2012 AUDI A3 check engine light

174 Trailer towing
Trailer towing Driving with a trailer
General information
Your Audi was designed primarily for passen­
ger transportation .
If you plan to tow a tra iler, p lease remember
that the addit ional load will affect durability,
economy and performance.
T railer towing not on ly places more stress on
the vehicle, it also calls for more concentra­
tion from the driver.
F or this reasons, always follow the operating
and drivi ng in str uctions provided and use
common sense.
Technical requirements
Traile r hitch
Use a weight-carrying hitch conforming to the
gross trailer weight. The hitch must be suita­
b le for your veh icle and trailer and must be
mounted securely on the ve hicle's chassis at a
technically sound location. Use only a trailer
h itch with removable ba ll mount. Always
check with the tr ailer hitch manufac turer to
make sure tha t you are using t he cor rect
hitch.
Do not us e a bumper hitch .
The hitch must be installed in such a way that
it does not interfere with the impact-absorb­
ing bumper syst em. No modifications should
be made to the vehi cle exhaust and brake sys ­
tems. From time to time, check th at a ll hitch
mo unt ing bo lts remain securely fastened.
When you are not towing a trailer, remove the
tra iler hitch ball mount. This prevents the
h itch from causing damage sho uld your ve hi­
cle be str uck from behind
¢ A .
Tire pressure
When tow ing a traile r, inflate the t ires of your
ve hicle to the co ld tire pressure listed under
"Full load"on the stick er on the rig ht doo r- jamb. Inflate trailer tires to trailer and tire
manufacturers' specifications.
Lights
T he headlight set tings sho uld be checked with
t h e trai le r attached before d riving o ff. Have
the headlights adjusted as necessary so tha t
yo u can see t he road ahead b ut not blind on­
coming traffic.
Check to make sure bo th ve hicle and tr ailer
lights are wo rk ing properly .
Engine cooling system
T owing a t railer makes the engine work hard­
er.
It i s impo rtant that the cooling system's
performance stands up to the additional
stra in. Make sure tha t the cooling sys tem has
enough fluid.
Trailer brakes
If your trailer is equipped with a brak ing sys­
tem, c heck to be sure t hat it conforms to all
regula tions.
The trailer hyd raulic brake system must not be
directly connected to the vehicle's hydraulic
brake system.
Safety ch ains
Be sure trailer safety chains are properly con­
nected from the trailer to the hitch on the ve­
hicle. Leave enough slack in the cha ins to per­
mit turning co rne rs. When yo u in stall safety
c h ains, ma ke sure they will not drag on the
r oad when you a re driving.
The chains should cross under the t railer
tong ue to prevent it from dropping in case of
separation from the h itch.
Trailer lights
Trai ler lights must meet all regulations. Be
sure to check w ith your authorized Audi dealer
for correct w ir in g, sw itches and re lays .
Mir rors
If you are unable to see the traffic behind you
us ing the regular outside mirrors, then you

(D Note
- Never use chemical solvents (e.g . lighter
flu id, turpentine), waxes, shoe polish or
s imilar products on Alcantara ® surfaces.
- To avoid damage, have stubborn stains
removed by a commercia l cleaning spe­
cialist.
- Do not use brushes, stiff sponges or sim­
ilarly abrasive cleaning aids.
Safety belts
Only well-maintained safety belts work relia­
bly when needed.
.. Keep belts clean .
.. For cleaning, use a mi ld soap and water sol­
ution . Let be lts dry thoroughly and away
from direct sunlight.
.,. Do not allow inertia reel safety belts to re­
tract before they are completely dry.
.,. Check the condition of your safety belts
reg­
ularly .
Heavily soiled safety belts may not retract
properly .
A WARNING
Damaged safety belts can break in a crash.
- Anything that might damage your safety
belts could mean that you and your pas­
sengers wou ld not be adequately pro­
tected in an acc ident.
- Safety belt performance depends on cor­
rect installation. Never remove belts
from the vehicle to clean them.
- Do not use chemical cleaning agents,
bleach o r dyes. They have corros ive prop­
erties whi ch weaken the webbing.
- When cleaning your safety belts, inspect
them for damage.
If you discover dam­
age, see your a uthorized Audi dea ler.
- Always read and heed all WARN INGS and
other information
Q page 178.
l ) Use o nly the correct cleaning sol utions. Neve r use gas­
oline or d iese l fuel.
Cleaning and protec tion
Engine compartment
Be especially careful when cleaning the en­
gine compartment.
A lw ays switch o ff the ign it ion before cle an ­
i ng the eng ine
c> ,& .
Plenum pan el
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 enter ing
the vehicle interior through the heating and
vent ilat ion ducts.
Co rro sio n protect ion
The engine compartment and transmission
have been corrosion-protected at the factory.
Good anti -corrosion treatment is very impor­
tant, partic ularly in the winter.
If the vehicle
is frequently driven on salt treated roads, the
entire engine compartment and p lenum panel
should be thoroughly cleaned at the end of
winter and retreated to prevent salt damage.
At the same time, the underside of the vehicle
shou ld be washed as well.
If the engine compartment is cleaned at any
time with grease remov ing solutions
1> , or if
you have the engine washed, the anti-corro­
s ion treatment is almost always removed as
well.
It i s therefo re essentia l to have a long­
lasti ng cor rosion pro tect ion reapplied to all
surfaces, seams, joints and components in the
engine compartment .
A WARNING
Be aware: The engine compartment of any
motor vehicle is a potentially hazardous
area.
- Before work ing in the engine compart­
ment, be sure to read the information
c>page 194.
- Before reaching into the front plenum
panel, a lways remove the ignit ion key.
187
•
•

194 Checking and filling
Checking and filling
Engine hood
Releasing the engine hood
The engine hood is released from inside the
vehicle .
Fig. 155 Driver' s side footwe ll: e ngin e hood release
lever
.. Open the driver's door.
.. Pull the release lever on the left under the
instrument panel
c> fig . 155 in direction of
the a rrow .
The hood pops up slight ly under spring pres­
sure.
Opening the engine hood
Fig . 156 Engine hood releas e le ve r
Before opening the eng ine hood, make sure
that the windshie ld wipers are folded flat
against the windshield . Otherwise, they could
damage the paint on the hood.
.. Pull the release lever
r=;,fig . 156 in the direc­
tion indicated by the arrow . This release the
hook under the hood .
.. Open the hood all the way.
A 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 coo lant escaping from the eng ine
compartment . Wait unt il no steam or
coolant can be seen or heard before care­
fu lly opening the hood.
Closing the engine hood
.. Pull the hood down until the pressure from
the strut is reduced .
.. Let the hood
drop down and latch in p lace.
Do not try to push it shut; it may fail to en­
gage
c> .&, .
A WARNING
--
A hood that is not completely latched
could fly up and b lock your view while dr iv­
i ng.
- When you close the engine hood, check it
to make sure the safety catch has proper­ly engaged . The hood shou ld be flush
with the surrounding vehicle body parts.
- If you notice while dr iv ing that the hood
is not secured properly, stop at once and
close it .
Working in the engine compartment
Be especially careful whenever you work in
the engine compartment!
Whene ve r you must pe rform any wo rk in the
eng ine compartment, for e xample chec king
and filling differ ent fluid s, the re i s a risk of
injury , burns and accident s. T o pr event p er­
s onal injury alwa ys observe the foll owing
WARNING S. Th e engin e c ompartm ent of an y
v e hicl e is a hazardou s area!
r=;, .&.
A WARNING
To help avoid injury, before yo u check any­
thing under the hood:
- Turn off the engine .
- Remove the ignition key.

names etc.) that conform to Audi oil standard
VW 502 00 (vehicles with gasoline engine) or
VW 507 00 (vehicles with diesel engine).
C hang ing th e engin e oil
The engine oil and oi l filter must be changed
according to the m ileage (kilomete rs) and
time inte rva ls specified in yo ur vehicle's War­
ranty
& Maintenance booklet. Do not exceed
these intervals -harmful deposits from old
engine oil can reduce engine performance and
can lead to expensive eng ine repairs.
Changing the o il at the recommended inter ­
va ls is so very important because the lubricat ­
ing properties of oi l decrease gradually during
norma l vehicle use . If you are not sure when
you have your oi l changed, ask your author­
ized Audi Service Advisor.
Under some circumstances the engine oi l
should even be changed more frequently.
Change o il more often if you drive mostly
short distances, operate the vehicle in dusty
areas or mostly under stop-and-go traffic con­
d itions, or when you use your veh icle where
temperatures stay below freezing point for
l ong periods.
Detergent addit ives in the o il w ill make fresh
oil look dark after the eng ine has been run­
n ing for a short time. This is norma l and is not
a reason to change the o il mo re often than
r ecommended.
D amage or ma lf u nction s du e to lac k of
ma int enance
It is essential that you change your oil at the
recommended interva ls using only engine oil
that complies with Audi oil standard
VW 502 00 (veh icles with gasolin e engine) or
VW 507 00 (veh icles with diese l engi ne). Yo ur
L im ited New Vehicle Warra nty does not cover
damage or ma lfunctions due to failure to fol­
l ow recommended maintenance and use re­
quirements as set forth in the A udi Owner's
Manual and Warranty
& Maintenance book let.
Your dealer will have to deny warranty cover­ age un less you present to the dea ler proof in
the form of Service or Repa ir Orders that a ll
Checking and fillin g 199
scheduled maintenance was performed in a
timely manner.
· Engine oil consumption
The engine in your vehicle depends on an ade ­
quate amount of oil to lubricate and cool all
of its moving parts.
In order to prov ide effective lubrication and
cooling o f inte rna l engine components, all in ­
ternal combustion engines consume a certain amount of oil. Oil consumpt ion varies from
engine to engine and may change sign ificantly
over the life of the engine. Typically, engines
with a spec ified break-in period (see
Q page 169) consume more oil during the
break-in pe riod than they consume after o il
consump tion has stabilized.
Under normal cond itions, the rate of oi l con­
sumption depends on the quality and viscos ity
of the oil, the RPM (revolut ions per minute) at
which the engine is operated, the ambient
temperature a nd road conditions. Further fac ­
tors are the amount of oil dilut ion from wa ter
condensation or fue l residue and the oxida ­
tion level of the oi l. As any engine is subject to
wear as mi leage builds up, the oil consump­
tion may increase over time until replacement
of worn components may become necessary.
With a ll these variab les coming into p lay, no
standard rate of oil consumption can be es­
tablished or spec ified. There is no alternative
to regular and frequent check ing of the oil lev­
el, see
Not e.
If the yellow engine oil level warning symbo l
in the instrument cluster
Ill! lights up, you
shou ld check the oil leve l as soon as possib le
with the oil dipstick q page 200 . Top off the
o il at your earliest conven ience
Q page 200.
&_ WARNING
Before you chec k anything in the engine
compartment, always read and heed al l
WARNI NGS
Q .&. in Working in the engine
compartment on page 194 .
•
•

204 Checking and filling
Checking the engine coolant level
The engine coolant level can be checked with
a quick glance .
Fig. 162 Engine compartme nt: coo lant expansio n tank
Before you check anything i n the eng ine com­
partment,
a lw ays rea d and h eed all WARN­
ING S ¢&. in Working in the engine compart­
ment on page 194.
.. Park your vehicle on a level surface.
.. Turn
off the ignit ion .
.. Read the eng ine coolant leve l from the
coolant expansion tank<=>
fig. 162 . With a
cold eng ine, the coo lant level should be be­
tween 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 illus­
tration
i:> page 196.
To obtain an accurate read ing, the engine
must be switched
off.
The expansion tank in yo ur vehicle is equipped
with an e lectric coolant level sensor .
When the coolant level is too low, the warning light in the Auto -Check System
c> page 17 w ill
blink until you add coo lant and the level has
been restored to norma l. Even though there is
an electric coolant level sensor, we still rec­
ommend you check the coolant level from
time to time.
Coolant lo ss
Coolant loss may indicate a le ak in the cooling
system . In the event of coolant loss, the cool­
ing system should be inspected immediately by your authorized Audi dea
ler .
It is not
enough merely to add coolant .
In a
se aled system, losses can occur on ly if
the boiling point of the coo lant is exceeded as
a res ult of overheating.
(D Note
Do not ad d any type of radiator leak sea l­
ant to your veh icle's engine coolant . Add­
i ng radiator repair fl uid may adverse ly af ­
fect the funct ion and performance of your
cooling system and could result in damage not covered by your New Veh icle Limited
Warranty .
Adding coolant
Be very careful when adding engine coolant.
Before you check anything in the eng ine com ­
partment,
a lw ays re a d and heed all WARN­
INGS c::> A in Working in the engine compart ­
ment on page 194 .
.. Turn off the engine .
.. Let the engine cool down.
.. Place a thick rag over the coolant expansion
tank
c::> page 204, fig . 162 and ca refull y
twist the cap counter-clockwise c::> A.
.. Add coo lant .
.. Twist the cap on aga in
tightly .
Replacement engine coolant must conform to
exact spec ificat ions
c::> page 203, Coolant.
Even in an emergency, if coolant addi-
t ive G12++ . G 12+ or G12 is not ava ilable, do
n ot use a d iffe rent addit ive. Use plain water
instead unt il you can get the correct add itive
and can restore the correct ratio. This shou ld
be done as soon as possible .
If you have lost a considerab le amou nt of
c oolant, then you sho uld add cold ant ifree ze
and co ld wate r on ly when the engine is cold.
Always use
new engine coo lant when refilling .
Do not f ill coolant above the
"MAX" mark. Ex­
cess coolant will be forced out through the
pressure relief valve in the cap when the en -
gine becomes hot .
Iii>

206 Checking and filling
Brake fluid
Checking brake fluid level
The brake fluid level can be checked with a
quick glance .
Fig. 163 Engine compartme nt: brake flu id reservo ir
Before you check anything i n the engine com ­
partment,
a lwa ys rea d and h eed a ll WA RN·
ING S c:> & in Working in the engine compart ­
ment on page
194.
~ Read the brake fluid level from the bra ke
fluid reservoir. The brake fluid Level must be
between the "MIN" and "MAX" markings
9fig. 163 .
The brake f lu id rese rvoir is located at the rear
partition of the engine compartment on the
L eft side
¢page 196.
The fluid level may drop slightly after some
time due to the automatic adjustment of the b rake pads . This is not cause for alarm .
I f the b rake fluid Level falls
considerably be­
low the "MIN" mark, the brake wa rning/ind i­
cator Light (U.S. models:
1111 , Canadian
models:
llllt will come on c:> page 15 . Do not
continue to operate the vehicle . The complete
brake system sho uld be thoroughly checked
by an authorized Audi dealer or other quali­
fied facility and the cause corrected. If the
brake fluid level is too low, the brake warn ing/
indicator Light w ill illuminate . Contact an au­
thor ized Audi dealer
imm ediatel y.
Changing brake fluid
Have the brake fluid changed by an experi­
enced technician .
Brake fluid absorbs moisture from the air. If
the water content in the brake fluid is too high, corrosion in the brake system may result
after a period of time . The boiling point of the
brake flu id will also decrease conside rably and
decrease braking pe rformance.
Therefore, the brake fluid must be changed
eve ry two y ears. Always use new brake flu id
which conforms to Federal Motor Veh icle
Standard "F MVSS 116 DOT 4".
The brake fluid reservoir can be diff icult to
reach, therefore, we recommend that you
have the b rake fluid changed by your author­
ized
Audi dealer . Your dealer has the correct
tools, the right brake fl uid and the know -how
to do this for you.
A WARNING
- Brake fluid is poisonous . It must be stor­
ed only in the closed original container
out of the reach of children!
- Brake failure can resu lt from o ld or inap­
propriate brake flu id. Observe these pre­
cautions:
- Use only brake f luid that meets SA E
specifica tion
J 1 7 03 and conforms to
Federa l Moto r Ve hicl e Standard 1 16.
Always check with yo ur authorized Aud i
dealer to make sure yo u are using the
correct brake fluid. The correct type of brake f lu id is also ind icated on the
brake flu id reservoir.
- The brake fluid must be new. Heavy use
of the brakes can cause a vapor lock if
the brake fluid is left in the system too
l ong. This can seriously affect the effi­
c iency of the brakes as well as your
safety. This cou ld resu lt in an accident.
(D Note
Brake fluid will damage the paint of your
vehicle .

@ For the sake of the environment
Because of the problem of proper disposal
of brake fluid as we ll as the special tools
req uired and the necessary expert ise, we
recommend that you have the brake fluid
changed by your author ized Audi dealer.
Battery
General information
All work on the battery requires technical
knowledge!
F ig . 1 64 Eng ine co mpa rtment: Batte ry w it h cover*
The battery is located in the engine compart­
ment
c::> fig. 164 and is near ly m ain te nance­
fre e.
The condition of the battery is checked in the
framework of the inspection.
Disconnecting the battery
The batte ry should not be disconnected. Some
ve hicl e functions such as power windows are
unavailable if the battery termina ls are dis­
connected. These funct ions have to be re­
l earned after the battery term inals are con­
nected aga in. To prevent this, the battery
should only be disconnected from the vehicle
electrical system if absolutely necessary .
Function
Power window
one-touch up/
down function
Master key with
remote control
Reprogramming
c::, page 45, Reactivating
the system after battery
disconnection
Synchronization
~page 38
Checkin g and fillin g 207
Reprogramming
Digita l clock c::, page 11
ESP indicator light The indicator ligh t goes
out after driving a few
meters
Vehicl es not driven for long periods and
sho rt -d is tance op eration
If you do no t drive your vehicle for several
days or weeks, electrical consumers are grad ­
u ally scaled back or switched off . This reduces
energy use and ensures the vehicle will be
able to start after long periods of time
c::, page 167. Some convenience functions
such as opening w it h the remote control key
may not be available. These conve nience func­
tions wi ll be available again once you switch
the ignit io n on and sta rt the engine. Even
whe n consume rs a re switched off, the battery
will become deeply discharged by stand -by
power consumers if the vehicle is not driven
for several months . Deep discharging results
in a chemical reaction that destroys the inside
of the battery. The battery must be charged
every month to prevent th is
c::, page 209. Do
not disconnect the battery or the anti-t heft
alarm system* will not work .
Winter operation
Cold weather places higher demands on the
battery. This results in reduced starting abili­
ty. Have the battery checked and recharged if
necessary befo re the cold weather begins.
Avoid unnecessary power consumpt ion, par­
ticularly in city traffic or when traveling only
short distances . Let your authorized Audi
dealer check the capacity of the vehicle bat­
tery before winter sets in
c::, page 209 . A well
c harged bat tery will not o nly prevent s tarti ng
problems when the weather is cold, but will
also last longer .
(D Note
-All wo rk on the batte ry requ ires techn i­
cal know le d ge. P lease con ta ct an Audi
dealership or another authorized fa cility
lill>

-When a battery is charged, it produces
hydrogen gas which is explosive and
could cause personal injury.
- Always keep the battery well out of the
reach of children.
- Before work is done on the electrical sys­
tem, disconnect the negative ground ca­
ble.
- Before performing any work on the elec­
trical system, switch off the engine and
ignition as well as any electrical equip­
ment. The negative cable on the battery
must be disconnected. If you are just go­
ing to replace a light bulb, then it is
enough to switch off the lights.
- Before disconnecting the battery, switch
off the anti-theft alarm system! Other­
wise you will set off the alarm.
- When disconnecting the battery, first
disconnect the negative cable and then
the positive cable.
- Before reconnecting the battery, make
sure all electrical consumers are switch­
ed off. Reconnect the positive cable first
and then the negative cable. Never inter­
change the cables -this could start a fire!
- Never charge a frozen or a thawed-out
battery. It could explode! If a battery has
frozen, then it must be replaced. A dis­
charged battery can freeze over at
32 °F
(0 oc).
-Mak e sure the vent hose is always attach­
ed to the opening on the side of the bat­
tery.
- Never use batteries which are damaged.
There is the danger of an explosion! Al­
ways replace a damaged battery.
_& WARNING
California Proposition 65 Warning:
- Battery posts, terminals and related ac­ cessories contain lead and lead com­
pounds, chemicals known to the State of
California to cause cancer and reproduc­
tive problems. Wash hands after han­ dling.
Checking and filling 209
(D Note
- Do not disconnect the vehicle battery
when the ignition is switched on or when
the engine is running, otherwise, you will
damage electronic components in the
electrical system.
- When working on the engine, protect the
battery housing from ultraviolet (UV)
rays by not parking the vehicle in direct
sunlight .
- If your vehicle is going to stand for a
long period of time without being driven,
protect the battery from "freezing", oth­
erwise it will be damaged and will then
have to be replaced
~ page 209.
Charging of battery
All work on the battery requires technical knowledge!
Fig. 165 E ngine compart ment: conne ctors for a charg­
er and jump start cables
A charged battery ensures good starting per­
formance . A discharged battery can
freeze at
temperatures of only
O 0C. A frozen or thawed
battery must be replaced, as the battery
housing may be cracked due to freezing and
could therefore leak acid.
.,. Always read and heed all WARNINGS be­
low~ .&, and ~.&, in
Working on the bat­
tery on page 208.
... Switch off the ignition and all electrical con­
sumers .
.,. Make sure the area is well ventilated when
you charge the battery.
.,. Connect charger cables.
Charger cables
must always be connected POSITIVE
G to ..,.