2015 AUDI A6 check engine

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Using the proper engine oil is important for
the functionality and service life of the en­
gine. Your engine was factory -filled with a
high-quality oil which can usually be used
t h roughout the entire year.
Your Limited New Vehicle Warranty does not cover damage or malfunctions due to
failure to follow recommended mainte­
nance and use requirements as set forth in
the Audi Owner's Manual and Warranty
&
Maintenance booklet .
- Use only a high quality engine oil that ex­
pressly complies with the Audi oil quality
standard specified for your vehicle's en­
gine . Using any other oil can cause seri­
ous engine damage.
- Do not mix any lubricants or other addi­
tives into the engine oil. Doing so can
cause engine damage.
If you need to add oil and there is none
available that meets the Audi oil quality
standard your engine requires, you may
add a total of no more than 0.5 quart/liter
of a high-quality "synthetic"oil that meets
the following specifications.
- Vehicles with gasoline engine: ACEA A3
or API SM with a viscosity grade of
SAE 0W-30, SAE SW-30 or SA E SW-40.
- Vehicles with diesel engine: ACEA C3 or
API CF with a viscosity grade of
SAE 0W-30 or SAE SW-30.
- For more information about engine oil
that has been approved for your vehicle, please contact either your authori zed
Audi dealer or Audi Customer Relations
at 1 (800) 822 -2834 or visit our web site
at www.audiusa.com or
www.audicanada .ca.
Checking and filling 225
Engine oil consumption
T he engine in your vehicle depends on an ade­
quate amount of oil to lubricate and cool all
of its moving parts .
In order to provide effec tive lubrication and
cooling of internal engine components, all in ­
ternal 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
c::> page 200) consume more oil during the
break-in period than they consume after oil
consumption has stabili zed.
Under normal conditions , the rate of oil con­
sumption 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 condi tions. Further fac­
tors are the amount of oil dilution from water
condensation or fuel residue and the oxida­
tion 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 es ­
tablished or specified . There is no alternative
to regular and frequent checking of the oil lev­
el , see
Note.
If the yellow engine oil level warning symbol
in the instrument cluster
II lights up, you
should check the oil level as soon as possible
c::> page 226. Top off the oil at your earliest
convenience
c::> page 226.
A WARNING
--
Before you check anything in the engine
compartment, always read and heed all
WARNINGS
c::> & in Working in the engine
compartment on page 222.
(D Note
Driving with an insufficient oil level is like-
ly to cause severe damage to the engine. .,.
•
•

226 Checking and filling
@ Tips
-The oil pres sure warning display. is
not an indicator of the oil level. Do not
rely on it. Instead , check the oil level in
your engine at regular intervals, pref­
erably each t ime you refuel, and always
before going on a long trip.
- If you have the impression your engine
consumes excessive amounts of oil, we
r ecommend that you consult your Audi
dealer to have the cause of your concern
properly diagnosed. Keep in mind that
the accurate measurement of oil con­
sumption requires great care and may
take some time. Your Audi dealer has in ­
str uctions about how to measure oil con­
sumption accurately.
Checking the engine oil level
Fig. 189 Display: o il level indicato r
"'"Park your vehicle on a level surface .
"'"Shu t the engine off when it is warm.
"'" Switch only the ignition back on.
"'"W ait approximately two min utes .
"'" Se lect:
I CAR I function button > (Car)* sys-
tems
con trol button > Servicing & checks >
Oil level.
"'"Check the oil level in the display¢ fig. 189 .
Add engine oil if the bar of the oil level indi­
cator is near "min" ~
page 226 .
Depending on the way the veh icle is driven
and the operating conditions, oil consumption
can be up to 1/2 quart per 600 m iles (0.5 liter
per 1,000 km) . Consumption may be higher
within the f irst 3,000 miles (5,000 km).
(D Tips
The oil leve l indicator in t he MMI Display is
on ly an information display. If the oil level
i s low, a min imum oil warn ing appears in
the instrument cluster. Add oil
¢
page 226. If the hood has been opened,
the current oil level is shown in the instru­
ment cluster the next t ime the ignition is
switched on.
Adding engine oil~
Fig . 190 Engine compa rtment: cover on the e ngin e oi l
filler neck
Before you check anything in the engine com­
partm ent,
always read and heed all WARN­
INGS
¢ A in Working in the engine compart­
ment on page 222.
"'" Shut the eng ine off.
"'"U nscrew the cap
'1:::::11 to the engine oi l filling
hole ¢
fig. 190, ¢ page 224, fig. 188 .
"'"Carefully top off with 0 .5 quarts (0 .5 liters)
of the appropriate oil¢
page 224.
"'" Check the oil level again after two minutes
¢ page 226, Checking the engine oil level.
"'"Top off the o il aga in, if necessary .
"'" Screw the cap back on the fi lling hole .
_&. WARNING
-While topping off, the oil must not come
in contact with hot e ngine parts -fire
hazard!
- The oil filler cap must be properly se­
cured to prevent oil from being sprayed
on the hot engine and exhaust system
when the engine is running -fire hazard! ..,_

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-If your skin has come in contact with the
engine oil, you must subsequent ly
cleanse it thoroughly.
0 Note
- Check the oil leve l using t he M MI. If the
message
Please reduce oil level appears,
contact your author ized Audi dealer or
other qualified workshop to have excess
oi l extracted if necessary .
-Audi does not recommend the use of oil
add it ives. They may damage the engine
and adversely affect your New Vehicle
Warrant y.
@ For the sake of the environment
-Under no circumstances ca n the o il come
i n contact wit h the sewage network or
the soil.
- Observe and fo llow lega l regu lations
when disposing of em pty oil con tainers .
Changing the engine oil
We recommend tha t have your oil changed by
an authorized Audi dealer or a qualified serv ­
ice station .
Before you check any thing in the engine com­
pa rtment,
always read and heed all WARN ­
INGS
~ .&. in Working in the engine compart­
ment on page 222 .
The engine oil must be changed according to
the intervals specified in your Warra nty
&
Ma intenance book let . This is very important
because the l ubr icating prope rties of oil di­
m inish gradua lly dur ing no rmal veh icle use.
Unde r some circumstances the engine o il
should be changed more frequently . Change
oil more often if you driv e most ly short dis­
tances , ope rate the vehicle in d usty areas or
u nd er predomin antly stop-and-go t raff ic con­
di tions , or have your veh icle w here tempe ra­
tures remain below free zing fo r ex tended pe ­
riods .
D etergen t additi ves i n the o il w ill ma ke fresh
oil look dark a fter the eng ine has been run -
Checkin g and fillin g 22 7
ning for a sho rt time. This is normal an d is not
a reaso n to cha nge the oil more often t han
recommended.
Bec ause of t he pro blem o f proper disposal,
along wi th the specia l tools and necessa ry ex ­
pertise req uired, we st ro ngly recommend that
you have your oil changed by an a uthorized
Audi dealer or a qualified service station.
If you choose to change your oil yourself ,
please note the following important info rma ­
t ion:
_& WARNING
To reduce the risk of pe rsonal inj ury if you
must change the eng ine oil in your vehicle
yourself:
- Wear eye protect io n.
- To reduce t he risk of burns from hot en -
gine oil, let the engine c ool down to the
touch.
- When removing the o il dra in p lug with
your fingers, stay as fa r away as possible .
Always keep you r forearm parallel to the
grou nd to help prevent hot o il from run­
ning down you r arm.
- Dra in the oil into a container designed
for this purpose, one la rg e enough to
hold at l east the tota l am ou nt of oil in
your engine.
- Engine oil is poisonous. Keep it well o ut
of the rea ch of childre n.
- Con tinuous contact wit h used eng ine o il
is harmful to yo ur ski n. A lways protect
your skin by washi ng oil off t horoughly
w it h s oap and w ater.
d) Note
N eve r mix oil additives wi th you r engine
oil. Th ese additives can damage your en­
g ine and adversely affect your Au di Li m it­
e d N ew Vehicle Warr anty.
(® For the sake of the environment
- Befor e changi ng your oil, first make s ure
yo u k now where yo u ca n prope rly dispose
o f the used oil.
1J11>
•
•

228 Check ing and filling
- Always dispose of used engine oil proper ­
l y . Do not dump it on garden soi l, wood­
ed areas, into open streams or down
sewage dra ins.
- Recycle used engine oil by taking it to a
used engine oil collection facility in your
area, or contact a service station.
Engine cooling system
Coolant
The engine coolant performs two functions: it
keeps the engine from overheating and it pro­ tects the engine from freezing in the winter.
The cooling system is sealed and generally re­
qu ires little attention.
The cooling system has been filled at the fac­
tory with a permanent coolant which does not need to be changed. The coolant consists of a
mixture of spec ially conditioned water and the
manufacturer's glycol-based coolant addi-
tive G13 antifreeze with ant icorros ion addi­
tives (50% for USA models; 60% for Canadian
models). This mixture both assures the neces­
sary frost protection and protects metal com­
ponents in the engine's coo ling system from
corrosion and scaling . It also raises the boil­
ing point of the coolant.
Do not reduce the concentration of the coo l­
ant in the summer by adding plain water.
The
p ropo rtion of coolant add itive must be at
l e a st 50 % but not mo re th an 60 %
to ma in­
tain antifreeze protection and cooling efficien­
cy . If the coolant frost protect ion is too low,
the coo lant cou ld freeze and damage the veh i­
cle heating and eng ine cool ing system.
For year-round driving, antifreeze is added at
the facto ry for temperatures down to:
- -31°F(-35°C)USA
- -40 °F ( -40 °C) Canada.
If you m ust add coo lant, use a m ix tu re of wa ­
ter and coo lant addit ive . M ixing the coolant
additive with disti lled water is recommended .
A WARNING
Before you check anything in the engine
compartment, always read and heed all
WARNINGS~ &.
in Working in the engine
compartment on page
222 .
(D Note
-Before winter sets in, have the coolant
checked to see if the coolant additive in
your vehicle is sufficient to meet the cli­ mate conditions. This is especia lly impor­
tant if you live in a reg ion where t he win ­
t er is ex treme ly cold. If necessary, in­
crease the p roportion of coo lant add it ive
to 60% .
- When adding coolant addi tive to yo ur
c ooling sys tem, remembe r:
- We recommend us ing on ly coolant ad­
d itive G12++ or G13 (check the label)
for your vehicle . This coolant additive is
ava ilable at autho rized Aud i dea le rs.
Other types of antifree ze ca n sign ifi­
ca ntly reduce co rros io n protec tion. The
res ulting corrosion c an cause a loss of
coolant and serious engine damage.
- Do not add any type of r ad iator le ak seal­
ant to yo ur vehicle 's engine coolant .
Adding radiator repair flu id may adverse­
ly affect the function and performance of
your cooling system and cou ld resu lt 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.
F ig. 1 91 Engi ne compartment: cover on the coola nt
expansio n tank

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Before you check anything in the engine com­
partment,
al ways r ead and heed all W ARN­
ING S r=;, A in Working in the engine compart­
ment on page 222.
.. Park your vehicle on a level surface.
.. Switch
off the ignition .
.. Read the eng ine coolant leve l from the cool­
ant expansion tank¢
fig. 191, ¢ page 224,
fig. 188.
With a cold engine, the coolant
level should be between the "min" and
"max" markings. When the engine is warm,
the leve l may be slightly above the "max"
mark ing .
The location of the coolant expans ion tank
can be seen in the engine compartment illus­
tration ¢
page 224.
To obta in an accurate read ing, the engine
must be switched
off.
The expansion tank in your vehicle is equipped
with an electric coolant level sensor.
When the coo lant level is too low, the warning
light in the Auto-Check System
¢ page 16 will
illum inate until yo u add coolant and the level
has been restored to normal. Even though
there is an electric coo lant level sensor, we
still recommend you check the coolant leve l
from time to time .
Coolant loss
Coolant loss may indicate a lea k in the cooling
system. In the event of coolant loss, the cool­
ing system should be inspected immediately
by your authorized Audi dealer . It is not
enough merely to add coola nt.
In a
sealed system, losses can occur only if
the boiling point of the coolant is exceeded as
a result of overheat ing .
A WARNING
The coo ling system is unde r pressure and
c an get ve ry ho t. Reduce the risk of s cald­
ing from h ot coolan t by followi ng these
steps .
- T urn
off the engine and allow it to coo l
down.
Checkin g and fillin g 229
-Protect your face, hands and arms from
escaping flu id and steam by covering the
cap with a large, th ick rag.
- Turn the cap slowly and very carefully in
a counter-clockwise d irect ion while ap­
plying lig ht, downward pressure on the
top of the cap .
- To avo id being burned, do not sp ill anti­
freeze or coolant on the exhaust system
or hot engine parts. Under certa in cond i­
tions, th e ethylene glycol in engine coo l­
ant can catch fire.
(D Note
Do not add any type of radiator leak sea l­
ant to your ve hicle's engine coolant. Add-
i ng radiator repa ir flui d may adverse ly af­
fe ct the funct ion a nd pe rfo rma nce of you r
co oling system and could re sult in damage
not covered by your New Vehicle Limi ted
War ranty.
Adding coolant
Be very careful when adding engine coolant.
Before you ch eck anyth ing in the eng ine com­
partment,
alway s re ad and heed all WARN­
INGS ¢ A in Working in the engine compar t­
ment on page 222.
.. Requirement: The re must be a residua l
amount of coolan t in the expansion ta nk
¢(D .
.. Tu rn off the engine.
.. Let the engine cool down.
.. Place a thick rag ove r th e coo lant expansion
tank
¢ page 228, fig . 191 and carefully
twist the cap counte r-clockwise ¢.&, .
.. Add coo lant m ixed in the correct ratio
¢
page 228, Coolant up to the MAX mark ­
ing .
.. Make s ure that the flu id leve l remains sta-
b le. Add more coo lant if ne cessary.
.. Twis t the cap o n again
t ightly.
Replacement engine coo lant must confo rm to
exact spec ificat ions
r=;, page 228, Coolant. ..,.
•
•

230 Check ing and filling
We recommend using on ly coo lant addi-
tive
Gl2++, Gl3 or in an emergency Gl2 +. Do
not use a different additive . In an emergency
use plain water unt il 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 cons iderable amount of
coolant, then you should add co ld antifree ze
and cold water only when the engine is co ld.
A lways use
new engine coolant when refilling.
Do not fill coolant above the "MAX" mark. Ex­
cess coolan t will be forced out through the
p ressure relie f valve in the cap when the en ­
gine becomes hot.
A WARNING
- The coo ling system is under press ure and
can get very hot. Reduce the risk of
sca lding from hot coolant by following
these steps.
- Turn off the eng ine and a llow it to cool
down.
- Protect your face, han ds and arms from
escap ing fl uid and steam by cover ing
the cap with a large, thick rag.
- Tur n the cap slowly and very c arefully
in a counter-clockwise d irect ion while
applying light, downward press ure on
the top of the cap .
- To avo id being burned, do not sp ill an ­
tifreeze or coolant on the exhaust sys ­
tem or hot engine parts. Under certain
conditions, the ethylene glyco l in en­
g ine coolant can catch fire.
- Antifreeze is poisonous. Always store an­
t ifreeze in its or iginal container and well
out of the reach of children.
- If you drain the coolant, it must be
caught and safely stored in a proper con­
tainer clear ly marked "poison".
- Do not add coolant if the expansion tank
is empty. A ir could enter the cooling sys­
tem and damage the eng ine. If this is the case, do not cont
inue driving . Seek
professiona l assistance .
- Coo lant poll utes the environmen t and
co uld cause an engine fire . Excess cool­
ant will be forced out thro ugh the pres­
sure relief valve in the cap when the en­
gine becomes hot.
- If, in an eme rgency, only wate r can be
added, the correct ratio between water
and antifreeze
c::> page 228 must be re­
stored as soon as possible .
@ For the sake of the environment
Drained coolant should not be reused . A l­
ways d ispose of used coolant while observ­
i ng all environmental regulations .
Radiator fan
The radiator fan switches on automatically by
itself.
An a uxiliary electric radiator fan switches on
and off depending on coolant temperature
and other vehicle operat ing condit ions .
After yo u switch the engine off, the auxi liary
fan can continue r unning for up to 10 minutes
- even w ith the ignition off . It can even switc h
on again later by itself
c::> .& , if
- the temperature of the engine coo la nt rises
due to the heat build- up from the engine in
the engine compartment, or
- the engine compa rtment heats up because
the vehicle is parked in intense sunlight.
A WARNING
- To reduce the risk of personal injury nev­
er touch the radiator fan.
- The a uxiliary electric fan is temperat ure
controlled and can sw itch on suddenly
even when the engine is not ru nning .
- The a uxiliary radiator fan sw itches on a u­
tomatically when the engine coo lant
reaches a certai n temperature and will
continue to run until the coolant temper­
ature drops.

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Brake fluid
Checking brake fluid level
Fig. 192 Engine co mpa rtment: cove r on the b rake f luid
reservo ir
Before you check anything in the engine com­
partment,
al ways r ead and h eed all WARN·
ING S ¢ &. in Working in the engine compart­
ment on page 222.
.. Read the brake fluid level from the brake
fl uid reservoir¢
fig. 192, ¢ page 224,
fig. 188 .
The brake f luid level must be be­
tween the "MIN" and "MAX" markings .
The location of the brake flu id reservo ir can be
seen in the engine compa rtment illust rat ion
¢ page 224.
The fluid level may drop slightly after some
time due to the automatic adjustment of the brake pads. This is not cause for alarm.
If the brake fluid level falls
considerably be­
low the "MIN" mark, the brake wa rning/indi­
cator ligh t. (U .S. models) . (Canad ian
models) will come on ¢
page 15. Do not con­
tinue to operate the vehicle. The comp lete
brake system shou ld be thoroughly checked
by an authorized A udi dealer or other quali­
fied facility and the cause corrected.
If the
br ake fluid level is too low, the brake warn ing/
indicator light w ill illuminate. Contact an au·
thor ized Audi dealer
imm ediately .
Checkin g and fillin g 231
Changing brake fluid
Have the brake fluid changed by an experi·
enced technician .
Brake fluid absorbs mois ture from the air. If
the wa ter 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 dec rease considerably and
decrease braking pe rformance.
Therefore, the brake fluid must be changed
ev ery two years. Always use new brake flu id
which conforms to Federal Motor Vehicle
Standard "F MVSS 116 DOT 4".
The brake fluid reservo ir can be d iff icult to
reach, the refore, we recommend that you
have the brake fluid changed by your author­
i zed
Audi d ealer . Your dealer has t he correct
tools, the right brake fl uid and t he 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 f luid. Observe these pre­
cautions:
- Use only brake fluid that meets SAE
spe cificat ion
J 1 7 03 and conforms to
Federa l Moto r Ve hicl e Standard 116.
Always check with yo ur authorized Audi
dealer to make sure yo u are using the
correct bra ke fluid. The correct type of
brake f luid is also indicated on the
brake f luid 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. Th is cou ld resu lt in an accident.
(D Note
Brake fluid will damage the paint of your
vehicle .

234 Checking and filling
(D Note
-Do not disconnect the vehicle battery
when the ignition is on or when the en­
gine is running, otherwise, you will dam­
age electronic components in the electri­
cal system.
- If your vehicle is going to stand for a
long period of time without being driven,
protect the battery from "freezing", oth­
erwise it w ill be damaged and w ill then
have to be replaced.
Battery charging
Starting the engine requires a well charged
battery.
Fi g. 19 3 Engine compartment : connectors for a charg ·
er and jump sta rt cables
Alway s re ad and h eed all WARNINGS below
c:> & and c:> & in Working on the battery on
page 233 .
• Switch off the ignitio n and all electrical con­
sumers.
• Make sure the area is well vent ilated when
yo u charge the battery .
• Open the engine hood
i=!.> page 222.
• Open the red cover o n the pos itive pole
e!.>fig. 193.
• Connect the charger connectors according to
the instructions to the
jump start bolt s.
(Bolts under the red cover= "positive", Bolts
with hex head= "negative").
• Only now plug the mains lead for the charg­
ing equipment into the wall outlet and turn
it on
c::> .&,. .
• Mak e sure th e charging rate is not over
30 amp s/14 .8 Volt .
• When the battery is fully charged: Turn the
charging equipment off and remove the
mains lead from the wall out let.
• Now remove the clamps for the charging
equ ipment.
• Close the red cover on the positive pole.
• Close the hood
c::> page 223 .
A discharged battery can freeze at tempera­
tures of only 32 F
0 (0 °C). Allow a frozen bat­
tery to thaw completely before attempting to charge it
c::> ,&. . However, we recommend not
u sing a thawed batte ry aga in because the bat­
tery casing can be c racked due to ice fo rm a­
t io n an d can leak battery a cid.
Battery charging (Maximum charging rate
of
30 amps/14.8 Volt )
When charg ing at low vo lt a ges (e.g. wi th a
trickle charger ), the battery cables do not
have to be disconnected firs t. T he battery
caps should
not be opened when charg ing a
battery .
It is no t necessa ry to remove the battery from
the luggage compartment, and it is a lso not
necessary to d isconnect the cab les .
Fast charging the battery (charging rate
above 14.8 Volts )
For technica l reasons do not use a battery
c h arger that uses voltage greater than
14.8
Volts to charge yo ur vehicle's battery.
Ln._ WARNING
--
Charging a battery can be dangerous.
- Always follow t he operati ng instructions
provided by the battery charger manu­
facturer when charg ing your battery.
- Never cha rge a frozen battery . It may ex­
p lode because of gas trapped in the ice.
Allow a frozen batte ry to thaw out f irst.
- Do not reuse batteries wh ich were fro­
zen. The battery housing may have
cracked and weakened when the battery
froze.