2008 AUDI S4 wheel

Safe driving
188Correct sitting positionsCorrect sitting position for driver
The correct driving position is important for safe and
fatigue-free driving.For your own safety, and to reduce the risk of injury in the
event of an accident, we re commend the following driving
position.
– Adjust the steering wheel so there is a distance of at least 25 cm between the steering wheel and your breastbone
⇒fig. 199. – Move the driver's seat forwards or backwards so that you
can press the accelerator, brake and clutch pedals all the
way to the floor with your knees slightly bent ⇒.
– Make sure that you can comfortably reach the top of the steering wheel.
– Adjust the head restraint so that the top of the head restraint is level with the top of your head ⇒fig. 200.
– Adjust the backrest to an upright position so that your back remains in contact with the upholstery.
– Fasten your seat belt correctly ⇒page 194 .
– Keep both feet in the footwe ll so that you are in full
control of the vehicle at all times.
For detailed information on how to adjust the driver's seat, see
⇒ page 73, “Seats and storage”.
WARNING
•
A driver who is not sitting in the correct position or who is not
wearing a seat belt can be fatally injured if the airbag is triggered.
•
Adjust the driver's seat so there is a distance of at least 25 cm
between your breastbone and th e centre of the steering wheel
⇒ fig. 199.
•
While driving, always hold the steering wheel with both hands
on the outside of the rim at about the 9 o'clock and 3 o'clock posi-
tion. This reduces the risk of injury if the driver's airbag inflates.
•
Never hold the steering wheel at the 12 o'clock position, or
with your hands inside the rim or on the steering wheel hub. This
could result in serious injuries to the arms, hands and head if the
driver's airbag inflates.
•
To reduce any risk of injury to the driver during a sudden brake
application or in an accident, neve r drive with the backrest tilted
Fig. 199 Minimum
distance between
driver and steering
wheelFig. 200 Correct head
restraint position for
the driver
document_0900452a81b1b9de.book Seite 188 Donnerstag, 26. Juli 2007 9:16 09
--4 -
-T
-+ +-

Seat belts
196The physical principles involved in a frontal collision are relatively
simple:
Both the moving vehicle and the passengers possess energy, which
is known as “kinetic energy” ⇒ page 195, fig. 204. The amount of
“kinetic energy” depends on the speed of the vehicle and the weight
of the vehicle and passengers. The higher the speed and the greater
the weight, the more energy there is to be absorbed in an accident.
The most significant factor, however, is the speed of the vehicle. If
the speed doubles from 25 km/h to 50 km/h, for example, the kinetic
energy increases by a factor of four. Because these passengers are
not restrained by seat belts, the entire amount of kinetic energy has
to be absorbed at the point of impact ⇒fig. 205. This would result
in serious or potentially fatal injury.
Even at urban speeds of 30 km/h to 50 km/h, the forces acting on the
occupants in a collision can reach the equivalent of 1 ton (1000 kg)
or more. At greater speed these forces are even higher. A rule of
thumb: if the speed doubles, the forces increase by a factor of four.
Passengers who do not wear seat belts are not “attached” to the
vehicle. In a frontal collision they will continue to move forward at
the speed their car was travelling just before the impact.
What happens to passengers not wearing seat belts?
Passengers not wearing seat belts risk fatal injuries in the
event of an accident.In a frontal collision, unbelted passengers will be thrown forwards
and make violent contact with the steering wheel, dashboard, wind-
screen, etc ⇒ fig. 206. Passengers not wearing their belts risk being
thrown out of the car, resulting in potentially fatal injuries.
The common belief that occupants can brace their weight with their
hands in a minor collision is false. Even at low speeds the forces
acting on the body in a collision are so great that it is not possible
to hold yourself in the seat.
Fig. 205 The vehicle
crashes against the
wall
Fig. 206 A driver not
wearing a seat belt can
be thrown forwardsFig. 207 A rear
passenger not wearing
a seat belt can be
thrown forwards
document_0900452a81b1b9de.book Seite 196 Donnerstag, 26. Juli 2007 9:16 09
--4 -
-T
-+ +-
•

Airbag system203
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data
Front airbagsDescription of front airbags
The airbag system is not a substitute for the seat belts.The front airbag for the driver is located in the padded hub of the
steering wheel ⇒fig. 214. The front airbag for the front passenger
is in the dashboard above the glove box ⇒fig. 215. The locations of
the airbags are marked with the word “AIRBAG”.
In conjunction with the three-point seat belts, the front airbags give
additional head and chest protection for the driver and front
passenger in the event of a severe frontal collision ⇒ in “Impor-
tant safety notes on the front airbag system” on page 204.
How the front airbags work
When fully inflated, the airbags reduce the risk of head or
chest injury.The airbag system is designed so that the airbags for the driver and
front passenger are triggered in a severe frontal collision.
In certain types of accident the front airbags, side airbags and one
of the head-protection airbags may be triggered together.
When the system is triggered, the airbags fill with a propellant gas
and open out in front of the driver and front passenger ⇒fig. 216.
In order to provide the desired extra protection in an accident, the
airbags have to inflate extremely rapidly (within fractions of a
second). The fully deployed airbags cushion the forwards move-
ment of the front occupants and help to reduce the risk of injury to
the head and the upper part of the body.
Special openings in the airbag allow the gas to escape at a
controlled rate to restrain the fo rward movement of the occupant's
head and torso. Once the impact has been absorbed, the airbag
deflates sufficiently for the front occupants to see forward.
Fig. 214 Driver's
airbag in steering
wheelFig. 215 Front
passenger's airbag in
dashboard
Fig. 216 Front airbags
in inflated condition
document_0900452a81b1b9de.book Seite 203 Donnerstag, 26. Juli 2007 9:16 09
--4 -
-T
-+ +-
•
•

Airbag system
204Important safety notes on the front airbag system
There are a number of safety points concerning the airbag
system which you should remember. This will help to
reduce the risk of injury in an accident.
WARNING
•
It is important for th e driver and front passenger to maintain a
distance of at least 25 cm from the steering wheel or dashboard
⇒ fig. 217. The airbag system will not be able to give the required
protection if you sit too close to the steering wheel or dashboard.
There is also a risk of injury if the airbags are inflated. The front
seats and head restraints must always be positioned correctly for
the height of the occupant.
•
If you do not wear a seat belt, if you lean forward or to the side,
or are not seated correctly while th e vehicle is in motion, you are
at greater risk of injury. Should the airbag system be triggered in
an accident there is an even greater risk of injury.
•
Never let a child travel on the front seat without an appropriate
restraint system. If the airbag is tr iggered in an accident, the child
could sustain serious or fatal injuries ⇒page 210, “Child safety”.
•
Never install a rearward-facing child safety seat on the front
passenger's seat unless the fron t passenger's airbag has been deactivated. However, if you have
no alternative but to use a rear-
ward-facing child seat on the front passenger's seat, the front
passenger's airbag must be deac tivated beforehand by means of
the key-operated switch* ⇒page 208 . Failure to observe this
precaution could result in serious or potentially fatal injury.
•
Occupants sitting in the front of the car must never carry any
objects or pets in the space between them and the airbags, or
allow children or other passengers to travel in this position.
•
Do not cover or stick anything on the steering wheel hub or the
soft plastic surface of the airbag unit on the passenger's side of
the dashboard, and do not obstruct or modify them in any way.
These parts should only be cleaned with a dry cloth (or with a
cloth moistened with plain water). It is also important not to
attach any objects such as cup holders or telephone mountings to
the surfaces covering the airbag units.
•
Any work on the airbag system or removal and installation of
the airbag components for other repairs (such as repairs to the
steering wheel or removal of seats) must be performed by a qual-
ified workshop.Note
If necessary, you can deactivate the front passenger's airbag by
means of the key-operated switch* ⇒page 208 .
Fig. 217 Minimum
distance from steering
wheel
WARNING (continued)
document_0900452a81b1b9de.book Seite 204 Donnerstag, 26. Juli 2007 9:16 09
--4 -
-T
-+
f------&
-----------i
+-
[I]
•

Intelligent technology
222Intelligent technologyElectronic stabilisation program (ESP)DescriptionESP increases the car's stability. It reduces the tendency to skid and
improves the stability and roadhold ing of the vehicle. ESP detects
critical handling situations, such as understeer, oversteer and
wheelspin on the driven wheels. It stabilises the vehicle by braking
individual wheels or by reducing the engine torque. The warning
lamp
 in the instrument cluster starts flashing as soon as the ESP
intervenes.
The ESP incorporates the functions of the anti-lock brake system
(ABS), the traction control system (ASR), the electronic differential
lock (EDL) and the dynamic steering*.
Anti-lock brake system (ABS)
ABS prevents the wheels from locking up under braking until the
vehicle has reached a virtual standstill. You can continue to steer the
vehicle even when the brakes are on full. Keep your foot on the brake
pedal and do not pump the brakes. You will feel the brake pedal
pulsate while the anti-lock brake system is working.
Brake assist system
The brake assist system can speed up the braking process and
shorten the braking distance. It au tomatically boosts the braking
force if you press the brake pedal quickly in an emergency. On vehi-
cles with adaptive cruise control*, the brake assist system will build
up a small amount of pressure in the hydraulic brake system if it
senses that you are too close to the vehicle in front.
Traction control system (ASR)
In the event of wheelspin, the traction control system reduces the
engine torque to match the amount of grip available. This helps the
car to start moving, accelerate or climb a gradient. Electronic differential lock (EDL)
When the EDL detects wheelspin, it brakes the spinning wheel and
directs the power to the other driven wheel (or wheels on quattro*
versions). This function is active up to about 100 km/h.
To prevent the disc brake of the braked wheel from overheating, the
EDL cuts out automatically if subjected to excessive loads. The
vehicle can still be driven. The EDL will switch on again automati-
cally when the brake has cooled down.
Dynamic steering*
On vehicles with dynamic steering*, the ESP can also intervene in
the steering to stabilise the vehicle in critical situations.
WARNING
•
The grip provided by the ESP,
ABS, ASR, EDL and dynamic
steering* systems is still subject to the physical limits of adhesion.
Always bear this in mind, especia lly on wet or slippery roads. If
you notice the systems cutting in , you should reduce your speed
immediately to suit the road and traffic conditions. Do not let the
extra safety provided tempt you into taking any risks when driving
– this can cause accidents.
•
Please remember that the acciden t risk always increases if you
drive fast, especially in corners or on a slippery road, or if you
follow too close behind th e vehicle in front of you. Please bear in
mind that even ESP, ABS, brak e assist, EDL, ASR and dynamic
steering* cannot compensate for the increased accident risk.
•
When accelerating on a uniformly slippery surface (for instance
all four wheels on ice or snow), pr ess the accelerator gradually and
carefully. The driven wheels may ot herwise start to spin (in spite
of the integrated control systems), which would impair the car's
stability and could lead to an accident.
document_0900452a81b1b9de.book Seite 222 Donnerstag, 26. Juli 2007 9:16 09
--4 -
-T
-+ +-

Intelligent technology223
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data
Note
•
To ensure that the ASR works properly, all four wheels must be
fitted with identical tyres. Any differences in the rolling radius of the
tyres can cause the system to reduce engine power when this is not
desired.
•
Should a malfunction occur in the ABS or EDL, both the ABS
warning lamp
 and the ESP warning lamp
 ⇒ page 19 will light
up.
•
In the event of a malfunction in the ESP system, the warning
lamp  ⇒ page 17 will light up.
•
If a malfunction should occur in the ABS, the ESP, EDL and ASR
will also be out of action.
•
The systems can make noises when they intervene.
Switching on and off
The ESP is switched on automatically when the engine is
started.
Switching off the traction control system (ASR)
In particular circumstances, it may be advisable to switch off the
traction control system (ASR) to allow a certain amount of wheel
slip. For example:•
Rocking the car backwards and forwards to free it
•
Driving in deep snow or on loose surfaces
•
Driving with snow chains
Press the button briefly ⇒fig. 232 or ⇒fig. 233. The
warning lamp
 will light up and the message ASR off will appear
in the driver information system display.
The traction control system (ASR) can only be switched off at speeds
below 50 km/h on vehicles with front-wheel drive. At 70 km/h it will
switch on again automatically. The ASR can be deactivated at any
speed on vehicles with four-wheel drive.
Switching off the ESP
Press the button for longer than 3 seconds. The ESP
warning lamp  will light up and the message ESP switched off will
appear in the display. The ASR is also deactivated when the ESP is
switched off.
Switching on
Press the button again. The message ESP/ASR on will
appear briefly on the display.
Fig. 232 Version A:
Centre console
(bottom), ESP OFF
button
Fig. 233 Version B:
Centre console (top),
ESP OFF button
ESP OFFESP OFFESP OFF
document_0900452a81b1b9de.book Seite 223 Donnerstag, 26. Juli 2007 9:16 09
--4 -
-
(I]
T
•
-+
I I
+-
I I
I I

Intelligent technology
224
WARNING
You should switch off the ESP only if your driving ability and traffic
conditions allow you to do so safely. Please note that, when the
ASR and ESP are switched off, the driven wheels may start to spin,
causing the vehicle to lose grip, in particular on slippery or wet
roads - danger of skidding!
Note
The ASR and ESP cannot be switched off when the adaptive cruise
control (ACC)* is on.BrakesNew brake pads
New brake pads do not give full braking effect for the first 400 km,
they must first be “bedded in”. However, you can compensate for
the slightly reduced braking effect by applying more pressure on
the brake pedal. Avoid placing a heavy load on the brakes during the
running-in period.
We ar
The rate of wear on the brake pads depends a great deal on how you
drive and the conditions in which the vehicle is operated. Negative
factors are, for instance, city tra ffic, frequent short trips or hard
driving with abrupt starts and stops.
Wet roads; road salt
When you are driving at a speed higher than 80 km/h and have the
windscreen wipers switched on the brake pads are very briefly
brought into contact with the brak e discs. This automatic process
which goes unnoticed by the driver is carried out at regular intervals
and is intended to improve braking response in wet conditions. In certain conditions, such as in heavy rain, or after washing the car
or driving through water, the full braking effect can be delayed by
moisture (or in winter by ice) on the discs and brake pads. The
brakes should be “dried” by pressing the pedal to restore full
braking effect.
The effectiveness of the brakes can also be temporarily reduced if
the car is driven for some distance without using the brakes when
there is a lot of salt on the road in
winter. The layer of salt that accu-
mulates on the discs and pads can be removed with a few cautious
brake applications.
Corrosion
There may be a tendency for dirt to build up on the brake pads and
corrosion to form on the discs if the car is used infrequently, or if
you only drive low mileages without using the brakes very much.
If the brakes are not used frequently, or if corrosion has formed on
the discs, it is advisable to clean off the pads and discs by braking
firmly a few times from a moderately high speed ⇒.
Faults in the brake system
If the brake pedal travel should ever increase suddenly, this may
mean that one of the two brake circuits has failed. Drive immedi-
ately to the nearest qualified workshop and have the fault rectified.
On the way to the dealer, be prepared to use more pressure on the
brake pedal and allow for longer stopping distances.
Low brake fluid level
Malfunctions can occur in the brake system if the brake fluid level is
too low. The brake fluid level is monitored electronically.
Brake servo
The brake servo amplifies the pressure you apply to the brake pedal.
It only works when the engine is running.
document_0900452a81b1b9de.book Seite 224 Donnerstag, 26. Juli 2007 9:16 09
--4 -
-T
[I]
•
-+ +-

Intelligent technology225
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data
WARNING
•
When applying the brakes to clean off deposits on the pads and
discs, select a clear, dry road. Be sure not to inconvenience or
endanger other road users; do not risk an accident.
•
Never let the car coast with the engine switched off (this can
cause accidents).Caution
•
Never let the brakes “drag” by leaving your foot on the pedal
when you do not really intend to brake. This overheats the brakes,
resulting in longer stopping distances and greater wear.
•
Before driving down a long, steep gradient, it is advisable to
reduce speed and move the selector lever to a lower gear. In this
way you will make use of the engine braking effect and relieve the
load on the brakes. If you still have to use the brakes, it is better to
brake firmly at intervals than to apply the brakes continuously.Note
•
If the brake servo is out of action due to a malfunction, or if the
car has to be towed, you will have to press the brake pedal consid-
erably harder to make up for the lack of servo assistance.
•
If you wish to equip the car with accessories such as a front
spoiler or wheel covers, it is impo rtant that the flow of air to the
front wheels is not obstructed, otherwise the brakes can overheat.
Power steering (servotronic)The power steering assists th e driver when turning the
steering wheel (with the engine running).The power steering assists the driver by reducing the force needed
to turn the steering wheel. The degree of power assistance is
adapted electronically , depending on the speed. If a fault should occur in the
servotronic system the power steering
will still operate. The degree of power assistance will, however, no
longer adapt to different speeds. If the electronic regulating system
is not working properly, this is most noticeable when turning the
steering wheel at low speeds (for instance when parking) – more
effort will be required than usual. The fault should be corrected by
a qualified workshop as soon as possible.
The power steering does not function when the engine is switched
off. In this case the steering wheel is very hard to turn.
If the steering is held at its turning limit when the car is stationary,
this will place an excessive load on the power steering system. In
this case, the power steering system will make noises. It will also
reduce the idling speed of the engine.
Caution
Do not keep the steering in the full-lock position for longer than
15 seconds when the engine is running – this could cause damage
to the power steering system.
Note
•
If the power steering should fail at any time or the engine is
switched off (for instance when being towed), the car can still be
steered. However, more effort will be required to turn the steering
wheel.
•
If the system is leaking or malfunctioning, please take the car to
a qualified workshop as soon as possible.
•
The power steering requires a special hydraulic fluid. The fluid
reservoir is located at the front of the engine compartment on the
left ⇒page 256 . The correct fluid level in the reservoir is important
for the power steering to function properly. The hydraulic fluid level
is checked at the Inspection Service.
document_0900452a81b1b9de.book Seite 225 Donnerstag, 26. Juli 2007 9:16 09
--4 -
-T
CD
-+
CD
[I]
[I]
+-
•
•