2012 AUDI A8 brakes

Audi adaptive cruise control and braking guard 91
Driving in stop-and-go traffic
Applies to vehicles: with Audi adaptive cruise control
The adaptive cruise control system also as­
sists you in stop-and -go traffic. If a previous
detected vehicle ahead s tops, yo ur vehicle will
brake to a stop, within the limits of the sys ­
tem .
.,. To resume driv ing with adap tive cruise con ­
tro l, tap the accelerator peda l or
.,. Pull the lever toward you into position @
¢ page 89, fig. 90.
(D Tips
-If adaptive cru ise contro l is active and
your vehicle does not start driving as ex­
pected after pulling the lever once, you
can start out aga in by tapping the accel­
erator pedal.
- If an obstacle is detected when your ve­
hicle starts dr iv ing, the system w ill
prompt you to take over
¢ page 92.
Your vehicle w ill drive more slowly when
starting. This may also happen in some
s ituations when there no obstacle is ap­
parent.
Interrupting cruise control
Ap plies to vehicles: with Audi adaptive cruise control
Fig. 93 Selecto r level
Requirement: adaptive cruise control must be
switched on .
Overriding crui se control
.,. To accelerate manua lly, pull the lever to­
ward you into position @and hold it there.
The message
ACC override appears. Or
.,. press the accelerator pedal. .,.
To resume cruise contro l, release the lever
or take your foot off the accelerator pedal.
Canceling cruise control while driving
.,. Move the lever into position @. The mes­
sage
ACC standby appears . Or
.,. press the brake pedal.
.,. To resume the stored speed, move the lever
into position @ .
Canceling cruise control when stopped
.,. Push the lever away from you into pos ition
@ . Th e message
ACC standby appears.
.,. To resume cruise control, press the brake
pedal and pu ll the lever toward you into po­
sition @.
A WARNING
-
Never resume the stored speed if the
speed is too high for prevailing road, traf­
fic or weather conditions.
Setting the distance
App lies to vehicles: with Audi adapt ive cr uise contro l
Fig. 94 Selector lever: setting th e dista nce
.,. Tap the switch to display the current set dis­
tance
¢ fig. 94 .
.,. To increase or reduce the distance by incre­
ments, tap the switch again to the left or
right. The distance between the two vehicles
w ill change in the instrument cluster dis ­
play.
When approaching a moving vehicle up ahead,
the adapt ive cruise control system automati­
cally brakes to match that object's speed and
then maintains the stored distance . If the ve-
hicle ahead accelerates, adaptive cruise ..,.

Audi adaptive cruise control and braking guard 93
Audi braking guard
Description
Applies to vehicles: with Audi adaptive cruise control
Fig. 96 Instrument cluster: approach warning
Audi braking guard uses radar sensors and a
video camera. It also functions within the lim­
its of the system when adaptive cruise control
is switched off.
What can Audi braking guard do?
When detected in time, the system can assess
situations when a vehicle ahead brakes sud­
denly or if your own vehicle is traveling at a
high speed and approaching a vehicle up
ahead that is moving more slowly . Audi brak­
ing guard does not react if it cannot detect
the situation.
The system advises you of various situations:
- The
distance warning is given if you are too
close to the vehicle ahead for a long time. If
the vehicle ahead brakes sharply, you will not be able to avoid a collis ion. The indicator
light
I i n the display comes on .
- The
approach warning is given when a de­
tected vehicle up ahead in your lane is mov ­
i ng much more slowly than you are or if it
brakes sharply . When this warning is given,
it may only be possible to avoid a collision
by swerving or braking sharply. The indicator
light
I and indicator in the display will warn
you about the danger
c::> fig . 96. You will a lso
hear an acoustic signal.
If you do not react fast enough or do not react
at all to the situation, Aud i braking guard will
11
This is not ava ilable in som e coun tri es.
intervene by braking and the message braking
guard intervention
will appear.
- If a coll is ion is imminent, the system wi ll
first provide an
acute warning by briefly and
sharply applying the brakes.
- If you do not react to the acute warning,
braking guard can brake with increas ing
force within the limits of the system. This
reduces the vehicle speed in the event of a
collision.
- The system can initiate complete dece lera­
tion shortly before a collision
1>. Full deceler­
ation at high speeds occurs only in vehicles
with adaptive cruise control and side assist
(pre sense plus).
- If the Audi braking guard senses that you
are not braking hard enough when a colli­
sion is immi nent, it can increase the braking
force.
- The pre sense functions also engage when a
collision is imm inent
c::> page 185 .
Which function s can be controlled?
You can switch Audi braking guard and the
distance/approach warning on or off in the
MMI c::> page 94, Settings in the MMI.
A WARNING
Lack of attention can cause collisions, oth­
er accidents and serious personal injuries .
The Audi braking guard is an assist system
and cannot prevent a collision by itself.
The driver must always intervene. The driv­
er is always responsib le for braking at the
correct time.
- Always pay close attention to traffic,
even when the Audi braking guard is
switched on. Be ready to intervene and
be ready to take complete control when ­
ever necessary. Always keep the safe and
legal distance between your veh icle and
veh icles up ahead.
- Audi brak ing guard works within limits
and will not respond outside the system
lim its, for example when approaching a

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> ,& . ..,.

194 Driving and environment
Driving and
environment
The first 1,000 miles
(1,500 km) and
afterwards
New engine
The engine needs to be run-in during the first
1,000 miles (1,500 km).
For the fir st 600 miles (1,000
kilometers ):
.,. Do not use full throttle.
... Do not drive at engine speeds that are more
than 2/3 of the max imum permitted RPM.
... Avoid hig h engine speeds.
From 600 to 1,000 mile s (1 ,000 to
1,500 kilometers):
... Speeds can gradually be increased to the
max imum pe rm iss ible road or eng ine speed .
During and after break-in per iod
.,. Do not rev the engine up to high speeds
when it is cold. Th is app lies whether the
transm ission is i n N (Neutra l) or in gear.
After the break-in period
... Do not exceed maximum engine speed un­
der any circumstances.
.,. Upshift into the next hig her gear
before
reaching the red area at the end of the tach­
ometer scale
c:> page 10.
During the first few hours of driving, the en­
g ine's interna l friction is higher than later
when all the moving parts have been broken
in . How well this break- in p rocess is do ne de­
pends to a conside rable extent on th e way the
ve hicl e is driven d uring the first 1,0 00 miles
(1, 500 k ilome ters).
0 Note
E xtremely high engi ne speeds are auto­
mat ica lly reduced. However, these rpm
lim its are progr amme d for an engine well
r u n- in, not a new engine .
{® For the sake of the environment
Do not drive with unnecessarily high en­
g ine speeds - upshifting ear ly saves fuel,
reduces no ise and protects the environ­
ment.
, New tires
If your vehicle is runni ng on new tires, drive
part icularly caref ul for the first 350 miles
(500 kilomete rs) afte r fitt ing .
A WARNING
New tires tend to be sl ippery and mus t al­
so be "broken -in" . Be s ure to remember
this dur ing the fi rst 350 mi les ( 500 kilo ­
meters) . Brake gently . Avoid fo llow ing
closely behind other vehicles or other sit­
uations that m ight require sudden, hard
braking .
New brake pads
Remember that new brake pads do not have a
full bra king effect dur ing the fi rst 250 m iles
(400 kilomete rs) afte r they a re insta lled .
New brake pads have to be "burnished in" be­
fo re t hey have optima l grab
c:> A .
During the break- in period, you should avoid
putting severe loads on the brakes. Severe
l oads include, for example, sudden hard brak­
i ng, in particular at very high speeds or, for
example, on mounta in passes .
A WARNING
New b rake pa ds don't have t he bes t stop­
pi ng power and mus t be "broke n-in " dur­
i ng the in iti al 1 00 to 150 mi les (150 to
20 0 k ilometers) of no rma l city driving . You
can compensate for this by pressing the
br ake peda l mo re f irm ly . This also applies
l ater when new pads are installed.

196 Driving and en vironm ent
Driving through water
on roads
Note the following to avoid vehicle damage
when driving through water, for example on
flooded roads:
- The water must not be any higher than the
bottom of the vehicle body.
- Do not drive faster than wa lking speed.
A WARNING
After driving through water, mud, slush,
etc., the brakes may be slow to take effect
because of wet brake rotors and pads. Dry
the brakes first by braking carefully to re­
sto re the full braking effect.
@) Note
Vehicle components such as the engine,
transmiss ion, suspension or electrical sys­
tem can be severely damaged by driving
through water.
- Check the depth of the water before dr iv­
i ng through it.
- Do not stop the vehicle, drive in reverse
or switch the engine off when driving
through water .
- Keep in mind that oncoming vehicles
may create waves that raise the water
level and make it too deep for your vehi­
cle to drive through safely.
- Avoid dr iving through salt water because
i t can cause corrosion.
Operate your vehicle
economically and
minimize pollution
General
Your personal style of driving will determine
the economy of your vehicle, as well as ex­
haust and noise levels.
Fuel economy, environmenta l impact, and
wear on your engine, brakes and tires largely
depend on three factors:
- your personal driving style
- operating conditions
- technical limitations
If you anticipate what you need to do next and
drive economically, you can easily cut your
fuel consumpt ion by 10-15 percent . This sec­
t ion will give you some tips on how you can
help the env ironment and your pocketbook.
@ Tips
The consumption estimates as published
by ENVIRONMENTAL PROTECTION AGENCY
(EPA) and Transport Canada may not corre­
spond to your actual consumption on the
road, which will vary depending upon vehi­
cle load and speed, road and weather con ­
ditions, trip length, etc.
Drive smoothly and keep a lookout
ahead
Vehicles use the most fuel when they are ac­
celerating.
.,. Avoid unnecessary accelerating and braking.
Vehicles use the most fuel when they are ac­
ce lerating. If you anticipate what is going to
happen next, you will need to brake less and,
thus, acce lerate less . Let the vehicle coast
whenever possible - for example when you see
that the next traffic light is red.

Trailer towing Driving with a trailer
General information
Your Audi was designed primarily for passen­
ger transportation .
If you plan to tow a trai ler, p lease remember
that the addit ional load will affect durab ility,
economy and performance .
Trailer towing not on ly places more stress on
the vehicle, it also calls for more concentra­
tion from the driver.
F or this reason, a lways fo llow the operating
and d riving instr uctions provided and use
common sense.
(D Note
If you are going to tow a trai ler, you must
activate the trailer operat ion mode
~ page 199, Operating instructions.
Technical requirements
Trailer hitch
Use a weight-carrying hitc h co nforming to the
gross trailer we ight. The hitch must be suita­
b le for your veh icle and trailer and must be
mounted secure ly on the veh icle's chassis at a
technically sound location . Use only a trailer
hi tch wit h a removab le ball moun t. A lways
check with t he trail er hitch ma nufactur er to
make sure tha t you are using the corre ct
hi tch.
Do not use a bumper hitch.
The hitc h must be installed in such a way that
i t does not interfere with the impac t-absorb­
i ng bumpe r sys tem. No mod ifica tio ns should
be made to the vehicle exh aust a nd brake sys­
tems . From time to time, check that a ll hitch
mo unt ing bolts remain securely fastened.
W hen you are not towing a trail er, remove the
traile r hitch ball mount. Th is prevents the
hi tch from causing damage sho uld your ve hi­
cle be str uck from behind ¢& .
Trailer towin g 199
Trailer brakes
If your trailer is equippe d wi th a br akin g sys ­
tem, check to be s ure that i t conforms to all
r egulations .
T he trailer hy draul ic brak e sys tem mus t not be
direc tly connec ted to the vehi cle' s h ydraulic
brake system .
Safety chains
Always use safety chains between your veh icle
and the tra ile r.
Trailer lights
Trai ler lights must meet all regu lations. Be
su re to check with your Audi dealer for cor rect
wir ing, swi tches and relays .
Mirrors
If you are unable to see the traffic behind you
us ing the reg ular o utside mirrors, then you
must insta ll extended mirrors. It is imp ortant
that you
always have clea r v is ion to the rear.
A WARNING ...__ -
Afte r removing the trailer hitch, do not
stor e it i n yo ur v ehicl e. In cas e o f sudden
b ra king, the hitch co uld fly forwar d and in­
ju re you or your p ass en ger s.
Operating instructions
Fi g. 168 MM I dis pl ay: tow ing mode on
Ma ximum trailer weight
A trai ler fo r you r vehicle is limited to a typical
class 1 or class 2 tra iler.
ll>