle going in the intended di­
rection. If you are traveling at a speed that
causes you to run off the road before ESC can
provide any assistance, you may not experi­
ence the benefits of ESC.
•
•

188 Intelligent technology
ESC includes and/or works together with the
anti-lock braking system (ABS), brake assist
system, anti-s lip regulat ion (ASR), e lectronic
d ifferential lock ( EDL), dynamic steering* and
e lectronic interaxle differentia l lock*. ESC is
switched on all the time. I n certa in s ituations
when you need less tract io n, you ca n sw itch
off ASR by pressi ng the button above
~ page 189, fig. 167 the se lector lever. Be
sure to sw itch ASR on ag ain when you no lon­
ger need less trac tion.
Anti -lock braking system (ABS)
ABS prevents t he wheels from locking up
when braking. The veh icle can still be st eered
even d uring ha rd b rak ing . Apply steady p res­
sure to the br ake ped al. Do no t pu mp the ped­
a l. A puls ing in t he bra ke peda l ind icates that
the system is he lping yo u to b rake the vehicle .
Brake assist system
The brake assist system can decrease b ra kin g
d ista nce. It increases braking powe r w hen the
d river p resses the brake pedal quickl y in eme r­
gency situa tions . You mus t press and ho ld the
b rake peda l until the situation is over. In vehi­
cles with adaptive cruise control*, the brake
assist system is more sensitive i f the d istance
detected to the vehicle ahead is t oo smal l.
Anti-slip regulation (ASR)
ASR reduces engine power w hen the drive
wheels begin to spin and adapts the fo rce to
the road condit ions. This makes it eas ier to
start, accelerate and drive up hills.
Electronic differential lock (EDL )
The E DL brakes wheels that are spinn ing and
transfers the drive powe r to the o ther d rive
wheel o r whee ls if the vehic le is equipped with
a ll whee l drive*. This funct ion is available up
to about 7S mph (120 km/h).
I n extreme cases , EDL automatica lly swit ches
off to help keep the brake on the braked whee l
from overheating. ED L wi ll switch on again au­
tomatically when conditions have returned to normal.
Dynamic steering*
On vehicles wi th dynam ic s teeri ng, ES C helps
stab ilize the steer ing in cer tain sit uations.
Electronic interaxle differential lock
function*
T he ele ctronic i nte raxle di fferentia l lock f unc ­
tion ac tiva tes when dr iving t hrough curves.
B ra king is targeted towar d the whee ls on the
inside of the curve as needed . This helps to
min imi ze front whee l skid, improves traction
and allows for more precise driving throug h
cu rves .
A WARNING
- ESC, ABS, ASR , EDL, dynamic steering*
and the elect ronic interaxle differential
loc k function* cannot ove rcome t he laws
of physics . This is espe cially im po rtant
on slippery o r we t road s.
If the sys tems
begin actin g to stabilize your veh icle, you
should immediately change yo ur speed
to match the road and t raffic conditions .
Do not let the increased safety provided
by these systems tempt you to take risks. Doing so will increase the risk of a loss of
veh icle cont ro l, collision and ser io us per­
sonal injur ies .
-Always ada pt your speed to road , traffic
and wea ther conditions. The risk of los­
ing contr ol of the vehicle i ncreases wh en
d riving too fast, espe cially through
curve s and on slippe ry or wet roads, and
when dr iv ing too close to vehicles up
ahead. ESC, ABS, the brake ass ist sys ­
tem, EDL, ASR, dynam ic steering * and
the elect ron ic interaxle differential lock
function * cannot prevent co llisions.
- Always accelerate with s pecial care on
even, smooth s urfaces such as those that
are wet or covered with ice and snow.
The drive wheels can spin even w ith
these assistance sys tems that cannot al­
ways he lp to red uce the risk of loss of ve ­
h icle co nt ro l.
-

@ Tips
-ABS and ASR on ly work correctly when
all four wheels are equ ipped with identi­
cal t ires. Different tire s iz es can lead to a
reduct ion in eng ine power.
- You may hear noises when the systems
described are working.
- If the indicator light
D] or m (USA
models) ;£1 (Canada models) appears,
there may be a malfunction¢
page 19,
c> page
18 .
Switching on and off
ESC
turn s on au tomatically when you s tart
the engine .
Fig. 167 Cen te r con sol e wit h ES C OF F but ton
Switching ASR off (sport mode )
In certain sit uat ions, you can switch ASR and
ESC in to sport mode by pressing the bu tton
[ru
c> fig. 167 . The indicator light I comes o n
and the message
Cauti on! R edu ced t ra cti on
appears. ASR deactivates completely and the
assistance provided by the ESC system is lim it­
ed . Switch to sport mode only when your driv ­
ing skills, traffic and weathe r conditions per­
mi t.
I n some s ituations, it may be useful to switc h
ASR off to let the wheels slip. Example:
- Rocking the vehicle back and forth when it is
stuck
- Driv ing in deep snow or on loose ground
- Driving with snow cha ins
Switching ASR on
Press the button [fil again. The message Sta­
bility program on
appears.
Intelligen t technolog y 189
A WARNING
-Drive whee ls can sp in and you can lose
control of the vehicle more eas ily when
ASR and ESC are in sport mode, especial­
ly whe n the road is slippe ry .
- Sw itch to sport mode only when your
driving skills, traff ic and weather condi­
tions permit.
(D Tips
You cannot sw itch sport mode on whe n
adaptive cruise control* is working .
Braking
General information
What affects braking efficiency?
Operating cond itions and driving h abits
The brakes o n today's automobiles are still
subject to wear, depend ing largely on operat­
i ng condit ions and driving habits ¢&, . On ve­
hicles that a re either dr iven most ly in stop­
and-go c ity t raff ic or are dr iven hard, the
brake pad s should be checked by yo ur author ­
i zed Audi dealer more often than specified in
the
Warranty & Maintenance booklet. Failure
to have your brake pads inspected can result in reduced brake performance.
On steep slopes, you sho uld use the braking
effect of the eng ine . T his way, you prevent un­
necessary wear on the brake system . If you
must use your brakes, do not hold the br akes
down cont inuous ly . Pump the brakes a t in ter­
vals .
Moisture o r ro ad sa lt
Under certa in conditions, for example, when
driv ing through water or very heavy ra in, or
even after washing your veh icle, the braking
effec t can be reduced due to moisture (or in
freez ing cond itions ice) on the brake pads . A
few carefu l brake applications should dry off
the b ra ke pads or remove a ny ice coatings.
When you are driving a t higher speeds with
the windsh ie ld w ipers on , the brake pads will
IJJJ,

190 Intelligent technology
briefly touch the brake discs in regular inter ­
va ls so as to improve reaction time when brak­
ing on wet surfaces. You the driver wi ll not no­
tice anything.
The effectiveness of the brakes can be reduced
when the vehicle is driven on a salt-covered road and the brakes are not used. Here too,
you sho uld clean off accumu lated salt coat ing
from brake d iscs and pads with a few careful
applicat ions of the brake¢,& .
Cor ro sion
There may be a tendency fo r dirt to bui ld up
on the brake pads and corrosion to form on
the discs if the car is not dr iven regularly or
only for short trips with little use of the
brakes .
If the brakes are not used frequently, or if cor­ rosion has formed on the discs, it is advisab le
to clean off the pads and discs by brak ing
firm ly a few times from a moderately high
speed <=>,& .
Fault s in the brake sy stem
If you should notice a sudden increase in
brake peda l travel, then one of the two brake
circu its may have failed¢,& .
Low brake flu id le vel
M alfunctions can occur in the brake system if
the brake fl uid level is too low. The brake fluid
leve l is monitored electronically .
Brake lining wear status
Brake lin ing wea r may be chec ked by v is u al in­
spection of the condition of the brake pads
through the openings in the whee l. If neces ­
sary, the whee l may be removed for this in­
spection ¢ page 2 59, Changing a wheel.
A WARNING
-You should perform brak ing maneuvers
for the purpose of clean ing the brake
system on ly if road con ditio ns pe rmit.
Oth er road users must not be put at r isk -
yo u may cause an ac ciden t! -
Before descend ing a steep grade, red uce
speed and sh ift transmission into a lower
gear or lower dr iving range. Do not ride
the brakes or hold the pedal down too
long o r too often . This could cause the
brakes to get hot and diminish braking
efficie ncy.
- Do not "ride the brakes" by rest ing you r
foot on th e pedal whe n you do not intend
to b rake. This may c ause the brake s to
overhea t, prem ature wear and incre ased
stopping distance.
- Unde r cert ain cl im atic and ope rat ing
conditions s uch as passing thro ugh wa ­
ter, driving in heavy rain o r after washing
the vehicle, the effectiveness of the brakes can be reduced. In winte r, ice can
accumu late on the brake pads, lin ings,
d iscs and drums. Carefully app ly brakes
for a test. Brakes will dry and ice coat­ i n gs w ill be cleaned off after a few care­
fu l brake applicat ions.
- Driving for an extended period of t ime on
salt-covered roads without using your
b rakes can a lso affect bra kin g efficiency .
Clea n off accum ulate d sal t coa ting from
b rake discs and pads wi th a few c areful
b rake applications .
- If you d am age t he fron t spoiler, or i f yo u
install a diffe rent spoiler, be s ure the a ir
f low to the front brakes is not obstruc t­
e d. Otherwise the brake system could
overheat reducing the effectiveness o f
the entire brake system.
- Fa ilure of one brake circuit will impa ir
the braking capab ility result ing in an in­
creased stopping distance. Avoid driving
the vehicle and have it towed to the near­
est A udi dealer or qualified workshop .
Brake booster
The brake booster adds extra braking power.
T he brake booster wo rks with vacuum pres­
s ur e which is created only when the engine is
runn ing
c> ,& . ..,.

& WARNING
-Never let the vehicle roll to a stop with
the engine shut
off.
- If the brake booster is not working, for
example when towing your vehicle, or
because the brake booster has somehow
been damaged, the brake pedal must be
pressed considerably harder to make up
for the lack of booster assistance.
Servotronic ® -
advanced power
steering system
-
The power steering systems use the power of
the running engine to allow precise steering
with little effort.
The advanced Servotronic ® power steering
system senses the road speed and e lectroni­
cally adjusts power ass istance to provide com­
fortable and safe steering response exactly matched to the veh icle speed.
Power steering wi ll not work if the engine is
off. As a resu lt, the steering whee l wi ll be hard
to turn.
The power steering fluid level is checked dur­ ing the scheduled maintenance services.
(D Note
I f there is an electronic malfunct ion, ser­
votronic
will sti ll function like a conven­
tional 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 steer ing whee l at low speeds (for examp le
when parking), -more effo rt will be re­
qui red than usual.
- Be awa re of the different than usual
steering response and adjust your stee r­
i ng fo rce accord ingly.
- Have the p roblem checked and set right
by an Aud i dealer as soon as possib le .
Int ellig ent technolog y 191
(D Tips
-When the engine is running, never ho ld
the steering wheel turned all the way to
the right or to the left for longer than 15
seconds. The power steering pump will
overheat the hydrau lic fluid if you keep
holding the stee ring wheel turned all the
way. This is likely to damage the power
steering system.
- If the powe r stee ring system should fa il
entire ly, o r if the e ngine is not run ning
(for example, wh ile be ing towed), you
w ill still be able to stee r the veh icle.
However,
considerably more effor t will
be required to do so .
- If the power stee ring system sho uld
have a lea k, or is not functioning proper ­
ly, contact your authorized A udi dealer
immediately.
- The power steering system req uires a
specially formu lated hydra ulic fluid. The
power steering fluid reservoir is located
in the engine compartment
Q page 221.
The correct fluid level in the reservoir is
important for proper functioning of the
powe r stee ring.
Driving with your
quattro ®
With All Wheel Drive, all four wheels ore driv­
en.
General information
Wi th A ll Wheel Drive, power is dis tributed to
all four w heels. This happens automatically
depend ing on your driving style and the road
conditions at the time . See a lso
Q page 187.
With the sport different ia l*, power distribu­
tion to the rear wheels is variable and can be
adjusted with Audi drive select*
Qpage 103.
Always read and follow safety precautions
Q&_ ,
Winter tires
When dr iving in the winter, yo ur vehicle with
A ll Wheel Drive has an advantage, even w ith
regular tires. In winter road conditions it may ..,. •
•