2018 AUDI A6 check engine

Checking and Filling
Fuel filler door emergency release
If the central locking system is faulty, the fuel
filler door can be unlocked manually.
Fig . 17 4 Right side trim in the luggage co mpartme nt: re­
mov ing the tr im
F ig. 175 Luggage compa rtment: fuel fille r doo r eme rgency
r elease
The emergency opening mechanism is located
behind the right side trim pane l in the luggage
compartment.
Removing th e side trim
• To remove the right side trim, first remove the
retaine r from the mounts @¢
fig. 174.
• Turn both locking mechanisms 90° to the left
us ing a coin or a similar object and remove the
locking mechanisms.
• Tilt the reta iner upward and pull the trim out .
Lay the trim down on its side, because there is
an electrical w ire for the socket* on the back .
Fuel filler d oor em ergenc y relea se
• Loosen the strap from its bracket and pu ll on it
¢ fig. 175 ¢(D. The filler door is released.
• Presson the left side of the fuel f iller door to
open it
¢page 186, fig. 172.
188
(D Note
Only pu ll on the loop until you feel resistance .
You will not hear it re lease . Otherwise you
could damage the emergency release mecha­ nism.
Emissions control
system
Cat alytic converter
The vehicle may only be driven w ith unleaded
gaso line , otherwise the catalytic converte r will be
dest royed .
Never dr ive until the tank is completely empty.
The irregular supply of fuel that results from that can cause engine misfires. Uncombusted fuel will
enter the exhaust system, which can cause over­
heating and damage to the catalytic converter .
&_ WARNING
The temperature of the exhaust system is
h igh, both when driving and a fter stopp ing
the engine.
-
- Never tou ch the exhaust tail pipes once they
have become hot. This cou ld resu lt in burns.
- Do not park your vehicle over flammable
materials s uch as grass or leaves because
the high temperature of the emissions con­
trol system could start a fire .
- Do not apply unde rbody protectant in the
exhaust system area, beca use this increases
the risk of fire.

Checking and Filling
belt, alternator and radiator fan) and from
the high-voltage ignition system.
- Do not under any circumstances give gas in­
advertently (for example, by hand from the
engine compartment) if the vehicle is sta­
tionary but the engine is running and a gear
is engaged. Otherwise, the vehicle will start
to move immediately and this could result
in an accident.
- Pay attention to the following warnings list­
ed when work on the fuel system or on the
electrical equipment is required.
- Do not smoke.
- Never work near open flames.
- Always have a working fire extinguisher
nearby.
- All work on the battery or electrical system
in your vehicle can result in injuries, chemi­
cal burns, accidents or burns. Because of
this, all work must be performed
only by an
authorized Audi dealer or authorized Audi
Service Facility.
- To reduce the risk of electric shock and in­
jury, never touch the following components when the engine is running or is being start­
ed:
- Ignition cable
- Other components in the electronic high-
voltage ignition system
- If you must check or perform work on the
engine while it is running:
- Set the parking brake and place the selec­ tor lever in the P (park) position first.
- Always proceed with extreme caution so that clothing, jewelry or long hair do not
become caught in the radiator fan, fan
belt or other moving components or do
not come into contact with hot compo­
nents. Tie back long hair before beginning
work and do not wear clothing that can
hang down into the engine.
- Limit your exposure to exhaust and chemi­
cals to as short a time as
possible~ &..
A WARNING
California Proposition 6S Warning:
190
-Engine exhaust, some of its constituents,
and certain vehicle components contain or
emit chemicals known to the State of Cali­
fornia to cause cancer and birth defects and
reproductive harm . In addition, certain flu­
ids contained in vehicles and certain prod­
ucts of component wear contain or emit
chemicals known to the State of California
to cause cancer and birth defects or other
reproductive harm.
- Battery posts, terminals and related acces­
sories contain lead and lead compounds,
chemicals known to the State of California
to cause cancer and reproductive harms.
Wash hands after handling.
@ Note
When filling fluids, be sure not to mix the flu­
ids up. Otherwise severe malfunctions and en­
gine damage will occur.
@ For the sake of the environment
You should regularly check the ground under
your vehicle in order to detect leaks quickly. If there are visible spots from oil or other fluids, bring your vehicle to an authorized Audi deal­
er or authorized Audi Service Facility to be
checked.

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N
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0 0 <..:l ' Opening/closing the hood
The hood is released from inside the vehicle.
Fig. 177 Dr ive r footwell: release leve r
Fi g. 178 Rocker sw itc h under the hood
Make sure the w iper arms are not raised up from
the windshield . Otherwise the pa int could be
damaged .
Opening the hood
.. With the driver's door open, pu ll the leve r be­
low the instrument panel in the direct ion of the
arrow ¢ fig. 177 .
Checking and Filling
.. Raise the hood slightly ¢.&_ .
.. Press the rocker switch under the hood upward
¢
fig. 178. T his releases the catch .
.. Open the hood.
Closing the hood
.. Push the hood down until yo u over ride the
force of the strut .
.. Let the hood fall lightly into the latch. Do not
press it in.
¢ .&_ .
A WARNING
-
-Never open the hood when there is steam or
coolant escaping from the engine compart­ ment, because there is a risk that you could
be burned . Wait unti l no steam or coolan t is
escaping.
- For safety reasons, the hood m ust always be
closed securely while driv ing . Because of
this, always check t he hood afte r closing i t
t o make sure it is latched correct ly . T he
hood is latched if the front corners cannot
be lifted.
- If you no tice that the hood is not latched
while you are d riving, stop immed iately and
close it, because drivi ng when the hood is
not latched increases the r isk of an accident .
191

Checking and Filling
Engine compartment overview
The most important check points.
Fig. 179 Typical location of the rese rvoir and the engine o il filler open ing
(D Jump start point(-) with hex head screw
~page 198, ¢page 239
@ Jump start point(+) under the cover
~ page 198, ¢ page 239
® Engine oil label* with VW standard
¢page 192
@ Brake fluid reservoir ((0)) ¢page 197
® Eng ine oil filler opening(~)¢ page 194
@ Coolant reservoir ( - L) ~ page 196
(j) Washer fluid reservoir (0) ¢ page 199
The engine oil filler opening ® may be located in
a different area depending on the specific engine.
& WARNING
Read and follow all WARNINGS before check­
ing anything in the engine
compartment¢ &
in Working in the engine compartment on
page 189.
192
Engine oil
If the engine oil level is too low
If you need to add engine oil, use an oil that is
listed on the sticker.
The sticker is located at the
front of the eng ine
compartment¢ page 192,
fig . 179 .
If the recommended engine oil is not availab le,
in an emergency you may add a maximum of 1
quart(! liter) of ACEA C3 or API SN eng ine oi l
one time until the next oil change .
For more information on the correct eng ine oil
for your vehicle, contact an authorized Audi deal­
er or authorized Aud i Serv ice Facility . Have the oil
c h anged by an authorized Audi dealer or author­
ized Service Facility.

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" N .... 0 0 \,;J ' Audi rec ommends
~ Castrot /lftlg;'f.E@t Frtrrr.::--.~lri,'lAl.
A ud i recomm ends using the Lo ng Life h igh ­
perfo rm ance eng ine oil from Aud i Genu ine
Parts .
Checking the engine oil level
The engine oil level can be checked in the Info ­
tainment system
Observe the safety precautions ¢ A in Working
in the engine compartment on page 189.
~ Park your vehicle on a level surface.
~ Shut the engine off when it is warm .
~ Switch only the ignition back on.
~ Wait approx imately two minutes.
~ Select : the ICARI function button > (C ar)* Sys ­
tem s
control button > Service & control > O il
l e v el.
~ Read the o il level in the display. Add eng ine oil
i f t he ba r in the oil leve l ind icator is just before
"min" ¢ page 194.
(UJ) Note
The engine oil leve l mus t not be unde r the
"min" mark ing, as this will increase the risk of
engine damage.
(D Tips
The o il level indica tor in the disp lay is on ly an
informationa l display. If the o il level is too
low, a minimum oi l warning appears in the in ­
strument cluster. Add oil and close the hood.
The current oil level is d isplayed in the Info­
tainment system the next t ime the ignition is
sw itched on.
(D Tips
The engine oil consumption may be up to
0.5 quart/600 m iles (0.S liter/1,000 km), de­
pending on driving style and operating condi­
tions. Consumpt ion may be h igher during the
first 3,000 miles (5,000 km). Because of this,
the eng ine oil level m ust be checked regu lar­
ly. I t is best to chec k each t ime yo u refuel
your veh icle and befo re long d rives .
Ch eck ing and F illing
-In order to prov ide effective lubrication and
cooling of interna l engine components, a ll
internal comb ustion engines consume acer ­
tain amount of oil. Oi l consumption var ies
from engine to engine and may change sig­
nificantly over the life of the engine . Typi­
cally, eng ines with a specified break-in peri­
od consume mo re o il du ring the break-in pe­
r iod than they consume afte r oil cons ump­
t ion has s tabilized.
-Under norma l co ndit io ns, the rate of oil
cons umption depe nds on the q ual ity and
vis cos ity of the oil , the R PM (revo lutions per
m inute) a t which the engine is operated, the
ambient temperature and road conditions .
Further factors are the amount of oi l di lu­
tion from water condensat ion or fue l resi­
due and the oxidation level of the oil. As any
eng ine is subject to wear as m ileage builds
up, the oil consumption may increase over
t ime until replacement of worn components
may become necessa ry.
-With all these var iables com ing into play,
no sta ndard rate of o il consumption can be
established o r specified. There is no a lter na­
ti ve to c hec king the oil leve l reg ularly and
frequently.
-If you have the impress ion your e ngine co n­
sumes excessive amo unts o f oil, we recom ­
mend that you consult an author ized Audi
dea ler to have the cause of your concern
properly diagnosed . Keep in mind that t he
acc urate measurement of o il cons umption
requires great care and may take some
time . An authorized Aud i dealer has instruc­
tions about how to measu re o il consump­
tion accurate ly.
-You can find informat ion on engine oil and
eng ine o il capacit ies for the USA at
www.aud iusa.com/he lp/ma intenance, o r
for Ca nada at www.aud i.ca/ ca/web/en/
cu stomer -area/ ca re -and -m a i ntena nee/ a u di ­
serv i ce -sched u les. htm l, or ca ll
800 -822-2834 .
193

Check ing and F illing
Adding engine oil
F ig. 180 Engine co mpartment : en gin e oil fille r opening
cove r
Observe the safety precaut ions ¢&. in Working
in the engine comportment on page 189 .
"'Turn the eng ine off.
"' Open the hood ¢ page 191.
"'Unscrew the cap~ for the eng ine oi l filler
opening ¢
fig. 180.
"'Carefu lly add 0.5 quart (0 .5 liter) of the correct
oi l
¢pag e 192.
"'Close the engine oil filler opening cap .
"'Close the hood.
"'Restart the ign ition after two mi nutes and read
the current o il level in the Infotainment system
¢ page 193 , Checking the engine oil level .
"'Add more oil if necessa ry .
,& WARNING
- Whe n add ing o il, do not let oil d rip onto hot
engine components . This increases the r is k
of a fire.
- Yo u m ust seal the cap on the oil fi lle r open ­
ing correctly so that oil does not leak o ut
onto the hot engine and exhaust system
when the eng ine is r unning, because this is
a fire hazard.
- Always clean skin thorough ly if it comes into
contact with engine oil.
- Engine oil is poisono us and must be kept
o ut o f reach of chi ld ren.
- Store the engine oi l sec urely in the original
container.
(LlJ) Note
- If the message Ill Oil l evel i s too full.
Plea se redu ce oil le vel.
appears, there is too
194
much oil in the engine and the re is a r isk o f
cata lytic converter and engine damage. Do
not start t he engine. Contact an autho rized
Audi dealer or author ized Audi Service Fa­
cility to have excess eng ine o il extracted if
necessary .
- Your L imited New Vehicle Warranty does
not cover damage or ma lfunctions due to
failure to follow recommended mai nte­
nance and use requ irements as set fort h in
the A udi Owne r's Manual and War ranty
&
Ma inte nan ce bookle t.
- Use on ly a high quality engine o il that ex­
press ly complies with the A ud i oi l quality
s ta ndard spec ified fo r yo ur vehicle 's eng ine.
Us ing any othe r oi l c an cause ser io us eng ine
damage .
- Do not mix any add it io na l lubr ic a nts in to
t he engine oil. Damage ca used by such add i­
tives is not covered by the warranty .
@ For the sake of the environment
- Oil sho uld neve r en ter the sewer sys tem or
come in to contact with the g round .
- Pay attent ion to lega l re quir emen ts when
disposing o f emp ty o il conta iners.
Changing the engine oil
We recommend that hove your oil changed by on
authorized Audi dealer or a qualified servi ce sta ­
tion.
Befo re yo u check anything in t he engine compart ­
ment,
alway s read and h eed all WARNINGS ¢ &
in Working in the engine comportment on
page 189.
The eng ine o il must be changed according to the
i nte rvals spec ified in yo ur War ranty
& Ma inte ­
nance boo klet. This is ve ry important because the
l ubricating prope rties of oil diminish gradua lly
during norma l vehicle us e.
Un der some circumstances the engine oil should
be c hanged more freq uent ly. Change oi l more of ­
ten if you drive mostly s hort distances, operate
the ve hicle in dusty areas or under
predominantly ..,.

a co .... N
" N .... 0 0 \,;J ' stop-and-go traffic conditions, or have your vehi­
cle where temperatures remain below freezing
for extended periods.
Detergent additives in the oil will make fresh oil
l ook dark after the engine has been running for a
short time. This is norma l and is not a reason to
change the oil more often than recommended.
Because of the problem of proper disposa l, along
with the special tools and necessary expertise re­
quired, we strong ly recommend that you have
your oil changed by an authorized
Audi dealer or
a qualified service station .
If you choose to change your oil yourself, please
note the following important information:
A WARNING
To reduce the risk of personal injury if you
must change the engine oil in your veh icle
yourself:
- Wear eye protection.
- To reduce the risk of burns from hot engine
o il, let the eng ine cool down to the touch.
-
-When removing the oil drain plug with your
fingers, stay as far away as possible. Always
keep your forearm parallel to the ground to
help prevent hot oil from running down your
arm.
- Drain the oil into a container designed for
this purpose, one large enough to hold at
least the total amount of oil in your engine .
- Engine oil is poisonous. Keep it well out of
the reach of children.
- Cont inuous contact w ith used engine oil is
harmful to your sk in. Always protect your
sk in by washing oil off thoroughly w ith soap
and water.
@ Note
Never mix oil addit ives with your engine o il.
These additives can damage your eng ine and
adversely affect your Audi Limited New Vehi­
cle Warranty.
Checking and Filling
@) For the sake of the environment
-Before changing your oi l, first make sure
you know where you can properly dispose of
the used oil.
- Always dispose of used engine oi l properly.
Do not dump it on garden soil, wooded
areas, into open streams or down sewage
drains.
- Recycle used engine o il by tak ing it to a used
eng ine oil collection fac ility in your area, or
contact a service station .
Cooling system
Coolant
The engine cooling system is filled wit h a mixture
of purified water and coolant additive at the fac ­
tory. This coolant must not be not changed.
T he coolant level is monitored through
the . in­
dicator light
r=:>poge 13. However, we do recom­
mend occasionally checking the coolant leve l
manua lly.
If you must add coolant, use a mixture of water
and coolant additive. Mixing the coo lant additive
with distilled water is recommended.
Coolant additive
The coolant additive is made of anti-freezing and
corrosion protection agents. Only use the follow­
ing coolant additives. These additives may be
mixed with each other .
Coolant additive Specification
Gl2evo
TL 774 L
Gl2++ TL 774 G
Gl3 TL 774
J
The amount of coolant additive that needs to be
mixed with water depends on the climate where
the vehicle wi ll be operated .
If the coolant addi ­
tive percentage is too low, the coolant can freeze
and damage the engine.
.,.
195

Checking and Filling
Coolant Freeze protec-
additi ve tion
Warm min. 40% min. -13 °F
regions max. 45% (-25 °C)
Cold min. 50% max. -40
°F
regions max. 55% (-40 °C)
([) Note
- Before the start of winter, have an author­
ized Audi dealer or authorized Audi Service
Facility check if the coolant additive in your
vehicle matches the percentage appropriate
for the climate. This is especially important
when driving in colder climates.
- If the appropriate coolant additive is not
available in an emergency, do not add any
other additive. You could damage the en­
gine. If this happens, only use water and re­ store the correct mixture ratio with the
spec ified coolant additive as soon as possi­
ble.
- Only refill with new coo lant.
- Radiator sealant must not be mixed w ith
the coo lant .
Adding coolant
F ig. 181 Engine compartment: coolant expans ion tank
cover
Observe the safety precautions~ page 189,
Working in the engine compartment .
Checking the engine coolant level
• Park the vehicle on a leve l surface .
• Switch the ignition off.
• Read the coolan t leve l on the coo la nt expansion
tank~ page 192, fig . 179. The coolant level
must be between the MIN and MAX markings
196
when the engine in cold. When the engine is
warm it can be slightly above the MAX marking .
Adding coolant Requirement: there must be a residual amount of
coolan t in the expansion tan k
~CD -
• Let the engine cool down .
• Place a cloth over the coolant expansion tank
cap and unscrew the cap counterclockw ise
~ & -
... Add coo lant m ixed in the cor rect ratio
~ page 195 up to the MAX marking.
• Make sure that the fluid level remains stab le .
Add more coolant if necessary .
• Close the cap securely.
Coolant loss usually ind icates there is a leak . Im­
mediate ly drive your vehicle to an authorized
Audi dealer or authorized Audi Service Fac ility
and have the cooling system inspected. If the
cooling system is not leaking, a loss can come
from the coolant boiling through overheat ing
and being pushed out of the cooling system .
A WARNING
- The cooling system is under pressure. Do
not open the coo lant expansion ta nk cap
when the engine is hot. This increases the
risk o f bur ns.
- The coolan t addi tive and the coolant can be
dangerous to your health. For t his reason,
keep the coolant in the original container
and away from children. There is a risk of
poisoning.
- When working in the engine compartment,
remember that the radiator fan can switch
on even if the ignition is switched off, which
increases the risk of injury.
(D Note
Do not add coolant if the expansion tank is
empty. A ir cou ld enter the cooling system and
damage the engine. If this is the case, do not
continue driving. See an authorized Audi deal­
er or authorized Audi Serv ice Facility for assis­
tance.