2018 AUDI A4 service

-For safety reasons in severe accidents, the
alternator and starter are separated from
the vehicle battery with a pyrotechn ic circuit
interrupter.
-Work on the pyrotechnic circ uit interrupt ­
er must only be performed by
a qualified
technicians who have the experience, in ­
formation and special tools necessary to
perform the work safely.
-I f the vehicle or the circuit interrupter is
scrapped, all app licab le safety precautions
must be followed .
@) For the sake of the environment
Undeployed airbag modu les a nd pretension ­
ers might be classified as Perch lorate Materi­
al
-special handling may apply, see
www.dtsc .ca.gov/hazardouswaste/perchlo­
rate. When the vehicle or parts of the re­
straint system including airbag modules and
safety belts with pretensioners are scrapped,
all applicable laws and regulations must be
observed. Your authorized Audi dealer is fa­
m iliar with these requi rements a nd we recom­
mend t hat you have you r dealer perform this
service for you.
Other things that can affect Advanced
Airbag performance
Changing the vehicle's suspension system can
change the way that the Advanced Airbag System performs in a crash . For example, using tire-r im
comb inat ions not approved by Audi, lowering the
ve hicl e, chang ing the stiffness of the suspens io n,
in clud ing the spr ings, suspens ion str uts, shock
absorbers et c. can change the forces that are
measured by the airbag sensors and sent to the
e lectronic contro l unit. Some suspension changes
can, for example, increase the force levels meas­
ured by the sensors and make the airbag system
deploy in crashes in wh ich it would not deploy if
the changes had not been made. Other ki nds of
changes may reduce the fo rce levels meas ured by
the sensors and prevent the airbag from deploy­
in g when i t should .
Airbag sys tem
A WARNING
-Changing the vehicle's suspension including
use of unapproved tire-rim combinations can
change Advanced Airbag performance and in­
crease the risk of serious persona l injury in a
crash.
- Never install suspension components that
do not have the same pe rformance charac­
teristics as the components o rigina lly ins tal­
led on your vehicle.
- Never use tire-rim combinations t hat have
not been approved by Audi.
Knee airbags
Description of knee airbags
The knee airbag system can provide supplemen­
tal protection to prop erly restrained front sea t
occupants.
F ig. 2 42 D river 's knee a irbag
The driver knee airbag is in the instrument panel
u nderneath the steering whee l
~fig. 242, the
airbag fo r the p asse nger is at about the same
height in the instr ument pane l underneath the
glove compa rtment.
T he knee airbag offers add itiona l protection to
the driver's and passenge r's knees and uppe r and
lower thigh areas and supp lements the protec­
tion provided by the safety be lts .
If the front airbags deploy, the knee airbags a lso
deploy in fron tal coll is ions when the deploymen t
threshold stored in the cont rol un it is me t
~ page 281, More important things to know
about front airbags.
287

Checking and Filling
fill up at busy gas stations where the seasonal
adjustm ent is more likely to be mad e in time.
0 Note
- Methanol fuels which do not meet these re­
quirements may cause corrosion and dam­
age to plastic and rubber components in the
fuel system.
- Do not use fuels that fail to meet the speci­
fied criteria in this chapter .
- If you are unable to determine whether or
not a particular fuel blend meets the speci­
fications, ask your service station or its fuel
supplier.
- Do not use fuel for which the contents can­
not be identified.
- Fuel system damage and performance prob­
lems resulting from the use of fuels differ­
ent from those specified are not the respon­
sibility of Audi and are not covered under
the New Vehicle or the Emission Control
System Warranties.
- If you experience a loss of fuel economy or
driveability and performance problems due
to the use of one of these fuel blends, we
recommend that you switch to unblended
fuel.
Gasoline additives
Applies to: vehicles with gasoline engine
A major concern among many auto manufactur­
ers is carbon deposit build-up caused by the type
of gasoline you use .
Although gasoline grades differ from one manu­
facturer to another, they have certain things in
common. All gasoline grades contain substances
that can cause deposits to collect on vital engine parts, such as fuel injectors and intake valves.
Al­
though most gasoline brands include additives to keep engine and fuel systems clean, they are not
equally effective .
Audi recommends using TOP TIER Detergent Gas­
oline. For more information on TOP TIER Deter­
gent Gasoline, please go to the official website (www.toptiergas .com) .
316
After an extended period of using inadequate
fuels, built-up carbon deposits can rob your
en­
gine of peak performance.
([) Note
- Damage or malfunction due to poor fuel
quality is not covered by the Audi New Vehi­
cle Limited Warranty.
- Do not add aftermarket fuel additive prod­
ucts to your fuel tank.
Diesel fuel
Applies to: vehicles with diesel engine
Always use ULSD (Ultra Low Sulfur Diesel) No. 2.
The ULSD No. 2 meets the ASTM 0975.
Diesel fuel with concentrations of biodiesel high­
er than 5
% such as 811,820 or 8100 are strictly
prohibited.
Service station fuel pumps are labeled with the
correct fuel information for easy recognition by
the user. If the diesel fuel pump is not labeled
ask the station operator what fuel is being dis­
pensed before filling up your vehicle.
ULSD No. 2 may not be available outside the USA
and Canada. Be sure to check before traveling to
other countries.
ULSD No. 2 can become thicker in very cold tem­
peratures, and this can impair the engine's start­
ing and running . Depending on the season , gas
stations provide ULSD No. 2 that flows better in
cold temperatures so that you can continue oper­
ating your vehicle as usual.
(D Note
- Your vehicle's diesel engine was designed
soley for use with ULSD No. 2. Therefore,
never use gasoline, heating oil, other fuels
or flow improvers. These contain substances
that will severely damage the fuel system
and the engine. Such damage will not be
covered by your New Vehicle Limited War­
ranty.
- If you put any amount of incorrect fuel in
the fuel tank, do not start the engine under
.,..

any circumstances. Immediately contact the
nearest authorized Audi dealer or author­
ized Audi Service Facility for assistance.
These fuels contain substances that can se­
verely damage the fuel system and the en­
gine if the engine is started.
Refueling
Fuel filler neck
The fuel filler neck is located on the right rear
side panel behind the fuel filler flap.
If the power locking system should fail, you can
still open the flap manually
-for detailed instruc­
tions see
¢page 319.
You can find the fuel tank capacity of your vehicle
in
¢page 381.
The label on the inside of the fuel filler flap tells
you the correct fuel for your vehicle. For more in­
formation about fuel specifications, see
<=?page 315.
Your veh icle fuel tank has an onboard refuelling
vapor recovery system. This feature he lps to pre­
vent fuel vapors from escap ing from the tank and
polluting the environment while you refuel your
vehicle . In order to fill the tank properly while
protecting the environment, please follow this
refueling procedure carefully.
A WARNING
Under normal operating conditions, never car­
ry additional fuel containers in your car. Gas
canisters and other containers used to trans­
port fuel can be dangerous. Such containers,
full or empty, may leak and could cause a fire
in a collision. If you must transport fuel to
use for your lawn mower, snow blower, etc.,
be very careful and always observe local and
state laws regarding the use, transportation
and storage of such fuel containers. Make cer­
tain the container meets industry standards
(ANSI/ASTM F8S2
-86).
(D Note
Never dr ive your vehicle until the fuel tank is
completely empty. The irregu lar supply of
Checking and Filling
fuel can cause misfiring. Gasoline could enter
the exhaust system and damage the catalytic
converter.
Fueling procedure
Fig. 260 Right rear side of the vehicle: opening the fuel
f ilte r door
Fig. 261 Fuel filler door with attached fuel cap
The fuel filler door is unlocked or locked by the
central locking system.
Opening the fuel cap
.,. Press the left side of the fuel filler door to open
it¢
fig. 260 -arrow-.
.,. Unscrew the tank cap counterclockwise.
.,. Place the cap from above on the open fuel filler
door¢
fig. 261.
Closing the fuel cap
.,. Turn the fuel cap to the right until it stops.
.,. Close the fuel filler door until it latches.
Once the pump nozzle switches off, the fuel tank
is "full". Do not fill the tank more. Otherwise the
expansion space in the tank will be filled.
The correct fuel type for your vehicle can be
found on a label located on the inside of the fuel
.,.
317

an authorized Audi dealer or authorized Audi
Service Facility for assistance.
Fuel filler door emergency release
If the central locking system is faulty, the fuel
filler door can be unlocked manually.
Fig. 262 Luggage co mpartment: opening the side trim
panel
Fig . 263 Luggage compartment: fuel filler door e merge ncy
r elease
The emergency opening mechanism is located
behind the right side trim panel in the luggage
compartment.
... Open the cover in the side panel ¢fig. 262.
... Loosen the loop c;, fig. 263 from the retainer
and then pull on the loop carefully
¢(D . The
filler door is released .
... Press on the left side of the fuel filler door to
open it
¢ page 317, fig. 260.
(D Note
Only pull on the loop until you feel resistance.
You will not hear it release . Otherwise you
could damage the emergency release mecha­
nism.
Checking and Filling
Selective catalytic
reduction (AdBlue/DEF)
General information
Applies to: vehicles with selec tive catalytic reduction
In vehicles with selective catalytic reduction, a
urea solution (AdBlue/DEF) is injected into the
exhaust system in front of a nitrogen oxide cata­
lytic converter to reduce nitrogen emissions. The
urea solution is known as Ad Blue or DEF (Diesel
Exhaust Fluid). The information that follows w ill
use the name AdBlue.
The Ad Blue is carried in a separate tank in the ve­
hicle. The AdBlue usage accounts for approxi­
mately 1.0% to 4 .0% of the diesel fuel that is
used .
When a message about refilling the AdBlue ap­
pears in the instrument cluster display, you must
refill the AdBlue yourself or have it refilled by an
authorized Audi dealer or authorized Audi Service
Facility
c;, page 320 .
{D Tips
-The display indicates the distance remaining
that can be dr iven
c;, page 319. If the Ad Bl­
ue tank is completely empty, the engine will
not start again after the ignition is switched
off.
-Ad Blue is required by law to operate this ve­
hicle.
Messages in the instrument cluster display
Appl ies to: vehicles wi th selective catalytic reduction
The display indicates if the Ad Blue level is low or
if there is a system malfunction.
AdBlue level low
You will be informed in the instrument cluster
display if the AdBlue in the tank drops below a
certain level. Add at a minimum the amount of
AdBlue shown in the message:
II Refill with at least x qt (l) Ad Blue. Range
x mi (km )
319

Checking and Filling
This message appears when there is only enough
Ad Blue left to drive the distance indicated in the
instrument cluster . Fill the Ad Blue .
• Refill with at least x qt (l) Ad Blue. No en­
gine start in x mi (km). See owner's manual
This message appears when there is only enough
Ad Blue left to drive the distance indicated in the
instr ument cluster. Fill the Ad Blue. Otherwise
the engine will not start again if you stop it once
the d istance indicated has been driven .
• Refill with at least x qt (l) AdBlue. Engine
start not possible . See owner's manual
This message appears when the AdBlue tank is
empty. Fill the AdB lue. Otherwise you will not be
able to start the engine again once you stop it .
The AdBlue must be refilled when the amount in
the tank has reached the minim um level
c::> page 320, Preparation.
Incorrect filling/system malfunction
A message appears if the Ad Blue tank was filled
with a fluid other than AdBlue and the system has detected that the tank was fi lled incorrectly ,
or if there is a system malfunction .
II Ad Blue: malfunction! No engine start in
x mi (km). See owner's manual
This message appears when it is only possible to
drive the d istance ind icated in the instrument
cluster. Drive to the nearest authorized Audi
dealer or authorized Aud i Serv ice Facility to have
the malfun ction corrected. Otherwise the engine
will not start again if you stop it once the dis­
tance indicated has been driven .
• Ad Blue: malfunction! No engine start possi­
ble. See owner's manual
This message appears if the system has detected
that the tank was filled incorrectly or that there
is a malfunction . Drive immediately to the near ­
est authorized Aud i dealer or authorized Audi
Service Facility to have the malfunction cor rect­
ed. Otherwise you will not be able to start the en­
g in e again once you stop it .
320
Preparation
App lies to : vehicles with selective cata lyt ic reduct ion
Fig. 264 R ig ht re ar sid e o f th e ve hicle: removing th e Ad B l­
ue cap
The Ad Blue tank open ing is located near the die­
sel tank opening. Add at least the amount of
Ad Blue shown in the instrument cluster display.
This is the minimum amount required to ensure
the system detects the refilling and to start the
engine. You can add a maximum of 6 .3 gallons
(24
L) .
Requ irement: the request to add Ad Blue must
appear in the instrument cluster display .
.. Switch the ignition off.
.. Open the tank fille r doo r c::> page 317 .
.. Turn the tank filler neck cap to the left to re­
move
c::> fig. 264 .
.. Refill Ad Blue using a pump no zzle c::> page 321,
a canister c::> page 321 or a bottle c::>page 321.
A WARNING
AdBlue can irritate the skin, eyes and respira­
tory system .
If there is contact with the fluid,
flush immed iately w ith plenty of water . Con­
sult a physician if necessary .
(D Note
-Only use Ad Blue that conforms to the
standard ISO 22241-1. Do not mix any addi­
ti ves wi th the Ad Blue and do not dilute it
with water .
- Do not add AdBlue to the diesel tank or add
diesel fuel to the Ad Blue tank. Do not start
the engine under any circumstances if the
wrong fuel is filled in the tank. There is a

Check ing and F illing
"' Position the bottle on the filler tube and turn
the bottle clockwise unti l it stops turning.
"' Press lightly aga inst the bottom of the bott le
to empty it. Continue pressing the bottom of
the bottle until it is empty or unti l fluid stops
flowing into the tank .
"' Remove the bottle and seal the filler neck
¢ page 322, Completing AdBlue refill .
0 Note
Only use refill bottles that are approved for
your vehicle. Us ing other systems can ca use
Ad Blue to leak.
-You can obta in refill bottles from an author­
i zed Audi dealer or authorized A udi Service
F ac ility.
- A pe rm itted refill bottle conta ins approxi­
mately 0 .5 gallon ( 1.9 liters) of Ad Blue.
Completing AdBlue refill
Applies to: vehicles with selective catalytic reduction
Closing the filler neck
"'Turn the Ad Blue cap to the r ight on the filler
tube unti l th e cap cl ic k s into
p lace ¢.&. in
Prepara tion on page 320,
¢ (Din Preparation
on page 320 ..
"' Then press on the left side of the tank door un-
ti l it latches.
After filling
The vehicle must be driven so tha t the system
recognizes t hat the Ad B lue was refilled. This can
t ake severa l m in utes.
"' If there was no Ad Blue left in the tank and a
r ange of O mi (0 km) was shown in the d isplay,
swi tch the ign ition on fo r abo ut 30 seconds be­
f ore star ting the engine .
(D Tips
Ad Blue in the tank can free ze at very low tem­
pera tures. If this happens, the system will
not detect that the AdB lue was refilled and it
w ill contin ue to inform you of the low AdBlue
322
leve l. The message tu rns off as soon as the
tank thaws out again .
Emissions control
systems
Cat alytic converter
Applies to: vehicles with gasoline engines
T he vehicle may only be driven w ith un leaded
gaso line, otherwise the catalytic converter will be
destroyed .
Never drive unti l the tan k is comp lete ly empty .
T he irregu lar supply of fuel that resu lts from that
can cause eng ine misfires. Uncombusted fuel will
enter the exhaust system , which can cause over­
heating and damage to the catalytic converte r.
Di esel particulate filt er
Applies to: vehicles with diesel engines
The diese l particulate filter filters nearly all of
the soot part icles out of the exhaust. The filter
cleans itself automat ica lly under norma l dr iv ing
cond it io ns. If the filter cannot clean itself (for ex­
amp le, because yo u are on ly driving short distan ­
ces), the filter becomes clogged with soot and
the
1111 i ndicato r light for the diese l particulate
filte r tu rns
on ¢ page 33.
_&. WARNING
The tempera ture o f the e xhaust sys tem is
h igh, both when driving and a fter stopping
the engine.
-
-Never tou ch the e xhaus t tail p ipes o nce they
have become hot. This cou ld resu lt in burns.
-D o not p ark your vehicle over flamm able
materials such as grass or leaves because
the hig h temperature of the emissions con­
trol system (catalyt ic converter or d iese l
pa rticu late filter) co uld start a fire.
- Do not apply underbody protectant in the
exhaust system area, beca use this increases
the risk of f ire.

Checking and Filling
_& WARNING
California Proposition 65 Warning:
- 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.
(D 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.
Opening and closing the hood
The hood is released from ins ide the vehicle.
Fig. 266 Drive r footwell : rele ase le v er
324
Fig. 267 Unlocked hood: lev er
Make sure the wiper arms are not raised up from
the windshield. Otherwise the paint could be
damaged .
Opening the hood
"'With the driver's door open, pull the lever be­
low the instrument panel in the direction of the
arrow
9 fig . 266 .
"' Raise the hood slightly 9 ,&.
"'Press the lever ~ fig. 267 in the direction of the
arrow. This releases the hooks.
"' Open the hood.
Closing the hood
"' Push the hood down until you override the
force of the struts .
"'Let the hood fall lightly into the latch . Do not
press it in.
9 ,& .
_& 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. Wai t until no steam or coolan t is
escaping.
- For safety reasons, the hood must always be
closed securely while driving . Because of
this, always check the hood after closing it
to make sure it is latched correctly . The
hood is latched if the front corners cannot
be lifted .
- If you notice that the hood is not latched
while you are driving, stop immediately and
close it, because driving when the hood is
not latched increases the risk of an accident.
,...

-If the hood is not latched completely, it
could fly up while you are driving and ob­
struct your vision.
Engine compartment overview
The most important check points.
Checking and Filling
Fig. 268 Typical location of the reservoir a nd t he engine o il filler ope ning
(!) Washer fluid reservoir (O) c::> page 332
@ Jump start po int( +) under a cover,(-) w ith
hex head screw
¢page 332 c:>page 374
@ Engine oil filling opening ( © Engine oil label* w ith VW standard
c:> page325
® Coolant expansion tank (- L) c::> page 329
® Brake fluid reservoir ((0) c::> page 330
The location of the engine oil filling opening and
the coolant expansion tank ¢
fig. 268 (items@
and@) may differ depending on the engine ver­
sion .
_& WARNING
-Read and follow all WARNINGS before check-
in g anything in the engine compartment
c:> page 323.
Engine oil
Engine oil specifications
The engine oil used must conform to exact speci­
fications.
The service interval display in the instrument
cluster of your vehicle will inform you when it is
time for an oi l change . We recommend that you
have your oil changed by an authorized Audi Serv-
ice Advisor.
.,..
325