2008 AUDI A4 AVANT check engine light

• USA models: illumin ation of the in strument clu ste r (gauge s and
needle s), dash and center con sole around the gear shift lever i s
c ontrolled by a light sen sor l oca ted in the in strument panel . The
instrument panel illum ination will automatic ally become dimmer
a s the d aylight f ade s aw ay a nd e ventuall y will go out completel y
wh en out side light is very low . Thi s is to remind you , the driver , to
s witch on the he adlight s before it get s too dark.
• Canada model s: instrument panel illum ination will sta y br ight
rega rdle ss of the inten sity of ambient light . Al ways be aw are of
changes in outside light conditions while you are driving . Respond
in time to fading daylight by tu rning the light switch to position
1[D
(or "AUTO" if your car is equipped with this feature) to turn on your
he adlight s.
•
App lies to veh icle s: w it h xe non head lig hts
Xenon headlights
After sta rting the engine, the xenon head lights are automatica lly
adjusted to the load and angle of the veh ic le ( for example, during
accel eration and braking) . This prevents oncoming traffic from
experienc ing unnecessary headlight glare from your xenon head ­
lights.
I f the system is not operating properly, a warning symbol in the
Auto-Check Control is
displayed=> page 34. •
Controls and equip ­
ment
Cl ea r vision
Emergency flasher ~
The emergency flasher ma kes other motorists aware that
you or your vehicle are in an emergency situation .
Fig. 77 Ce nter
co nso le: e merg en cy
fl as he r sw it ch
- Press the switch &1. ~ fig. 77, to switch t he eme rgency
flasher on or off.
When the emergency flasher is on, all four turn signal blink at the
same time. The turn signal indicator lights ¢
9 in the instrument
c luster, as we ll as the light in the emergency flasher
switch ~ blink
likewise.
The emergency flasher wi ll automatically switch on if you are in an
accident where the airbag has deployed .
[ i] Tip s
You shou ld switch on the emergency flasher when :
• you are the las t vehicle standing in a traffic jam so that any other
vehicles coming can see you, or when
• your vehicle has broken down or you are in an emergency situa -
tion, o r when _.,

_________________________________________ ___:l:.:.. n !.!t ~e :.:.11 :.!.ig ~e :.:..n !.!t :... t::.: e::.: c~ h:..:.:..,: n~o =.!l~o ~g Lly '.,_ _l!III
speed of the vehicle about its vertica l axis, the lateral acce leration
ac ting on the veh ic le, the brake pressure and the s teering ang le a re
a ll measured .
The direction in which the driver wishes to travel is determined with
the aid of the steering angle and veh icle speed and is continua lly
compared with the actual behavior of the vehicle. If the two do not
match, -for example, when the vehicle starts hydrop la ning on a
wet road -
, ESP will au tomatical ly brake the appropria te wheel to
correct the problem .
The vehicle is then stabi lized by the forces acting on the whee l
during braking . If the vehicle is
oversteering (r ea r tends to skid out
of the turn), t he brakes are main ly app lied on the whee l that is on
the outside of the curve . In the case of a vehicle that is
understeering
(tendency to s lide out of the curve) , the bra kes are applied at the
rear whee l that is on the inside of the curve. An acoustic signal indi ­
cates when ESP brake appl ication cuts in
=> & .
The system operates across the entire speed range in combination
wi th the ABS system
~ page 240. If the Ant i- Lock Brake Sys te m
(ABS) malfunctions, the ESP wi ll be out of act ion as well.
Ac tivat ion
When you turn on the engine, ESP will automatica lly be activated
and will perfo rm a self -test.
You can activate a deactivated ESP or deact ivated ASR as requ ired
by pressing the
=> page 236, fig. 199 button.
D eac tiva tion
Norma lly, the ESP should always be on .
When necessary, you can deact ivate Anti -Slip Regulat ion (ASR) or
the Electronic Stabilization Program (ESP) by pressing the button
=> page 236, fig. 199 .
• Dea ctivating A SR: Tap briefly on the ESP button . In certain excep ­
t iona l situations (e .g. driving wit h tire chains or a t a forced pace
around a track), the Anti-S lip Regu lation (ASR) can be deactivated
Controls and equip­
ment Safety first Vehicle operation
=> page
238 . The ESP check light flashes . T ap the ESP button again
t o r eact ivate ASR. The ESP check light g oes out .
• Deactiv ating ESP : Press the ESP button for more than 3 seconds .
W ith ESP deactivated, the ESP check ligh t illum inates cons tant ly .
Press the ESP button again to reactivate ESP . The ESP check light
g o es out .
& WARNING
The Electronic Stabilization Program i s neve rthele ss subject to the
laws of physi cs . It is part icularly important to pa y attent ion to thi s
fact on we t and slippery roads . It is therefore important that you
always adapt your driving to the condit ion of the road and traffic
c onditions. Do not allow the inc reased safety provided by the Elec ­
tronic Stabiliz ation Program sy stem to lull you into a ccepting
additional safety ri sk s.
• Plea se note that when ESP or ASR is dea ctivated , the drive
wheels can spin on icy and slippery roads and the vehicle can
break a way -da nger of skidding! •
Electronic differential lock (EDL)
The elec tr o nic differen tial l ock mon itors t he r ota tion al
speed of the drive wheels .
Gener al not es
The elec tronic d if f erential l ock (EDU helps the ca r to start mov ing,
accelerate and c limb a grad ient on surfaces providing poor or
a lmost n o grip. W ithout EDL, th is w ould be difficult, if no t impos ­
sib le.
How the system works
The EDL operates automatical ly. It monitors the rotational speed of
the drive whee ls on an ax le with the he lp of t he ABS senso rs
=> page 2 40 . If a noticeable difference in rotational speed between
the drive wheels on one axle is de tected (e .g. on sl ippery grou nd
on .,,.
Vehicle care Do-it-yourself service Technical data

-Intelligent technology
------~----- ~~--------------------------------------
one side), the spinning wheel is braked, thereby transferring power
to the other drive wheel or wheels (all- wheel drivel. This is done up
to a speed of about 60 mph (100 km/h). Noises from the brake
system signal that wheel spin is being control led.
Driving off
When driving off, always be sure to keep road conditions in mind as
you accelerate. If one drive wheel spins because it is on a surface
with less grip, gradual ly increase the pressure on the accelerator
pedal until the car starts to move. The wheel less able to transfer
power spins.
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
veh ic le remains operational and behaves in the same way as a
vehic le 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
ca n 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
stabilization program (ESP) . When the vehicle starts up and acceler­
ates, the wheels are prevented from sp inning by adjus tin g the
engine power to match the amount of grip availab le from the road
surface.
How the system works
ASR performs automatical ly, i.e . w ithout the driver's intervention.
With the aid of the ABS
sensors=> page 240, 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 shou ld
occur in the ABS, the ASR will also be out of act ion.
Activation
The ESP is automatica lly activated when the eng ine is started, and
it performs a self-test. You can activate a deactivated ASR, if
requ ired, by pressing
t h e=> page 236, fig . 199 button .
Deactivation
You can deactivate the ASR, if required, by pressing the button (for
less than 3
seconds) => page 236, fig. 199. With the ASR deactivated,
the ESP check light flashes,
see=> page 22.
Normally, the ESP shou ld always be on, however, it may be advanta­
geous to turn off the system in certai n special cases when some
degree of wheel spin is desired such as :
• when driving with snow chains

llffl.___l_n _t _e _ll _ig =- e_n _ t_ te_ c_h _n_ o_ lo-'g'"'-=- y ___________________________________________ _
&, WARNING (continued )
• Before des cending a steep grade , reduce speed and shift trans­
mi ssion into a lo wer gear or lower driving po sition . Do not ride the
brake s or hold the pedal down too long or too often . This could
cau se the brake s to get hot and dimini sh braking efficiency .
• Do not ride the brakes by resting your foot on the ped al when
you do not intend to brake. This may cause the brakes to overheat, premature wear and in creased stopping distan ce.
• Under certain climati c and operating conditions such a s
passing through water, driving in heavy rain or after washing the
v ehicle , the effectiveness of the brakes can be reduced . In winter ,
ice can a ccumulate on the brake pads , linings , discs and drums .
Cautiously apply brakes for a te st. Brakes will dry and ice coating s
will be cleaned off after a few cautious brake applicat ions .
• Driving for an extended period of time on salt-co vered roads
without using your brakes can also affect braking effi ciency . Clean
off accumulated salt coating from brake discs and pads with a few
c autious brake appli cations .
• If you damage the front spoiler , or if you install a different
spoiler , be sure the air flow to the front brakes is not obstructed .
Otherwise the brake system could overheat reducing the effective ­
ness of the entire brake system .
• Failure of one brake circuit will impair the braking capability
resulting in an increased stopping distance . Avo id driving the
vehicle and have it towed to the nearest Audi dealer or qualified
workshop .•
Brake booster
T he brake booster add s ex tra braking power.
The bra ke booster works wit h vacuum pressure which is created
only whe n th e e ng in e is
runn ing=> &,.
& WARNING
• Never let the vehi cle roll to a stop with the engine shut off .
• If the brake booster is not working , for example when towing
your vehicle , or because the brake booster has somehow been
damaged, the brake pedal must be pre ssed considerably harder to
make up for the lack of booster assistance . •
Functioning of Anti-Lock Brake System (ABS)
A BS preven ts th e wh eels fr om lock ing up und er b rak ing.
T he ABS contributes effectively to vehicle contro l since it prevents
th e w heels from
lo cki ng w he n t he brakes a re a ppli ed. T h is 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 .
However, do not expect that the ABS shortens braking distance
u nder all circum sta nces. Whe n driving o n gravel or on newly fa lle n
snow on top of icy surfaces, braking distance may be even longer,
t herefore, under these ci rcums tances, it is espec ial ly i mpo rtant th at
you driv e slowly and with great care.
How the ABS system works
An automatic check is made when a speed of about 4 mph (6 km/h)
i s r eac hed . Wh en th is happe ns, a pumpi ng noi se can be hea rd.
I f a n indiv idual wheel be gins to rotat e too slowly i n relation to
vehic le speed and tends to lock, the ABS automatical ly reduces
brake pressur e to prevent tha t whee l from loc king .
Th is a utomatic adjustment process wi ll cause a
slight vibration of
t he brake peda l a nd s om e noi ses t o a lert y ou th at ve hicle spee d
must be adapted to existing road and traffic conditions. _..

____________________________________________ ln_t_ e_ l_ li _,..g "- e_ n
_ t_t_e _c_ h_ n_o _l_o _....g ,_,y'-----'IJIII
& WARNING
Although the ABS is very effective, always remember that braking
capability is limited by tire traction. Always adjust your driving
speed according to the road and traffic 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
• If ABS is not functioning properly, a warning light will come on.
See~ page 21.
• If a fault occurs in the ABS , the EDL is also not functioning. This
is indicated by the ABS warning light. •
Brake assistant
The brake assistant is designed to achieve the optimum
braking effect.
The brake assistant helps to increase the effective braking power
and thus to achieve a shorter stopping distance . If the driver
presses the brake pedal very quickly, the brake assistant automati ­
cally 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 assis ­
tant switches itself off as soon as you release the brake pedal.
The brake assistant will not be operative if there is a malfunction in
the ABS.
Controls and equip­
ment Safety first
Vehicle operation
& 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. An increased accident
risk cannot be compensated even by the brake assistant, so
always maintain a safe speed. •
Servotronic® -advanced power
steering system
The power steering systems uses the power of the
running engine to allow precise steering with little effort. Your Audi is equipped with the electronically controlled
Servotronic® advanced power steering system. It adjusts
the degree of steering assistance to the roadspeed.
The advanced Servotronic ® power steering system senses the road
speed and electronically adjusts power assistance to provide
comfortable and safe steering response exactly matched to the
vehicle speed .
Power steering will not work if the engine is off. As a result, the
steering wheel will be hard to turn.
The power steering fluid level is checked during the scheduled
maintenance services.
0 Note
If there is an electronic malfunction, servotronic will still function
like a conventional power steering system, providing a constant
steering support force that is no longer proportionate to the vehicle
speed . This is most noticeable when turning the steering wheel at
low speeds (for example when parking), -more effort will be
required than usual.
.,.
Vehicle care Do-it-yourself service Technical data

lffll.,__ __ D_r_ i_v _i_n _.g..,_ a_ n_d_ e_ n_v _ i
_ r_o _ n_ m_ e_ n_ t _______________________________________________ _
one half. Never drive faster than the posted speed limit and weather
conditions permit. •
Reducing unnecessary idling
Even when your car is just idling it burns up fuel.
- Shut the engine off when you are not driving the vehicle .
- Do not warm up the vehic le by letting the engine run at
id le .
It makes sense to shut off the engine in traff ic jams, when waiting
for tra ins to pass at rai lroad crossings , or at traffic lights that have
long waits on red. Turning the engine off for just 30 -40 seconds
saves more fue l than is burned starting the engine again .
It takes a long time for the engine to warm up fu lly when it is
running at idle. However, wear and noxious emiss ions are espec ially
high when the engine is warming up . So you should drive away as
soon as you sta rt the engine and avoid running at high rpms w hile
the engine is sti ll warming up.
0 Note
Do not leave engine idling unattended after starting . If warning
lights should come on to indicate improper operation, they would
go unheeded. Extended id ling also produces heat, which could
resu lt in overheating or other damage to the vehic le or other
property .•
Regular maintenance
A badly tuned engine unnecessarily wastes a lot of fuel.
- Have your ve hicle serviced at regular intervals .
By having your vehicle regularly serviced by an Audi dealer helps to
ensure that it runs properly and economical ly . The cond ition of your
vehic le not only affects its safety and abi lity to hold its value, it also
affects
fuel consumpt ion .
Check your oil ea ch time you fill your t ank .
The amount of oil used is related to engine load and speed.
I t is norma l for the oi l consumption of a new engine to reach its
lowest value after a certain mi leage has been driven.
You must drive your vehicle about 3,000 miles (5,000 kilometers) before you can properly assess oil consumption .
This also applies to fue l consump tion and engine output .
0 Note
• Have your vehicle maintained properly and in accordance with
t he service recom mendat io n s in your Maintenance
& Wa rranty
booklet. Lack of proper ma intenance as well as improper use of the
vehic le wi ll impai r the function of the emission cont rol system and
cou ld lead to damage.
• Do no t alte r or remove any component of the Emission Contro l
System unless approved by the manufacturer .
• Do not alte r or remove any dev ice, such as heat shields,
switches, ignition wires, valves, which are designed to protec t your
vehic le's Emission Control System and other important veh ic le
components .•
Fewer short trips
Fuel consumption will alw ays be rel atively high on short
t r ips.
- Try to avo id driving short dis ta n ces wi th a cold engine. ~

lllffl.___T_ r_a _il _e_ r_ t_o _vv_ i_ n """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 t hat the add it ional load
wi ll affect durability, economy and performance.
Trailer towing not only p laces more stress on the veh icle, it a lso ca lls
for more concentration from the driver.
For th is reasons, always fo llow the operating and dr iving instruc ­
t ions provided and use common sense. •
Technical requirements
Trailer hit ch
Use a weight -carrying hitch conforming to the gross trailer weight.
The hitc h must be suitab le for your veh ic le and tra iler and must be
mounted securely on the vehicle's chassis at a technically sound
l ocation. Use only a tra iler hitch with removable bal l mount. A lways
check with the trai ler hitch manufacturer to make sure that you are
using t he correct hitch .
Do not use a bumper hit ch .
The hitch must be installed in such a way that it does not interfere
with the impact-absorb ing bumper system . No mod ifications
shou ld be made to the vehicle exhaust and brake systems. From
time to time, check that all hitch mount ing bo lts re main securely
fastened.
When you are not towing a trai ler, remove the trailer hit c h ball
mount. Th is prevents the hitch from causing damage s hou ld your
vehic le be struck from
behind ~& .
Tire pre ssure
When towing a trailer, inf late the tires of your vehic le to the cold tire
pressure listed under "Full load" on the s ticker on the right door­
jamb . Inflate trai ler tires to tra iler and tire manufacturers' specifica­
t ions.
Lights
T he head ligh t settings shou ld be checked with the trailer at tached
before driving off. Have the head lights adjusted as necessary so
t hat you can see t he road ahead bu t not bl ind oncom ing traffic.
Check to make sure both vehicle and trailer lights are working prop ­
e rly .
Engine cool ing sy stem
Towing a t railer makes the eng ine work ha rder. It is imp ortant tha t
the cooling system's performance stands up to the additiona l
strain. Make sure that the coo ling system has enoug h fluid.
Traile r br ake s
If your tra ile r i s eq uipped wi th a braki ng system, check to be s ure
that it conforms to al l regu lations .
T he tra iler hydraulic brake system must no t be direct ly connected to
the vehic le's hydrau lic brake system .
Safety chains
Be sure trailer safety chains are properly connected from the trai ler
t o the h itch on the vehicle. Leave enough s lack in t he chains to
permit turning corners. When you install safety chains, make sure
they will not drag on the road when you are driving.
T he chains shou ld cross under t he trailer tongue to prevent it from
dropping in case of separation from the hitch. _,,,

_______________________________________________ C_l_ e _a_ n_ in---= g'-- a_n_ d
_.:.. p_r_o _ t_ e_ c_ t·_
1o _ n __ l9III
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.
• 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 the information
=> page 254. •
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
21 , or if you have the engine washed , the anti­
corrosion treatment is almost always removed as well. It is therefore
essential to have a long-lasting corrosion protection reapplied to all
surfaces, seams, joints and components in the engine compart ­
ment.
& WARNING
Be aware: the engine compartment of any motor vehicle is a
potentially hazardous area.
• Before working in the engine compartment, be sure to read the
information
=> page 265 . .,,_
21 Use only the corr ect cleaning solutions. Never use gasoline or diesel fuel.
Vehicle care