ECU AUDI S8 2008 Owner's Guide

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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 add it ional load
wi ll affect durability, economy and performance.
Tra iler 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 ope rating and driv ing instruc tions
provided and use common sense.
(D Note
If you are go ing to tow a trai ler, you must activate the trailer opera ­
tion
mode => page 189, "Towing a Trailer". •
Technical requirements
Traile r hit ch
Use a we ight-carrying hitch conforming to the gross trai ler weight.
The hitch must be suitable for your vehic le 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 wit h the trai ler hitch manufacturer to make s ure that
you are using the correct hitch .
Do not use a bumper hit ch.
The hitc h must be installed in such a way t hat it does not interfere
with the impact-absorbing bumper system. No modifications
should be made to the veh ic le exhaust a nd brake systems. F rom time to time, check that all hitch mounting bolts remain secure
ly
fastened .
When yo u are no t towing a trailer, re move the tra ile r hitch ball
mount. This prevents the hitch from causing damage shou ld your
vehic le be struck from
behind =>& .
Traile r br ake s
If your tra iler is equipped with a braking syste m, check to be sure
that it conforms to al l regu lations .
The tra iler hydraul ic brake sys tem must not be di rect ly co nnected to
t he vehic le's hydrau lic brake system .
Safety chains
Always use safety chains between your vehicle and the trailer.
Trailer light s
Trai ler lights must meet a ll regulations. Be sure to check with your
Aud i dea ler for correc t wir ing, sw itch es and relays .
Mirrors
If you are unable to see the traf fic behind you using the regu lar
outside mirrors, then you
must instal l extended mirrors. It is impor ­
t ant that you
always have c lear v ision to the rear.
& WARNING
After removing the tr ailer hitch , do not store it in your vehi cle . In
ca se of sudden braking , the hitch could fl y forward and injure you
or your p assenger s.•

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Operating instructions
M ax im um tra iler weig ht
A trailer for your vehicle is limited to a typ ical c lass 1 or class 2
trailer.
T ra ile r l oad d is tributi on
Be sure the load in the trailer is he ld securely in place to prevent it
from shifting forward, backward or s ideways .
Never a llow a pass enger to r ide in a trailer:::::, & in "Driving instruc­
t ions" .
Engin e coo lin g sys te m
Tow ing a trai ler makes the engine 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 press ure
When towing a trailer, inflate the tires of your veh icle to t he 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 trailer 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 s ure trailer safe ty chains are properly connected from the trailer
to the hitch on the vehicle. Leave enough slack in the chains to
permit turning corners . When yo u insta 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
0 Note
If you are go ing to tow a trai ler, you must activate the tra iler opera­
tion
mode :::::, page 189, "Towing a Trailer". •
Driving instructions
Driving with a trailer always requires extra care and
consideration.
To obtain the best possib le handling of ve hicle and trailer,
p lease note t he following :
- Do not tow a loaded trailer when your car itself is not
loaded.
- Be especia lly careful whe n passing other vehic les .
- Observe speed limits .
- Do not drive at the maximum permiss ible speed .
- Always apply brakes early.
- Monitor t he temperature ga uge .
W eight d istr ibu tion
Towing a loaded trailer with an empty car results in a highly
unstable d istribution 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
t he tow vehicle should be loaded to the extent possible and permis ­
sib le, while keeping the trailer as light as possib le under the circum ­
stances . Whenever possible, transfer some cargo to the 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.
• I I • • I
& 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

Tires a nd wh eels -
----------------
•
0 Not e
Driving without valve stem caps can cause damage to the tire
valves. To prevent this, a lways make sure that factory instal led valve
stem caps on a ll whee ls are securely mounted on the va lve .
W Fo r the sake of the env ironm ent
Underinflated tires wil l a lso increase the fuel consumption. •
Tires and vehicle load limits
There are lim its to t he amount of load or weight that any ve hicle and
any tire can carry . A vehicle that is overload ed wil l not hand le well
and is more difficu lt to stop. Overload ing can not only lead to loss
of vehic le control , but can a lso damage important parts of the
vehic le and ca n lead to sudden t ire fa ilure, inc luding a blowout a nd
sudden deflation that can cause the vehic le to crash.
Your safety and that of your passengers also depends on making
sure that load l imits are not exceeded. Vehicle load includes every­
body and everything in and on the vehic le. These load limits are
technica lly referred to as the vehicle's
Gross Ve hicle We ig ht R ating
("GVWR").
The "GVWR" includes t he weight of the bas ic ve hicle, al l factory
insta lled accessories, a full tank of fuel , oil , coolant and other fluids
p lus maximum load . The maximum load i ncludes 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 h itch and the
tongue we ight of the loaded trai ler must be included as part of the
vehic le load.
The
Gros s Axle We ight Rating ("GAWR") is the maximum load t hat
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 comp liance s ticker label loca ted either on
the driver's side B-pillar or on the inside of the fuel fil ler 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. Eac h seating position has a safety be lt
~ page 209, "Safety be lts".
The fact that there is an upper limit to your veh icle's Gross Vehicle
Weight Rating means that the total weight of whatever is being
carried in the veh ic le ( including t he we ight of a trai ler hitch and the
tongue weight of the loaded trai ler) is limited . The more passengers
in the vehicle or passengers who are heavier than the standa rd
we ights assumed mean that less weight can be carried as luggage .
The tire pressure labe l on your Audi also lists the maximum
combined we ight of a ll of the occupants and luggage or other cargo
that th e vehicle can carry. For the location of the lab el
~ page 328 ,
fig. 272 .
& WARNING
Overloading a v ehicl e can cau se loss of vehicl e control , a cras h or
o ther ac cident , serious p ers on al injur y, and eve n de ath.
• C arrying more weight th an your vehi cle was designed to c arry
will prevent the vehicl e from handling prop erl y and in cre a se the
ri sk of the l oss of vehi cle control.
• The br akes on a vehi cle that has b een overload ed may not be
a bl e to sto p the vehi cle within a safe di sta nce.
• Tir es on a ve hic le th at ha s bee n ov erlo ad ed c an fail sudd enl y,
in clu din g a bl owout and sud den d efl atio n, ca usi ng loss of con trol
and a crash .
• Al ways m ake sur e th at the total lo ad being tr ansp orted -
includin g th e w eight of a tr ailer hitch and th e tong ue weight of a
load ed tr ailer -do es not m ake the vehi cle he avie r than the
vehicle 's Gro ss Vehicl e W eight R ating. •
Vehicle care

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[ i J Tips
If you no longer have your original warni ng triang le and need to
equip your vehic le with a new one, contact you r authorized Audi
d ea ler for a r eplace men t. •
Jack, tools and spare wheel
Jack
The jack is store d unde rnea th the floor panel in the
lug gage co mpartm en t.
Fig . 280 Luggage
c ompartment vehicle
jack
Before s tori ng the jack, make su re i t is wound back down as far as it
wi ll go.
& WARNING
Improper use of the vehi cle ja ck can cause serious personal inju ­
ries .
• Never use the jack supplied with your Audi on another vehi cle,
particularly on a heavier one. The jack is only suitable for u se on
the vehi cle 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 st ands
s pecifically designed for this purpose .
• Never use the he xagonal socket in the handle of the s crew­
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 v ehicle in an a ccident or
sudden maneuver .
[ i J Tips
Before you can raise your vehicle using the jack, yo u must act ivate
the jack ing mode ::}
page 188. •
Vehicle care Do-it-yourself service irechnical data

llffl!I What do I do novv?
'---------------------------------------------
Tools
The vehicle tools are stored in the luggage compartment
lid.
Fig . 281 Trunk lid:
Opening the cover
Fig . 282 Trunk lid:
Vehicle tools
-To open the cover, turn the retainer in the direction of the
arrow and pull the cover down
~ page 350, fig. 281.
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
• Screwdr iv e r with reversible blade •
10 x 13 open ended wrench
• Towing loop
[ i] Tips
Some of the on board 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 . 283 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 wheel
- Raise the floor panel at the plastic 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. 283. 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 349.
& 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

-What do I do now? PW-------------------------
&, 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] 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 7 88. •
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 188.
2. Remove the decorative wheel cover*. For more details
see also
=> page 353, "Decorative wheel covers" or
=> page 353, "Wheels with wheel bolt caps" .
3. Loosen the wheel bolts => page 354.
4. Locate the proper mounting point for the jack and align
the jack below that
point=> page 354.
5. Lift the car with the jack=> page 354.
6. Remove the wheel with the flat tire and then install the
spare
=> page 356 .
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 354.
10. Replace the decorative wheel cover*.
11. Deactivate the vehicle jacking mode => page 188 .
& WARNING
Always read and follow all WARNINGS and information ~ & in
"Raising the vehicle" on
page 354 and ~ page 357. •
After changing a wheel
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] 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 . .,_

What do I do now? -
-----------------
Fig. 288 Clos e-up :
prope r positioning of
jack
- Activa te the ve hicle ja cking mode before c ha ngin g a
w heel
=> p age 188.
- Posi tio n th e jack bel ow th e doo r sill und er t he mounting
point
th at is c los est to th e w hee l to be cha nged
=> p age 354 , fig. 28 7.
- Exten d the
jack und er the li ftin g po int on the do or sill
un til it s a rm is posi tio ned direct ly und er t he lif tin g p oint
=>& .
- Alig n the j ack so tha t its a rm @ en gag es t he plast ic
lif tin g p oint on the door sill a nd the mova ble base ® is
fl at on the
groun d=> fig . 288.
- Wind t he jack up furt her u ntil the flat t ire co mes off the
gr oun d=> &-
The jack must be installed only at the places indicated ~ page 354,
fig. 287 . There is exa ctly on e loca tion for e ach w heel. The ja ck m ust
not be positioned at any other
l ocation~ &.
The jack sho uld be posit ioned ap pro xima tely 8 in . (2 0 cm) be hind
th e fro nt whe el or 6 i n. (1 5 c m) in fr ont o f the rear w heel.
A n unstab le surfac e under th e jack can cause the vehicl e to s lip off
t h e jack . A lways pro vide a firm base for th e ja ck on the grou nd. If
necessary place a s turdy board or similar support under the ja ck. On ha
rd, s lippery surfaces (such as ti les) us e a rubb er mat or similar to
p revent th e ja ck fro m
slippin g~ & .
& WARNING
• You or your pa ssengers 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 surfa ce under the ja ck 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
Befo re c hangi ng th e wheel, yo u must ac tivate the jac king mode, s o
that the automatic controls for the Adapt ive Air Suspension do not
make it more difficult to lift the veh ic le with the
jack ~ page 188. •
Vehicle care Do-it-yourself service irechnical data

What do I do now? -
----------------
•
hub. Remove all dirt from these surfaces before remounting the
wheel. •
Tires with unidirectional tread design
Tires with unidirectional tread design must be mounted
with their tread pattern pointed in the right direction.
Using a spare tire with a tread pattern intended for use
in a specific direction
When using a spare tire with a tread pattern intended for use in a specific direction , please note the following:
• The direction of rotation is marked by an arrow on the side of the
tire .
• If the spare tire has to be installed in the incorrect direction, use
the spare tire only temporarily since the tire will not be able to
achieve its optimum performance characteristics with regard to
aquaplaning, noise and wear.
• We recommend that you pay particular attention to this fact
during wet weather and that you adjust your speed to match road
conditions.
• Replace the flat tire with a new one and have it installed on your
vehicle as soon as possible to restore the handling advantages of a
unidirectional tire. •
Notes on wheel changing
Please read the information =:> page 336, "New tires and replacing
tires and wheels" if you are going to use a spare tire which is
different from the tires on your vehicle.
After you change a tire :
• Check the tire pressure on the spare immediately after installa­
tion. •
Have the wheel bolt tightening torque checked with a torque
wrench as soon as possible by your authorized Audi dealer or a
qualified service station .
• With steel and alloy wheel rims, the wheel bolts are correctly
tightened at a torque of 90 ft lb (120 Nm}.
• 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.
• Replace the flat tire with a new one and have it installed on your
vehicle as soon as possible. Remount the wheel cover.
Until then, drive with extra care and at reduced speeds .
& WARNING
• If you are going to equip your vehicle with tires or rims which
differ from those which were factory installed, then be sure to read
the information
=:> page 336, "New tires and replacing tires and
wheels".
• Always make sure the damaged wheel or even a flat tire and
the jack and tool kit are properly secured in the luggage compart­
ment and are not loose in the passenger compartment.
• In an accident or sudden maneuver they could fly forward,
injuring anyone in the vehicle .
• Always store damaged wheel, jack and tools securely in the
luggage compartment . Otherwise, in an accident or sudden
maneuver they could fly forward, causing injury to passengers in
the vehicle .
• Do not use commercially available tire sealants. Otherwise, the
electrical components of the tire pressure monitoring system will
no longer work properly and the sensor for the tire pressure moni ­
toring system will have to be replaced by a qualified workshop. •
Do -it -yourself service