2013 AUDI A8 brakes

Audi adaptive cruise control and braking guard 97
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 97, fig. 100.
(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 98.
Your vehicle w ill drive more slowly when
starting. This may also happen in some
s ituations when no obstacle is apparent.
Interrupting cruise control
Applies to vehicles: with Audi adaptive cruise contro l
Fig. 100 Selector lever
Requirement : adaptive cruise control must be
switched on .
Overriding cruise control
.,. To accelerate manually, 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. 101 Selector lever: setting the distance
.,. Tap the switch to display the current set dis­
tance
¢ fig. 101 .
.,. 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 adaptive cruise control system automati­
cally brakes to match that object's speed and
Ill-

Audi adaptive cruise control and braking guard 99
Audi braking guard
Description
Applies to vehicles: with Audi adaptive cruise control
Fig. 103 Instrumen t cl uste r: ap proac h warn ing
Braking guard uses radar sensors and a video
camera . It a lso functions within the lim its of
the system whe n adapt ive cruise control is
switched off .
What can braking guard do? When detected in time, the system can assess
situations when a vehicle ahead brakes sud­
denly or if y our own veh icle is traveling at a
high speed and approaching a veh icle up
ahead that is moving more slowly . Bra king
g ua rd does not react if i t cannot detect th e
si tuation.
The system advises you of va rious 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 col lisio n. The indicator
light
I i n the display comes on .
- The approach warning is g iven when a de­
tected vehicle up ahead in yo ur lane is mov ­
i ng much more slowly tha n you are o r if it
b rakes sha rply . When this wa rning is given,
i t may only be possib le to av oid a collision
by swerving or br aking sh arply . Th e ind ic a tor
li gh t
I and indicator in the disp lay will warn
yo u about the danger
c::> fig . 103 . You will al­
so hear an acoustic sig na l.
If yo u do not re act fast enoug h or do not re act
at all to the situat io n, braking g uard will inte r-
11
Thi s is not ava ilable in som e coun tri es.
vene by braking and the message braking
guard intervention will appea r.
- If a coll is ion is im minen t, the sy st em w ill
first provi de an acute warning by brie fly and
shar ply a pplying the brakes.
- If you do not re act t o the acu te war ning,
bra king g uard can brake w ith increas ing
force w ith in the lim its of the system. T his
red uces the vehicle speed in the event of a
co llision.
- The system can initiate maximum brak ing
short ly before a co llision
ll. Full dece leration
at high speeds occurs only in vehicles with
adapt ive cr uise control and side assist (pre
sense plus).
- If the brak ing g uard senses that yo u are not
braki ng hard enough w hen a co llision is im­
m inent, it can inc rease t he b ra ki ng fo rce .
- The pre sense functions also engage whe n a
col lision is imm inent
c::> page 196 .
Which function s can be controlled?
You can switc h braking guard an d the dis ­
tance/approach warning on or off in the M MI
c::> page 100, Settings in the MMI.
&_ WARNING
Lack of attent ion can cause collisions, ot h­
e r accidents and serio us pe rsonal inj uries .
Th e braking gua rd is an assist system and
ca nnot pr ev en t a collisi on by its elf . T he
dr iver must always in tervene. The drive r is
al way s res pons ible f or br aki ng a t the cor­
rect t ime.
- Always pay clos e att ention to traffic ,
e v e n w hen the bra king g uard is swi tched
on. Be ready t o intervene and be ready to
take comp lete contro l whenever necessa­
ry. Always keep the sa fe and legal dis ­
tanc e between your ve hicle an d veh icles
up ahead.
- Braking guard works wi thin limits and
wi ll not respo nd outside t he system lim­
its, for e xamp le w hen approaching a
stopped vehicle o r stationary obstacle ..,.

118 Autom atic Tran smissi on
preve nt the vehicle from "creep ing" , you
must keep your foot on the brake in all
selector lev er positions except P and N
when the e ng ine is r unning. Do not inad­
vertently press the accelerator pe dal
w hen the veh icl e is stationary . Otherwise
the vehicle will s tart to move immediate­
ly, even if the park ing brake is se t. This
cou ld result in a c rash.
- Do not ride the brakes or press the brake
peda l too often or too long when dr iving
down a hill. Constant braking causes the
brakes to ove rheat and s ubstant ially re­
duces braking performance, increases
braking distance or causes comp lete fail­
ure of the brake system.
Hill descent control
The hill descent control system assists the
driver when driving down declines.
H ill descent control is activated when these­
lector lever is in D/S and you press t he b rake
pedal. The transmission automat ically se lects
a gear that is suitab le for the incline. Hill de­
scent control tries to maintain the speed ach­ ieved at the time of brak ing, within physical
and techn ical limitations. If may still be nec­
essary to adjust the speed with the brakes .
H ill descent control switches off once the de­
cline levels out or you press the accelerator
pedal.
Hill descent control is also activated when the
speed is set by starting the cruise control sys­
tem c:>
page 90.
A WARNING -
Hill descent control ca nnot overcome
physical limitations, so it may not be able
t o maintain a constant speed under all
condi tion s. Alw ays be ready to ap pl y the
bra kes.
Shifting manually
The shift paddles allow the driver to shift the
gears manually .
Fig . 1 25 Steer ing whee l: sh ift in g manually
" To shift to a higher or lowe r gear tempo rari ­
ly, tap the
0 or 0 shift padd le c:> fig. 125.
" To switch manual mode on, press the~
button. An M and the gear that is current ly
engaged appear in the instrument cluster
disp lay @ c:>
page 115, fig. 122.
" To shift up one gear, tap the rig ht shift pad­
dle
0 c:> fig . 125 .
" To s hift down one gear, tap the left shift
paddle Q.
" To swi tch manual mode off, press the~
but ton again, or
" Move the se lector lever back and release it .
T he transm iss io n automatically sh ifts up or
down before cr itical engine spee d is reached.
T he transm iss ion only allows manual sh ifting
whe n the eng ine speed is w ith in the pe rmit­
ted range .
The eng ine braking effect increases when you
downsh ift when going downhill .
Kick-down
Kick-down enables maximum acceleration .
When you press the accelerator pedal down
beyond the resistance point, the automatic
transmission downsh ifts into a lower gear, de­
pending on veh icle speed and eng ine RPM . It
shifts up into the next higher gear once the
max imum specified engine RP M is reached .
Iii>

ESC includes and/or works together with the
anti-lock braking system (ABS), brake assist
system, anti-s lip regulat ion (ASR), electronic
d ifferential lock (EDL), dynamic steering* and
electronic interaxle differential lock*. ESC is
sw itched on all the time . In certain s ituations
when you need less tract ion, you can sw itch
off ASR by pressing the button above
~ page 200, fig. 188 the se lector lever. Be
sure to sw itch ASR o n aga in when yo u no lon­
ger need less traction.
Anti -lock braking system (ABS)
ABS prevents the wheels from locking up
when braking. The veh icle can still be steered
even du ring ha rd b raking . Apply steady p res­
sure to the brake pedal. Do not p ump the ped­
a l. A pulsing in the brake peda l indicates that
the system is he lping you to brake the vehicle .
Brake as sist system
The brake assist system can decrease bra king
d istance.
It increases braking power when the
driver presses the brake pedal qu ick ly in eme r­
gency situations . You must p ress and ho ld the
brake peda l until the situation is over. In
vehicles with adaptive cruise control*, the
brake assist system is more sensit ive if the
d istance detected to the vehicle ahead is too
small.
Anti- slip regulati on (A SR )
ASR reduces engine power when the drive
wheels begin to spin and adapts the force to the road condit ions. This makes it eas ier to
start, accelerate and drive up hills.
Electronic diff erential lo ck (EDL )
The ED L brakes wheels that are spinning and
transfers the drive power to the other drive
wheel or whee ls if the vehicle is equipped with
all whee l drive*. This funct ion is available up
to about 75 mph (120 km/h).
In extreme cases, EDL automatica lly switches
off to help keep the brake on the braked whee l
from overheating. EDL w ill switch on again au­
tomatically when conditions have returned to normal.
Int ellig ent technolog y 199
Dynamic ste ering *
On vehicles with dynam ic steering, ESC helps
stabilize the steering in certain situations.
Electronic intera xle differential l ock
function*
T he electron ic i nteraxle differential lock f unc ­
tion activa tes when dr iving th ro ugh curves.
Braking is targeted toward the wheels on the
inside of the curve as needed. This he lps to
minimize front whee l skid, improves traction
and allows for more precise driving through curves .
A WARNING
- ESC, ABS, ASR, EDL, dynamic steering*
and the elect ronic interaxle differential
loc k function* cannot ove rcome the laws
of physics. This is espec ially important
on slippery or we t roads.
If the systems
begin acting to stabilize your veh icle, you
should immediately change yo ur speed
to match the road and traffic 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 contro l, collision and ser ious per­
sonal injur ies.
- Always adapt your speed to road, traffic and weather conditions. The risk of los­ing con trol of the vehicle increases when
driving too fast, espe cially through
curves a nd on slippe ry or wet roads, and
when dr iving too close to vehicles up
ahead. ESC, ABS, the brake assist sys­
tem, EDL, ASR, dynam ic steering* and
the electron ic interaxle d ifferential lock
function" cannot prevent co llisions.
- Always accelerate with spec ial care on
even, smooth surfaces such as those that
are wet or covered with ice and snow.
The drive wheels can spin even w ith
these assistance systems that cannot al­
ways he lp to red uce the risk of loss of ve­
hicle control.
-
•
•

200 Intelligent technology
-ABS and ASR on ly work correctly when
all four wheels are equipped w ith ident i­
ca l tires. Different tire s izes can lead to a
reduction in engine power.
- You may hear noises when the systems described are working.
- If the indicator light
DJ or m:11 (USA
models) ;tiJ (Canada models) appears,
there may be a malfunct ion
c::;, page 19,
c::;, page 18 .
Switching on and off
ESC turns on automatically when you start
the engine.
Fig. 188 Center console w ith ESC OFF button
Switching ASR off (sport mode)
In certain situat io ns, you can switch ASR and
ESC into sport mode by pressing the button
l!l
c::;, fig. 188. The indicator light II comes on
and the mess age Stabilization control (ESC ):
Off warning! Reduced stability appears. ASR
deactivates completely and the assistance provided by the ESC system is limited. Switch
to sport mode on ly when your driving skills,
traffic and weather cond itions permit .
I n some situations, 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
- Driving in deep snow or on loose ground
- Driving with snow cha ins
Switching ASR on Press the button[!] aga in. The message Stabi­
lization control (ESC): On appears.
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 when the road is slippery.
- Sw itch to sport mode only when your
driving skills, traff ic and weather condi­
tions permit.
@ Tips
You cannot sw itch sport mode on when
adaptive c ruise control* is working.
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 operat­
ing condit ions and driving habits
c::;, &. . On
vehicles that are either dr iven mostly in stop­
and-go city traffic or are driven hard, the
brake pads should be checked by your author­
ized Audi dea ler 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 should use the braking
effect of the engine. This way, you prevent un­
necessary wear on the brake system. If you
must use your brakes, do not hold the brakes
down continuously. Pump the brakes at inter­
vals .
Operating noise
Noises may occur when braking depending on
the speed, braking force and outside condi­
tions such as temperature and humidity.
Due to the nature of the materia ls used in ce­
ramic brake rotors*, noises may become more
apparent at low speeds. .,..

Effect of w ate r and ro ad sa lt
In certain situa tions, for example after driving
through water, in heavy rain, after overnight
condensation or after washing your car, the
braking effect can be reduced by moisture or
ice on the brake rotors and brake pads. The
brakes must be dried first wit h a few careful
brake applications.
At higher speeds and with the windshield wip ­
ers turned on, the brake pads press against
the brake rotors for a short amount of time.
This occurs at regular intervals w ithout the
driver noticing and provides for better brake response time under wet condit ions.
The effectiveness of the brakes can be reduced
when the vehicle is dr iven o n a salt-covered
road and the brakes are not used . Likewise,
you clean
off accumulated sa lt coating from
brake discs and pads with a few caut ious ap­
p lications of the brake¢&. -
Due to their surface characteristics, ceram ic
brake roto rs* absorb mo isture in such condi­
tions. This can cause a temporary reduction in
b rak ing fo rce compared to d ry brakes. You can
compensate for this by pressing the brake pedal harder .
Corrosion
There may be a tendency for dirt to build up
on the brake pads and corrosion to form on
the discs if the car is not dr iven regularly or
on ly for short t rips with little use of the
brakes.
I f t he b rakes are not used frequently, or if co r­
rosion has formed on the dis cs, it is advisable
to clean
off the pads and discs by brak ing
firm ly a few times from a moderately high
speed ¢.&. .
Faults in the brake system
If you should notice a sudden increase in
b rake peda l travel, then o ne of the two bra ke
circuits may have failed~ .&..
Int ellig ent technolog y 201
Low br ake fluid level
Malfunctions can occu r in the bra ke system if
the b rake fluid level is too low. The brake fluid
level is monitored electronica lly.
Brake lining wear status
B rake lining wear may be checked by visual in­
spe ct ion of the condition of the brake pads
through the open ings in the wheel. If neces­
sary, the whee l may be removed for this in­
spection
r=;, page 2 7 3, Changing a wheel.
_& WARNING
-You should perform braking maneuvers
for the purpose of cleaning the brake
system only if road conditions permit.
Other road users must not be put at risk -
you may cause an accident!
- Before descend ing a steep grade, reduce
speed and sh ift transmission into a lower
gear or lower dr iving range . Do not ride
the brakes or hold t he pedal down too
long o r too often. Th is could cause the
brakes to get hot and diminish braking
efficiency .
- Do not "ride the brakes" by rest ing you r
foo t on the pedal when you do not intend
to b rake . This may cause the brakes to
overheat, premature wear and increased
stopping distance.
- Under certain climatic and operating
conditions such as passing thro ugh wa­
ter, dr iv ing in heavy rain or after washing
the vehicle, the effectiveness of the brakes can be reduced. In winter, ice can
accumu late on the brake pads, lin ings,
discs and drums . Carefully app ly brakes
for a test. Brakes w ill dry and ice coat­
ings w ill be cleaned
off after a few care­
fu l brake applicat ions.
- Driving for an extended period of time on
salt- cove red roads without using your
brakes can a lso affect braking efficiency .
Clean
off accum ulated salt coating from
brake discs and pads with a few careful
brake applications.
•
•

202 Intellig ent technol ogy
- If you damage the fro nt spoiler, or if you
install a different spoiler, be sure the air
flow to the front brakes is not obstruct­ ed . Otherwise the brake system could
overheat reducing the effectiveness of
the ent ire brake system .
- Failure of one brake c ircuit will impair
the braking capability resulting in an in­ creased stopp ing distance. Avoid driv ing
the vehicle and have it towed to the near­ est Aud i dea ler or qualified workshop .
Brake booster
The brake booster adds extra braking power .
The brake booster works with vacuum pres­
sure which is created only when the engine is
running ¢& .
& WARNING
-Never let the vehicle ro ll to a stop w ith
the engine shut off.
- If the brake booster is not work ing, for
example when towing your vehicle, or
because the b rake booste r has somehow
been damaged, the brake pedal must be
pressed considerab ly 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 powe r ass istance to p rov ide com ­
fortable and sa fe stee ring response exactly
matc hed to the ve hicle speed .
Power steering w il l not work if the eng ine is
off . As a result, the steering whee l w ill be hard
to turn.
The power steering fluid level is chec ked dur­
ing the scheduled ma intenance serv ices.
(D Note
If there is an e lectronic malfunction, ser­
votronic
will still function like a conven­
tiona l power steering system, providing a
constant steering support force that is no
l onger proportionate to the vehicle speed.
This is most not iceable when t urning the
steering wheel at low speeds (for example
when pa rking), - more effort w ill be re­
q uired than us ual.
- Be aware of the diffe rent than usual
steering response and adjust your steer­
ing force acco rding ly.
- Have the problem checked and set right
by an A udi dealer as soon as poss ible.
(D Tips
- When the eng ine is running, never ho ld
the stee ring wheel turned all the way to
the rig ht or to the left fo r longer than 15
seconds. The powe r stee ring pump will
overheat the hydraulic fluid i f yo u keep
holding the stee ring wheel turned all the
way. This is likely to damage the power steering system.
- If the powe r steering system sho uld fai l
entire ly, or if the engine is not runn ing
(for example, wh ile be ing towed), you
w ill still be able to stee r the veh icle.
However,
considerably more effort will
be requi red to do so.
- If the power steering system should
have a leak, or is not functioning proper­
ly, contact your author ized Audi dealer
immed iately.
- The power steer ing system req uires a
specially fo rmu lated hyd raulic fluid. The
powe r stee ring fluid reservoir is located
in the engine comp art ment¢
page 234.
T he cor rect fluid level in the reservoir is
impo rtant fo r proper functioning of the
powe r stee ring .

208 Driving and en vir onm 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 eng ine,
transmission, suspension or electr ical
system can be severely damaged by driv­ i ng th rough water.
- Always switc h off the Start-Stop-System
when driving through water~
page 87.
(1) Tips
-Check the depth of the water before dr iv­
i ng through it.
- Do not stop the veh icle, dr ive 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 th rough 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 limitat ions
If you ant ic ipate 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 w ill give you some tips on how you can
help the env ironment and your pocketbook.
@ Tips
The consumption estimates as published
by ENVIRONMENTAL PROTEC TION AGENCY
( E PA) and Transpo rt 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 a re ac­
ce lerating. If you anticipate what is going to
happen next, you will need to brake less and,
t hu s, acce lerate less . Let the vehicle coast
whenever possible -for examp le when you see
that the next traff ic light is red.