ECU AUDI S8 2009 Owner's Guide

___ T_ r _a_ il_e _r_ t_ o_ vv_ in__... g,_ __________________________________________________ _
Trailer towing
Driving with a trailer
General information
Your Audi was designed primarily for passenger transpor­
tation.
If you plan to tow a trailer, please remember that the additional load
wi ll affect durability, economy and performance.
Trai ler towing not on ly p laces more stress on the vehicle, it a lso ca lls
for more concentration from the driver.
For this reason, always fol low the operating and driving instructions
provided and use common sense.
0 Note
If you are going to tow a trai ler, you must activate the trailer opera­
tion mode =>
page 192, "Towing a Trailer".
Technical requirements
Tra iler hitch
Use a weight-carrying hitch conforming to the gross trailer weight .
The hitch must be suitable for your vehicle and trailer and must be
mounted secure ly on the ve hicle's chass is at a
technically sound
location. Use only a trailer hitch with a removable ball mount.
Always check with the trai ler hitch manufacturer to make sure that
you are using the correct hitch .
Do not use a bump er hit ch.
The hitch must be installed in such a way tha t it does not interfere
with the impact-absorbing bumper system. No modifications should be made to the vehic le exhaust and brake systems. From time to time, check that all hitch mounting bolts remain securely
fastened.
When you are no
t towing a trailer, remove the traile r hitch ball
mount. This prevents the hitch from causing damage shou ld your
vehic le be struck from behind=>& .
Traile r br akes
If your trailer is equipped with a braking system, check to be sure
that it conforms to al l regu lations .
The trai ler hydraulic brake system must no t be direct ly connected to
the vehicle's hydraulic brake system.
S afet y c hains
Always use safety chains between your vehicle and the trailer.
Trailer light s
Trailer lights must meet all regulations. Be sure to check with your
Audi dealer for correc t wiring, swi tches and relays .
Mirrors
If you are unable to see the traf fic behind you using the regu lar
outside mirrors, then you
must install extended mirrors. It is impor­
tant that you
always have c lear vision to the rear.
& WARNING
After rem oving the tr aile r hitch , do not store it in your vehi cle. In
ca se of sudde n braking , the hit ch co uld fl y for ward and injure you
or your p asseng ers. a

Operating instructions
Max im um tra iler weight
A trailer for your vehicle is limited to a typical class 1 or class 2
trailer.
T ra ile r l oa d di stributio n
Be sure the load in the trailer is he ld securely in place to prevent it
from shifting forward, backward or sideways .
Never allo w a passe nger to r ide in a tr aile r~ & in "Driving instruc­
tions" .
Engin e c oolin g sys te m
Towing a trailer makes the eng ine work harder. It is important that
the cooling system's performance is up to the additiona l load. Make
sure that the coo ling system has enough fluid .
Tire pr ess ure
When towing a trailer, inflate the tires of your vehicle to the co ld tire
pressure listed under "Full load" on the labe l located either on the
driver's side B -pil lar (visible when the door is open) or inside the fuel
filler flap . Inflate trai ler tires to trai ler and tire manufacturers' spec­
ifications.
L ig ht s
The head light settings should be checked wit h the trai ler attached
before driving off. Check to make sure both vehicle and trai ler lights
are working properly .
Safe ty c ha in s
Be sure traile r safety chains are properly connected from the trailer
to the hitch on the vehicle. Leave enough slack in the chains to
perm it turning corners . When you i nsta ll safety chains, make sure
they will not drag on the road when you are driving.
T he chains should cross under the trailer tongue to prevent it from
dropping in case of separat ion from the hitch.
Controls and equip­
ment Safety first Vehicle operation
Tr
aile r t owing
0 Note
If you are going to tow a trai ler, you must activate the trailer opera­
tion mode ~
page 192, "Towing a Trailer". •
Driving instructions
Driving with a trailer always requires extra care and
consideration.
To obtain the best possible handling of veh icle and trailer,
please note t he following :
- Do not tow a loaded trailer when your car itself is not
loaded.
Be espec ia lly careful whe n passing other vehicles.
- Observe s peed limits .
Do not drive at the maximum permiss ible speed .
Always apply brakes ear ly.
Moni tor t he temperature ga uge.
Weight distr ibution
Towing a loaded trailer with an empty car results in a highly
unstable distr ibution of weight. If this cannot be avoided, drive at
very low speeds only to avoid the risk of losing steering control.
A "balanced" rig is easier to operate and control. This means that
the tow vehicle should be loaded to the extent possible and perm is ­
s ib le, while keeping the trailer as light as possib le under the circum ­
stances . Whenever possible, transfe r so me cargo to t he luggage
compartment of the tow vehicle whi le observing tongue load
requirements and vehicle loading considera tions . .,
Vehicle care Do-it-yourself service Technical data

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•
Closing the engine hood
- Pull the hood down until the pressure from the struts is
reduced .
- Let the hood
drop down and latch in place. Do not try to
push it shut;
it may fail to engage => &.
& WARNING
A hood that is not completely latched could fly up and block your
view while driving.
• When you close the engine hood, check it to make sure the
safety catch has properly engaged. The hood should be flush with
the surrounding vehicle body parts.
• If you notice while driving that the hood is not secured prop­
erly, stop at once and close it. •
Working in the engine compartment
Be especially careful whenever you work in the engine
compartment.
Whenever you must perform any work in the engine compartment,
for example checking and filling different fluids, there is a risk of injury, burns and accidents. To prevent personal injury always
observe the following WARNINGS. The engine compartment of any
vehicle is a hazardous area
~ & .
& WARNING
To help avoid injury, before you check anything under the hood :
• Turn off the engine.
• Remove the ignition key.
• Apply the parking brake .
& WARNING (continued)
• Move selector lever to "P" (Park).
• Always let the engine cool down. Hot components will burn
skin on contact.
• To reduce the risk of being burned, never open the hood if you
see or hear steam or coolant escaping from the engine compart­
ment. Wait until no steam or coolant can be seen or heard before
carefully opening the hood.
• Keep children away from the engine compartment .
• Never spill fluids on hot engine components. They can cause a
fire.
• Never touch the radiator fan. The auxiliary electric fan is
temperature controlled and can switch on suddenly.
• Never open the coolant reservoir cap when the engine is still
warm . The coolant system is pressurized and hot coolant could
spray out.
• Protect your face, hands and arm from steam or hot engine
coolant by placing a thick rag over the cap when you open the
coolant reservoir.
• If work on the fuel system or the electrical system is necessary :
- Always disconnect the battery.
- Never smoke or work near heaters or open flames . Fluids in
the engine compartment could start a fire.
- Keep an approved fire extinguisher immediately available.
• To avoid electrical shock and personal injury while the engine
is running or being started, never touch:
- Ignition cables
- Other components of the high voltage electronic ignition system.
• If you must perform a check or repair with the engine running: -First, fully apply the parking brake, move selector lever to "P"
(Park). .,
Vehicle care
I t •

Tires and wheels -
----------------
•
0 Note
Driving without valve stem caps can cause damage to the tire
valves. To prevent this, always make sure that factory installed valve
stem caps on all wheels are securely mounted on the valve .
W For the sake of the environment
Underinflated tires will also increase the fuel consumption. •
Tires and vehicle load limits
There are limits to the amount of load or weight that any vehicle and
any tire can carry . A vehicle that is overloaded will not handle well
and is more difficult to stop. Overloading can not only lead to loss
of vehicle control, but can also damage important parts of the
vehicle and can lead to sudden tire failure, including a blowout and
sudden deflation that can cause the vehicle to crash.
Your safety and that of your passengers also depends on making
sure that load limits are not exceeded. Vehicle load includes every­
body and everything in and on the vehicle. These load limits are
technically referred to as the vehicle's
Gross Vehicle Weight Rating
("GVWR"l.
The "GVWR" includes the weight of the basic vehicle, all factory
installed accessories, a full tank of fuel, oil , coolant and other fluids
plus maximum load. The maximum load includes the number of
passengers that the vehicle is intended to carry ("seating capacity")
with an assumed weight of 150 lbs (68 kg) for each passenger at a
designated seating position and the total weight of any luggage in
the vehicle. If you tow a trailer, the weight of the trailer hitch and the
tongue weight of the loaded trailer must be included as part of the
vehicle load.
The
Gross Axle Weight Rating ("GAWR"l is the maximum load that
can be applied at each of the vehicle's two axles. The
Gross Vehicle Weight Rating and the Gross Axle Weight Rating
are listed on the safety compliance sticker label located either on
the driver's side 8-pillar or on the inside of the fuel filler flap. Your
Audi has 5 seating positions, 2 in the front and 3 in the rear for total
seating capacity of 5. Vehicles with power individual rear seats*
have 4 seating positions, 2 in the front and 2 in the rear for total
seating capacity of 4. Each seating position has a safety belt
~ page 211, "Safety belts".
The fact that there is an upper limit to your vehicle's Gross Vehicle
Weight Rating means that the total weight of whatever is being
carried in the vehicle (including the weight of a trailer hitch and the
tongue weight of the loaded trailer) is limited. The more passengers
in the vehicle or passengers who are heavier than the standard
weights assumed mean that less weight can be carried as luggage.
The tire pressure label on your Audi also lists the maximum
combined weight of all of the occupants and luggage or other cargo
that the vehicle can carry. For the location of the label
~ page 330,
fig. 274.
& WARNING
Overloading a vehicle can cause loss of vehicle control, a crash or
other accident, serious personal injury, and even death.
• Carrying more weight than your vehicle was designed to carry
will prevent the vehicle from handling properly and increase the
risk of the loss of vehicle control.
• The brakes on a vehicle that has been overloaded may not be
able to stop the vehicle within a safe distance.
• Tires on a vehicle that has been overloaded can fail suddenly,
including a blowout and sudden deflation, causing loss of control
and a crash.
• Always make sure that the total load being transported -
including the weight of a trailer hitch and the tongue weight of a
loaded trailer -does not make the vehicle heavier than the
vehicle's Gross Vehicle Weight Rating. •
Vehicle care
I t •

__________________________________________________ T_ ir_e_ s_ a_ n_d _ w_ h_ e_ e_l_s __ _
•
• T he battery inside of the tire pressure sensor has a limited
service life.
• Always drive with the va lve stem caps securely mounted. We
recommend using fac tory insta lled valve stem caps . Ask your autho­
rized Audi dealer to replace lost valve stem caps .
T he installation of replacement tires with steel cord body plies in
the tire sidewall may cause malfunction of the tire pressure moni ­
toring system *, and is not recommended (cord material info rmation
i n molded on the t ire sidewa ll).
A lways check your tire pressure monitoring system * indicator after
replac ing one or more tires on you r veh ic le . If t he tir e pressure
monitoring system * indicator f lashes, or is on, your system is not
wo rking pr ope rly. Your re place ment tire might be i nco m patible wit h
your tire pr essure monitoring system *, or some component of the
t ir e pr ess ure moni toring system * m ay be da maged.
& WARNING
• Using incorrect or unmatched tires and / or wheels or improper
tire and wheel combinations can lead to los s of control , collision
and serious personal injury .
• Alway s use tires , rims and wheel bolts that meet the specifica ­
tions of original fa ctory -installed tires or other combination s that
have been specifically approved by the vehi cle manufacturer .
• Tires age even if they are not being used and can fail suddenly,
espe cially at high speeds . Tire s that a re more than 6 years old can
only be used in an emergency and then with special care and at
lo wer speeds .
• Never mount used tire s on your vehicle if you are not sure of
their "previous history ." Old used tires may have been dam aged
even though the damage cannot be seen that can lead to sudden
ti re failure and lo ss of vehicle control.
• All four wheels must be fitted with radial tires of the same type ,
size (rolling cir cumference ) and the same tread pattern . Driving
& W ARNING (continued )
with different tires redu ces vehicle handling and can lead to a loss
of control.
• If the spare tire is not the same as the tires that are mounted
on the vehicle -for example with winter tires -only use the spare
tire for a short period of time and dri ve with extra care . Refit the
normal road wheel as soon a s safely pos sible.
• Never drive faster than the ma ximum speed for which the tires
on your vehicle are rated because tires that are driven faster than
their rated speed can fail suddenly .
• Overloading tires cause heat build -up , su dden tire failure ,
includ ing a blowout and sudden deflation and loss of control.
• Temperature grades apply to tires that are properly inflated and
not over or underinflated .
• For te chni cal reasons it is not always po ssible to use wheels
from other vehicles -in some cases not even wheels from the
same vehicle model.
• If you install wheel trim discs on the vehicle wheels , make sure
that the air flow to the brakes is not blo cked . Redu ced airflow to
the brake s can them to overheat , increa sing stopping distances
and causing a collision.
• Run flat tires may only be used on vehicles that were equipped
with them at the fa ctory . The vehicle mu st have a cha ssi s designed
for run flat tires and a factory -installed tire pressure monitoring
s ystem* that indicates a lo ss of tire pressure . Incorrect use of run
flat tires can lead to vehicle damage or accident s. Check with an
authorized Audi dealer or tire specialist to see if your vehicle can
be equipped with run fl at tires . If run flat tires are used , they must
be installed on all four wheels . Mi xing tire types is not permitted.
0 Note
• Fo r techn ica l reaso ns, i t is no t genera lly p oss ibl e to use the
whee l rims from other vehicles . T his can hold true for wheels of the
sa me vehicle type. ..,.
Vehicle care
I t •

What do I do now? -
------------------
[ i J Tips
If you no longer have your original warning triang le and need to
equip your vehicle with a new one, contact your authorized Audi
dealer for a replacement .•
Jack, tools and spare wheel
Jack
The jack is stored underneath the floor panel in the
luggage compartment.
Fig . 282 Luggage
compartment vehicle
jack
Before stori ng the jack, make sure it is wound back down as far as it
will go.
& WARNING
Improper use of the vehicle jack can cause serious personal inju­
ries.
• Never use the jack supplied with your Audi on another vehicle,
particularly on a heavier one. The jack is only suitable for use on
the vehicle it came with.
& WARNING (continued)
• Using a bumper jack to raise the vehicle will damage the
bumper system. The jack may slip, causing injury.
• Never support your vehicle on cinder blocks, bricks or other
objects. These may not be able to support the load and could
cause injury when they fail.
• Never start or run the engine while the vehicle is supported by
the jack.
• If you must work under the vehicle, always use safety stands
specifically designed for this purpose .
• Never use the hexagonal socket in the handle of the screw­
driver to loosen or tighten the wheel bolts.
• Always make sure the spare tire and even a flat tire are secured
in place and not loose, otherwise they could fly forward , causing
personal injury to passengers in the vehicle in an accident or
sudden maneuver .
[ i J Tips
Before you can raise your vehicle using the jack, you must activate
the jacking mode~
page 191. •
Vehicle care Do-it-yourself service irechnical data

-What do I do novv? Pffl..._ _____________________ _
Tools
The vehicle tools are stored in the luggage compartment
lid.
Fig. 283 Trunk lid:
Opening the cover
Fig. 284 Trunk lid:
Vehicle tools
-To open the cover, turn the retainer in the direction of the
arrow and pull the cover down
=> page 352, fig. 283.
The onboard tool kit includes:
• Hook for removing wheel covers *
• Plastic hook to remove wheel bolt covers
• Whe el bolt wr ench
• Alignment pin for changing wheels
• Screwdriver with reversible blade •
10 x 13 open ended wrench
• Towing loop
[ i] Tips
Some of the onboard items listed above are provided on certain
models only or are optional extras .•
Spare wheel
The spare wheel is stored in the wheel well underneath
the floor panel in the luggage compartment.
Fig. 285 Luggage
compartment spare
wheel
Your vehicle is equipped with a regular spare wheel. It is
held in place by plastic retaining knurled screw.
Taking out the spare vvheel
- Raise the floor panel at the plast ic handle.
- Securely engage the handle in the luggage compartment
seal as illustrated to keep the floor panel up.
- Unscrew the knurled retainer bolt in the wheel center
=> fig. 285. Turn it counter-clockwise.
- Take out the spare wheel.

What do I do now? Ill
---------------~.;______
•
-Disengage and lower the floor panel before you close the
luggage compartment lid again.
Storing the replaced wheel
-Place the replaced wheel inside the spare wheel well in
the luggage compartment.
Tighten the knurled retaining screw clockwise to secure
the wheel in place.
- Disengage and lower the floor panel before you close the
luggage compartment lid again.
& WARNING
Loose items in the passenger compartment can cause serious
personal injury during hard braking or in an accident .
• Never store the spare wheel or jack and tools in the passenger
compartment.
• Always store all jacking equipment, tools, and the spare wheel
in the luggage compartment.
• Tighten the knurled retaining screw for the spare wheel
securely.
[ i] Tips
Check the inflation pressure of the spare tire periodically to keep the
tire ready for use. •
Changing a wheel
Before changing a wheel
Observe the following precautions for your own and your
passenger's safety when changing a wheel.
- After you experience a tire failure, pull the car well away
from moving traffic and try to reach level ground before
you stop
~ & .
- All passengers should leave the car and move to a safe
location (for instance, behind the guardrail) ~& .
- Engage the parking brake to prevent your vehicle from
rolling unintentionally ~& .
- Move selector lever to position P
~ &.
-If you are towing a trailer: unhitch the trailer from your
vehicle.
- Take the jack and the spare tire out of the luggage
compartment~
page 351.
& WARNING
You or your passengers could be injured while changing a wheel if
you do not follow these safety precautions:
• If you have a flat tire, move a safe distance off the road. Turn off
the engine, turn the emergency flashers on and use other warning
devices to alert other motorists.
• Make sure that passengers wait in a safe place away from the
vehicle and well away from the road and traffic.
• To help prevent the vehicle from moving suddenly and possibly
slipping off the jack, always fully set the parking brake and block
the wheel diagonally opposite the wheel being changed. When one ..,
Do-it -yourself service

1111 What do I do now? ..._ __________________________________________ _
& WARNING (continued )
front wheel is lifted off the ground , placing the Automatic Trans­
mission in "P" (Park) will
not prevent the vehicle from moving.
• Before you change a wheel, be sure the ground is level and firm.
If necessary , use a sturdy board under the jack.
• After installing the spare wheel, make sure that you replace the
flat tire/wheel in its storage area properly and tighten the knurled
retaining screw securely.
[ i J Tips
Before changing the wheel, you must activate the jacking mode, so
that the automatic controls for the Adaptive Air Suspension do not
make it more difficult to lift the vehicle with the jack =>
page 791. •
Changing a wheel
When you change a wheel, follow the sequence described
below step-by-step and in exactly that order.
1. Activate the vehicle jacking mode~ page 191.
2. Remove the decorative wheel cover*. For more details
see also
~ page 355, "Decorative wheel covers" or
~ page 355, "Wheels with wheel bolt caps" .
3. Loosen the
wheel bolts ~ page 356.
4. Locate the proper mounting point for the jack and align
the jack below that point~
page 356.
5. Lift the car with the jack~ page 356.
6. Remove the wheel with the flat tire and then install the
spare
~ page 358 .
7. Tighten all wheel bolts lightly. 8.
Lower the vehicle with the
jack.
9. Use the wheel bolt wrench and
firmly tighten all wheel
bolts
~ page 356.
10. Replace the decorative wheel cover*.
11. Deactivate the vehicle jacking mode~ page 191.
& WARNING
Always read and follow all WARNINGS and information :::::> 6 in
" Raising the vehicle" on
page 356 and => page 359. •
After changing a vvheel
A wheel change is not complete without the doing the
following.
- Store and secure the wheel you replaced in the spare
wheel well.
- Replace the tools and the jack in their proper location.
- Check the
tire pressure on the spare wheel immediately
after mounting it.
- As soon as possible , have the
tightening torques on all
wheel bolts checked with a torque wrench. The correct tightening torque is 90 ft lb (120 Nm) .
- Have the flat tire
replaced as soon as possible.
[ i J Tips
• If you notice that the wheel bolts are corroded and difficult to
turn while changing a tire, they should be replaced before you check
the tightening torque. .,_

_____________________________________________ W_ h_ a_t _d_ o_l _ d_o _ n_o_ w_ ? _ __._
Fig . 290 Close-up :
proper positioning of
jack
- Act iva te the ve hicle ja cking mode before c ha ngin g a
wheel ==>
page 19 1.
- Posi tio n th e jack below th e doo r sill und er t he mounting
point
that is clos est to the w hee l to be cha nged
==>
p age 356 , fig. 289.
- Exten d the
jack und er the li fting po int on the doo r sill
un til it s arm is po sitio ned d irect ly und er t he l if tin g p oint
==> & .
- Align the j ack so th at its a rm
@ en gag es th e plastic
lif ting point on the door si ll and th e mova ble base ® is
flat on the groun d==> fig. 290 .
- Wind th e jack up furt her u ntil the flat tir e co mes off the
gr oun d==> & .
The jack must be installed only at the places indicated~ page 356,
fig. 289 . Th ere is e xactly on e loca tion for e ach w heel. The jack m ust
not b e positioned at any oth er locatio n~ & .
T he jac k should be pos it ioned ap pro xim ately 8 in . (2 0 cm) be hind
the front wh eel or 6 i n. (1 5 c m) in fr ont o f the r ear w heel.
A n unstab le su rface unde r th e jac k can cause the vehicle to slip off
the jack. A lw ay s pro vi de a firm bas e for th e ja ck on the grou nd. If
necessary place a sturdy board or similar s up port under the jack. On ha
rd, sl ippery surfaces (suc h as til es) us e a ru bber mat or similar to
prevent th e ja ck fr om slippin g~ & .
& WARNING
• You or your passengers could be injured while changing a
wheel if you do not follow these safety precautions:
-Positioning the jack under the vehicle at any other place than
those indicated above may damage the vehicle or may result in
personal injuries.
- A soft or unstable surface under the jack may cause the
vehicle to slip off the jack . Always provide a firm base for the
jack on the ground . If necessary , use a sturdy board under the
jack .
- On hard , slippery surface (such as tiles ) use a rubber mat or
similar to prevent the jack from slipping.
• To help prevent injury to yourself and your passengers :
- Do not raise the vehicle until you are sure the jack is securely
engaged .
- Passengers must not remain in the vehicle when it is jacked
up .
- Make sure that passengers wait in a safe place away from
the vehicle and well away from the road and traffic .
- Make sure jack position is correct, adjust as necessary and
then continue to raise the jack.
[ i ] Tips
Be for e changi ng th e whee l, yo u m ust ac tiv ate the jac king mode , so
that the automat ic controls for t he Adapt ive Air Suspension do not
make it more diffic ult to lift the vehi cle with the jack~
page 191. •
Vehicle care Do-it-yourself service irechnical data