2018 AUDI A4 brake sensor

General information
Appl ies to: ve hicles with Audi adaptive cruise contro l
Fig. 108 Fro nt of the vehicle: sensors and video camera
The areas with the radar and ultrasonic sensors
and the video camera
c:> fig . 108 must not be cov ­
ered by stickers, deposits or any other objects, because this can inte rfere with the adaptive
cr uise control funct ion. For information on clean­
ing, see
c:> page 354 . The same app lies for any
modifications made in the front area.
In some d riving situations, the adaptive cru ise
control funct ion is restr icted:
- Vehicles can only be detected when they are within the sensor detection zones
c:> page 108,
fig. 107.
- The system has a limited abil ity to detect
vehicles that are a short distance ahead, off to
the side of your vehicle or moving into your
lane .
- Objects that are difficult to detect such as mo­
torcycles, vehicles with high ground clearan ce
or an overhanging load are detected late or not dete cted at all.
- When driving through curves
c:> page 110 .
-When the vehicle is stat ionary c:> page 110.
..&, WARNING
Always pay attent ion to the traffic aro und you
when adap tive cruise contro l is swi tched o n.
As the driver, you are s till responsible for your
own speed and the distance to other vehicles .
The adaptive cruise control is used to assist
you. The driver must a lways take action to
avoid a collision. The driver is a lways responsi­
ble for brak ing at the correct time.
A ss is ta nce syst ems
-For safety reasons, do not use adaptive
cru ise control when the road surface is in
poor condition and/or in bad weather condi­
tions (such as ice, fog, gravel, heavy rain and
hydroplaning). Using the system under
these conditions increases the r isk of an ac­
cident.
- Sw itch adaptive cruise control off tempora­
rily when dr iv ing in turning lanes, on ex­
p ressway ex its (except if predictive con trol
is switched on) or in const ruct ion zones.
This prevents the vehicle from acce lerating
to the stored speed when in these situa­
tions.
- The adaptive cruise contro l system will not
brake by itself if you put your foot on the ac­
celerator pedal. Doing so can override the
speed and distance regulation.
- When approaching stationary obstacles
such as stopped traffic, adaptive cruise con­
trol will respond with limited function.
- Adaptive cr uise control does not respond to
peop le, animals, or crossing or oncoming
objects.
- The funct ion of the radar sensors can be af­
fected by reflective objects such as guard rails, the entrance to a tunnel, heavy rain or
ice.
(D Note
The sensors can be displaced by impacts or
damage to the bumper, wheel housing and underbody. This can impair the adaptive
cruise control. Have an authorized Audi dealer
or authorized Audi Service Facility check
the ir
f u nct ion.
(D Tips
For an explanation on conformity with the
FCC regulations in the United States and the
Industry Canada regu lations, see
c:> page 38 6.
109

Assistance systems
This message appears if you would like to switch
the system on and there is a stationary object di­
rectly in front of your veh icle.
Door open
The system is not ava ilable when the door is
open.
Audi pre sense
Introduction
A pp lies to: ve hicles w ith Audi p re se nse
W ithin the limits of the system, the pre sense
functions can initiate measures in particularly
dangerous situations to protect the veh icle pas­
sengers and other road users .
- Due to the interlinking of various vehicle sys­
tems, crit ical dr iving s ituations can be detected
by
pre sense basic and measures for preventa ­
tive occupant protection are can be initiated .
- The
pre sense front system uses the data from
the adapt ive cruise control* radar sensors and
the camera to calculate the probab ility of a col­
li sion. Withi n the limits of the system, an im­
pending collision with vehicles can be dete cted
in both urban and rural speed ranges. In this
case, the system warns the driver visually,
acoustically and with a jerk on the brakes if nec­
essary. If needed, it can initiate a partial or full
deceleration to reduce the co llision speed or to
avo id the collision under certain c ircumstances .
In conjunct ion with pre sense basic/rear, the
front safety belts are also revers ibly tensioned
when needed . The pre sense front is also active
whe n adapt ive cruise control* is swit ched off.
- Pre sense rear contains pre sense basic func­
tions. It uses the data from the side assist* ra­
dar sensors and calculates within the limits of
the system the probab ility of a rear end coll i­
s ion with the vehicle behind you. Pre sense rear
is also active when side assist* is switched off.
- Within the limits of the system,
pre sense city
uses the camera data and can detect an im ­
pending collision with vehicles and pedestrians.
In this case, the system warns the driver visual ­
ly, acoustically and with a jerk on the brakes if
necessary. If needed, it can initiate a full decel­
eration to reduce the collision speed or to avoid
120
the collision under certa in circumstances . In
conjunction with pre sense basic/rear, the front
safety belts are also reversibly tensioned when
needed .
A WARNING
-
Read the general information inc> & in Gen-
eral information on page 109,
c> & in Gener­
al information on page 130.
(D Tips
- Certain pre sense funct ions sw itch off when
dr iving in reverse.
- The pre sense functions may not be availa­
ble if there is a malfunct ion in the ESC sys­
tem or the a irbag control module.
- Note that the reversible belt tensioner on
the front passenger's side deactivates when
the front passenger's airbag is deactivated .
- Switch the pre sense off when you are not
using public streets or when loading the ve­
hicle onto a vehicle carrier, tra in, sh ip or
other type of transportation. This can pre­
vent an undesired intervention from
the pre
sense system.
Audi pre sense basic
Description
App lies to : vehicles wi th Audi pre sense basic
The pre sense bas ic functions are activated at a
speed of approx imately 20 mph (30 km/h) or
higher .
The following functions can be triggered under certain condit ions w ith in the lim its of the sys­
tem:
- Tensioning of the safety belts (for examp le,
during heavy brak ing): the front safety belts
have reversib le be lt tens ioners. If a collision
does not occur, the safety belts loosen slightly
and are ready to trigger again.
- Closing the windows and sunroof* .
-

Ass is tan ce sys tems
your steering whee l ang le as long as you are ac­
tively steering. Evasive steering support is availa­
b le at speeds between approximately 20 mph
(30 km/h) and 90 mph (150 km/h).
Tu rn assist
When start ing to drive and up to speeds of maxi­
mum
6 mph (10 km/h), the turn assist uses a
braking intervention to prevent your vehicle from
colliding with an oncoming vehicle when turning
left or right (available in certain countries). The
braking intervent ion causes your vehicle to stay
in its lane.
A WARNING
-Pre sense front cannot overcome the laws of
physics.
It is a system des igned to assist and
it cannot prevent a collision in every circum­
stance. The driver must always i ntervene.
T he driver is always responsib le for braking
at the correct time. Do not let the increased
safety provided tempt you into taking risks .
This could increase your risk of a collision.
- The system can deploy incorrectly due to
system-specific limits .
- Please note that the sensors and the camera
do not always detect all objects or lane
markings. This increases the risk of an acci­
dent.
- Pre sense front does not react to people, an­
imals or ob jects that are crossing the veh i­
cle's path or that are difficu lt to
detect¢ .&.
in General information on page 109.
-Reflective objects such as guard rails or the
entrance to a tunnel, heavy rain and ice can
affect the fu nction of the radar sensors and
the system's ability to detect a coll is ion risk .
(D Note
The sensors can be displaced by impacts or
damage to the bumper, whee l housing and
underbody. Pre sense front can be impa ired
by this. Have an authorized Aud i dealer or au­
thorized Audi Service Fac ility check their func­
tion.
l ) Th is is not availab le in some countr ies.
122
(D Tips
- You can cancel the braking with increas ing
force that is initiated by the system by bra k­
ing yourself, by acce lerating not iceably or
by swerving.
- Keep in mind that pre sense front can brake
unexpectedly. Always secure any cargo or
objects that you are transporting to reduce
the risk of damage or injury.
- Specific pre sense front functions switch off
when the ESC is restricted or sw itched off
¢ page 147 or the hill ho ld assist" is
switched on
¢ page 148 .
Audi pre sense rear
Description
Applies to : vehicles wi th Aud i s ide ass ist
If the risk of a co llision with a vehicle ahead is de­
tected, the follow ing funct ions can be triggered:
- Reversible tensioning of the front safety belts
at the corresponding speeds .
- Closing the windows
and sunroof*.
- Infla ting the side bo ls ters* on the seat back-
rest.
- Ac tivat ing the emergency flashers with in -
creased frequency
l l.
The message Audi pr e sense. ¢ page 121,
fig. 122
will warn you about the danger.
Audi drive select": the function is not active de­
pending on the mode selected.
A WARNING
- To reduce the r isk of an accident, please
no te t hat the s ide assist* radar sensors do
no t always dete ct every object.
-
- Pre sense rear does not react to people, ani­
mals or objects that a re c ross ing the vehi­
cle 's path o r that are d ifficult to detec t.
- Ref lective objects such as gua rd ra ils, heavy
rain and i ce can impair the func tion of the
radar sensors an d the abili ty to detect a col­
lision risk.

a co .... N ,....
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(D Note
The radar sensors can be displaced by impacts
or damage to the bumper, wheel housing and
underbody. Pre sense rear can be impaired by
this. Have an authorized Audi dealer or au­
thorized Audi Service Facility check their func­
tion .
(D Tips
-The pre sense rear functions switch off
when towing a trailer .
- The pre sense rear functions may also
switch off if there is a malfunction in the
side assist* system.
Audi pre sense city
Description
Applies to: vehicles with Audi pre sense city
Within the limits of the system, pre sense city
can warn you of impending collisions with
vehicles and pedestrians and initiate the applica­
ble braking maneuver if needed. Pre sense city is
active at speeds of approximately 6 mph (10 km/ h) and higher.
A pedestrian warning can occur at speeds up to
50 mph (85 km/h), and vehicle warnings can oc­
cur at speeds up to 155 mph (250 km/h) . A pre
sense city braking maneuver is poss ible at speeds
up to 50 mph (85 km/h).
Warnings
Applies to: vehicles with Audi pre sense city
The system recognizes various dangerous s itua­
tions. The
early warning occurs if:
- a vehicle driving ahead brakes suddenly,
- your own vehicle approaches a significantly
slower vehicle or stationary veh icle in the direc­
t ion of travel.
- a pedestrian is standing in the lane or is moving
i nto the lane .
When this warning occurs, it may only be possi­ ble to avoid a collision by swerving or braking
strongly. The message
Audi pre sense .
Assistance systems
¢page 121, fig. 122 and a warning tone will
warn you about the danger.
Additionally, a jerk on the brakes may occur as an
acute warning when there is an imp ending colli­
sion . If you do not react to the acute warning, pre
sense city can brake to the point of complete de­
celeration within the limits of the system . T his
reduces the vehicle speed in the event of a colli­
sion. The message
Audi pre sense . also ap­
pears.
The following functions are triggered in conjunc­
tion with pre sense basic/rear:
- Reversible tensioning of the front safety belts.
- Closing the windows and sunroof* .
- Inflating the side bolsters* on the seat back-
rest.
Audi drive select*: the function is not act ive de­
pending on the mode selected.
A WARNING
- Pre sense city cannot overcome the laws of
physics.
It is a system designed to assist and
it cannot prevent a coll is ion in every circum­
stance. The driver must always intervene.
The driver is always responsible for braking
at the correct time. Do not let the increased
safety provided tempt you into taking risks.
This could increase your risk of a collision.
- The system can dep loy incorrectly due to
system-specific limits.
- To reduce the risk of an accident, please
note that the camera does not always detect
every object.
- Pre sense city does not react to anima ls,
crossing or oncoming vehicles, objects such
as bars, railings or railcars, and objects that
are difficult to
detect ¢ A in General infor­
mation on page 109 .
-In trailer mode, the braking behavior of the
tra iler can be d ifferent than usual during au­
tomatic braking.
A WARNING
-Pre sense city may be restricted or not availa-
ble in the following example situations:
- in heavy fog, ra in, spray or snow
~
123

Assistance systems
-when there are visual obstr uctions, such as
glare, reflections or variations in light
- when it is dark
- if the camera window or the windshie ld is
dirty, iced over, damaged or covered
- when driving on snow, ice or loose ground
- in curves
- if the ESC was restricted or switched off
- when towing a tra iler
- when the driver's seat belt is unfastened
- up to ten seconds after switching on the ig-
nition
(D Note
Impacts or damage to the camera mount on
the windshield can disp lace the sensor . Pre
sense city can be impa ired by this. Have an au­
thorized Audi dealer or authorized Aud i Serv­
ice Facility check the ir funct ion.
{D) Tips
- You can cancel the system braking interven­
tion if you accelerate considerably or swerve
away.
- Keep in mind that pre sense city can brake
unexpectedly. Always secure any cargo or
objects that you are transport ing to reduce
the r isk of damage or injury.
- Specific pre sense city funct ions sw itch off
when the ESC is limited or switched
off
¢ page 147 or the hill descent assist* is
switched on
¢page 148.
-When there is a malfunction in the camera,
the pre sense city funct ions also switch off.
Settings in the
Infotainment system
A pp lies to: ve hicles w ith Audi p re se nse
.,. Select in the Infotainment system: IMENU I but­
ton
> Vehicle > left control button > Driver as­
sistance
> Audi pre sense.
Turn on/off Audi pre sense
-the pre sense func­
tions can be turned on and
off.
124
If the system is switched off, it switches on again
automatica lly once the ignition is switched on
again.
Early warning -the early warning can be switch­
ed
off or the pre sense city/front warning point
can be set
( Early /Medium /Late ).
Set the warning time for the early warning to
Early at first . If this causes undesi red early warn­
ings to appear, then set the warning time to
Me­
dium .
The Late warning time should only be set
i n spec ial circumstances, for example, when driv­
i ng with a very dynamic style.
(D Tips
Your settings are automatically stored and as ­
signed to the remote control key being used.
Messages
Applies to: vehicles wi th Audi pre sense
II Audi pre sense: malfunction! Please contact
Service
This message appears when the pre sense func­
tion is affected . For example, th is could be
ca used by a faulty sensor. Drive to an authorized
Audi dealer or authorized Audi Service Facility im­ mediately to have the malfunction corrected.
II Audi pre sense currently restricted . Restrict­
ed sensor vision due to surroundings. See own­
er 's manual
This message appears if the radar sensor and
camera view is obstructed, for example by leaves,
snow, heavy spray or dirt. If necessary, clean the
sensors and the area around the camera
¢ page 109, fig . 108 or ¢page 129, fig. 130 .
II Audi pre sense: currently restricted. Towing
mode
For vehicles wi th a trailer hitch installed at the
factory, the pre sense rear functions switch
off
when the electrical connector at the socket is
plugged in. There is no guarantee the functions
will switch
off when using a retrofitted trailer
hitch.
II Audi pre sense: currently restricted

Ass is tance sy stems
- The display brightness for the ex it warning
system cannot be adjusted.
- The system is not available when towing a
trailer.
Rear cross-traffic assist
A pp lies to: ve hicles w ith rea r cross-tra ffic ass ist
F ig. 1 33 Example d is play
F ig . 134 In fo ta in me nt system : re ar cro ss -tra ffic ass ist dis­
p lay
The rear cross -traffic assis t can warn the drive r of
a po tential collis ion with approaching cross -traf­
f ic when driv ing i n reverse . Within its limits, the
system monitors the areas beh ind and n ext to
the vehicle using the radar sensors when leaving
a park ing space
c::> page 129, fig. 130. Moving ob­
jec ts tha t are approach ing, such as cars, are de­
tected
c::> fig . 133 .
If the system detects cr itical cross traffic when
ba cking out of a parking space, it will react as fol­
lows :
-Visual indicator : an indicator appea rs in the In­
fotainment system display with a red arrow
symbol. The arrow points in the direction from
which the object is approach ing
c::> fig. 134 .
-Audible warning signal : a continuous tone may
sound as an additional indicator when driving in reverse .
132
-Automat ic brake acti vati on: a brief activation
of the brakes may also warn you of a potentia l
co llision w ith an approaching object .
Requirements for using the rear cross -traffic
a ss is t :
-The parking aid must be switched on
<=> pag e 136.
-Reverse gear must be engaged.
- The speed mus t not be higher th an approxi-
mate ly 9 mph (15 km/h) .
&_ WARNING
-The rear cross-traffic assist is an assist sys­
tem and cannot prevent a collision by itself.
The drive r must always intervene. The driver
is always responsible for braking at the cor­
rect t ime .
-Please note that the rear cross-traff ic assist
may activate the brakes unexpected ly. Se­
cure any cargo that you are transporting to
reduce the ris k of damage or injury .
-An add itiona l brake activation may be trig­
ge red w ith in 20 seconds after an automatic
brake activation .
-If there is an acoust ic warning signal from
the rea r cross-traffic assist, then the park­
ing system may no t warn you of detected
obs tacles under certain circumstances.
- The v iew of the radar sensors may be im­
pa ired by leaves, snow, heavy sp ray o r dirt .
C lean the area in front of the sensors
c::> page 129, fig. 130 .
&_ WARNING
The re ar cross- traffi c assist is subject to limi ­
tations and cannot warn yo u before every im­
pending collision:
- I f the ve hicle is too wide for the parking
space and covered by the neighboring
veh icles.
- People, such as cyclists, joggers, inline skat ­
ers and pedestrians, may not be detected
under certain circumstances.
- If you are in a paralle l parking space or diag ­
onal parking space .

a co .... N ..... N .... 0 0
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(D Note
Also read the informat ion in c::> (D in General
information on page 130 .
@ Tips
-You can can ce l the au toma tic b rake activa ­
tion w ith increasing braki ng fo rce if you ap ­
p ly the brakes yourse lf or accelerate cons id­
erab ly.
-In some situations, rea r cross-traffic assist
may warn yo u even if there is no cross t raffic
i n a cr itical area, for examp le when back ing
i nto a parki ng space or maneuver ing.
-The rea r cross-traffic ass ist also switches of f
when you switch off the ESC.
-The rea r cross traffic assist switc hes on and
off thro ugh t he pa rking aid
c::>page 136.
-The system is not available when towin g a
trailer.
Messages
App lies to: ve hicles with Audi side assist
A message appears in the instrument cluster dis­
p lay if the s ide assist switches off automatically .
@t Audi side assist: malfunction! Please contact
Service
@t Audi side assist and exit warning : malfunc­
tion! Please contact Service
The system c annot guarantee th at it will detec t
ve hicl es co rrectly and i t has switched off. The
sensors have been moved o r are faul ty. Have the
system checked by an a uth orized Audi dea ler or
author ized Audi Service Facility soon.
@t Audi side a ssist: currently unavailable. Sen­
sor vision restricted due to surround ings . See
owner 's manual
at Audi side a ssis t and exit warning : currently
unavailable. Sensor vision restricted due to sur­ roundings
The rada r se nso r vis io n is impaire d. T he ar ea in
fr on t of the senso rs must no t be covered by b ike
ra ck s, st ick ers, leaves, snow or any othe r o bj ects.
C lea n the area i n front of the senso rs, if necessa ­
ry
c::> page 129, fig . 130 .
Assistance systems
@t Audi side assist : currently unavailable. See
owne r's manual
at Audi side assist and exit warning: currently
unavailable. See owner's manual
S id e assist ca nnot be sw itched on at this time be­
c a u se the re is a ma lfun ction ( for ex ample, the
ba ttery ch arge leve l may be too low).
@t Audi side assist: unavailable in towing mode
(it Audi side assist and exit warning: currently
unavailable. Towing mode
Sid e assist switches off automatically when the
electrica l connecto r in the factory-installed t rail­
er hitch is connected. There is no guarantee the
system will sw itch off when using a retrofitted
t railer h itch . Do not use side assist and the ex it
warning w hen tow ing a traile r.
111 Rear parking aid: obstacle detection restrict­
ed
T he rear cross-traffic ass ist is not available. E i­
t h er the ESC is sw itched off, or the rada r senso rs
may be cove red by a bike rack, sticke rs, leaves,
snow or other objects. Switc h the ESC on , or
clean the area in front of the senso rs if necessary
c::> pag e 129, fig . 130 . If thi s m essage continues
to be displayed, dr ive immedia tely to an author­
i z ed Audi de aler or author ized Audi Se rvice Facili­
ty to ha ve the mal fu ncti on re paire d.
Audi drive select
Introduction
Applies to : vehicles with Aud i drive se lect
Drive select makes it possib le to exper ience dif­
ferent types of ve hicle sett ings in one ve hicle .
T he driver can select
Offroad *, Comfort , Auto
and Dynamic mod es in the Info tainm ent system
t o swi tch b etwee n a sp orty and a comfo rtable
dr iv ing mo de, fo r ex ample . In t he
Individual
mode, the settings can be a djusted to you r per­
sona l p references . This makes it possible to com­
bine settings such as a sporty engine setting with
li ght steer ing.
133

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wash operator to reduce the risk of acci­dents.
- To reduce the risk of cuts, protect yourself
from sharp metal components when wash­
ing the underbody or the inside of the wheel
housings .
- After washing the vehicle, the brak ing effect
may be delayed due to mo isture on the
brake rotors or ice in the w inter . This in­
creases the risk of an acc ident. The brakes
must be d ried fi rst w ith a few careful b rake
applications.
(D Note
- If you wash t he vehicle in an automatic car
wash, yo u m ust fold the exte rior m irrors in
to reduce the risk of damage to the mirrors.
Power folding exte rior m irrors* must on ly
be fo lded in a nd out using the power folding
fu nct ion.
- To reduce the risk of damage to the rims
and tires, compare the width between the
whee ls on your vehi cle w it h t he dis tan ce be­
tween the g uide rai ls in the
car wash.
- To reduce t he risk of damage, compare the
height and width o f you r vehicle wi th the
Ca re and cleaning
height and w idth of the inside of the car
was h.
- T o red uce the risk of pa int damage, do not
was h the vehicle in d irect sun light .
- T o red uce the risk of d am age to the s urf ace,
do not use insect removing sponges, k itche n
sponges or similar items .
- Mat te finish painted veh icle components:
- To reduce the risk of damage to the sur-
face, do not use polishing agents or hard
wax .
- Never use protective wax. It can destroy
the matte finish effect .
- Do not place any stickers or magnetic
signs on vehicle parts painted with matte
finish paint . The paint cou ld be damaged
when the stickers or magne ts are re­
moved .
@ For the sake of the environment
Only wash t he vehicle in facilities s pec ially de­
s ign ed for that pu rpose . This will reduce the
r isk of dirty wate r contaminated with oil from
ente ring the sewe r sys tem.
Cleaning and care information
W hen cleani ng and ca ring for individua l vehicle
components, refer to the follow ing tables . The
i n formation contained there is simply recom­
mendations. For quest ions or for components t
h at are not liste d, co n su lt an autho riz ed Au di
dealer or authorized A udi Se rvice Fac ility . Also
fo llow the information found
in ¢ .&. .
Exterior cleaning
Component Situation Solution
Windshield wiper
Deposits c:> page 61, Cleaning the wiper blades
blades
Headlights /
Deposi ts So
ft spo nge wi th a mild so ap sol ution3>
Tail light s
S ensors /
Deposits Sensors: soft cloth w it h solvent-free cleaning solut ion
Camera len ses Camera le nses: soft clot h w ith alcohol-free cleaning solu-
tion
Snow/ice H
and br ush/solvent-free de-icing spray
Wheels Road salt Water
Brake dust Acid-free special cleaning solution
355