brake AUDI A4 2008 B8 / 4.G Workshop Manual

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 agents 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 tips 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 rapidly 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 inflated 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 compartment 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 trailer233
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data additional mirrors fitted. Both exterior mirrors should be mounted
on hinged extension brackets. Adjust the mirrors to give sufficient
vision to the rear.
Headlights
Before starting a journey, check the headlight beam settings with
the trailer hitched up. If necessary, alter the height of the headlight
beams by means of the headlight range control ⇒page 60.
Power supply
When you remove the ignition key the power supply to the trailer is
interrupted.
Removable ball joint coupling
Vehicles with a factory-fitted towing bracket are equipped with a
removable ball joint coupling. It is carried under the floor panel on
the left-hand side of the luggage compartment and is secured by a
strap.
Note
We recommend having the car serviced between the normal inspec-
tion intervals if it used frequently for towing a trailer.Applies to vehicles: with towing bracketTrailer stabilisation system
Trailer stabilisation helps to reduce the risk of the vehicle
skidding when towing a trailer.The trailer stabilisation system is operational only when the ESP is
switched on and there is no malfunction in the ESP ⇒page 17.
When is the trailer stabilisation system activated?
Trailer stabilisation is active when the following requirements are
met:•
The ESP must NOT be switched off ⇒page 222,
•
The trailer connector must be properly secured in the vehicle
socket.
•
Vehicle speed must be higher than approx. 60 km/h.
How trailer stabilisation works:
In many cases, the driver can stabilise a swaying trailer by manually
braking the vehicle.
However, if the ESP detects that the trailer is swaying and this is
affecting the towing vehicle, it will automatically brake the vehicle
to stabilise the trailer by slowing it down. The warning lamp
 will
light up in the instrument cluster. If possible, do not turn the
steering wheel at this stage.
In order to warn traffic behind you, the brake lights will come on
during this automatic braking operation.
A trailer weighing less than 70% of the kerb weight of the towing
vehicle may sway quite considerably without the trailer stabilisation
system intervening. This can happen when the swaying movements
of the light-weight trailer are not or hardly passed on to the towing
vehicle and are therefore not detected by the ESP.
If the system for activating the trailer brake lights is defective, this
will be indicated in the instrument cluster display ⇒page 37, “Bulb
monitor ”.
Requirements for correct functioning of the trailer
stabilisation system
If these conditions are not met in full, the trailer stabilisation system
will only intervene to a limited extent or not at all ⇒.
•
The electrical connection between the towing vehicle and the
trailer must be functioning correctly, without any defects.
•
The load on the trailer must be properly secured.
•
The tyre pressures on both the vehicle and the trailer must be
adapted to the load that is being carried.
•
Where possible, operate the trailer with the maximum permitted
draw bar weight.
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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 braked correctly, to avoid the vehicle
and trailer “jack-knifing” and to prevent 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 when driving – this can cause acci-
dents.•
The ESP and trailer stabilisation 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 equipped 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 bicycle 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 the 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 abrasive 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 public 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 and 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 must 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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Care of vehicle and cleaning 246Plastic partsPlastic parts will come clean with regular washing. If this is not suffi-
cient, plastic parts should only be treated with a special solvent-free
plastic cleaning agent. Do not use paint cleaners, polishes or wax on
plastic parts.Paint damageMinor damage to the paint, such as scratches or stone chips, should
be touched up without delay before the metal starts to corrode. Suit-
able touch-up brushes or sprays for your car can be obtained from
an Audi dealer.
The number of the original paint finish on the vehicle is given on the
data sticker ⇒page 321.
If corrosion is already visible it must be thoroughly removed by a
qualified workshop.Windows
Clear vision is an essential safety factor.The windscreen must not be cleaned with insect remover or wax,
otherwise the windscreen wipers will not function properly
(juddering).
Traces of rubber, oil, grease or silicone can be removed with a
window cleaning solution or a silicone remover. Wax residue can
only be removed with a special cleaner. Your Audi dealer will be able
to provide you with more detailed information.
The windows should also be cleaned on the inside at regular inter-
vals.
Use a separate cloth or chamois to dry the windows. Cloths used for
waxing and polishing contain residues that will cause smears on the
glass.
WARNING
Do not use water-repellent coatings on the windscreen. In bad visi-
bility conditions such as light rain, low sun or when driving at
night these coatings can cause increased dazzle, which is a
serious safety hazard. Such coatings can also cause the wiper
blades to judder.
Caution
•
Remove snow and ice from windows and mirrors with a plastic
scraper only. To avoid scratches caused by dirt on the glass, the
scraper should only be pushed in one direction and not moved to
and fro.
•
The heating element for the rear window is located on the inner
side of the window. To avoid damaging the heating element, do not
put stickers on the inner side of the window.
•
Never use warm or hot water to remove snow and ice from
windows and mirrors. This could cause the glass to crack!
Rubber seals (weatherstrips)The weatherstrips will remain pliable and last longer if they are
occasionally treated with a suitable care product (for example sili-
cone spray). This will also prevent premature ageing and leaks. The
doors will be easier to open as well. If they are kept pliable, the door
seals will be less likely to freeze up in the winter.WheelsThe wheels require regular attention to preserve their appearance.
It is important to remove road salt and brake dust by washing the
wheels at regular intervals, otherwise the finish will be impaired.
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Care of vehicle and cleaning247
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data After washing, the wheels should only be cleaned with an "acid-
free" cleaning agent for alloy wheels. This is available from Audi
dealers and specialist retailers. Never leave the cleaning agent on
the rims for any longer than specified in the instructions before
rinsing it off. If the wheel cleaner fluid contains acid it can attack the
surfaces of the wheel bolts.
Car polish or other abrasive agents should not be used. If the
protective paint coating is damaged by stone chips etc., the
damaged area should be touched up immediately.
WARNING
Please note when cleaning the wheels that water, ice and road salt
can impair the effectiveness of the brakes – this can cause an
accident.Care of interiorSound system / MMI* display screen and MMI control console*The display screen can be cleaned with a soft cloth and a special
“LCD cleaner” (available from retailers of electrical goods). Moisten
the cloth with a small amount of the cleaning fluid.
Clean the MMI control console with a fine brush first to prevent any
dirt from getting in between the control buttons and the housing.
We then recommend wiping the MMI control console using a cloth
moistened with washing-up liquid and water.
Caution
To avoid scratching the screen, do not wipe the display with a dry
cloth.
•
To avoid any possibility of damage, do not let any liquid get
inside the control console.
Plastic parts and leatherettePlastic parts and leatherette can be cleaned with a damp cloth. If
this is not sufficient, plastic parts and leatherette should only be
treated with a special solvent-free plastic cleaner.Textile covers and trim partsTextile covers and trim parts (e.g. seats, door trim) should be
cleaned regularly with a vacuum cleaner. This will remove surface
dirt which could otherwise be rubbed into the textile material
during use. Do not use steam cleaners, as the steam could carry the
dirt deeper into the textile material.
Normal cleaning
We recommend that you use a soft sponge or lint-free, micro-fibre
cloth for normal cleaning. Only use brushes on floor coverings and
mats, as other textile surfaces could become damaged.
In the case of normal surface dirt you can use a foam cleaner. Use a
sponge to spread the foam on the textile surface and to work it into
the material lightly. However, make sure that the textile material
does not become soaking wet. Then dab off the foam with a dry and
absorbent cloth (e.g. a micro-fibre cloth) and vacuum off any
residue once the surface is completely dry.
Removal of stains
To treat stains caused by spilled drinks (coffee, fruit juice or similar)
make up a solution with a mild detergent for sensitive fabrics and
apply it with a sponge. If the stains are difficult to remove, a
washing paste can be applied directly onto the stain and worked
into the fabric. The surface will then have to be wiped with clear
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Checking and topping up fluids255
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data
Working on components in the engine compartment
Extra caution is necessary when working on components
in the engine compartment.Always be aware of the danger of injury and scalding as well as the
risk of accident or fire when working in the engine compartment
(e.g. when checking and refilling fluids). Always observe the warn-
ings listed below and follow all normal safety precautions. The
engine compartment of any motor vehicle is a potentially
hazardous area. ⇒.
WARNING
•
Switch off the engine.
•
Remove the ignition key.
•
Apply the parking brake.
•
Put the gear lever in neutral or selector in P.
•
Wait for the engine to cool down.
•
Keep children away from engine compartment.
•
Never spill fluids on hot engine components. These fluids can
cause a fire (e.g. radiator anti-freeze).
•
Take care not to cause short circuits in the electrical system,
especially when working on the battery.
•
Do not touch the radiator fan when the engine is hot. The fan
may start running suddenly.
•
Do not unscrew the cap on the expansion tank when the engine
is hot. The cooling system is under pressure.
•
Protect face, hands and arms by covering the cap with a large,
thick rag to protect against escaping coolant and steam.
•
If any tests have to be performed with the engine running,
there is an extra safety risk from the rotating parts, such as the
drive belts, alternator and radiator fan, etc., and from the high-
voltage ignition system.
•
Vehicles with automatic gearbox: Never open the throttle inad-
vertently (for instance by hand from the engine compartment) if a
gear is engaged while the vehicle is stationary with the engine
running. The vehicle could otherwise start moving immediately
and possibly cause an accident.
•
Observe the following additional warnings if work on the fuel
system or the electrical system is necessary:
−Always disconnect the battery.
−Do not smoke.
−Never work near naked flames.
−Always keep an approved fire extinguisher immediately
available.Caution
When topping up fluids make sure the correct fluid is put into the
correct filler opening. This can otherwise cause serious malfunc-
tions or engine damage.
For the sake of the environment
Inspect the ground underneath your vehicle regularly so that any
leaks are detected at an early stage. If you find oil spots or other
fluids, have your vehicle inspected by a qualified workshop.
Note
On right-hand drive vehicles* some of the containers / reservoirs
mentioned below are located on the other side of the engine
compartment.
WARNING (continued)
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Checking and topping up fluids 256Closing the bonnet– To close the bonnet, pull it down to overcome the spring
pressure.
– Then let it drop into the catches; do not press down ⇒.
WARNING
•
For safety reasons the bonnet must always be completely
closed when the vehicle is moving. After closing it always check
that it is properly secured. The bonnet must be flush with the adja-
cent body panels.
•
Should you notice that the bonnet is not safely secured when
the vehicle is moving, stop the vehicle immediately and close the
bonnet properly, otherwise it could cause an accident.
Engine compartment layoutEngine compartment layout
Main components for checking and refillingFig. 252 Typical locations of fluid containers, engine oil dipstick and engine oil
filler cap
Jump-start terminal (+) under a cover . . . . . . . . . . . . .
Brake fluid reservoir (
) . . . . . . . . . . . . . . . . . . . . . . . .
Engine oil filler cap (

) . . . . . . . . . . . . . . . . . . . . . . . .
Engine oil dipstick* (orange) . . . . . . . . . . . . . . . . . . . . .
Radiator expansion tank () . . . . . . . . . . . . . . . . . . . . .
Jump-start terminal (-) with hexagon head . . . . . . . . .
Windscreen washer container (
) . . . . . . . . . . . . . . . .
Hydraulic fluid reservoir for power steering . . . . . . . .
A1
265, 294
A2
262
A3
259
A4
258
A5
261
A6
265, 294
A7
267
A8
225
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Checking and topping up fluids 262
WARNING
•
The cooling system is under pressure. Do not unscrew the cap
on the expansion tank when the engine is hot: you could be
scalded by escaping steam
•
The coolant and coolant additive can be a health hazard. Store
the coolant additive in the original container in a safe place out of
reach of children – risk of poisoning.For the sake of the environment
Drained off coolant should not be used again. Drain off the used
coolant into a suitable container and dispose of it in the proper
manner (observe environmental regulations).Radiator fan
The radiator fan can start running spontaneously.The radiator fan is driven by the engine via a poly V-belt. The speed
of the fan is varied by a viscous clutch according to the temperature.
There is also an auxiliary electric fan, which cuts in automatically
whenever the temperature of the coolant and the engine compart-
ment rises above a certain level.
The auxiliary fan can continue to run for as long as 10 minutes after
stopping the engine – even after the ignition is switched off. It may
also start running suddenly ⇒ after a while if•
residual heat raises the coolant temperature, or
•
the hot engine compartment is additionally heated up by the
sun.
WARNING
When working in the engine compartment be aware that the radi-
ator fan may start running suddenly – risk of injury.
Brake fluidChecking brake fluid level
The brake fluid level can be checked at a glance.– Check the fluid level on the brake fluid reservoir
⇒fig. 258. It should always be between the “MIN” and
“MAX” marks.In right-hand drive vehicles the brake fluid reservoir is on the other
side of the engine compartment.
The fluid level may drop slightly after a period of time due to the
automatic compensation for brake pad wear. This is quite normal.
However, if the level goes down noticeably in a short time, or drops
below the “MIN” mark, there may be a leak in the brake system. If
the fluid level in the reservoir is too low, this will be indicated by the
brake warning lamp ⇒page 32. If this should happen, take the car
to a qualified workshop immediately and have the brake system
inspected.
Fig. 258 Engine
compartment: Mark-
ings on brake fluid
reservoir
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