check engine light AUDI S8 2008 Owner's Manual

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Overheating of brakes
To prevent the disc brake of the braked wheel from overheating if
subjected to excessive loads, the EDL cuts out temporarily . The
vehicle remains operational and behaves in the same way as a
vehicle without EDL.
As soon as the brake has cooled down, EDL switches on again auto ­
matically.
& WARNING
• When accelerating on slippery surfaces, such as on ice or snow,
always be careful when depressing the accelerator pedal. Even
with the EDL working, the drive wheels can spin and reduce your ability to control your car. Risk of crash!
• The increased safety afforded by
EDL does not mean that you
can take safety risks. Always adapt your driving style to the road
conditions and traffic situation.
[ i] Tips
If a fault occurs in the ABS, the EDL is also not functioning. This is
indicated by the ABS warning
light => page 21. •
Anti-Slip Regulation System (ASR)
The Anti-Slip Regulation System prevents the driven
wheels from spinning when the car is accelerating.
General notes
The Anti-Slip Regulation System (ASR) is integrated in the electronic
stabili zation program (ESP) . When the vehicle starts up and acceler­
ates, the wheels are prevented from spinning by adjusting the
engine power to match the amount of grip available from the road
surface.
How the system works
ASR performs automatically, i.e. without the driver's intervention.
With the aid of the ABS
sensors=> page 272, ASR monitors the
speed of the driven wheels. If the wheels start to spin, the engine
power is reduced automatically until the tires find enough grip to
lock onto the road surface . The system is active across the entire
speed range.
The ASR works in conjunction with the ABS. If a malfunction should
occur in the ABS, the ASR will also be out of action.
& WARNING
The increased safety afforded by ASR does not mean that you can
take safety risks. Always adapt your driving style to the road
conditions and traffic situation.
[ i] Tips
To ensure that the ASR works properly, all four wheels must be fitted
with identical tires Any differences in rolling radius of the tires can
cause the system to reduce engine power when this is not desired.
See
also=> page 336, "New tires and replacing tires and wheels ".•
Braking
General information
What affects braking efficiency?
Operating conditions and driving habits
The brakes on today's automobiles are still subject to wear,
depending largely on operating conditions and driving
habits=:,& .
On vehicles which are driven mostly in stop-and-go city traffic or
which are driven hard, the brake pads should be checked by your
authorized Audi dealer more often than specified in the
Warranty &
Maintenance booklet. _,,,

-Intelligent technology
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& WARNING
• Never let the vehi cle roll to a stop with the engine shut off .
• If the brake boo ster i s not working, for example when towing
your vehicle , or because the brake booster has so mehow been
damaged, the brake pedal must be pres sed considerably harder to
make up for the la ck of booster as sistan ce . •
Functioning of Anti-Lock Brake System (ABS)
AB S pre vent s th e wh eels fr o m lo ckin g up un der braking .
The ABS contributes effective ly to ve hicle control s ince it prevents
th e whee ls from
lo cking w hen t he brakes are a ppl ied. This mea ns
that the vehicle remains steerable and is less likely to skid.
With ABS you do not need to pump the brake . Just hold the brake
pedal down.
H owever, do not expect the ABS to shorten braking distance under
all cir cum stances. W hen drivin g on g ravel o r on new ly fallen s now
on top of icy surfac es, bra king distance may be even longer, there ­
fo re, unde r th ese circum stances, i t is especially i mporta nt th a t yo u
drive slow ly and with great care .
How the ABS system works
An automatic check is made when a speed of about 4 mph (6 km/h)
is reac hed . When this ha p pens, a pumping n oise can be hea rd.
If an indiv idua l wheel begins to rotate too s lowly in relation to
vehic le speed and tends to lock, the ABS automatica lly reduces
brake pressure to prevent that whee l from loc king .
T his automat ic adjustment process wil l cause a
slight vibration of
th e br ak e pe dal a nd some noises to ale rt you th at ve hic le sp eed
must be adapted to existing road and traffic conditions.
& WARNING
Although the ABS is very effe ctive , always remember that braking
capability is limited by tire traction. Alway s adjust your driving
speed a ccording to the road and traffi c conditions . Do not let the
extra safety afforded by the ABS tempt you into taking extra risks.
The ABS cannot overcome the laws of physics.
[ i ] Tips
• I f ABS is not funct io ni ng properl y, a wa rn ing li ght will co me o n.
See ~ page 21.
• I f a fault occurs in the A BS, the EDL is also not functioning. This
i s indica ted by the ABS wa rn ing l igh t.•
Brake assistant
The brake assis tant is desig ned to ach ieve the o ptim um
brakin g eff ec t.
The br ake assistan t helps to in cr eas e the effec tive b raki ng pow er
and thus to achieve a shorter stopping distance . If the driver
p re sses the b rake pe dal very q uick ly, the brake assistan t auto mati ­
ca lly boosts the brakin g force to the maximum level, up to th e point
whe re the a nti-lock b rake functi on (AB S) int ervenes to sto p the
w hee ls from loc king . You s hou ld t hen k eep th e br ake pedal pressed
until t he vehicle ha s braked to the required speed . The brake a ssis ­
t ant s witches itse lf off as soo n as you re lease t he bra ke pedal.
T he b rake assistant will not be ope rative if there is a malfunction in
th e 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 the vehicle ahead of you too closely . Increased risk of an
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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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•
from fading . Slight color variations will develop in normal use and
are not an indication of material deterioration.
0 Note
• Never use chemical solvents (e.g. lighter fluid, turpentine),
waxes, shoe polish or similar products on Alcantara® surfaces.
• To avoid damage, have stubborn stains removed by a commer­
cial cleaning specialist.
• Do not use brushes, stiff sponges or similarly abrasive cleaning
aids. •
Safety belts
Only well-maintained safety belts work reliably when
needed.
- Keep belts clean.
- For cleaning, use a mild soap and water solution. Let
belts dry thoroughly and away from direct sunlight.
- Do not allow inertia reel safety belts to retract before
they are completely dry.
- Check the condition of your safety belts
regularly.
Heavily soiled safety belts may not retract properly.
& WARNING
Damaged safety belts can break in a crash.
• Anything that might damage your safety belts could mean that
you and your passengers would not be adequately protected in an
accident.
• Safety belt performance depends on correct installation. Never
remove belts from the vehicle to clean them.
&, WARNING (continued)
• Do not use chemical cleaning agents, bleach or dyes. They have
corrosive properties which weaken the webbing.
• When cleaning your safety belts, inspect them for damage. If
you discover damage, see your Audi dealer.
• Always read and heed all WARNINGS and other information
=> page 288. •
Engine compartment
Be especially careful when cleaning the engine compart­
ment.
Always switch off the ignition before cleaning the engine => &,.
Plenum panel
Remove leaves from the plenum panel in front of the windshield
under the engine hood. This prevents the water drain holes from
becoming blocked, and it prevents debris from entering the vehicle
interior through the heating and ventilation ducts.
Corrosion protection
The engine compartment and transmission have been corrosion­
protected at the factory.
Good anti-corrosion treatment is very important, particularly in the
winter. If the vehicle is frequently driven on salt treated roads, the
entire engine compartment and plenum panel should be thor­
oughly cleaned at the end of winter and retreated to prevent salt
damage. At the same time, the underside of the vehicle should be
washed as well.
If the engine compartment is cleaned at any time with grease
removing solutions
11 , or if you have the engine washed, the anti­
corrosion treatment is almost always removed as well. It is therefore .,_
11 Use only the correct cleaning solut ions. Never use gasoline or diesel fuel.
Vehicle care

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Checking and filling
Engine hood
Releasing the engine hood
The engine hood is released from inside the vehicle.
Fig. 259 Driver's side
footwell: engine hood
release lever
-Pull the release lever on the left under the instrument
panel ~ fig. 259 in the direct ion of the arrow.
The hood pops up slight ly under spring pressure. •
Opening the engine hood
Fig. 260 Release lever
under the engine hood
Before opening the engine hood, make sure that the wind­
shie ld wipers are flat against the windshield. Otherwise,
they could damage the paint on the hood.
Li ft the hood
slightly~ &.
-Pull up on the release under the hood:=} fig. 260. Thi s
releases the catch.
-Open the hood all the way.
The hood is kept in the open position by two gas struts.
& WARNING
Hot engine coolant can burn you.
• 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 . •

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& WARNING
B efor e you che ck an ything in the eng ine comp artm ent, a lw ays
read and heed all WARN ING S
~ & in "W orkin g in the engin e
c omp artment " on
page 30 7. •
Appl ies to vehicles: with 12- cy linder engine
Engine compartment overview : 1 2-cyl inder
engine
These are the most important items that you can check.
F ig . 262 Ty pi cal layout for c ontain ers, en gine oil dip st ic k a nd e ngine o il filler
ca p
G) Windshield/head light washer container ( Q ) . . . . . . . . 323
@ Brake fluid reservoir ( ) . . . . . . . . . . . . . . . . . . . . . . . . 317
© Engine oi l dipstick (orange) . . . . . . . . . . . . . . . . . . . . . . 311
© Engine oil filler cap ('t=:11) .. ...... .... ... ... ... .. . .
© Coolant expansion tank (- L l ..................... .
& WARNING
Before you check anything in th e engine co mpartment , alway s
read and he ed all W ARNI NGS
~ & in "Wo rking in t he engin e
c ompartm ent " on
page 307.
[ i ] Tip s
The coolant expansion tank is located under a cover .•
Engine oil
Engine oil specifications
312
315
The engine oil us ed in your Audi needs the right kind of
oil.
The engine in your Audi is a sophisticated powerplant that was built
to exacting specifications. This engine needs the right kind of engine oil that meets specifications regarding quality and viscosity
so that it can run smoothly and re liably. Choosing the righ t oil and
changing oil within the time and mileage interva ls printed in your
vehicle's Warranty
& Ma intenance book let matters a lo t more today
than it did years ago. Audi has developed a special quality standard
for engine oil that wil l help assure that your vehicle's engine wi ll get
the lubrication it needs for proper operation .
Mode rn engine lubrication has taken a quantum leap in the last few
years . Many syn thetic oils available today provide better engine
lubrication that can outlast traditional petroleum-based oils,
making them a smart choice for use throughout the life of your Audi.
Whether you use synthetic or petroleum -based engine oil, the oi l
that you use must conform to Audi's oi l qua lity standard VW 502 00
..,
Vehic le care I I irechnical data

Checkin g and fillin g 1111
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•
the form of Service or Repair Ord ers that all scheduled maintenance
was perfo rmed in a t imely man ner. •
Engine oil consumption
The engin e in your vehicle d ep ends on an adequate
amount of oil to lubricate and cool all of its moving parts.
In order to provide effect ive lubrication and cool ing of internal
engine components, all internal combustion engines consume a
certain amount of o il. Oil consumption varies from engine to eng ine
and may change significantly over the life of the engine . Typically,
eng ines wi th a specif ied break -in period
(see => page 2771 consume
more oil during the break -in period than they consume after oi l
consumption has stabi lized .
Under normal conditions, the rate of oil consumption depends on
the quality and viscosity of the oil, the RPM (revolutions per minute)
at which the engine is operated, the ambient temperature and road
conditions. Further factors are the amount of oil dilution from water
co ndensation or fue l residue and the oxidation level of the o il. As
any engine is subject to wear as mileage builds up, the oil consump ­
t io n may increase over time until rep lacement of worn components
may become necessary .
With all these variables coming into play, no standard rate of oil consu mption can be estab lished or specified. T here is no a lternative
to regular and frequent checking of the oil level, see
Note .
If the yellow eng ine o il level warni ng symbol in the instrume nt
cluster ~ lights up, you should check the oil level as soon as
poss ible
with the oil dipstick => page 311 . Top off the oil at your
earliest
convenience=> page 312.
& WARNING
Bef ore you che ck anything in the eng ine comp artment , alw ay s
read and heed all WARNINGS
=> & in "Working in the engine
c ompartment " on
page 307 .
0 Note
Driving with an insuff ic ie n t o il level is l ikely to cause severe damage
to the engine.
[ i ] Tip s
• The oil pr es sure warning displ ay level . Do not rely on it. Instead , check the oil level in your engine at
regular inter vals, preferably ea ch time you refuel , and al ways before
going on a long trip.
• I f you have the impression your engine consumes excessive
amounts of oi l, we reco mmend that you consult your Audi dealer to
have the cause of your concern properly diagnosed . Keep in mind
t hat t he acc urate measureme nt of oil consump tion requ ires g reat
care and may take some time. Your Audi dealer has instructions
about how t o measure oil consumpt ion accurately. •
Checking the engine oil level
Vehicle care
Fig. 26 3 Illu stration of
prin cipl e 1: Mar ker s on
o il dip sti ck ...

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0 Note
• Before winter sets in, have the coolant checked to see if the
coolant additive in your vehicle is sufficient to meet the climate
conditions. This is especially important if you live in a region where
the winter is extremely cold. If necessary , increase the proportion of
coolant additive to 60%.
• When adding coolant additive to your cooling system,
remember:
-We recommend using only coolant additive G12+ + (check the
label) for your vehicle. This coolant additive is available at autho­
rized Audi dealers. Other types of antifreeze can significantly
reduce corrosion protection . The resulting corrosion can cause a
loss of coolant and serious engine damage .
• Do not add any type of radiator leak sealant to your vehicle's
engine coolant. Adding radiator repair fluid may adversely affect the
function and performance of your cooling system and could result
in damage not covered by your New Vehicle Limited Warranty .•
Checking the engine coolant level
The engine coolant level can be checked with a quick
glance.
Fig . 267 Engine
compartment : Coolant
expansion tank
Before you check anything in the engine compartment,
always read and heed all WARNINGS => & in "Working in
the engine compartment" on
page 307.
Turn off the ignition.
Read the engine coolant level from the coolant expan­
sion
tank => fig. 267 . With a cold engine, the coolant level
should be between the "min" and "max" markings. When
the engine is warm, the level may be slightly above the
"max" marking.
The location of the coolant expansion tank can be seen in the
engine compartment illustration =>
page 308.
To obtain an accurate reading, the engine must be switched off.
The expansion tank in your vehicle is equipped with an electric
coolant level sensor.
When the coolant level is too low, the warning light in the Auto­
Check
System => page 31 will blink until you add coolant and the
level has been restored to normal. Even though there is an electric
coolant level sensor, we still recommend you check the coolant level
from time to time.
Coolant loss
Coolant loss may indicate a leak in the cooling system. In the event
of coolant loss, the cooling system should be inspected immedi­
ately by your authorized Audi dealer . It is not enough merely to add
coolant .
In a
sealed system, losses can occur only if the boiling point of the
coolant is exceeded as a result of overheating.
& WARNING
The cooling system is under pressure and can get very hot. Reduce
the risk of scalding from hot coolant by following these steps.
.,_
Vehic le care I I Technical data

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&, WARNING (continued)
• Turn off the engine and allow it to cool down.
• Protect your face, hands and arms from escaping fluid and
steam by covering the cap with a large, thick rag.
• Turn the cap slowly and very carefully
in a counter-clockwise
direction while applying light, downward pressure on the top of
the cap.
• To avoid being burned, do not spill antifreeze or coolant on the
exhaust system or hot engine parts. Under certain conditions, the
ethylene glycol in engine coolant can catch fire.
0 Note
Do not add any type of radiator leak sealant to your vehicle's engine
coo lant. Adding radiator repair fluid may adversely affect the func­
tion and perfo rmance of your cooling system and could result in
damage not covered by your New Vehicle Limited Warranty .
[ i] Tips
On vehicles with the 12-cylinder engine, the expansion tank is
located under a cover. •
Adding coolant
Be very careful when adding engine coolant.
Before you check anything in the engine compartment,
always read and heed all WARNINGS => & in "Wor king in
the engine compartment" on
page 307.
-Turn off the engine.
-Let the engine cool down.
-Place a thick rag over the coolant expansion tank
=> page 315, fig. 267 and carefully twist the cap counter­
clockwise
=> & .
-Add coolant.
-Twist the cap on again tightly.
Replacement engine coolant must conform to exact specifications
=> page 314, "Coolant". Even in an emergency, if coolant additive
G12++, G12+ or G12 is not available, do
not use a different additive.
Use plain water instead until you can get the correct additive and
can restore the correct ratio. This should be done as soon as
possible.
If you have lost a considerable amount of coolant, then you should
add cold antifreeze and cold water only when the engine is cold.
Always use
new engine coolant when refilling.
Do not fill coolant above the "MAX" mark. Excess coolant will be
forced out through the pressure relief valve in the cap when the
engine becomes hot.
& WARNING
• The cooling system is under pressure and can get very hot.
Reduce the risk of scalding from hot coolant by following these
steps.
-Turn off the engine and allow it to cool down.
- Protect your face, hands and arms from escaping fluid and
steam by covering the cap with a large, thick rag.
- Turn the cap slowly and very carefully
in a counter-clockwise
direction while applying light, downward pressure on the top
of the cap.
- To avoid being burned, do not spill antifreeze or coolant on
the exhaust system or hot engine parts. Under certain condi-
tions, the ethylene glycol in engine coolant can catch fire. .,,

Checking and filling -_______________________________ =..:..:..::...::.:..;~:.....:...;_.:..:..,__--=--.J
fl::. WARNING (continued )
• Antifr eez e is po isonous. Always stor e antifreeze in it s origin al
c ontainer and well out of the re ach of ch ildren .
• If you drain the coolant , it must be caught and saf ely stored in
a prop er co ntainer cle arly m arked "poi son ".
0 Note
• Coolant po llutes the environment and cou ld cause an engine
fire. Excess coolant will be forced out through the pressure relief
valve in the cap when the engine becomes hot.
• I f, in an emergency, only wa ter can be added, the correct ratio
between water and
antifreeze => page 314 must be restored as soon
as possib le .
W For the sake of the environment
Drained coolant should not be reused . A lways dispose of used
coolant while observing all environmental regulations . •
Radiator fan
The radiator fan switches on automatically by i tself .
The radiator fan is driven by the engine via the V-be lt. The viscous
clutch regulates the speed of the fan according to the temperature
of the coo lan t.
An auxiliary electric radiator fan * switches on and off depending on
coolant temperature and other vehic le opera ting condi tions.
After you switch the engine off , the auxiliary fan can continue
running for up to 10 minutes -even with the ignition off. It can even
switch on again later by
itself =>& , if
• the temperature of the engine coo lant rises due to the heat
bu ild -up fro m the engine in the engine c ompar tment , or •
the engine compartment heats up because the vehicle is parked
in intense sunlight .
& WARNING
• To reduce the ri sk of per sonal injury never tou ch the radiator
fan .
• The au xiliary elect ric fan i s te mperature controlled and can
switch on suddenly e ven when the engine is not running .
• The au xiliary radiato r fan switche s on auto matically when th e
eng ine coolant reache s a certain temperature and will continue to
run until the coo lant temperat ure drop s. •
Brake fluid
Checking brake fluid level
T he brake fluid level can be checked with a quick glance.
-w ;:;
Fig . 26 8 Engin e
c o mp artm ent: B ra ke
fluid r eservoir
Before you check anyth ing in the e ngine compartmen t,
always read and heed all WARNINGS ~ & in "Working in
t h e engi ne compartment " on
page 307. _,,,
Vehicle care I I irechnical data