2008 AUDI A5 brakes

Contents3
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data Airbag system
. . . . . . . . . . . . . . . . .
Description of airbag system . . . .
Front airbags . . . . . . . . . . . . . . . . . .
Side airbags . . . . . . . . . . . . . . . . . . .
Head-protection airbags
(sideguard) . . . . . . . . . . . . . . . . . . . .
Deactivating the front passenger's
airbag via the key-operated switch
Child safety
. . . . . . . . . . . . . . . . . . . .
Points to remember if children are
travelling in the car . . . . . . . . . . . . .
Child safety seats . . . . . . . . . . . . . .
Fitting child safety seats . . . . . . . .
Driving tips
. . . . . . . . . . . . . . . .
Intelligent technology
. . . . . . . . . .
Electronic stabilisation program
(ESP) . . . . . . . . . . . . . . . . . . . . . . . . . .
Brakes . . . . . . . . . . . . . . . . . . . . . . . .
Power steering (servotronic) . . . . .
Four-wheel drive (quattro®) . . . . . .
Power management . . . . . . . . . . . .
Your vehicle and the
environment
. . . . . . . . . . . . . . . . . . .
Running in . . . . . . . . . . . . . . . . . . . .
Emission control systems . . . . . . .
Driving abroad . . . . . . . . . . . . . . . . .
How to improve economy and
minimise pollution . . . . . . . . . . . . .
Environmental compatibility . . . . .
Towing a trailer
. . . . . . . . . . . . . . . .
Driving the vehicle with a trailer or
caravan . . . . . . . . . . . . . . . . . . . . . . .
Removable towing bracket . . . . . .
General maintenance
. .
Care of vehicle and cleaning
. . .
General notes . . . . . . . . . . . . . . . . . .
Care of exterior . . . . . . . . . . . . . . . . .
Care of interior . . . . . . . . . . . . . . . . .
Fuel and filling the tank
. . . . . . . .
Petrol . . . . . . . . . . . . . . . . . . . . . . . . .
Diesel . . . . . . . . . . . . . . . . . . . . . . . . .
Filling the tank . . . . . . . . . . . . . . . . .
Checking and topping up fluidsBonnet . . . . . . . . . . . . . . . . . . . . . . . .
Engine compartment layout . . . . .
Engine oil . . . . . . . . . . . . . . . . . . . . . .
Cooling system . . . . . . . . . . . . . . . . .
Brake fluid . . . . . . . . . . . . . . . . . . . . .
Battery . . . . . . . . . . . . . . . . . . . . . . . .
Windscreen washer . . . . . . . . . . . . . Wheels and tyres
. . . . . . . . . . . . . . .
Wheels . . . . . . . . . . . . . . . . . . . . . . . .
Accessories and modifications
to the vehicle
. . . . . . . . . . . . . . . . . . .
Accessories and replacement
parts . . . . . . . . . . . . . . . . . . . . . . . . . .
Modifications . . . . . . . . . . . . . . . . . .
Radio transmitters and business
equipment . . . . . . . . . . . . . . . . . . . . .
Self-help
. . . . . . . . . . . . . . . . . . . . .
Self-help
. . . . . . . . . . . . . . . . . . . . . . . .
Warning triangle . . . . . . . . . . . . . . . .
First-aid kit . . . . . . . . . . . . . . . . . . . . .
Fire extinguisher . . . . . . . . . . . . . . . .
To o l s a n d T y r e M o b i l i t y S y s t e m . . .
Compact temporary spare wheel*
Tyre repairs . . . . . . . . . . . . . . . . . . . .
Changing a wheel . . . . . . . . . . . . . .
Jump-starting . . . . . . . . . . . . . . . . . .
Tow-starting and towing away . . .
Fuses and bulbs
. . . . . . . . . . . . . . . .
Fuses . . . . . . . . . . . . . . . . . . . . . . . . . .
Bulbs . . . . . . . . . . . . . . . . . . . . . . . . . .
Changing bulbs for headlights . . .
Changing bulb for turn signals . . .
Changing bulb for side lights . . . . .
Changing bulb for front fog lights
Changing bulbs for rear lights in
side panel . . . . . . . . . . . . . . . . . . . . . .
Changing bulbs in boot lid . . . . . . .
Number plate light . . . . . . . . . . . . . . 176
176
178
180
181
183
185
185
186
189
195
196
196
199
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207208
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243250
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Instruments and warning/indicator lamps19
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data
Electro-mechanical parking brake

This warning lamp monitors the electro-mechanical
parking brake.The warning lamp
 lights up when the parking brake is applied
with the ignition on. After the ignition has been switched off the
lamp will stay on for about 30 seconds. The warning lamp will light
up for about 30 seconds if the parking brake is applied with the igni-
tion switched off.
The warning lamp should go out when the parking brake is released.
If the warning lamp flashes continuously after the parking brake has
been applied, the brake may not be strong enough to hold the
vehicle on a slope. This may be due to the brakes overheating.
Please note the following points:
•
If the gradient is too steep to park the vehicle safely, the display
will show the message Caution: Vehicle parked too steep.
•
In the event of a fault in the parking brake system the symbol

will also appear in the instrument cluster display together with the
message Parki ng b rake! You should have the fault corrected by a
qualified workshop without delay.
Brake system

The warning lamp flashes if the brake fluid level is too low
or if there is a fault in the ABS system or the parking
brake.If the warning lamp
 flashes, there is a fault in the brake system.
The symbol
 in the instrument cluster display will flash at the
same time. You can press the button to obtain a message
explaining the fault ⇒page 31.
If a failure should occur in the ABS, the ABS warning lamp
 will
light up together with the brake warning lamp
 ⇒.
WARNING
•
Before opening the bonnet and checking the brake fluid level,
observe the warning information on ⇒page 231, “Working on
components in the engine compartment”.
•
If the brake warning lamp does not go out, or if it lights up
when driving, the brake fluid level in the reservoir is too low – this
may cause an increased accident risk. Stop the vehicle and do not
drive on. You should obtain professional assistance.
•
If the brake warning lamp lights up together with the ABS
warning lamp, this can mean that the control function of the ABS
is out of action. As a result the rear wheels can lock relatively
easily when braking. This could cause the tail of the vehicle to skid
sideways. Drive carefully to the nearest qualified workshop and
have the fault rectified.
Fuel gaugeThe gauge only works when the ignition is switched on.
When the needle reaches the reserve zone, the symbol
 lights up
in the instrument cluster display ⇒page 36 together with the
message Please refuel. At this point there are still about 8 litres of
fuel left in the tank. This is your reminder to fill up soon.
The tank capacity of your vehicle is given in the Technical data
section ⇒page 293.
Caution
Never run the tank completely dry. If there is an irregular fuel supply,
misfiring can occur. This allows unburnt fuel to enter the exhaust
system, which could cause overheating and damage the catalytic
converter.
SET
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Seats and storage 82
WARNING
The rear backrest must always be securely latched so that objects
stored in the luggage compartment will not fly forward during
sudden braking.
Caution
When returning the backrest to an upright position, make sure that
the seat belts for the rear seats are in their guides so that they
cannot be caught up and damaged in the catches for the backrest.Applies to vehicles: with folding backrestsLocking the backrest–Turn the key ⇒fig. 91 to the right to lock the backrest.
– Turn the key to the left to unlock the backrest.When the backrest is properly engaged in its upright position, the
release handle can be locked and unlocked with the key. This
prevents unauthorised access to the luggage compartment from
inside the vehicle.
Caution
When returning the backrest to an upright position, make sure that
the seat belts for the rear seats are in their guides so that they
cannot be caught up and damaged in the catches for the backrest.Storage shelf
The storage shelf behind the rear backrest should only be
used to store light articles of clothing.
WARNING
Do not store any heavy or hard objects on the storage shelf. They
could cause injury if the brakes are applied suddenly.
Caution
Please note that hard objects could chafe against the wires of the
heating element in the rear window and cause damage.
Note
Make sure that the slots between the rear window and the storage
shelf are kept clear to ensure unimpaired ventilation.
Fig. 91 Locking the
backrest
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Driving123
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data braking force of the parking brake is only released when there is
enough power at the wheels to make the vehicle move in the desired
direction.
Note
For safety reasons the parking brake will only release automatically
if the driver's seat belt is engaged in its buckle.Driving away when towing a trailer
Please note the following points to prevent the vehicle
from rolling back unintentionally on a gradient.– Pull and hold the parking brake switch and press the
accelerator. The parking brake will remain engaged and
prevent any tendency to roll back down the slope.
– You can release the parking brake switch as soon as the
engine is delivering enough power to the wheels.Depending on the weight of the vehicle and trailer and the steep-
ness of the slope, there may be a tendency to roll back downhill
when driving away from a standstill. You can prevent this by pulling
out the parking brake switch as you press the accelerator (in the
same way as with a conventional handbrake).Emergency braking function
This feature enables you to stop the vehicle if the main
brake system should fail or if the pedal is obstructed.– Pull out and hold the parking brake switch to stop the
vehicle with the parking brake in an emergency.
– The brakes will be released immediately if you release the
switch or press down the accelerator.
If you pull out and hold the parking brake switch at a road speed
above about 8 km/h, this will initiate an emergency brake applica-
tion. The brakes are then applied hydraulically at all four wheels.
The effect is the same as an emergency stop (full brake application)
⇒
To prevent the emergency braking function from being used acci-
dentally, a warning buzzer sounds when the switch is operated. The
brakes are released immediately when you release the switch or
press down the accelerator.
WARNING
You should only use the emergency braking function in a real
emergency, for example if the brake system should fail or if the
brake pedal is obstructed. If you use the emergency braking func-
tion by activating the parking brake switch, the effect is similar to
a full brake application (emergency stop). Please remember that
the ESP (with its combined ABS, EDL and traction control func-
tions) is still subject to certain physical limits. In a corner or in bad
road or weather conditions an emergency stop can cause the
vehicle to skid or lose steering control.Driver messages in the instrument cluster displayCaution: Vehicle parked too steep
This message can appear when you apply the parking brake if the
car is parked on a gradient steeper than about 30%.
In this case the parking brake may not be strong enough to prevent
the vehicle from rolling back accidentally.
Please release parking brake
However, please remember that, for safety reasons, the parking
brake will only release automatically if the driver's seat belt is
buckled.
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Driving 126The cruise control system allows you to drive at a constant speed of
30 km/h or higher.
A constant speed is maintained by adjusting the engine power or
braking the vehicle accordingly (while in cruise mode).
The cruise control system is set using the control lever ⇒page 125,
fig. 138. The indicator lamp lights up while the system is operating
⇒fig. 139.
The cruise control system is automatically deactivated immediately
when you press the brake pedal.
On vehicles with a manual gearbox, the cruise control system will be
deactivated if the clutch is pressed for a long time.
WARNING
•
Always direct your full attention to the road, even when you are
using the cruise control system. It is always you who is respon-
sible for determining your speed and for keeping a safe distance
to the other vehicles on the road.
•
For safety reasons, the cruise control system must not be used
in city traffic, stop-go traffic, roads with a lot of bends or in diffi-
cult driving conditions (such as ice, fog, loose grit or gravel, heavy
rain, aquaplaning) - this could cause an accident!
•
When you take a turn-off, drive along a motorway exit lane or
pass through roadwork sections, please temporarily switch off the
cruise control system.
•
Please make sure you do not unintentionally rest your foot on
the accelerator - this will override the cruise control system which,
as a result, will not brake the vehicle.Caution
On vehicles with a manual gearbox: do not move the gear lever into
neutral without depressing the clutch when the cruise control
system is active. Otherwise the engine could rev up and be
damaged.
Note
•
On vehicles with a manual gearbox, the set speed cannot be
reached if the currently selected gear is too high or too low. Change
down to a lower gear when the engine no longer runs “smoothly” or
change up a gear to avoid overrevving the engine.
•
The brake lights come on when the system brakes the vehicle.
Cruise mode
Fig. 139 Indicator
lamp for the cruise
control system - lights
up when the system is
operating.
WARNING (continued)
Fig. 140 Symbol and
speed display while in
cruise mode (perma-
nent display)
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Intelligent technology 196Intelligent technologyElectronic stabilisation program (ESP)General notes
The electronic stabilisation program increases the car's
stability on the road.The ESP is designed to enhance the control over the vehicle in crit-
ical handling situations, such as when accelerating and cornering.
It reduces the tendency to skid under all road conditions and
improves the stability and roadholding of the vehicle. The system
works at all speeds.The anti-lock brake system (ABS), the electronic differential lock
(EDL) and the traction control system (ASR) are all integrated into
the electronic stabilisation program.
How the system works
The ESP control unit processes data from the three integrated
systems. It also processes additional inputs provided by other high-
precision sensors. These register the vehicle's rotation about the
vertical axis (yaw rate), lateral acceleration, brake pressure and
steering wheel angle.
The system uses the steering wheel angle and road speed to calcu-
late the changes of direction intended by the driver, and constantly
compares them with the actual behaviour of the vehicle. If the
desired course is not being maintained (for instance, if the car is
starting to skid), then the ESP compensates automatically by
braking the appropriate wheel.
The forces acting on the braked wheel effectively bring the car back
to a stable condition. If the car is oversteering (rear wheels losing
grip first) the brake application is concentrated on the outside front
wheel; if the car is understeering (front wheels losing grip first), ESP
brakes the inside rear wheel. This automatic brake application is
accompanied by characteristic noises.
The ESP works in conjunction with the ABS ⇒page 197. If a
malfunction should occur in the ABS, the ESP will also be out of
action.
Switching on
The ESP is switched on automatically when the engine is started
and performs a self-test routine. As soon as this routine is complete,
the system switches back to normal operating mode. You can press
the button ⇒fig. 203 or ⇒fig. 204 to switch on the ESP or traction
control system (ASR) if they have been switched off. The message
ESP/ASR on will appear briefly in the display.
Fig. 203 Without MMI:
Centre console with
ESP switchFig. 204 Centre
console with ESP
switch
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Intelligent technology199
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. Also refer to ⇒page 245, “Replacing wheels and tyres”.Electronic differential lock (EDL)
The electronic differential lock monitors the speed of the
driven wheels.General notes
The electronic differential lock (EDL) helps the car to start moving,
accelerate and climb a gradient in slippery conditions where this
may otherwise be difficult or even impossible.
How the system works
The EDL acts automatically. With the aid of the ABS sensors
⇒page 197, the system monitors the rotational speed of the driven
wheels on each axle. Whenever it detects a significant difference in
the speed of the driven wheels of one axle (for example, if the road is
slippery on one side) the system applies the brake to slow down the
spinning wheel so that more of the power is directed to the other
wheel of this axle (or to the three other wheels on vehicles with four-
wheel drive). This function is active up to about 100 km/h. The brake
system will make noises while it is working.
Driving away from a standstill
Sometimes one wheel has less grip and starts spinning, for
example, if one of the driven wheels is on ice. In this case, keep
pressing the accelerator gradually until the car starts moving, even
though the wheel with less grip will still spin.
Overheating of the brakes
To prevent the disc brake of the braked wheel from overheating, the
EDL cuts out automatically if subjected to excessive loads. The car remains operational and will behave in the same way as a car
without EDL.
The EDL will switch on again automatically when the brake has
cooled down.
WARNING
•
When accelerating on a uniformly slippery surface (for instance
all four wheels on ice or snow), press the accelerator gradually and
carefully. The driven wheels may otherwise start to spin (in spite
of the EDL), which would impair the car's stability and could lead
to an accident.
•
Even with EDL, you should always adjust your speed to suit the
conditions. Do not let the extra safety provided tempt you into
taking any risks when driving – this can cause accidents.Note
If the ABS warning lamp lights up, this can also mean there is a fault
in the EDL. Please contact a qualified workshop as soon as
possible.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
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Intelligent technology 200factors are, for instance, city traffic, 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 brake 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.
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 important that the flow of air to the
front wheels is not obstructed, otherwise the brakes can overheat.
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