sensor AUDI A5 COUPE 2010 User Guide
Page 94 of 360
Warm and  cold 
Button(s)  Meaning  Page 
@] Air  distribution => page 94 
--
~ Defrost => page  95 
~ Rear window defogger => page  95 
[AC] 
Turn  cooling  system => page  95 on/off 
QJ => page  105 
al The  regulator  is  also  used to set  the  fan  speed, air  distribution  and  seat 
he ating. 
[ i I Tips 
The  grille  on  the controls=> page  91, fig. 99  must  remain  unob
structed  and  must  not  be taped  over. Measuring  sensors  are located 
behind  it. • 
Applies  to  veh icles: w ith  de luxe automatic  cl imate  contro l 
Turning  the  climate  control  system  on  and  off 
Briefly  press  the  [ON] button,  or  press  the  [AUTO] button 
to  turn  the  climate  control  system 
on . 
- Press  the [ OFF] button  to  turn  the  climate  control  system 
off and  to  block  the  air  supply  from  the  outside. 
The  climate  control  system  switches  back  on  when  a control  button 
is  operated. • 
Applies  to vehicles:  with deluxe  automatic  climate  control 
Automatic  mode [AU TO) 
The  standard  operating  mode  for  all  times  of  the  year. 
Turning  on  automatic  mode 
Set  the  temperature  between  60°F  (+  16°C)  and  84°F 
(+28°C). 
- Press the  [AUTO]  button. 
Automatic  mode  ensures  constant temperatures  in the  interior  and 
dehumidifies  the air  inside  the  vehicle. Air  temperature,  volume  and 
distribution  are  controlled  automatically  to  reach  or  maintain  the 
desired  interior  temperature  as quickly  as  possible. Fluctuations  in 
exterior  temperature  and  the  effects  of  temperature  from  the  posi
tion  of  the sun  are compensated  for automatically . 
This  operating  mode  works  only  in an adjustable  temperature  range  of  60°F  (+  16°C)  to 84°F  (+28°Cl . If  a temperature  below  60°F (+ 16°C) 
is  selected,  LO appears  in  the  display.  At  temperatures  above  84°F 
( +28 °C), 
HI is displayed.  At  both  extreme  settings,  climate  control 
runs  continuously  at  maximum  cooling  or  heating  power . There  is 
no  temperature  regulation. •  
Page 101 of 360
Button( sl 
!OFF] 
IAUTOI 
-
Temperature  regu
lator 
1 a l 
Temperature  regu
lator  2a> 
-
1-= 1bi 
Mea nin g 
Turns  on  and  off 
Automatic  operation  -
driver's  side/  front  pas-
senge r's side 
-
Temperature  selection  -
driver's  side 
Temperature  selection  -
front  passenger's  side 
-Fan  -dr iver's  side/  front 
passenger's  side 
Recirculation  mode 
Air  distribution  -driver's 
side  / front  passenger's 
si de 
Defrost 
Rear window  defogger 
Turns  cooling  system  on 
and  off  P
ag e 
=> page  99 
=> page 99 
=> page 100 
=> page 100 
=> page 701 
=> page 701 
=> page 702 
=> page  102 
=> page 102 
-
al The  regu lator  is  a lso  used  to  set  the  fan  speed,  air  distr ibution  and  seat 
he ating . 
bl The  symbol  may  appear  sl ightly  differen t in  some  mo dels . 
[ i J Tip s 
• The  gril le on  the  controls=> page  98, fig. 106 must  remain  unob
structed  and  must  not  be taped  over. Measuring  sensors  are located 
behind  it. • 
Controls  and  equip 
ment 
W arm  and  cold 
Ap plies  to veh ic les :  with  D elux e a uto mat ic  clim ate co ntr ol plus 
Turning  the  climate  control  on  and  off 
Briefly  press  [ OFF],  or  press  [AUTO I to  turn  the  climate 
contro l 
on. 
- Press  the I OFF] button for  at  least 2 seconds to  t urn  the 
climate  control 
off and  to  block  the  air  supply  from  the 
outside. 
"OFF" appears  in  the  d isp lay. 
Climate  contro l turns  on  again  when  you  press  the te mp era tur e 
re gulat or• 
Ap plies  to  v ehicles : wit h De luxe  aut om at ic c lim ate co ntro l plu s 
Automatic  mode [AUTO) 
The standard  operating  mode  for  all  times  of  the  year. 
Turning  on  automat ic  mod e 
Set  the  temperature  between  60 °F (+ 16 °C) and  84 °F 
(+28  °C). 
- Press the  [AUTO I button. 
Automatic  mode  ensures  constant  temperatures  in the  interior  and 
dehumidifies  the  air  inside  the  vehic le. Air  temperature,  volume  and 
distr ibution  are  controlled  automatica lly to  reach  or  ma intain  the 
desired  interior  temperature  as quick ly as possible . Fluctuations  in 
exterior  temperature  and  the  effects  of  temperature  from  the  posi 
tion  of  the  sun  are  compensated  for  automatically . 
This  opera ting  mode  works  on ly in an adjustab le  te mperature  range 
of  60°F ( + 16°C) to  84 °F ( +28 °C). If  a temperature  below  60°F  ( + 16 °C) 
is  selected , 
LO appears  in  the  display . At  temperatures  above  84° F 
( + 28°C), 
HI is displayed.  At  both  extreme  settings,  climate  control 
runs  continuously  at  maximum  cooling  or  heating  power . There  is 
no  temperature  regulation .• 
I  • •  
Page 106 of 360
• .___w __ a _r _m _ a _n_d_ c_ o _ ld __________________________________________________  _ 
Applies to  vehic les:  with  Deluxe  automatic  c limate  con tro l plu s 
Economical  use  of  the  climate  control  system 
Economical  use of  the  climate  control  system  helps  save 
fuel. 
When  the  climate  control  system  is working  in  cooling 
mode,  engine  performance  is  reduced  and  fuel  consump
tion  is affected.  To keep  the  time  the  climate control  system 
is  on  as short  as  possible,  you  should  do  the  following: 
- To save  fuel,  turn off  cooling  mode  by  pressing  the  AC 
button  (indicator  light goes  out). 
- In addition,  if  you  open  the window  or  the  panoramic 
sliding/tilting  sunroof * while  driving,  turn  off  cooling 
mode  by  pressing  the  AC button  (indicator  light goes 
outl. 
- If the vehicle  is extremely  hot  due to  the heat of the  sun, 
briefly  open  doors  and windows. 
c£> For the  sake  of the  environment 
When  you  save fuel,  you  reduce  emissions  from  the  vehicle. • 
Deluxe  automatic  climate  control 
plus  - basic  settings 
Applies to  vehic les : with  Deluxe  automatic  climate  contro l plus 
General  information 
The basic  climate  control  settings  can  be  adjusted  in  the 
radio  or 
MM/* . 
Fig . 114  MMI  display: 
Setup  climate  control 
- Select:  Function button  [CAR]>  Control  button AC. 
The following  functions  can  be  selected: 
•  Automatic  recirculat.  => 
page 104 
• Synchronization=> page 105 • 
Applies  to  veh icles:  w ith Deluxe  automatic  clima te  co ntrol  p lus 
Automatic  recirculation 
An  air  quality  sensor  detects  increased  concentrations  of 
pollutants  in the  outside  air  and  automatically  switches 
to  recirculation  mode. 
We  recommend  that  you  always  keep  automatic  recirculati on ON to 
prevent  polluted  outside  air  from  entering  the  vehicle  interior.  .,_  
Page 107 of 360
___________________________________________________ W_ a_ r_m _ a_ n_d_ c_ o_ ld _ __.lffllll 
If  the a ir  qu alit y se nsor located  in  the  climate  control  system 
detects  polluted  outside  air,  the  sensor  decides  whether  the  air 
pollution  can  be  reduced  by  the  factory -ins tal led  pollutant  filter  or 
whether  it  is  necessary  to  switch  to  recirculation.  With  heavy 
concentrations  of  pollutants,  the  climate  control  system  is switched 
automatically  to  rec irculation  mode  and  the  supply  of  outside  air  is 
b locked.  As  soon  as the  concentration  of  pollutants  in  the  outs ide 
air  drops , fresh  air  is  supplied  to  the  vehicle  interior  again. 
In the  event  that  the  w indows  fog  up during  automatic  recirculation, 
press  the 
[ liW ) button  immediately. 
Under  certain  operating  conditions,  automatic  recirculation  is 
switched  off  automatically.  When  outside  temperatures  are  below 
about  50 °F 
( + 10 °C), automatic  recirculation  is  limited  to 
30 seconds . When  outs ide  temperatures  are  below  about  30 °F (-
1 °Cl,  automatic  r ecirculation  is  limited  to  15 seconds .• 
Ap plies  to vehicles:  with  D eluxe auto matic  cl imate  con trol  plus 
Synchronization 
One climate  control  setting  for  all  seats. 
After  Synchronization  is  set  to On , all  of  the  subsequent  cl imate 
c ontrol  se ttings  (excep t for  seat  heating *) for  the  driver  are  trans
ferred  to the  front  passenger . 
Synchronization  is canceled  when  settings  are adjusted  on the front 
passenger's  side. • 
Contro ls and  eq uip
ment 
Seat  heating 
Ap plies  to  vehi cles : wit h front  sea t heat ing 
Front  seat  heating~ 
The seat  cushion  and  the seat  back  of  the  front  seats  can 
be  heated  electrically. 
Press  the~  button. 
Fig.  115  Seat  heat ing 
b utt on  and  re gul ato r 
Rotate  the  reg ulator  to  the  desired  setting . 
In position 0, seat  heating  is turned  off . T he control  range  is from 1 
to  6. 
Seat  heating  only  functions  when  the  seats  are  loaded  with  body 
we ight . If  a person  is  no t si tting  on  the  front  seats,  seat  heating 
should  be switched  off  to  prevent  unin tentiona l heating  of  the  seat 
surfaces. 
(D Note 
To avoid  damage  to  the  heating  elements  in the  seats,  do  not  kneel  on  the  seats  or  place  heavy  loads  on  a small  area  of  the  seat.  .,,_ 
Vehicle  care I I Technical  data  
Page 120 of 360
-Adaptive  cruise  control .._ _ ______,:,.._ _______________________________________  _ 
Adaptive  cruise  control 
Speed  and  distance  control  system 
Applies to  vehicles:  with  adaptive cruise  contro l 
Description 
The adaptive  cruise  control  driver  assistance  program  is 
a  combined  speed  and  distance  control  system. 
Fig . 122  Front 
bumper:  Position  of 
radar  sensor 
Any  speed  between  about  20 mph  (30 km/h)  and  about  95  mph 
(150  km/h)  can  be set  and  held  with  the  adaptive  cruise  control.  The 
system  also  regulates  a pre-set  distance  from  the vehicle  ahead 
within  the  limits of  the  system  described. 
Driving  can  be more  relaxed,  particularly  on  long  trips  on  interstates 
or  on  other  highways  that  are  generally  straight. 
How  does  it work? 
You  can  operate  the  adaptive  cruise  control  using  the  lever  on  the 
steering  wheel  column:::::, 
page  121, "How  is the  speed  stored?"  and 
~ page  123, "How  is the  distance  (time  interval)  set?". 
Driver  information 
Important information  is brought  up  in the  speedometer  and  in the 
instrument  cluster  display  as  the vehicle  is  being  driven 
=:> page  124, "Driver  information". 
What  is  important  for  you  to  know 
The adaptive  cruise  control  is set  with  system -specified  limits,  that 
is,  as a driver,  you  will  have  to  adjust  the  speed  and  distance  to the 
vehicle  ahead  in  some  instances~ 
page  128, "Driver  intervention 
prompt"  and~ 
page  130, "System  limitations". 
& WARNING 
Improper  use of the  adaptive  cruise  control can  cause  collisions, 
other  accidents  and  serious  personal  injury. 
•  Never  drive  at  speeds that  are too  high  for traffic,  road  and 
weather  conditions. 
•  Never follow  the  vehicle  in front so closely that  you  cannot stop 
your  vehicle  safely. The  adaptive  cruise  control  cannot  brake the 
vehicle  safely when  you follow another  vehicle  too  closely. Always 
remember  that  the  adaptive  cruise  control has  a  braking  power 
that  is only about  25% of the  vehicle's  maximum  braking  ability, 
the  automatic  braking  function  cannot bring  the  vehicle to  a  stop. 
•  Never  use adaptive  cruise  control  on roads where  you  cannot 
drive safely at  a steady  speed, including  city,  stop-and-go or heavy 
traffic,  on winding  roads or when  road conditions  are  poor (for 
example,  on  ice, gravel , in  fog,  heavy  rain  or  on wet  roads that 
increase the  risk of  hydroplaning). 
•  The  radar  sensor's 
vision can  be  reduced  by rain,  snow  and 
heavy  spray. This  can  result  in vehicles  driving  ahead  being  inade
quately  detected  or, in some  circumstances,  not  detected at all.  If 
necessary, take  action  yourself!  ..,  
Page 121 of 360
_______________________________________________ A_ d_ a ---=- p_t_ i_v _e_ c_ r_ u_ i_ s _e_ c_ o_ n_t_ r _o _ l __ llll 
& WARNING  (continued) 
• Always  turn  off  adaptive  cruise  control  when  entering  turn 
lanes,  highway  exit  lanes  and  construction  zones  or similar  situa
tions  because  the  vehicle  will  automatically  accelerate  to  the 
stored  speed. 
•  Never  rest  your foot  on the  accelerator  pedal,  especially  when 
the  adaptive  cruise  control  is being  used  because  doing  so will  override  the  braking  function  and  prevent  the  brakes  from  being 
applied  by the  system when  it detects  a situation  when  the  brakes 
must  be  applied. 
•  Always  remember  that  the  adaptive  cruise  control  has limits  -
it  does  not  react  when  you drive  towards  an  obstacle  or  some
thing  else on or near  the  road that  is not  moving,  such as vehicles  stopped  in  a traffic  jam,  a  stalled  or  disabled  vehicle. 
•  Always  remember  that  the  adaptive  cruise  control  cannot 
detect  a vehicle that  is driving towards  you in your traffic  lane and 
that  it cannot detect narrow vehicles such as motorcycles and 
bicycles . 
[ i] Tips 
•  For safety  reasons,  the  stored  speed  is deleted  when  the  ignition 
is  turned  off. 
•  The  Electronic  Stabilization  Program (ESP) and  the  Anti -Slip 
Regulation  (ASR) cannot  be  deactivated  when  the  adaptive  cruise 
control  is switched  on.  If the  ESP and  the  Anti -Slip  Regulation  (ASR) 
has  been  deactivated  and  you  then switch  on  the adaptive  cruise 
control,  the  ESP function  will  also  be  activated  automatically. 
•  Damage  caused by accidents  (e.g.  if  the  vehicle  is damaged 
when  parking)  can  affect  the  radar  sensor  settings.  This can  cause 
the  system  to  malfunction  or  switch  off completely. 
•  The  radar  sensor  cover  is  heated.  In winter  conditions,  you 
should  still  check  before driving  to  make  sure it  is free  of  ice  and 
snow.  If  necessary,  clean  the  area  near  the  radar  sensor carefully 
=> 
page 118, fig.  122. 
Controls  and  equip 
ment 
•  To  ensure  that  the  radar  sensor  is  not  blocked,  foreign  objects 
(e.g.  stickers,  add -on  parts)  must  not  cover the area  near  the radar 
sensor=> 
page 118, fig.  122. The  area  near  the  radar  sensor  must 
not  be painted,  either. 
•  For Declaration  of  Compliance  to  United  States  FCC and  Industry 
Canada  regulations => 
page 342. • 
Applies  to  vehic les : with  adaptive  crui se  cont rol 
How  does  adaptive  cruise  control  work? 
Vehicles  traveling  ahead  are  detected  with  the  aid  of  a 
radar  sensor. 
I==;.===============-. ~ 
~ 
ll! 
Fig. 123  Radar  sensor 
measurement  range 
A  radar  sensor  is built  into  the  front  of  the  vehicle=> fig.  123, which 
is  subject  to  certain  system limits=> 
page 130. Stationary  objects 
are not  taken into  consideration.  The system  is intended  to  measure 
the  distance  to  reflective  surfaces.  The  system responds  after  the 
distance  measurement  has taken  place.  If a measurement  is not 
possible,  the  system  does  not  respond. 
Open  road 
When  the  road  is  clear,  the  adaptive  cruise  control  works  like cruise 
control.  It  maintains  a constant  target  speed  specified  by  the driver .~ 
I  • •  
Page 129 of 360
_____________________________________________ A_d_ a __,_ p_t_iv _ e_ c_r _u _is _ e_ c _ o_n_ t_ r_ o _ l __ !II 
Ap plies  to vehic les: with  adapt ive  cruise  cont rol 
System  status  indicator 
The text  messages  and  symbols  shown  in  this  area  of  the 
display  are  not  displayed  perm anently. 
T ime  in ter va ls  (s uch  a s c::;, __ __ c::;, } 
Fig . 132  System 
sta tus i ndicator 
The different  symbols  for the time  intervals  appear  if you change the 
settings ::::> fig.  132 . 
The  text  message  ... (three  whi te dots)  appears  if  a setting  cannot  be 
implemented  with  the  operating  lever . The  following  are  possib le 
reasons : 
•  If you  pull  the  control  lever  towards  you  to  resume  speed  but  no 
requested  speed  was  set . 
•  If you  push  the  lever  up  to  increase  (or  down  to  reduce)  speed 
when  no  speed  has  been  set  previously . 
•  I f  you  push  the lever  up  to  increase  (or  down  to  reduce)  speed 
and  this  speed  is  outside  the  range  from  20 to  95  mph  (Canada 
models : 30 to  150  km/h) . 
ACC functi onal it y  limited 
The  text  message ACC fun ctio na lit y lim ited appears  when  the  ACC 
system  does  not  detect  any  objects  over  an  extended  time  period. 
For  the  time  being,  the  distance  to  vehicles  up  ahead  is  not  being 
Controls  and  equip 
ment 
controlled . The ACC system  is  not  switched  off,  so  increased  alert
ness  is required.  The following  may  be reasons  for  the  text  message 
ACC Functiona lly  limited: 
•  The ACC sensor  is dirty.  The ACC system  is not  reacting,  or  is  not 
react ing  correctly,  to  veh ic les traveling  ahead. 
•  I t  is  possible  that  you  are  driving  on  a road  with  very  light  traffic 
without anything  at  the side  of  the road  (e.g.  guard  rai ls,  traffic 
signs,  trees).  As  soon  as a vehicle  is detected  by  the  system  again, 
it  returns  to  its  control  range  and  the  text  message  disappears . 
The ACC sensor  is  located  in  the  right  front  trim  grille::::> 
page 118, 
fig. 122 . If there  is a  loss  of  operation  due  to  heavy  contamination, 
this  area  should  cleaned to  restore  proper  operation . 
ACC not  available 
The  text  message ACC not  available appears , for  example,  if  the 
temperature  of  the  brakes  is  excessive.  Adaptive  cruise  control  is 
temporarily  not  availab le . A warning  tone  sounds  as a reminder . 
ACC not  a vailable ! 
The  text  message ACC not  ava ila ble! appears  in the  event  of  a 
malfunction . Adaptive  cru ise control  is turned  off . A warning  tone 
sounds  as a reminder.  Have the  system  inspected  by  a qua lified 
dea lership . 
ACC sensor  blo cked ! 
The  text  message ACC s ensor  blocked ! appears  when  the  ACC 
system  can  no  longer  guarantee  safe  detection  of  objects.  Adaptive 
cruise  control  is turned  off . A warning  tone  sounds  as a reminder. 
To decide  whether  it  is  necessary  to switch  off  the  ACC (ACC sensor 
b locked 
!) or  if  it  is  only  a temporary  condition  (ACC F unctionally 
limited),  the  system  wi ll  a lso takes  into  consideration  the  outside 
temperature  and/or  the windshield  wiper  operation. 
The  ACC senso r is  dirty  or  b locked  (e .g . leaves,  snow). 
The  sensor  should  be  cleaned  to  restore  proper  sensor  function 
::::> 
page 118, fig.  122 . 
I  • •  
Page 132 of 360
• ..__A_ d_ a-'- p_t _iv _ e_ c_r _u _ i_s _e _ c_o_ n_t _r _o _l _____________________________________________  _ 
System  limitations 
Applies  to  veh icles: wi th a dapt ive  cruise  contro l 
General  information 
Some driving  situations  which  affect  the  function  of  the 
radar  sensor  are  described  below. 
When  driving,  the  adaptive  cruise  con tro l is g overned  by  physical 
and  system -specified  limits . Also,  under  certain  circumstances,  the 
ACC system  may  react  unexpectedly  or  late  from  the  driver's  point 
of  view.  Therefore,  always  be  attentive  and  intervene,  if  necessary: 
•  when  driv ing  around  curves => 
page 130 
• when  vehicles  in front  are  not  in  line  with  your  vehicle 
=> 
page 131 
•  when  other  vehic les are  changing  lanes=> page 131 
• when o ther  vehicles  a re di fficu lt  to  detec t=> pag e 131. 
& WARNING 
The  radar  sensor's vision can  be reduced  by  rain,  snow  and  heavy 
spray . Th is can  result  in vehicles driv ing ahead  being  in adequate ly 
detected  or, in  some  circumstances,  not  detected  at  all.  If ne ces 
sary , take  a ction  yourself!  • 
Applies  to vehi cles : w it h  ad aptive  crui se co ntrol 
When  driving  around  curves 
k::;== ========= =,! 
~ 
[J 
Entering  a  curve 
Fig. 13 5  Ve hicle 
en teri ng a curv e 
Fig . 13 6 Vehicle 
le aving  a curv e 
When  entering  a curve , the  adapt ive  cruise  control  may  react  to  a 
vehicle  in the  next  lane  and  apply  the  brakes  in  your  vehicle 
=>  fig. 135. The  braki ng act ion  can  be overridde n by depressing  t he 
acce lerator  pedal. 
Lea ving  a  curve 
At  the  exit  from  very  long  curves  the  predictive  lane  reading  can 
cause  the  adaptive  cru ise control  to  react  to  another  vehicle  in  the 
next  lane  and  apply  the  brakes  in  your  ve hicle => fig . 136.  The 
braking  actio n can  be  overr idden  by  dep ressing  the  acce lerator 
p edal. •  
Page 133 of 360
Adaptive cruise  control  -____________ ____,_ __ ___. 
Applies to vehic les: with  adapt ive c ruise  contro l 
Vehicles  offset  to  one  side 
I IL 
F==================;;;g 
Fig. 137  Vehicle  trav
eling ahead outside  the 
detection  range of the 
radar  sensor 
Vehicles  traveling  ahead  and to  one  side  cannot  be detected  by the 
adaptive  cruise  control  unti l they  are  within  the detection  range  of 
the  sensor. • 
Appl ies  to  vehic les: with  adaptive cru ise  con trol 
Lane  changes  by  other  vehicles 
Fig . 138  A vehicle 
changes  lanes 
Vehicles  which move  into  your lane  a short  distance  ahead  cannot 
be  identified  by the  adaptive  cruise  contro l until  they  are in the 
radar  sensor's  detection range.• 
Contro ls and  eq uip
ment 
Ap plies  to veh ic les:  with  adaptive  cruise  contro l 
Vehicles  that  are  difficult  to  detect 
I IL F==================-;g 
Fig . 139  Two-wheeled 
vehicle  driving ahead 
Vehicles  that  are difficult  to  detect,  e.g.  two -wheeled  vehicles 
ahead,  vehicles  with high  ground  clearance,  protruding  load, are 
frequently  detected  late  or not  at  al l, under  some  circumstances .• 
A pplies to  veh ic les : with  ada ptive  c ruise  cont rol 
Stationary  vehicles 
Fig . 140  Turning  and 
stationary  vehicle  .... 
Vehicle  care I I irechnical data  
Page 134 of 360
-Adaptive 
cruise  contro l "----'-----------------
Fig. 141  Sheering  o ut 
and  stationary  vehicle 
If  a vehicle  that  has  been  detected  by  the  ACC system  turns  off  or 
sheers  out,  and  there  is a stationary  vehicle  ahead  of  that  vehicle, 
the  ACC system  does  not  respond  to  the  stationary  vehicle 
~ page 131, fig.  140  and~ fig.  141.  • 
Audi  braking  guard 
Applies to  vehicl es: wi th a dapt ive  c ruise  co ntrol 
Description 
Audi  braking  guard  warns  you  of  a  threatening  collision 
with  a  vehicle  ahead . 
Fig. 142  Display  in the 
instrument  cluster 
The Audi  braking  guard  is  active  from  a speed  of  approx.  20 mph 
(30 km /h) and  works  within  the system  limits~ 
page 130even  when 
the  adaptive  cruise  control  is deactivated . 
A  radar  sensor  is  built  into  the  front  of  the  vehicle~ 
page 118, 
fig. 122. The  system  is intended  to  measure  the distance  to  reflec
tive  surfaces.  If a measurement  is not  possible,  the  system  does  not 
respond. 
When  the  measurement  has taken  place,  the  system  can  assess  a  hazardous  situation,  when  a vehicle  ahead  suddenly  brakes  or when 
your  own  vehicle  is driving  at  high  speed  towards  a much  slower 
vehicle  ahead.  As  soon  as the  system  assumes  that  a possible  colli 
sion  with  the  vehicle  ahead  can  only  be avo ided  by  immediate  all
out  braking  or  by  an  avoiding  maneuver,  a warning  appears. 
The  system  has  a pre-set  response  time  to  be  able  to  warn  in good 
time.  This  system  response  time  is  automatically  reduced  if  you  acce lerate  actively,  for example  to  join  a highway.  Braking,  trans 
verse  acceleration  and  the  steering  angle  can  lead to  a reduced 
system  response  time.  The  warning  is deactivated  if  you  begin  to 
overtake  with  full  acceleration . 
The  system  draws  your  attention  to  two  different  hazardous  situa 
tions: 
Distance 
The  distance  warning  is issued  in  the  event  of  inadequate distance 
to  the  vehicle  ahead  a period  of  more  than  5 seconds . If the  distance 
is  less  than  30 feet  (9 meters)  at  50 mph  (80 km/h),  for  example,  an 
optical  display  is faded  in  on  the  instrument  cluster~ fig.  142. 
If  the  vehicle  ahead  brakes sharply,  a collision  cannot  be  avoided, 
even  in the  case of  an immediate  response.  In this  case , increase  the 
distance  to  the  vehicle  ahead. 
Speed 
If  there  is a much  slower  vehicle  ahead  in your  lane,  or  if  the vehicle 
ahead  brakes  sharply,  the  Audi  braking  guard  calculates  the  point 
from  which  a collision  can  only  be  avoided  by  all -out  braking  or  by 
~