ESP AUDI A5 2008 8T / 1.G Service Manual

Airbag system177
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data
•
The airbag system can only be activated once; if the airbag has
been triggered, the system must be replaced. Should the airbag
system or airbag modules have to be replaced, the qualified work-
shop carrying out the replacement will document all details in the
appropriate section of the Service Schedule.
•
If you sell the vehicle, please remember to pass on the
complete Service Wallet to the new owner. If any of the airbags
have been deactivated, it is important that the new owner is also
given the relevant documents.
•
The relevant safety requirements must be observed when the
vehicle or components of the airbag or belt tensioner systems are
scrapped.
•
In an accident in which one or more airbags are triggered the
alternator and the starter are - for safety reasons - both discon-
nected from the battery via a pyrotechnic circuit breaker.
−Any repairs to the pyrotechnic circuit breaker must always
be performed by a qualified workshop (accident risk).
−The relevant safety requirements must be observed when
the vehicle or the circuit breaker are scrapped.
When are the airbags triggered?
The airbag system is triggered in collisions with a severe
impact.The airbag system is designed so that the airbags for the driver and
front passenger are triggered in a severe frontal collision.
In severe side collisions the side airbags on the impact side of the
vehicle are triggered together with the head-protection airbag.
The front airbags, side airbags and one of the head-protection
airbags may be triggered together in certain types of accident.The airbag system is not triggered in minor frontal or side collisions,
or in rear collisions or if the car overturns. In these situations the
occupants are protected by wearing the seat belts.
Factors determining the triggering response
It is not possible to define the exact triggering response of the
airbag system in all possible situations, since the circumstances in
different types of accident will vary considerably. Important factors
include, for example, the nature (hard or soft) of the object which
the car hits, the angle of impact, vehicle speed and so on.
Whether the airbags are triggered depends primarily on the vehicle
deceleration rate resulting from the collision. By processing the
signals from the sensors located in the vehicle, the electronic
control unit is immediately able to evaluate the severity of the colli-
sion and activate the restraint systems accordingly. If the decelera-
tion rate is below the predefined reference value in the control unit
the airbags will not be triggered, even though the accident may
cause extensive damage to the car.
Note
The airbag releases a fine dust when it inflates. This is quite normal
and does not mean there is a fire in the vehicle.
WARNING (continued)
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Airbag system 184
– The front passenger's airbag can be reactivated by
turning the key to position .Deactivating front passenger's airbag when a child
safety seat is in use
If you have no alternative but to install a rearward-facing child safety
seat on the front passenger's seat you must deactivate the front
passenger's airbag beforehand.
We recommend, however, that child seats should be only fitted on
the rear seat so that the front passenger's airbag can remain func-
tional and provide protection in an accident ⇒page 185.
Monitoring of airbag system
The airbag warning lamp will light up for a few seconds every time
the ignition is switched on.
If the front passenger's airbag has been deactivated via the key-
operated switch, the indicator lamp “PASSENGER AIRBAG OFF” will
light up constantly as a reminder ⇒fig. 196. Please refer also to the
description of the
 warning lamp in the instrument cluster
⇒page 16.
When the front passenger's airbag is deactivated using the key-
operated switch, the seat belt warning lamp for the front passenger
 ⇒page 17 is also switched off.
WARNING
•
If you have no alternative but to install a rearward-facing child
seat on the front passenger's seat, the front passenger's airbag
must be deactivated beforehand. Potentially fatal injuries to the
child can result if the front passenger's airbag is not deactvated!
⇒page 186, “Using a child safety seat on the front passenger's
seat”
•
If you have deactivated the front passenger's airbag, reactivate
it as soon as the child seat is no longer needed so that the airbag
can continue to give the required protection.
•
It is the driver's responsibility to ensure that the key-operated
switch is set to the correct position.Note
All the other airbags in the car will remain functional if the front
passenger's airbag has been deactivated with the key-operated
switch.
AON
WARNING (continued)
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Child safety185
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data
Child safetyPoints to remember if children are
travelling in the carIntroduction
Statistics show that children are generally safer on the
rear seat than on the front passenger's seat.Children under 12 years of age should normally travel on the rear
seat
4). Children travelling on the rear seat must use a child restraint
system or the seat belts provided, depending on their age, height
and weight. For safety reasons, the child restraint system should be
installed behind the front passenger's seat.
The physical principles involved and the forces acting in a collision
apply to children just as much as adults ⇒page 171, “Forces acting
in a collision”. But, unlike adults, children do not have fully devel-
oped muscle and bone structures. This means that children are
subject to a greater risk of injury.
To reduce this risk, children must always use special child restraint
systems when travelling in the car.
Use only child restraint systems which are officially approved under
the European standard ECE R 44 and are suitable for the child. ECE R
refers to the Economic Commission of Europe Recommendation,
which categorises child restraint systems in 5 groups ⇒page 186,
“Child seat categories”. Child restraints that have been tested and
approved under the ECE R 44 standard bear the ECE-R 44 test mark
on the seat (the letter E in a circle with the test number below it).
We recommend using child restraint systems from the range of
Audi Genuine Accessories available from Audi dealers. The
“Huckepack” range includes suitable restraint systems for all ages. These systems have been specially developed and tested for use in
Audi vehicles and comply with the ECE-R 44 standard.
Follow the manufacturer's instructions and observe any statutory
requirements when installing and using child restraints ⇒ in
“Important safety notes for using child safety seats”.
Important safety notes for using child safety seats
Correct use of child safety seats can help to reduce the
risk of injury in an accident.
WARNING
•
All vehicle occupants, especially children, must wear a seat
belt while the vehicle is in motion.
•
Children who are less than 1.5 metres tall must not wear a
normal seat belt without a child restraint, as this could cause inju-
ries to the abdominal and neck areas.
•
Babies and children must never travel on another occupant's
lap.
•
A suitable child safety seat can protect your child ⇒page 186,
“Child safety seats”.
•
Never allow two children to occupy one child safety seat.
•
Never leave a child without supervision in a child safety seat.
•
Never allow a child to travel in the car without a suitable child
restraint.
•
Never allow a child to stand up or kneel on a seat while the car
is moving. In an accident, the child could be catapulted through
the car, causing possibly fatal injuries to itself and other occu-
pants.
4)Observe any restrictions or regulations to the contrary.
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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 technology197
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data Switching off
The ESP should normally be left switched on at all times. If required,
you can press the ESP OFF button to switch off the traction control
system (ASR) or the electronic stabilisation program (ESP).
•
Switching off the traction control system (ASR): Press the ESP
button briefly. The traction control system (ASR) can be switched off
in special driving conditions, e.g. if you are driving with snow chains
⇒page 198. The message ASR off will appear in the display.
•
Switching off the ESP/traction control system (ASR): Press the
ESP button for longer than 3 seconds. The ESP/ASR warning lamp
lights up when the system is switched off, see ⇒page 16. The
message ESP switched off will appear in the display.
WARNING
•
The ESP is not able to overcome the physical limits of adhesion.
Even with ESP, you should always adjust your speed to suit the
conditions. Please bear this in mind, especially on wet or slippery
road surfaces. Do not let the extra safety provided tempt you into
taking any risks when driving – this can cause accidents.
•
Please note that, when the ESP or ESP/traction control system
(ASR) is 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!
Anti-lock brake system (ABS)
ABS prevents the wheels from locking up under braking.The anti-lock brake system (ABS) is an important part of the car's
active safety system. However, the ABS will not necessarily guar-
antee shorter stopping distances in all conditions. For instance, on
loose gravel or fresh snow on top of an icy surface (conditions which
anyway require extreme care and reduced speed), the stopping
distance with ABS may even be slightly longer.How the ABS works
The system runs an automatic self-check when the car reaches a
road speed of about 6 km/h. This may be accompanied by a noise
from the ABS pump.
If one of the wheels is turning too slowly in relation to the road
speed, and is close to locking up, the system will reduce the pres-
sure in the brake line to this wheel. The driver is made aware of this
control process by a pulsating of the brake pedal and accompa-
nying noise. This is a deliberate warning to the driver that one or
more of the wheels is tending to lock up and the ABS control func-
tion has intervened. In this situation it is important to keep the brake
pedal fully depressed so the ABS can regulate the brake application
- do not “pump” the brake pedal.
WARNING
The grip provided by ABS is still subject to the physical limits of
adhesion. Always bear this in mind, especially on wet or slippery
roads. If you notice that the ABS is working (to counteract locked
wheels under braking), you should reduce 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.
Note
If a malfunction should occur in the ABS, this is indicated by a
warning lamp ⇒page 18.Brake assist system
The brake assist system helps the driver to achieve
optimum braking effect.The brake assist system helps to increase braking power and thus to
achieve a shorter stopping distance. If the driver presses the brake
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Intelligent technology 198pedal very quickly, the brake assist system automatically boosts the
braking force to the maximum level, up to the point where the anti-
lock brake function (ABS) intervenes to stop the wheels from
locking. You should then keep the brake pedal pressed until the
vehicle has braked to the required speed. The brake assist system
switches itself off as soon as you release the brake pedal.
The brake assist system will not be operative if there is a malfunc-
tion in the ABS.
WARNING
Please remember that the accident risk always increases if you
drive too fast, especially in corners or on a slippery road, or if you
follow too close behind the vehicle in front of you. An increased
accident risk cannot be compensated even by the brake assist
system, so always be sure to maintain a safe speed.Traction control system (ASR)
The traction control system prevents the driven wheels
from spinning when the car is accelerating.General notes
The traction control system (ASR) is one of the functions incorpo-
rated in the electronic stabilisation program (ESP).
The traction control system (ASR) 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 ASR acts automatically i.e. without the driver's intervention.
With the aid of the ABS sensors ⇒page 197, the ASR monitors the
speed of the driven wheels. If the wheels start to spin, the engine
power is reduced automatically to match the amount of grip avail-
able. The system works at all speeds.The ASR works in conjunction with the ABS. If a malfunction should
occur in the ABS, the ASR 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. If the traction
control system (ASR) has been deactivated (for one of the reasons
noted below) you can switch it back on manually by pressing the
switch ⇒page 196, fig. 203. The message ESP/ASR on will appear
briefly in the display. If the traction control system (ASR) has been
deactivated, it will switch back on automatically at a speed of about
70 km/h on vehicles with front-wheel drive.
You can switch the traction control system (ASR) on again if neces-
sary by pressing the switch ⇒page 196, fig. 203.
Switching off
If required, the ASR can also be switched off manually by pressing
the switch briefly ⇒page 196, fig. 203 (for less than 3 seconds). The
ESP warning lamp lights up when the traction control system (ASR)
is switched off, see ⇒page 16. The message ASR off will appear in
the display. For safety reasons, the system can only be switched off
at speeds below 50 km/h on vehicles with front-wheel drive. The
ASR can be deactivated at any speed on vehicles with four-wheel
drive.
The traction control system should normally remain switched on at
all times. It should only be switched off manually in particular
circumstances where a certain amount of wheel slip may be desir-
able. For example:
•
when driving with snow chains
•
when driving in deep snow or on loose surfaces
•
when rocking the car backwards and forwards to free it.
The ASR should be switched on again afterwards as soon as
possible.
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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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Intelligent technology201
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data
Power steering (servotronic)The power steering assists the 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 232. 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.
Applies to vehicles: with four-wheel driveFour-wheel drive (quattro
®)
On quattro models the engine power is distributed to all
four wheelsGeneral notes
On four-wheel drive vehicles, the engine power is distributed to all
four wheels. The distribution of power is controlled automatically
according to your driving style and the road conditions. Also refer
to ⇒page 199, “Electronic differential lock (EDL)”.
The four-wheel drive is specially designed to complement the supe-
rior engine power of your Audi. This combination gives the car
exceptional handling and performance capabilities – both on
normal roads and in more difficult conditions, such as snow and ice.
Even so (or perhaps especially for this reason), it is important to
observe certain safety points ⇒.
Winter tyres
Thanks to its four-wheel drive, your car will have plenty of traction
in winter conditions, even with the standard tyres. Nevertheless, we
still recommend that winter tyres or all-season tyres should be fitted
on all four wheels when winter road conditions are expected, mainly
because this will give a better braking response.
Snow chains
On roads where snow chains are mandatory, this also applies to cars
with four-wheel drive ⇒page 248, “Snow chains”.
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Intelligent technology 202Replacing tyres
On vehicles with four-wheel drive, all four tyres must have the same
rolling circumference. Also avoid using tyres with varying tread
depths ⇒page 245, “Replacing wheels and tyres”.
Off-roader?
Your Audi does not have enough ground clearance to be used as an
off-road vehicle. It is therefore best to avoid rough tracks and
uneven terrain as much as possible.
WARNING
•
Even with four-wheel drive, 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 acci-
dents.
•
The braking ability of your car is limited by the grip of the tyres.
In this respect, your car is no different from a car without four-
wheel drive. So do not be tempted to drive too fast on icy or slip-
pery roads just because the car still has good acceleration in these
conditions (accident risk).
•
On wet roads bear in mind that the front wheels may start to
“aquaplane” and lose contact with the road if the car is driven too
fast. If this should happen, there will be no sudden increase in
engine speed to warn the driver, as with a front-wheel drive car. So
do not drive too fast in the wet: adjust your speed to suit the
conditions (accident risk).
Power managementThis system helps to ensure reliable starting
The power management controls the distribution of elec-
trical energy and thus helps to ensure that there is always
enough power available to start the engine.If a vehicle with a conventional electrical system is left parked for a
long time, the battery will gradually lose its charge because certain
electrical equipment (such as the immobiliser) continues to draw
current even when the ignition is off. In some cases there may not
be enough power available to start the engine.
Your vehicle is equipped with an intelligent power management
system to control the distribution of electrical energy. This signifi-
cantly improves reliability when starting the engine, and also
prolongs the life of the battery.
The main functions incorporated in the power management system
are battery diagnosis, residual current management and dynamic
power management.
Battery diagnosis
The battery diagnosis function constantly registers the condition of
the battery. Sensors detect the battery voltage, battery current and
battery temperature. This enables the system to calculate the
current power level and charge condition of the battery.
Residual current management
The residual current management reduces power consumption
while the vehicle is parked. It controls the supply of power to the
various electrical components while the ignition is switched off. The
system takes the battery diagnosis data into consideration.
Depending on the power level of the battery, the individual electrical
components are switched off one after the other to prevent the
battery from losing too much charge and to ensure that the engine
can be started reliably.
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Intelligent technology203
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data Dynamic power management
While the vehicle is moving, this function distributes the available
power to the various electrical components and systems according
to their requirements. The power management ensures that on-
board systems do not consume more electrical power than the
alternator can supply, and thus maintains the maximum possible
battery power level.
Note
•
The power management system is not able to overcome the
given physical limits. Please remember that the power and life of
the battery are limited.
•
A warning message will appear ⇒page 204, “Driver message in
the instrument cluster display” if the battery power has dropped to
a level where reliable starting is impaired.
Points to remember
Starting ability has first priority.Short trips, city traffic and low temperatures all place a heavy load
on the battery. In these conditions a large amount of power is
consumed, but only a small amount is supplied. The situation is also
critical if electrical equipment is in use when the engine is not
running. In this case power is consumed when none is being gener-
ated.
In these situations you will be aware that the power management
system is intervening to control the distribution of electrical power.
When the vehicle is parked for long periods
If you do not drive your vehicle for a period of several days or weeks,
the power management will gradually shut off the on-board
systems one by one, or reduce the amount of current they are using.
This limits the amount of power consumed and helps to ensure reli-
able starting even after a long period.Please note that certain convenience features, such as the Audi
advanced key*, the remote control key or the electrical seat adjust-
ment may not be available when you unlock the vehicle. These func-
tions will be restored when you switch on the ignition and start the
engine.
With the engine switched off
If you listen to the radio or use the other MMI functions when the
engine is not running, this will discharge the battery.
The MMI display will show this warning message before the battery
power drops to a level where the starting ability is impaired.
Please start engine, otherwise system will switch off
in 3 minutes.
This message warns you that the system you are using will be
switched off automatically after 3 minutes. You should therefore
start the engine if you wish to continue using the system.
When the engine is running
Although the alternator generates electrical power, the battery can
still become discharged while the vehicle is being driven. This can
occur when a lot of power is being consumed but only a small
amount supplied, especially if the battery is not fully charged
initially.
To restore the necessary energy balance, the system will then
temporarily shut off the electrical components that are using a lot
of power, or reduce the current they are consuming. Heating
systems in particular use a large amount of electrical power. If you
notice, for instance, that the seat heating* or the rear window
heater is not working, they may have been temporarily switched off
or regulated to a lower heat output. These systems will be available
again as soon as sufficient electrical power is available.
You may also notice that the engine runs at a slightly faster idling
speed. This is quite normal, and no cause for concern. The increased
idling speed allows the alternator to meet the greater power
requirement and charge the battery at the same time.
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