2018 AUDI A4 brakes

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* .
-

-Activating the emergency flashers l).
The message Audi pre sense . ¢ page 121,
fig. 122 will warn you abo ut the danger.
Aud i drive select*: the trigger t imes are adjusted
depending on the mode selected.
Audi pre sense front
Description
Applies to: veh icles with Audi adaptive cruise control
Within the limits of the system, pre sense front
can warn you of impending collisions and initiate
the corresponding braking maneuvers or the sup­ porting measures when avoiding a collision .
If detected in time, the system can rank the dan­
gerous situation as critical if a vehicle driving
ahead brakes suddenly, if your own vehicle is ap­
proaching a significantly slower vehicle at high
speed or when there is an oncoming vehicle dur­
in g a turning maneuver .
If detection is not possible, then pre sense front
does not react .
Warnings
Applies to: ve hicles with Audi adaptive cruise control
Fig. 122 In strument cluste r: approac h warning
General information
The system recognizes various dangerous situa­
tions . The
early warning occurs if:
-a vehicle driving ahead brakes suddenly,
-your own vehicle approaches a significantly
a s lower vehicle or stationary vehicle in the direc-co
;::; tion of travel. ,....
N .... 0 0
3 1) This is not availa ble in some co untrie s. co
Assistance systems
When this warning occurs, it may only be possi­
ble to avoid a collision by swerving or braking
strongly. The message
Audi pre sense.
¢ fig. 122 and a warning tone will warn you
about the danger .
If you do not react enough or not at all to a dan­
gerous situation that was detected by the sys­
tem, pre sense front provides assistance by ap­ plying the brakes .
If a collision is imminent, the system will first
provide an
acute warning by braking sharply. You
will also warned by an indicator in the instrument
cluster
display¢ fig. 122. If you do not react to
the acute warning, pre sense front can brake with i ncreasing fo rce within the limits of the
system
1>. This reduces the vehicle speed in the
event of a collision. At low vehicle speeds, pre
sense front can in itiate a complete deceleration
shortly before a collision with a vehicle driving
ahead
l). If pre sense front determines that you
are not braking strongly enough when a collision
is imminent, it can increase the braking force.
T he following functions trigger in conjunction
with pre sense basic/rear at corresponding vehi ­
cle speeds:
-Reversible tensioning of the front safety belts.
-Closing the windows and sunroof* .
-Inflating the side bolsters* on the seat back-
rest .
Audi drive select*: depending on the mode se­ lected, the reversible belt tensioner, the closing
of the w indows and sunroof*, and the inflating of
the side bolsters* on the seat backrest may not be active.
Evasive steering support
Evasive steering support helps you to steer the
vehicle around an obstacle in a critical situation .
If you avo id an obstacle after the acute warning,
then the evasive steer ing support ass ists you by
applying slight stee ring adjustment to correct
.,.
121

a co .... N ,....
N .... 0 0
3 co
(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

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
3 co
(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

Intelligent Technology
Intelligent Technology
Electronic stabilization
control (ESC)
Description
Elect ronic stabilization control (ESC) supports
driver safety.
It red uces the risk of slipping and
improves driving stability. ESC detects crit ica l sit­
uations such as when the vehicle is oversteering
and understeering or the wheels are spinning.
The vehicle is stabilized by applying the brakes or reducing eng ine torq ue. When the ESC engages,
the hJ ind icator light blinks in the instrument
cluste r.
The fo llow ing systems are integrated in the ESC:
Ant i-loc k bra king system (ABS)
ABS prevents the whee ls from locking when brak­
ing. The vehicle can sti ll be steered even during
hard brak ing. Apply steady pressure to the brake
pedal. Do not pump the pedal. A puls ing in the
brake pedal indicates that the system is acting to
stabilize the vehicle .
Brake assist system
The brake assist system can decrease brak ing dis­
tance . It increases braking power when the driver
presses the brake pedal quick ly in emergency sit­
uations . You must press and hold the b rake pedal
until the dangerous situat io n is over . In veh icles
with adapt ive cr uise control*, the bra ke assist
sys tem is more sensitive if the d ista nce detec ted
t o the vehicle dr iv ing ahead is too small.
Anti -Slip Regulation (ASR )
ASR reduces eng ine power when the drive wheels
begin sp inning a nd adapts the force to the road
conditions . This makes it easie r to start, acceler­
a te and dr ive up h ills.
Electron ic differenti al lock (EDL )
The EDL applies the brakes to a wheel that starts
spinning and transfers the drive power to the
other driving wheel or wheels ( if the veh icle is
eq uipped w ith all whee l dr ive*) . T his function is
not available at higher speeds.
146 In extreme cases,
ED L automat ically switches off
to keep the brake on the braked wheel from over­ heating. The veh icle is still working correct ly. ED L
will switch on again automatically when condi­
tions have returned to normal.
Steering r ecommendat ion
The ESC he lps to stabilize the vehicle by changing
the steering torque.
In veh icles with dynamic s teer ing*, ESC a lso
helps to stab ilize the steering in cr it ica l situa ­
tions.
Selective wheel torque control
Se lective whee l torque cont rol is used when d riv­
i ng on curves. The front whee l on the inside of
t h e curve or both whee ls on the i nside of the
curve are braked se lectively as needed. This al­
l ows more precise driving in curves.
Automatic post -collision b raking system
The "automat ic post-collis io n braking system"
can help to reduce the risk of sliding and of addi­
tiona l collisions after an acc ident. If the a irbag
contro l modu le detects a collision, the ve hicle is
braked by the ESC.
The veh icle does not bra ke automatically if:
-the dr iver presses the accelerator pedal, or
-the ESC, the brake system or the veh icle electri-
cal system are not functioning.
&_ WARNING
-The ESC and its integrated systems cannot overcome the lim its imposed by natura l
phys ica l laws. This is espec ially important
on sl ippery or wet roads. If the systems be­
gin acting to stabilize your vehicle, you
should immediately alter your speed to match the road and traffic conditions. Do
not let the increased safety provided tempt
you into taking risks. This could increase
your r isk of a coll is ion.
-Please note the r isk of a coll is ion increases
when dr iv ing fast, especially through curves
and on slippery or wet roads, and when dr iv­
ing too close to objects ahead . The ESC and
its integrated systems cannot always

Intelligent Technology
Applies to: allroad
Offroad mode on
ESC/ASR off Offroad mode off or
ESC /ASR on
Beha vior
T he ESC and ASR stabiliza -The stabi lization f unction is The f ull stabilization tune -
tion functions are limited not available
¢ .&. . ESC and tion of the ESC and ASR is
¢ & . ASR are sw itched off . available aga in .
Operation Press the l~ m l button b rief- Press an d ho ld the l~ "'' I but- Press the l~ "" I button again .
ly. ton longer than three sec-
onds.
Indicator II turns on. Iii and lf'tii•)H turn on. II turns off or II and
light s li'tii•)H turn off .
Message s Stabilization cont
rol (ESC ): Stabiliza tion control (ESC ): Stabilization cont rol (ESC ):
offroad . Warning! Redu ced off . Warning! Restricted
on
s tability stability
A WARNING
You should only switch sport/offroad mode
on or switch ESC/ASR off if you r drivi ng abili­
ties and road cond it ions permit .
- The stabilization function is lim ited w hen
sport mode/offroad mode is swi tched on.
T he driving w heels could sp in and the veh i­
cl e could swerve, especi ally o n slick or slip­
pery road sur faces.
- T here is no vehicle sta biliz at ion when ESC/
ASR a re swi tched off.
Hill descent assist
Applies to: allroad
Hill descent assist makes it possible to drive
down a hill at a constant speed.
F ig. 1 56 Center co nso le: hil l desce nt ass ist button
~ To switc h hill descent assist on, press the !"~I
button. The LED in the button t urns on.
~ Press the button again to switch it off. The LED
in the button turns off.
148
Hill descent assist brakes a ll four wheels auto­
matically in order to limit speed when d riving ei­
ther forward or reverse on hills with a grade from
approximately 6 to 60%. The wheels will not lock
u p because the ABS remains activated.
When hill descent assist is on, the speed your ve ­
hicle was traveling when it entered the hill is
maintained. It is only possib le to sw itch on the
ass ist when driving slower tha n 37 mph (60 km/
h) . The ass ist beg ins shortly af ter you start dr iv­
i ng and cont inues up to app roxima tely 19 mph
(30 km/h). The d rive r ca n in crease o r de crease
t h e ve hicle spee d wit hin these lim its by press ing
t h e accelerator or brake pedal.
However, there must be enough t ract ion . Hill de­
sce nt assist
cannot function as e xpec ted, if fo r
ex ample the h ill is icy o r if t he surface is loose
¢ &.
Active regulat io n of a speed up to approximate ly
19 mp h (30 km/h) is s ignaled in the instr ument
cl us ter by an ind ic a tor light
• . The in dica tor
li gh t tur ns on when i n the ready mode.
II.
The system does not work at speeds between ap­
prox imately 19 and 37 mph (30 and 60 km/ h).
The system is the n in ready-mode. This is indica t­
ed by the L ED in the b utton t urnin g on. The sys­
tem a utomatica lly switched o ff when you drive
faster than 37 mph (60 km/h). The LED w ill also
turn off in this scenar io.
Hill descen t assis t is au tomatically ac tiva ted un-
der the fo llowing cond itions:
.,.

a co .... N ..... N .... 0 0
3 co
-the LED in the button turns on
-the vehicle speed is lower than 19 mph (30 km/
h)
-the h ill angle is at least app rox imately 6%
_& WARNING
-Always adapt yo ur speed to the weather,
road and traffic conditions. Do not let the
increased safety provided tempt you into
tak ing risks, because this increases the risk
of an accident.
-
-T he hill descent assist system cannot over­
come the laws of physics. Your driving style
must a lways be adapted to the current road
and traffic conditions.
- Hill descent assist may not be able to hold your vehicle at a constant speed under a ll
condit ions while driving on a hill (for exam­
ple if ground under the veh icle is loose) .
Brakes
New brake p ads
New brake pads do not ach ieve the ir full braking
effect during the first 250 mi (400 km). They
must be "broken
in" first. However, you can com­
pensate for the slightly reduced brak ing fo rce by
p ressing firmly o n the brake pedal. Avoid heavy
b raking during t he b reak-in per iod.
Wear
B rake pad
wear depends largely on the way the
veh icle is driven a nd on operat ing cond itions.
This is especia lly true if you are d riving frequently
in t he c ity and on c urves or wi th a sporty driving
style.
Operating noise
Noises may occur when braking depend ing on the
speed, braking force and outs ide cond itions such
as temperature and humidity .
Wet conditions or road salt
In certain situations, for example after driving
through water, in heavy ra in or after washing
your car, the brak ing effect may be reduced due
to moisture or ice on the brake rotors and brake
Intellig ent Technology
pads. The brakes m ust be "dried" first with a few
carefu l brake app lications.
At higher speeds and w ith the win dshield wipe rs
tu rned on, the brake pads press agains t the b rake
roto rs fo r a short amount of time. This action,
which is not felt by the driver, happens at regu lar
i nterva ls and ensures a better reaction t ime for
the b rakes in wet weather.
T he brak ing effec t can a lso be reduced if yo u are
driving on salted roads and yo u do not app ly the
brakes for long per iods of t ime. The layer of sa lt
on the brake rotors and pads m ust be worn off
first whe n the brakes are applied.
Corrosion
Leaving the vehi cle parked for long periods o f
time, low mileage and avoiding heavy b raking
can contrib ute to corros ion on the brake rotors
and to dirty brake pads.
If you usu a lly avoid heavy bra king or if there is
corrosion present, occasiona l heavy braking at
high speeds is recommended to clean the brake
roto rs and
pads ¢~ -
Brake system malfunction
If you notice that the bra ke pedal trave l has sud­
denly increased, then a brake circuit in the dua l­
ci rcuit brake system may have malfunctioned.
Drive to an authorized Audi dealer or authorized
Audi Service Facility immed iate ly to have the
problem corrected. On the way there, drive w ith
reduced speed and keep in mind t hat you will
need a longer distance to stop and you will need
to press the bra ke ped al ha rder.
Low brake fluid level
When the bra ke fluid level is low, malfunctions in
the brake system may occur. The brake fluid level is elec tronically monitored.
Brake booster
The brake booster ampli fies the p ressure you ap-
ply to the brake pedal.
.,..
149