2012 AUDI A8 Owners Manual

Audi adapt ive crui se c ontrol an d bra kin g guard 8 7
Audi adaptive cruise
control and braking
guard
Introduction
App lies to vehicles: with Audi adaptive cruise control
The adaptive cruise control system assists the
driver by regu lating vehicle speed and helping
to maintain a set distance to the vehicle
ahead, within the limits of the system . If the
system detects a moving vehicle up ahead,
adaptive cruise control can brake and then ac­
celerate your vehicle . Th is he lps to make driv­
ing more comfortable both on long highway
stretches and in stop-and-go traffic.
The braking guard system can warn you about
an impending collision and initiate braking maneuvers ¢
page 93.
Adaptive cruise control and Audi braking
guard have technica l limitations that you
must know, so p lease read this section care­
fully, understand how the system works and use them properly at all times.
General information
General information
Applies to vehicles: with Audi adaptive cruise control
Fig. 86 Front of the veh icle: sensors and video came ra
The areas that conta in the radar and ultrason ­
ic sensors and the v ideo camera ¢
fig. 86
must neve r be covered by stickers or other ob­
jects or obstructed w ith dirt, insects, snow or
ice that will interfere w ith the adaptive cruise
control system and Audi braking guard. For in­
formation on cleaning , refer to ¢
page 205.
The same applies for any modifications made
in the front area.
T he function of the Adaptive cruise cont ro l
system and A udi braking guard is limited un­
der some conditions.
- Objects can on ly be detected when they are
w ith in sensor range
¢page 89, fig. 89 .
-The system has a limited ability to detect
objects that are a shor t distance ahead,
off
to the side of your vehicle or moving into
your lane.
- Some kinds of ve hicles are hard to detect;
for examp le motorcycles, vehicles with high
ground clearance or overhanging loads may
be detected when it is too late or they may
not be detected at a ll.
- Stationary objects¢
page 88.
-When driving throug h curves ¢ page 88.
& WARNING
Always pay attent ion to traffic when adap ­
tive cruise contro l is switched on and brak­
ing g uard is active. As the driver, you are
still respons ible for start ing and for ma in­
taining speed and distance to other ob­
jects . Braking guard is used to assist you .
The driver must a lways take action to avo id
a collis ion. The driver is a lways responsible
for braking at the co rrect time.
- Improper use of adaptive cru ise control
can cause collisions, other acc idents and
serio us pe rsonal in jury.
- Never let the comfort and conven ience
that adaptive cruise control and Audi
braking guard offer dist ra ct you from the
need to be a lert to t raff ic condi tions and
the need to remain in full con trol of yo ur
vehicle at a ll times,
- Always remember that the adaptive
cruise contro l and Audi braking guard
have limits -they will not s low the vehi ­
cle down or maintain the set d istance
when you drive towards an obstacle or
something on or near the road that is not
mov ing, such as vehicles stopped in a
traffic jam, a stalled or disabled vehicle .
I f regis tered by the radar sensors,

88 Audi adapti ve cruise control and bra king gu ard
vehicles or obstacles that are not moving
can trigger a collision warning and if con­
firmed by the v ideo camera, an acute col­
lis ion warn ing .
- For safety reasons, do not use adaptive
cruise co ntrol when driving on roads with
many curves, when the road surface is in
poor condit ion and/or in bad weather
(such as ice, fog, gravel, heavy rain and
hydroplan ing) . Using the system under
these cond it ions cou ld result in a co lli ­
sion .
- Swi tch adap tive c ruise control off tempo­
rar ily when driv ing in turning lanes, on
expressway exits or in construction
zones . This prevents the vehicle from ac­
celerat ing to the set speed when in these
situations.
- The adapt ive cruise control system wi ll
not brake by itse lf if you put your foot on
the accelerator pedal. Doing so can over­
ride the speed and d istance regulation .
- When approaching stationary objects such as stopped traff ic, adaptive cruise
co ntrol will not respond and braking
guard w ill have limited function.
- The adapt ive cruise control system and
braking guard do not react to people, an­
imals, objects c rossing the road or on­
coming objects .
- The function of the radar senso rs can be
affected by reflective objects such as
guard rai ls , the entrance to a tunnel,
heavy rain or ice.
- Never follow a ve hicle so closely that you
cannot stop your vehicle safe ly. The
adaptive cruise contro l canno t slow or
brake the vehicle safely when you follow
another vehicle too closely. Always re­
member that the automatic braking
function cannot br ing the vehicle to a
sudden or emergency stop under these condit ions.
- To prevent unintended operation, always switch ACC off when it is not being used. (D Note
The sensors can be displaced by impacts or
damage to the bumper, wheel housing and
underbody. That cou ld affect the adaptive
cruise control system and brak ing guard.
Have your authorized Aud i dea ler or au ­
thorized Audi Service Facility check their
funct ion .
In curves
Applies to vehicles: with Audi adaptive cru ise contro l
I
Fig. 87 Ex ampl e: dri ving in to a curve
When d riving into a curve c> fig. 87 and out of
a curve, the ad aptive cruise control may react
to a vehicle in the next lane and apply the
brakes. You can override or prevent the brak­
i ng by pressing the acce lerator pedal b riefly .
' Stationary objects
Applies to vehicles: with Audi adaptive cruise control
Fig. 88 Exampl e: objec t ch anging l anes and sta tio nar y
object
T he adaptive cru ise control system only reacts
to objects that a re mov ing o r that the system
has already detected as moving . For examp le,
if a vehicle @, which has already been detect-
ed by the adaptive c ruise contro l, tu rns off o r
ch anges lane and ano ther stationary veh icle .,.

Audi adaptive cruise control and braking guard 89
@ is located in front o f that veh icle, the sys ­
tem wi ll not react to the stationary vehicle.
Audi adaptive cruise
control
Description
Applies to vehicles: with Audi adaptive cruise co ntrol
Fig . 8 9 Detection ra nge
What can adaptive cruise control do?
The adaptive cruise co ntrol system uses video,
radar and ultrasound . Mov ing vehicles ahead
can be r ecognized up to about 650 fe et
(200 m) away.
On ope n roads w ith no traff ic, adaptive cruise
contro l works like a reg ular cruise control sys­
tem. The stored speed is ma in tained . When
approaching a moving veh icle detected up
ah ead, the adap tive cr uise control sys tem au­
tom atically s lows dow n to matc h that vehi­
cle's speed and the n main tains t he d istance
that the driver p revio usly sto red. As soon as
the system does not detect a vehicle up
ahead, adaptive cruise control acce lerates
back up to t he stored speed.
I n stop-an d-go t raffic, adapt ive cr uise contro l
can bra ke until the vehicle stops and acce le r­
ate again under certain conditions and if this
is poss ible within the system's limits and ca­
pabilit ies
c> page 91. Adaptive cru ise cont ro l
will not make a n emerge ncy stop .
Which functions can be controlled?
When you switch adaptive cruise contro l on,
you can set the current speed as the "control speed"
c> page 89, Switching on and off.
When driving, yo u can stop cruise cont ro l
c> page 91 or change the speed c> page 90
at any time .
You can also set the dis tan ce to the object
ahead and se t the adapt ive cr uise control d riv ­
ing program
c> page 91 .
Switching on and off
Applies to vehicles: with Audi adaptive cruise control
Fig. 90 Selector lever: switching o n/off
Fig . 91 Instrument cluste r: adaptive cru ise control
You can set any sp eed between 20 mp h and
9 5 mp h (3 0 and 150 km/h).
Ind icator lamps a nd messages in the i nstru ­
ment cluster d isp lay inform yo u about t he cur­
r ent syst em stat us and sett ing s.
Switching adaptive cruise control on
... Pull the lever toward you into position (D
c> fig. 90. ACC standby appears in the in­
strument cluster display.
Setting the speed and a ctivating
regulation
... To set the current speed, press the ISETI
button c> fig . 90. The set speed is shown in
t he tachome ter @ and is also shown briefly
in th e display @
c> fig. 91 . ..,..

90 Audi adaptive cruise control and braking guard
• You must also press the brake pedal when
the vehicle is stopped.
Switching adaptive cruise control off
• Push the lever away from you into position
@ until it clicks into p lace. The message
ACC off appears.
@ Indicator lights
II-Adaptive cruise control is switched on . No
vehicles are detected up ahead. The stored
speed is maintained.
I-A moving vehicle is detected up ahead .
The adaptive cruise control system regulates
the speed and d istance to the moving vehicle
ahead and acce lerates/bra kes automatica lly.
f§ . Adaptive cru ise control is switched on . A
mov ing vehicle up ahead was detected. Your
vehicle remains stopped .
I -When automatic braking is not able to
keep enough distance to a p reviously detected
mov ing vehicle up ahead, you must take con­
trol and brake¢
page 92, Prompt for driver
intervention.
© Display
If adap tive cruise control is not shown in the
d isplay, you can call it up with the multifunc ­
tion steering wheel buttons~
page 23.
Based on the symbols in the display , you can
determ ine if the system is maintaining a dis­
tance to the vehicle ahead and w hat that dis ­
tance is.
No vehicle -No vehicle ahead was detected.
White vehicle -A vehicle ahead was detected .
Red vehicle -Prompt for the driver to take ac­
tion ¢
page 92.
Both
arrows on the scale © indicate the dis­
tance to the vehicle ahead . No arrow appears
when the vehicle is on an open road and there is no object ahead. If an object is detected
ahead, the arrow moves on the scale.
The green zone on the scale shows the stored d istance. For information on changing the stored distance, refer to
¢
page 91. If the
distance se lected is too close or may soon be­
come too close, the arrows move into the red
z one on the sca le.
A WARNING
Improper use of the adaptive cruise con­
trol can cause collisions, other accidents
and serious personal injur ies .
- Pressing the
!SET ! button when driving at
speeds below 20 mph (30 km/h), w ill au­
tomatically accelerate the vehicle to 20
mph (30 km/h), which is the minimum
speed that can be set .
(D Tips
-If you switch the ignit ion or the adaptive
cruise control off, the set speed is erased
from the system memory.
- You cannot switch the Electron ic Stabili­
ty Control (ESC) to the SPORT mode
when adaptive cruise control is switched
on .
Changing the speed
Applies to vehicles: with Audi adaptive cru ise control
0
f
• 0
Fig. 92 Selecto r lever : chang ing t he spee d
• To increase or reduce the speed in incre ­
ments,
tap the lever up or down.
-
-a)
N
q :r
~
"' To increase or reduce the speed qu ickly,
hold the lever up or down until the red L ED
@ reaches the desired speed ¢ page 89,
fig . 91.
Following any changes, the new stored speed
will be displayed briefly in the display @
¢page 89, fig. 91.

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 ..,.

92 Audi adaptive cruise control and braking guard
control will also accelerate up to the stored
speed.
The higher the speed , the greater the distance
in yards (meters)¢ .&.. T he
Distance 3 setting
is recommended .
The distances p rov ided are spec ified values.
Depending on the driving situation and the
how the vehicle ahead is dr iving, the actual
distance may be more or less than these tar­
get distances .
The various symbols for the time increments
appear briefly in the info rmation line @
¢ page
89, fig. 91 when you change the set­
tings .
c:::,_c:::, ___ 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.
c:::, __ c:::, __ Distan ce 2: Thi s setting corre­
sponds to a dis tance of 118 feet/36 meters
when traveling at 62 mph ( 100 km/h), or a
time interva l of 1.3 seconds.
c:::, ___ c:::,_ 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 interva l of 1.8 seconds.
c:::, ____ c:::, 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.
.&_ WARNING
Following other vehicles too closely in­
creases the risk of collisions and serious
personal injury.
- Setting short distances to the traffic ahead reduces the t ime and distance
available to br ing 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 distance for the traffic, 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
tro l key being used.
Selecting the driving mode
Applies to veh icles: w ith Audi adapt ive cr uise contro l
.,. Select the desired driving mode in dr ive se­
lect
¢ page 103 .
@ Tips
Your settings are automatically stored and
assigned to the remote control key being
used.
Prompt for driver intervention
Applies to vehicles : w it h Audi ada ptive cr uise cont ro l
Fig. 95 Instrument cluster: request for driver inte rven ­
tio n
In certa in s ituations, the system will prompt
yo u to take action . Thi s 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
I and the symbol in the
display will warn you about the situa tion
¢fig.
95. You w ill also hear an acoustic signal.
- Press the brake pedal to slow your vehicle
down.

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

94 Audi adap tive cruise control and br aking guard
stopped vehicle or stationary obstacle
(end of a traffic jam or veh icle that has
broken down in traffic).
- Always remember that the radar sensor
for the Audi braking guard works only
within defined detection and range limits
that may prevent the proper detection of
other vehicles .
- The radar sensor's function and range
can be reduced by rain, snow and heavy
spray. Moving vehicles up ahead may not
be promptly detected or may not be de­
tected at al l.
- Reflective surfaces includ ing crash barri­
ers or tunnel entrances may impair the
func tion of the radar sensor.
{D) Tips
- You can cancel the braking w ith increas­
i ng force that is initiated by the system
by braking yo urself, by accelerating no­
ticeab ly or by swerving.
- Audi braking guard error messages
¢page 94.
- Keep in mind that braking gua rd can
brake u nexpectedly. Always secure any
ca rgo or objec ts th at yo u are transport­
i ng to reduce the risk of damage or in­
ju ry.
Settings in the MMI
Applies to vehicles: with Audi adaptive cruise co ntrol
.. Se lect: I CARI function button > Ca r sys tem s
control button > Drive r assist > Audi b rak­
ing guard .
System -
Switch Audi braking g uard On and
Off . When you switch the ignition on, the
message
Aud i braking gua rd off appears if
the system is switched off.
Ea rly warnin g -The distance and approach
warn ings in the display can be switched
On /
Off .
(D Tips
- Your settings are automatically stored
and ass igned to the remote control key being used at the times the settings are
made.
- If you switch the ESC to sport mode, A u­
di braking gua rd switc hes off a utomat i­
cally r=:>page
189.
- Switch A udi braking guard off when you
are loading the vehicle onto a vehicle car­
rier, train, ship or other type of transpor­
tat ion. This can prevent undesired warn­
ings from the braking guard system.
Messages
Applies to vehicles: with Aud i adaptive cru ise contro l
ACC unavailable
ACC and b raking gua rd: unavailable
T he system cannot detect moving vehicles up
ahead correctly and is switched off. The sen­
sors have been displaced or a re not working
proper ly . The Audi pre sense functions may a l­
so be affected. Drive to your authorized Audi
dealer or authorized A udi service facility im­
med iate ly to have the malfunction corrected.
ACC: unavaila ble at thi s time. No sen sor vi­
sion
ACC and braking guide: un ava ilabl e at thi s
time . No s ensor vi sion
Th is message appears if the sensor v iew is ob­
structed, for examp le by leaves, snow, heavy
spray o r d irt. Clean the sensors
r=;, page 87,
fig. 86 .
ACC: unavailabl e at this time. Inclin e too
s teep
The road exceeds the max imum possible an­
gle for proper adaptive cru ise control opera­
t ion. Adaptive cru ise cont rol is switched off.
ACC: only selector lever pos itions D , S or M
available
Se lect the D, Sor M selector lever position .
ACC: un available at thi s time . Parking brake
s et
T he adapt ive cru ise control system switches
off au tomatically if the par king b rake is set. .,.