2008 AUDI S4 brakes

adaptive cruise control (ACC)143
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data
which can shorten the system response time. The warning will be
deactivated if you press the accelerator pedal right down in order to
overtake.
The system draws the driver's attention to two different hazardous
situations:
Distance !
A distance warning will be given if you travel too close to the vehicle
in front for longer than 5 seconds. For example, if the distance is
less than 9 m at 80 km/h, a message
will appear in the instrument
cluster display ⇒page 142, fig. 156.
If the vehicle in front were to brake hard, a collision would no longer
be avoidable, even if you reacted immediately. In this case, you
should leave more room between yo ur car and the vehicle in front.
Speed
If the vehicle in front of you is travelling in the same lane at a much
slower speed or if it brakes hard, the Audi braking guard will calcu-
late the time at which a collision can be avoided only by emergency
braking or evasive action. When the system warns you, it is possible
to avoid a potential collision with the vehicle in front by braking or
changing lane. There are two warning levels:
•
Early warning: A message will appear in the instrument cluster
display and you will also hear a warning tone.
•
Acute warning: The second (acute) warning will be triggered if
you do not react to the advance warning. There will automatically be
a short dab of the brakes to remind you to concentrate on the traffic.
If you brake hard, the brake assist system ⇒page 222 helps you to
achieve the optimum braking effect.
WARNING
Please always direct your full attention to the road, even when the
Audi braking guard is activated. It is always you who is responsible for determining your speed and for
keeping a safe distance to the
other vehicles on the road.
•
Always maintain the statutory mi nimum safety distance to the
vehicle in front (risk of accident).
•
Due to the system limi tations, the Audi braking guard will not
react in certain situations, fo r example when approaching a
stationary obstacle (such as the end of a traffic jam or a broken-
down vehicle).
•
Please note that the Audi braking guard is subject to limita-
tions in tight bends on account of the radar sensor's field of vision.
This means that obstacles may not be detected in certain situa-
tions.
•
The radar sensor's "field of vision" can be impaired by rain,
snow or a lot of water on the road. This results in vehicles not
being reliably recognised or, in some circumstances, not being
detected at all. Always keep the ro ad ahead within your field of
vision.
•
Reflecting objects, such as crash barriers or the entrance to a
tunnel, could impair the function of the radar sensor.
Applies to vehicles: with adaptive cruise controlStatus messages in the instrument cluster displaybraking guard brake jolt
This driver message appears when the brakes are dabbed due to an
acute warning.
braking guard off
This driver message appears when the system is switched off in the
MMI. The message also appears briefly after you begin driving if the
system is switched off.
WARNING (continued)
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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.
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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.
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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.
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Your vehicle and the environment229
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data
Your vehicle and the environmentRunning inA new vehicle should be run in over a distance of 1,500 km. For the
first 1,000 km the engine speed should not exceed 2/3 of the
maximum permissible engine speed – do not use full throttle and do
not tow a trailer or caravan. From 1,000 to 1,500 km you can gradu-
ally increase the engine rpm and road speed.
During its first few hours of running, the internal friction in the
engine is greater than later on when all the moving parts have
bedded down.
How the vehicle is driven for the first 1,500 km also influences the
engine quality. After the first 1,500 km you should continue driving
at moderate engine speeds, in particular when the engine is cold.
This helps to reduce wear and tear on the engine and increases the
potential mileage which can be covered by the engine.
You should also avoid driving with the engine speed too low.
Change down to a lower gear when the engine no longer runs
“smoothly”. Excessively high engine speeds are prevented by an
automatic rev limiter.Emission control systemsCatalytic converter
Applies to vehicles with petrol engine: The vehicle must only be
used with unleaded petrol, otherwise the catalytic converter will be
destroyed.
Never run the tank completely dry. The irregular fuel supply can
cause misfiring, which would allow unburnt fuel to enter the
exhaust system, which could cause overheating and damage the
catalytic converter. Diesel particulate filter
Applies to vehicles
with diesel engine: The diesel particulate filter
can filter out almost all soot particles contained in the exhaust gas.
In normal driving conditions the filter is self-cleaning. Should the
self-cleaning function of the filter not be able to operate, e.g. when
the vehicle is continuously used only for short trips, the filter
becomes obstructed with soot and the symbol

for the diesel
particulate filter lights up ⇒page 38 .
WARNING
•
Because of the high temperatures which can occur in the emis-
sion control system (catalytic converter or diesel particulate
filter), do not park the vehicle where the exhaust can come into
contact with flammable materials under the car (e.g. on grass or
at the forest edge). - Fire hazard!
•
Do not apply any underseal agen ts in the area around the
exhaust system - fire hazard!
How to improve economy and minimise pollutionFuel economy, environmental impact and wear on the engine,
brakes and tyres depend largely on the way you drive the vehicle. By
adopting an economical driving style and anticipating the traffic
situation ahead, you can reduce fuel consumption by 10-15%. The
following section gives you some ti ps on lessening the impact on
the environment and reducing your operating costs at the same
time.
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Your vehicle and the environment
230Anticipate well in advance
A car uses most fuel when accelerating. If you anticipate hazards
and speed changes well in advance, you will need to brake less and
thus accelerate less. Wherever possible, let the car slow down grad-
ually with a gear engaged , for instance when you can see that the
next traffic lights are red. This takes advantage of the engine
braking effect, reducing wear on the brakes and tyres. Emissions
and fuel consumption will drop to zero due to the overrun fuel cut-
off.
Change gear early to save fuel
An effective way of saving fuel is to change up quickly through the
gears. Running the engine at high rpm in the lower gears uses an
unnecessary amount of fuel.
Manual gearbox: Shift up to second gear as soon as possible. If
possible, we recommend shifting up to the next gear at approx.
2,000 rpm.
Automatic gearbox: Press the accelerator slowly and avoid using
the “kick-down” feature.
Avoid driving at high speed
Avoid travelling at top speed. Fuel consumption, exhaust emissions
and noise levels all increase very ra pidly at higher speeds. Driving at
moderate speeds will help to save fuel.
Do not let the engine idle for longer than necessary
It is worthwhile switching off the engine when waiting in a traffic
jam, at level crossings or at traffic lights with a long red phase. The
fuel saved after only 30 - 40 seconds is greater than the amount of
fuel needed to restart the engine.
The engine takes a very long time to warm up when it is running at
idling speed. Mechanical wear and pollutant emissions are also
especially high during this initial warm-up phase. It is therefore best
to drive off immediately after starting the engine. Avoid running the
engine at high speed. Regular servicing
Regular servicing can establish a basis for good fuel economy
before you start driving. A well-serviced engine gives you the
benefit of
improved fuel efficiency as well as maximum reliability
and an enhanced resale value. A badly tuned engine can consume
up to ten percent more fuel than necessary.
Avoid short trips
The engine and emission control system need to reach their proper
working temperature in order to minimise fuel consumption and
emissions.
A cold engine uses disproportionately more fuel. The engine only
reaches its working temperature after about four kilometres, when
fuel consumption will return to a normal level. This is the reason
why we recommend avoiding short trips wherever possible.
Maintain the correct tyre pressures
Always make sure the tyres are in flated to the correct pressures
⇒ page 268 to save fuel. If the tyre pressures are just 0.5 bar too low,
this can increase the fuel consumption by as much as 5 %. Due to
the greater rolling resistance, under-inflation also increases tyre
wear and impairs handling.
Do not use winter tyres all through the year; they will increase fuel
consumption by up to 10 %.
Avoid carrying unnecessary loads
Every kilo of extra weight will increase the fuel consumption, so it is
worth checking the luggage comp artment occasionally to make
sure that no unnecessary loads are being transported.
A roof carrier is often left in place for the sake of convenience, even
when it is no longer needed. At a speed of 100-120 km/h your car will
use about 12 % more fuel as a result of the extra wind resistance
caused by the roof carrier - even when it is empty.
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Towing a trailer
234•
The trailer overrun brake must be set correctly. This is important
to ensure that the trailer can be br aked correctly, to avoid the vehicle
and trailer “jack-knifing” and to pr event excess braking of the trailer.
•
At low outside temperatures, both the towing vehicle and the
trailer should be fitted with winter tyres.
WARNING
It is essential that you adjust your speed to suit the weather, road
and traffic conditions. Do not let the trailer stabilisation system
tempt you into taking any risks wh en driving – this can cause acci-
dents.•
The ESP and trailer stabilisatio n system cannot defy the laws
of physics. This should be kept in mind, particularly on slippery
and wet roads and when towing a trailer with a light load.
•
The trailer stabilisation system is functional, regardless of
whether the trailer has a mechanical overrun brake or not.
•
The trailer stabilisation system is not always able to detect
swaying of trailers with a light load and will therefore not inter-
vene.
•
A trailer can still “jack-knife” on slippery roads with little grip,
even if the towing vehicle is eq uipped with the trailer stabilisation
system.
•
Trailers with a high centre of gravity may even tip over before
they start to sway sideways.
•
If you are not towing a trailer, but the trailer socket is being
used (e.g. for an illuminated bicycl e rack), the trailer stabilisation
system may be activated in extreme driving conditions.
•
Please note the additional information and warnings
⇒ page 234 .
Notes on towing
Driving with a trailer always requires extra care.Weight distribution
Try to avoid towing a loaded trailer with an unladen vehicle. If this
cannot be avoided, drive extra slowly to allow for the unbalanced
weight distribution.
Speed
The stability of the car and trailer is reduced with increasing speed.
For this reason it is advisable not to drive at the maximum permis-
sible top speed in unfavourable road, weather or wind conditions.
This applies especially on a downhill gradient.
You should always reduce speed immediately if the trailer shows
the slightest sign of swaying. Never try to stop the swaying by accel-
erating further.
Always brake in good time. If the trailer has an overrun brake, apply
the brakes gently at first and then firmly. This will prevent the jerking
that can be caused by the trailer wheels locking. Change down in
good time before going down a steep hill so that you can use the
engine braking effect to slow down the vehicle.
Swaying and pitching can be reduced by stabiliser aids. We recom-
mend having stabiliser aids installed when towing trailers with a
high trailer weight. They can be purchased and installed at an Audi
dealer.
Overheating
When climbing long hills in hot weather with the engine running
fast in low gear, you should keep an eye on the coolant temperature
gauge ⇒page 11 . Reduce speed immediately if the needle moves to
the top end of the scale. If the temperature warning lamp
 in the
instrument cluster should start flashing, stop the car and let the
engine cool down by running it at idling speed for a few minutes.
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Care of vehicle and cleaning245
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data
WARNING
•
Do not wash the vehicle with the ignition switched on – risk of
accident.
•
Do not clean the underside of th e car or inside the wheel arches
without protecting your hands and arms. You may cut yourself on
sharp metal parts.
•
Take care when washing the car during the winter: moisture
and ice on the brakes may affect braking efficiency – this could
cause an accident.Caution
•
Do not wash the vehicle in direct sunlight – otherwise the paint
can be damaged.
•
Do not use insect sponges or ab rasive household sponges, etc.
– they can damage the surfaces.
•
The headlights should only be washed with water – do not wipe
them with a dry cloth or sponge . It is best to use soapy water.
•
Never wash tyres with a jet that sprays the water out in a direct
stream. This could damage the tyres – even if the spray is kept at a
distance and only used for a very short time.For the sake of the environment
The car should only be washed in special wash bays. This prevents
oily water from getting into the pu blic drains. In some districts,
washing vehicles anywhere else may be prohibited.Waxing and polishingWaxing
Waxing protects the paintwork. It is time to apply a good coat of wax
when water no longer forms droplets and rolls off the clean paint-
work. Even if a
wax solution is used regularly in the car wash, it is advis-
able to protect the paint with a coat of wax at least twice a year.
In the summer, you will find it is much easier to remove dead insects
(which accumulate on the bumper an d the front of the bonnet) if the
car has been waxed recently.
Polishing
Polishing is only necessary if the paint has lost its shine, and the
gloss cannot be brought back by putting on wax.
The car must be waxed after polishing if the polish used does not
contain wax compounds to seal the paint.
Caution
Matt painted and plastic parts mu st not be treated with wax or
polish.Ornamental trim and mouldingsThe metal brightwork on the body is made of aluminium rather than
chrome (for environmental reasons).
Dirt or marks on the trim mouldings should be removed with an
acid-free cleaning agent (do not use a chrome cleaner). Body polish
is also unsuitable for use on trim mouldings. The intensive cleaning
fluids often used before the car goes into a car wash may contain
alkaline substances, which can cause dull or milky patches when
they dry out.
Audi dealers carry stocks of cleaning products which have been
tested for use on your vehicle and are not harmful to the
environment.
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