2015 AUDI A8 brakes

Audi adaptive cruise control and braking guard 97
When approaching a moving vehicl e up ahead,
the adaptive cruise contro l system automati­
cally brakes to match that object's speed and
then maintains the stored distance.
If the ve­
hicle ahead accelerates, adaptive cruise con­
trol will also accelerate up to the stored
speed .
The higher the speed, the greater the distance
in yards (meters) ¢.&. . The
Distance 3 setting
is recommended .
The distances prov ided are specified values .
Depending on the driving situation and the
how the vehicle ahead is driving, the actual
distance may be more or less than these tar ­
get distances.
The various symbols for the time increments appear briefly in the information line @
¢
page 94, fig . 101 when you change the set ­
tings .
,::::::,_,::::::, ___ Distance 1: This setting corre-
sponds to a distance of 92 feet/28 meters
when traveling at 62 mph (100 km/h), or a
time interval of 1 second.
,::::::, __ ,::::::, __ Distance 2: This setting corre­
sponds to a distance of 118 feet/36 meters
when traveling at 62 mph (100 km/h), or a
time interval of 1.3 seconds .
,::::::, ___ ,::::::,_ Distance 3: This setting corre-
sponds to a distance of 164 feet/SO meters
when traveling at 62 mph (100 km/h), or a
time interval of 1.8 seconds .
,::::::, __ __ ,::::::, Distance 4: This setting corre-
sponds to a distance of 210 feet/64 meters
when traveling at 62 mph (100 km/h), or a
time interval of 2.3 seconds .
A WARNING
Following other vehicles too closely in­
creases the risk of collisions and serious
personal injur y.
- Setting short distances to the traffic
ahead reduces the time and distance
available to bring your vehicle to a safe
stop and makes it even more necessary
to pay close attention to traffic. -
Always obey applicable traffic laws, use
good judgment, and select a safe follow­
ing d istance for the traff ic, road and
weather conditions .
(D Tips
-Distance 3 is set automatically each time
you switch the ignition on.
- Your standard settings are automatically
stored and assigned to the remote con­
trol key being used.
Selecting the driving mode
Applies to vehicles: with Audi adaptive cruise control
.. Select the desired driving mode in dr ive se­
lect <=;>
page 108.
(D Tips
Your settings are automat ically stored and
assigned to the remote control key being
used.
Prompt for dr iver intervention
Applies to vehicles: with Audi adaptive cruise contro l
Fig. 105 Instrument cluste r: request fo r dr ive r inter­
vent ion
In certain situations, the system will prompt
you to take action . This could happen, for ex­
amp le, if braking by the adaptive cruise con­
trol system is not enough to maintain enough
distance to the veh icle ahead .
The indicator light . and the symbol in the
display will warn you about the situation
<=;> fig. 105. You will also hear an acoustic sig-
nal. ..,.

98 Audi adaptive cruise control and braking guard
-Press the brake peda l to slow your vehicle
down.
Audi braking guard
Description
Ap plies to vehicles: with Audi adaptive cruise co ntrol
Fig. 106 Instrume nt cluste r: approac h warn ing
Braking guard uses radar sensors and a video
camera. It also functions within the limits of
the system when 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 your own vehicle is traveling at a
h igh speed and approaching a vehicle up
ahead that is moving more slowly . 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. in 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 wa rning is given,
it may only be possible to avoid a collision
by swerving or braking sharply. Th e indicator
li ght . and indicator in the display will
warn you about the danger~
fig. 106. You
will also hear an acoustic signa l.
ll This is not av ailable in some coun tri es.
If you do not react fast enough or do not react
at all to the situation, braking guard wi ll inter·
vene by braking and the message
braking
guard intervention
will appear.
- If a collision 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 wit h increas ing
force w ithin the limits of the system . This
reduces the vehicle speed in the event of a
collision.
- The system can initiate max imum brak ing
shortly before a collision
1> . Full deceleration
at high speeds occurs only in vehicles with
adapt ive cr uise control and side assist (p re
sense plus) .
- If the brak ing guard senses that you are not
braking hard enough when a collision is im·
minent, it can increase the brak ing force.
- The pre sense functions also engage when a
col lision is imminent ~
page 194.
Which functions can be controlled?
You can switch braking guard and the dis­
tance/approach warn ing on or off in the MMI
~ page 99, Settings in the MMI.
A WARNING
-
Lack of attention can cause collisions, oth-
er accidents and serious personal injuries .
The braking guard is an assist system and
ca nnot prevent a collision by itself. The
driver must always intervene. The driver is
a lways respons ible for braking at the cor­
rect time.
- Always pay close attention to traffic,
even when the braking guard is switched
on. Be ready to intervene and be ready to
take comp lete control whenever necessa­
ry. Always keep the safe and legal dis­
tance between your vehicle and veh icles
up ahead .
- Braking guard works within limits and
will not respond outside the system

rl N
rl N
0 J:
""'. rl I.O
"' rl
"' ......
prevent the vehicle from "creeping", you
must keep your foot on the brake in all
selector lever positions except P and N
when the eng ine is running. Do not inad­
vertently press the accelerator pedal
when the veh icle is stationary. Otherwise
the vehi cle will s tart to move immediate­
ly, even if the park ing brake is set. This
cou ld result in a crash.
- Do not ride the brakes or p ress the brake
peda l too often or too long when dr iv ing
down a hill. Constant braking causes the
brakes to overheat and substant ially re­
duces b raking performance, increases
braking distance or ca uses 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 the brake
pedal. The transmission automatically selects
a gear that is suitab le for the incline. Hill de­
scent control tries to maintain the speed ach­
ieved at the time of braking, within physical
a nd techn ical limitations.
It may st ill 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 contro l sys­
tem c::>
page 90.
A WARNING
Hill descent control can not overcome
phys ical limitations, so it may not be able
to main tain a constant speed under a ll
condi tions. Always be re ady to app ly the
br akes.
Automatic Tra nsmi ssi on 11 7
Shifting manually
The shift paddles allow the driver to shift the
gears manually .
Fig . 1 26 Steer ing w heel: sh ift ing manually
.,.. To shift to a h igher or lowe r gear tempo rari­
ly, tap the
0 or 0 shift padd le c::> fig. 126 .
.. To switch manua l mode on, press the~
button . An Mand the gear that is currently
engaged appear in the instrument cluster
disp lay @ c::>
page 114, fig. 123.
.. To shift up one gear, tap the right shift pad­
dle
0 c::> fig . 126 .
.. To sh ift down one gear, tap the left shift
paddle Q.
.. To switc h manua l mode off, press the~
button aga in, or
.. Move the selector lever back and release it .
T he transm iss ion automatically sh ifts up or
down before cr itical engine speed is reached.
The transm iss ion only allows manual sh ifting
whe n the eng ine speed is w ith in the pe rmit­
ted range.
The engine braking effect increases when you
downshift when going downhill.
Kick-down
Kick-down enables maximum acceleration.
When you press the accelerator pedal down
beyond the resistance point, the automatic
transmission downshifts into a lower gear, de­
pending on veh icle speed and eng ine RPM .
It
shifts up into the next higher gear once the
maximum specified engine RPM is reached . ..,.

198 Intelligent technology
vehicles with adaptive cruise control*, the brake assist system is more sensitive if the
d istance detected to the vehicle ahead is too
smal l.
Anti-slip regulati on (ASR )
ASR reduces engine power when the d rive
wheels begin to spin and adapts the force to
the road conditions. This makes it easier to
start, accelerate and drive up hills.
Electronic diffe rential lock (EDL )
The EDL brakes wheels that are spinn ing and
transfers the drive power to the other d rive
wheel or whee ls if the vehicle is equipped with
all whee l drive*. This function is available up
to about 75 mph (120 km/h).
I n extreme cases, ED L automatica lly switches
off to help keep the brake on the braked whee l
from overheating . EDL wi ll switch on again au­
tomatically when conditions have returned to normal.
Dynamic steer ing*
On vehicles with dynamic steering, ESC he lps
stabilize the steering in certain situations .
Selective wheel torque control
The se lective wheel torque cont ro l operates
when dr iving thro ugh cu rves. The front wheel
on the ins ide of the curve or both w heels on
the inside of the curve are braked selective ly
as needed. This minimizes sliding in the front
wheels and a llows for more precise driving
through curves. The applicab le system may
not activate when driving in wet or snowy con­
d itions .
Post- coll isio n br ake assis t
"Post-collision brake assist" can assist the
driver during a collision by reducing the dan­
ger of slipp ing and further collision and by au­
tomatic braking.
"Post-collision brake assist" functions d uring
collisions when the a irbag contro l modu le de­
tects a trigger level and the collision takes place at a certa in driving speed. The brak ing
of the vehicle happens automatically via the ESC as
long as the ESC, the brake system, and
the vehicle electrical system are not damaged
from the collision.
T he following ac tivit ies override the au toma t­
ic braking during a co llision:
- I f the driver p resses the acce le rator pedal.
There is no automa tic brak ing .
- When the force on the press brake peda l is
st ronger tha n the braking force initiated by
t he system. The veh icle is manua lly braked.
- When the ESC is damaged, the "Post-colli­
sion brake assist" is not available.
,&. WARNING
- ESC, ABS, ASR, ED L, dynamic steeri ng *
and the select ive wheel torque control
cannot overcome the laws of physics .
This is especially important on s lippery
or wet roads. If the systems beg in acting
to stabilize your veh icle, you should im­
mediately change your speed to match
the road and traffic conditions. Do not let the increased safety provided by
these systems tempt you to take r is ks.
D oing so will increase the risk of a loss of
veh icle contro l, col lision and ser ious per ­
sonal injuries.
- Always ad apt your speed to road, traffi c
and weather conditions . The risk of los ­
ing contro l of the vehicle increases when
driving too fast, espec ially through
curves and on slippery 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 selective wheel torque cont ro l can­
not prevent collisions.
- Always accelerate with special care on
even, smooth s urfaces such as those that
are wet or covered with i ce and snow.
The drive wheels can spin even w ith
these assistance systems tha t cannot al­
ways he lp to red uce the risk of loss of ve -
-
hicle control. IJJ,,

200 Intellig ent technol ogy
to have your brake pads inspected can result
in reduced brake performance.
On steep slopes, yo u shou ld use the b rak ing
effect of the engine. Th is way, you prevent un­
necessary wear on the brake system. If you
must use your brakes, do not hold the brakes
down continuously. P ump the brakes at inter ­
vals.
Operating nois e
Noises may occur when braking depending on
the speed, braking force and outside condi­
tions such as temperature and humidity.
E ff ect of water and road salt
In certain situat ions, for example after driving
through water , in heavy ra in , after overn ight
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 with 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 without the
driver noticing and provides for bet ter brake
response time under wet condit ions .
The effectiveness of the brakes can be reduced
when the vehicle is dr iven on a salt-covered
road and the brakes are not used . Likew ise,
you clean off accumulated salt coating from
brake discs and pads with a few caut ious ap­
plications of the brake
c:::> .&, .
Cor ro sion
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
only for short t rips with little use of the
b rakes .
If the brakes are not used frequently , or if cor­
rosion has formed on the discs, it is advisable
to clean off the pads and discs by braking
firm ly a few times from a mode rately high
speed
c:::> .&, .
Faults in the brake syste m
If you shou ld notice a sudden increase in
brake pedal trave l, then one of the two brake
circuits may have fai led
c:::> & .
Low bra ke fluid lev el
Malfunctions can occu r in the bra ke system if
the b rake fluid level is too low. The brake flu id
level is monitored electro nica lly.
Brake booster
The brake booster works with vacuum pres­
sure which is created only when the eng ine is
runn ing
c:::> .&, .
Brake lining we ar statu s
Brake lining wear may be checked by visual in­
spect ion of the condition of the brake pads
through the open ings in the wheel. If neces­
sary, the wheel may be removed for th is in­
spect ion
c:::> page 269, Changing a wheel .
_& WARNING
-You shou ld 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 ca use an accident!
- Before descending 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 the pedal down too
long or too often . This could cause the
brakes to get hot and diminish braking
efficiency.
- Do not "ride the brakes" by rest ing your
foot on the pedal when you do not intend
to b rake . This may cause the brakes to
overheat, p remature wear and increased
s topping distance .
- Unde r ce rtain cl imatic and ope rat ing
conditions such as passing thro ugh wa­
ter, dr iving in heavy rain o r after washing
the vehicle, the effectiveness of the brakes can be reduced. In winter, 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

,....,
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.... ..,., ....
coatings will be cleaned off after a few
careful brake applicat ions.
- Driving for an extended period of time on
salt-covered roads without us ing your
brakes can also affect braking efficiency.
Clean off accumulated salt coating from
brake discs and pads w ith a few careful
brake applicat ions.
- If you damage the front 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 bra ke c ircui t will impair
t he braking capabi lity res ulting in an in­
creased stopp ing distance . Avoid driv ing
the vehicle and have it towed to the near ­
est Aud i dea le r or q ualified workshop .
- Never let the vehicle ro ll to a stop w ith
the engine shut off.
- If the bra ke booster is not work ing, the
brake pedal must be pressed considera ­
bly harder to make up for the lack of
booster assistance.
Electromechanical
power assist, dynamic
steering
The electrome chanical power assist helps the
driver when steering.
Powe r stee ring adapts electronically based on
the veh icle speed.
Indicator lights and mess ages
• Stee ring defecti ve! Stop th e vehicle
If th is ind icator light turns on and stays on
and this message appears, the power steering
may have fa iled.
Do
not co ntinu e driving . See yo ur authorized
Aud i dea ler or other qualified repa ir facility
for assistance .
'Tj Steering: System fault You can contin ue
driving
Int ellig ent technolog y 201
If the indicator light turns on and the mes­
sage appears, the steering may be more diffi­
cu lt to move or more sensitive than usual. The
steering wheel may also be at an ang le when
driv ing straight.
Drive slowly to your a uthorized Audi dealer or
qualified workshop to have the ma lf u nction
corrected.
'T-ij Dynamic stee ring: Init ializing
If this d rive r message appears and the i ndica­
tor lig ht is flas hing on the instrumen t panel,
dynam ic s teer ing* is being rein it ia liz ed. After
starting the engine, the stee ring wheel will
move s light ly . Re-initialization might be nec­
essary if the steering wheel was moved hard
to the left and right whi le the vehicle was not
moving. The display goes out as soon as initi­
alization is complete .
Drive slowly to your authorized Audi dea ler or
qualified workshop to have the malf u nction
corrected.
A WARNING
H ave the dy namic steering* system mal­
f u nction repa ired as soon as possible by an
authorized Audi dea ler or qua lified wor k­
shop -risk of acc ident!
(D Tips
If the . or 'Tj indicator light only stays
on for a short t ime, you may continue dr iv­
i ng .
- The dynamic steering* stab il ity systems
are not ava ilab le in the event of a system
ma lfunction .
- For add itiona l information o n dynamic
steering*, refer to
~page 108.
•
•

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Driving and
environment
The first 1
1000
miles
(11500 km) and
afterwards
New engine
The engine needs to be run-in during the first
1,000 miles (1 ,500 km) .
For the first 600 mile s (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 high engine speeds .
From 600 to 1,000 mile s (1 ,000 to
1,500 kilometers):
.. Speeds can gradually be increased to the
maximum pe rm iss ib le 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. This applies whether the
transmission is i n N (Neutra l) or in gear.
After the break- in peri od
.. Do not exceed maximum engine speed un­
der any circumstances.
.,. Upshift into the next higher gear
before
reaching the red area at the end of the tach­
ometer scale
¢ 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
i n. How well this break-in p rocess is done de­
pends to a considerable extent on the way the
ve hicl e is driven du ring the first 1,000 miles
(1 ,500 ki lome ters).
(D Note
Extremely h igh engine speeds are auto­
mat ica lly reduced. However, t hese rpm
lim its are progr amme d for an eng ine well
r u n- in , not a new engine .
Driving and environment 205
@) For the sake of the environment
Do not drive with unnecessarily high en­
g ine speeds -upshifting ear ly saves f uel,
reduces noise and protects the environ­
ment.
New tires
If your vehicle is running on new tires, drive
particularly caref ul for the first 350 miles
(500 kilomete rs) afte r fitt ing.
.&, WARNING
N ew tires tend to be sl ippery and mus t al­
so be "b roken -in" . Be sure to remember
this dur ing the f irst 350 m iles (500 kilo­
meters) . Brake gently . Avoid fo llowing
closely behind other vehicles or other sit­
uations that m ight require sudden, hard
b raking .
New brake pads
Remember that new brake pads do not have a
full brak ing effect dur ing the first 250 m iles
(400 ki lomete rs) afte r they are installed.
New brake pads have to be "broken in" before
they have optima l grab ¢,&. .
D uring the brea k-in period, yo u should avo id
putting severe loads on the brakes. Severe
l oads include , for example, sudden hard brak­
i ng, in particular at very h igh speeds or, for
example, on mounta in passes .
.&, WARNING
New b rake pads don 't have the best stop­
p ing power and must be "broken-i n" dur­
ing the initi al 100 to 150 miles (150 to
2 00 kilometers) o f no rma l ci ty driving . You
can compensate for this by pressing the b rake peda l more fi rm ly . This also applies
later when new pads are installed.
•
•

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.... ..,., ....
A WARNING ,~
- Do not park your vehicle over flammable
materials such as grass or leaves because
the high temperature of the diesel par­
t icu late filter cou ld start a fire .
- Do not apply an underbody protectant in the exhaust system area or a fire could start .
Shutting down vehicle
If you would like your veh icle to remain inop ­
erat ive for a longer period of time, contact an
Aud i or other specia lized dealer. They can ad­
vise you on necessary precautions e.g . corro­
sion prevention, ma intenance and storage.
Pay attention to additiona l information con­
cerning the battery. Refer to~
page 240.
Avoid damaging the
vehicle
When you a re driving on poor roads, or over
curbs, steep ramps, etc., make certain that low-lying parts such as spoilers and exhaust
system parts do not bottom out and get dam­
aged.
This is especially true for vehicles with low­
slung chassis (sports chassis)* and fully load ­
ed vehicles.
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 veh icle 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
-
Drivin g and environment 207
the brakes first by braking carefully to re­
store the full braking effect.
(D Note
- Vehicle components such as the engine,
transmission, suspension or electrical
system can be severely damaged by driv­
ing through water.
- Always switch off the Start-Stop-System*
when driving through water
~ page 87.
(D Tips
-Check the depth of the water before driv­
ing 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 driving through salt water because
it can cause corrosion.
Operate your vehicle
economically and minimize pollution
General
Your personal style of driving will determine
t he economy of your vehicle , as well as ex­
haus t and noise levels.
Fuel economy, environmental impact, and
wear on your engine, brakes and tires largely
depend on three factors:
- your personal driving style
- operating conditions
- technical limitations
If you ant icipate what you need to do next and
drive economically, you can easily cut your
fuel consumpt ion by 10-15 percent . This sec­
tion w ill give you some tips on how you can
help the env ironment and your pocketbook. •
•