2009 AUDI A4 CABRIOLET check engine light

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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 additional load
will affect durability, economy and performance.
Trailer towing not on ly p laces more stress on the vehicle, it a lso calls
for more concentration from the driver.
For this reasons, always fo llow the operating and driving instruc ­
tions provided and use common sense. •
Technical requirements
Trailer hitch
Use a weight -carrying hitch conforming to the gross trailer weight.
The hitch must be suitab le for your veh ic le and tra iler and must be
mounted securely on the vehicle's chass is at a technically sound
l ocation. Use only a trailer hitch with removable bal l mount. A lways
check with the trailer hitch manufacturer to make sure that you are
using the correct hitch .
Do not u se a bumper hit ch .
The hitch must be installed in such a way that it does not interfere
with the impact-absorbing bumper system . No modifications
should 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 hitch ball
mount. This prevents the hitch from causing damage shou ld your
vehic le be struck from behind
=:, & .
Tire pre ssur e
When towing a trailer, inflate 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 trai ler and tire manufacturers' specifica ­
tions.
Lights
The head ligh t sett ings should be checked with the trai ler attached
before driving off. Have the head lights adjusted as necessary so
that you can see the road ahead but not blind oncoming traffic.
Check to make sure both vehicle and trailer lights are working prop ­
erly .
Engine cooling sy stem
Towing a trailer makes the engine work harder. It is important tha t
the cooling system's performance stands up to the additional
strain. Make sure that the coo ling sys tem has enough fluid .
Trailer brakes
If your traile r is equipped wi th a braking system, check to be sure
that it conforms to all regu lations .
The trailer hydraul ic brake system must not be direct ly connected to
the vehic le's hydraulic brake system .
Safety chains
Be sure trailer safety chains are properly connected from the trai ler
to the hitch on the vehicle. Leave enough slack in the chains to
permit turning corners. When you install safety chains, make sure
they will not drag on the road when you are driving.
The chains shou ld cross under the trailer tongue to prevent it from
dropping in case of separation from the hitch.
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Safety belts
Only well-maintained safety belts work reliably when
needed.
Heavily soiled safety belts may not retract properly.
- 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 condit ion of your safety belts
regularly.
& 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 230. •
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.
I f 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 242. .,.,
21 Use only the correct cleaning solutions. Never use gasoline or diesel fuel.

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Checking and filling
Engine hood
Releasing the engine hood
The engine hood is released from inside the vehicle.
Fig . 194 Driver's side
footwell: engine hood
release lever
-Pull the release lever on the left under the instrument
panel => fig. 194 in direction of the arrow.
The hood pops up slightly under spring pressure .•
Opening the engine hood
Fig. 195 Release lever
under the hood
Before opening the engine hood, make sure that the wind­
shield wipers are flat against the windshield. Otherwise,
they could damage the paint on the hood.
Lift the hood slightly =>& .
- Pull the release under the hood
=> fig. 195. This releases
the catch.
- Open the hood all the way.
The hood is kept in the open position by a gas strut .
& 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. •
Vehicle care irechnical data

-Ch
ecking and filling
_ _..;:::;__=----------------
©
©
0
Coolant expansion tank (.J_ J .. .. .. .. . ... .. .. .... .
Windshield/head light washer container ( O ) ..... .. .
Po wer steering re servoi r
& WARNING
Before you check anything in the engine compartment , always
read and heed all WARNINGS
=> & in "Working in the engine
c ompartment " on
page 250. •
Applies to veh icles : w ith 6 ·cy lind er engine
3.2 liter , 6-cylinder engine (255 hp)
258
266
217
Th ese a re t he most im por tan t it em s th at you c an ch eck.
F ig . 197 Engine compartment : 3.2 liter , 6- cylinder
G) Battery ... ... .. ...... .... ... .... .... .... ..... .
0 Bra ke fluid reservoir ( l ....... .. .. .. .. ...... .. .
© Engine oil fi ller cap ('t:::n) ..•. ..• ..... .•. ...• ..•..
26 1
260
255
©
©
©
0
Engine oil dipstick (orange) ...... ..... ... .... ... .
Coolant expansion tank
( -L J .. ... ... . .... ... ... .. .
W indshield/headligh t washer c ontainer (O l .. .... . .
Powe r steering rese rvoir
& WARNING
Before you check anything in the engine compartment, always
read and heed all WARNINGS
=> & in "Working in the engine
compartmen t" on
page 250. •
Engine oil
Engine oil specifications
254
258
266
2 17
The engine oil used in your Audi needs the right kind of
oil.
The engi ne in y our Audi is a sophisticated powe rp lan t tha t was built
to exacting specifications. This engine needs the right kind of
eng ine oil that meets specifications regarding quality and viscos ity
so that it can run smoothly and reliably . Choosing the right oil and
changing oil within the time and mileage interva ls printed in your
vehic le's Warranty
& Maintenance booklet matters a lot more today
than it did years ago. Audi has developed a special quality standa rd
f or e ngin e oil tha t w ill help assure that your vehicle's engine will get
the lubrication it needs for proper operation.
Modern engine lubrication has taken a quantum leap i n the last few
years. Many synthetic oils ava ilable today provide better engine
lubrication that can o utlast traditional petro leum -based oil s,
making them a smart choice for use throughout the life of your Audi.
Whether you use synthetic or petro leum -based engine oil, the oi l
tha t you use mus t conform to Audi 's oi l qual ity standard VW 502 00
to help keep your vehicle's engine running smoothly and help ._

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the form of Service or Repair Orders that all scheduled maintenance
was performed in a timely manner. •
Engine oil consumption
The engine in your vehicle depends on an adequate
amount of oil to lubricate and cool all of its moving parts.
In order to provide effective lubrication and cooling of internal
engine components , all internal combustion engines consume a
certain amount of oil. Oil consumption varies from engine to engine
and may change significantly over the life of the engine. Typically,
engines with a specified break -in period (see~
page 219) consume
more oil during the break-in period than they consume after oil
consumption has stabilized.
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
condensation or fuel residue and the oxidation level of the oil. As
any engine is subject to wear as mileage builds up , the oil consump­
tion may increase over time until replacement of worn components
may become necessary .
With all these variables coming into play, no standard rate of oil
consumption can be established or specified. There is no alternative
to regular and frequent checking of the oil level, see
Note.
If the yellow engine oil level warning symbol in the instrument
cluster lights up, you should check the oil level as soon as
possible
with the oil dipstick~ page 254. Top off the oil at your
earliest convenience~
page 255.
& WARNING
Before you check anything in the engine compartment, always
read and heed all WARNINGS
~ & in "Working in the engine
compartment" on
page 250.
0 Note
Driving with an insufficient oil level is likely to cause severe damage
to the engine.
[ i] Tips
• The oil pressure warning display 't!::r. is not an indicator of the oil
level. Do not rely on it. Instead, check the oil level in your engine at
regular intervals, preferably each time you refuel, and always before
going on a long trip.
• If you have the impression your engine consumes excessive
amounts of oil, we recommend that you consult your Audi dealer to
have the cause of your concern properly diagnosed . Keep in mind
that the accurate measurement of oil consumption requires great
care and may take some time . Your Audi dealer has instructions
about how to measure oil consumption accurately. •
Checking the engine oil level
Fig. 198 Illustration of
principle 1: Markers on
oil dipstick ..,_

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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 . 202 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 250.
Turn off the ignition.
- Let the eng ine cool down.
Place a thick rag over the coolant expansion tank
~ fig. 202 and carefully twist the cap counter-clockwise
~& .
Read the engine coolant level in the open coolant expan­
sion tank~ fig. 202. 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 252.
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 l evel 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. ..,.

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•
& WARNING
The cool ing system i s under pre ssure and can get very hot . Redu ce
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 cover ing the cap with a large , thick rag .
• Turn the cap slowly and very carefully
in a counter -clockwi se
dire ction 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
coolant. Adding radiat or repa ir fl uid may adversely affect t he func ­
tion and performance of your coo ling system and could resu lt in
damage not cove red by y our New Vehicle Limi ted Wa rran ty .•
Adding coolant
B e very c are ful when addi ng engi ne cool ant.
Be fore you check a nything in the e ng ine comp artmen t,
always read and heed all WARNINGS=> & in "Work ing in
t h e eng ine compa rtment" on
page 250 .
-Tur n off th e engine.
- Le t th e eng in e co ol d ow n.
- Place a t hick rag over the coo la nt expansio n tank
~ page 258 , fig. 202 an d carefully tw is t th e cap coun te r­
cl ockw ise
~ & .
Add co o lant .
- Twist the cap on aga in
tig htly .
Replacement engine coolant must conform to exact specifications
~ page 257 , "C oola nt". Even in an eme rgency, if co ola nt addi tive
G 12 ++, G12+ or G1 2 is not availab le, do
not use a different additive .
Us e pla in wate r instead until you can ge t the co rrect add itive and
can res tor e th e correc t ra tio. T his shou ld be don e as soon as
pos sible.
If y ou have los t a co nsid era ble amount of coo la nt, t hen y ou should
add cold antifreeze and cold water only when the engine is cold.
A lways use
new engine c oo la nt whe n refil ling .
Do not fill coola nt a bove the "M AX" mark. Excess coo lant w ill be
forced out through the pressure relief va lve in the cap when the
eng ine beco mes hot.
& WARNING
• The cooling system i s 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 exhau st system or hot engine parts. Under certain condi ­
tions, the ethylene glycol in engine coolant can catch fire .
• Antifreeze is poisonous . Always store antifreeze in its original
container and well out of the reach of children .
• If you drain the coolant , it must be caught and safely stored in
a proper container clearly marked "poison ". _,.
Ve hic le care

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0 Note
• Coolant pollutes the environment and could cause an engine
fire. Excess coolant will be forced out through the pressure relief
valve in the cap when the engine becomes hot.
• If, in an emergency, only water can be added, the correct ratio
between water and antifreeze~
page 257must be restored as soon
as possible.
<£> For the sake of the environment
Drained coolant should not be reused. Always dispose of used
coolant while observing all environmental regulations. •
Radiator fan
The radiator fan switches on automatically by itself.
The radiator fan is driven by the engine via the V-belt. The viscous
clutch regulates the speed of the fan according to the temperature
of the coolant.
An auxiliary electric radiator fan* switches on and off depending on coolant temperature and other vehicle operating conditions.
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 coolant rises due to the heat
build -up from the engine in the engine compartment, or
• the engine compartment heats up because the vehicle is parked
in intense sunlight.
& WARNING
• To reduce the risk of personal injury never touch the radiator
fan .
_& WARNING (continued)
• The auxiliary electric fan is temperature controlled and can
switch on suddenly even when the engine is not running .
• The auxiliary radiator fan switches on automatically when the
engine coolant reaches a certain temperature and will continue to
run until the coolant temperature drops. •
Brake fluid
Checking brake fluid level
The brake fluid level can be checked with a quick glance.
Fig. 203 Engine
compartment: Brake
fluid reservoir
Before you check anything in the engine compartment,
always read and heed all WARNINGS:::::, & in "Working in
the engine compartment" on
page 250.
Pull the rubber strip@ up partially and lift the cover @
slightly :::::, fig. 203.
- Read the brake fluid level from the brake fluid reservoir
©. The brake fluid level must be between the "MIN" and
"MA X" markings. _..