2018 AUDI A4 check engine light

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engaged, for example when you notice that the next traffic light is red . This produces an engine
braking effect, which helps to protect the brakes
and tires and reduces the emissions and fuel con ­
sumpt ion to zero (fuel shut-off dur ing decelera­
tion) .
Shift efficiently
Upshifting earlier is an effective way to save fuel.
Staying in a gear too long uses fuel unnecessari­
ly.
Applies to: vehicles with manual transmission
Shift as soon as possible from first to second
gear. S hifting to the next highest gear at approxi­
mately 2,000 RPMs if poss ible is recommended.
Applies to: vehicles with automatic transmissions
Press down on the acce le rator peda l slowly and
avoid "kick -down".
Avoid full acceleration
You should rarely travel at the maximum vehicle
speed. High speeds cause a disproportionately
high increase in fuel consumption, emissions and
traffic noise. Driving more slowly saves fuel.
Reduce idling time
The Start/Stop system* he lps to reduce the idling
time automatically. In vehicles without the Start/
Stop system*, it is efficient to switch the engine
off when stopped at railroad cross ings and long
r ed lights. Stopping the engine for 30-40 sec­
onds already saves more fuel than the amount of
extra fuel needed to restart the eng ine.
It takes a very long time in idle to warm the en­
g ine up to operating temperature. Wear and
emissions are especially h igh in the wa rm-up
phase . Therefore, you should begi n driving im­
mediately a fter starting the engine . Avoid high
RPMs while do ing this .
Have maintenance performed regularly
By having maintenance performed regu larly on
your veh icle, yo u ca n he lp to reduce f uel con­
sumption before yo u even start to drive. The
maintenance condition of your vehicle not only
affects traffic safety and long-term value but a l-
Driving
so impacts fuel consumption . A poorly main ­
tained engine can lead to fuel consumption that is 10% higher than norma l.
Avoid short trips
The eng ine and exhaust cleaning system must
reach their optimal operat ing temperatu re to ef­
f ectively reduce consumption and emissions.
A cold engine uses a disproportionately high
amount of fue l. The engine reaches operating
temperat ure and consumption normalizes on ly
after approximate ly 2.5 miles (4 km).
Check the tire pressure
To save fuel, make sure the tires are always in­
flated to the correct press ure
~ page 344. The
fuel consumption can increase by 5% if the pres­
s u re is only 0.5 bar too low. Due to the increased
rolling resistance, low tire pressures wi ll also
l ead to greater tire wear and will affect driving
behavior.
Do not drive on winter tires year-round, as this
will consume up to 10% more fuel.
Eliminate unnecessary weight
S in ce eve ry po und of ext ra weight increases f uel
consumption , a quick inspection of the luggage
compartment may be worth it to avoid unneces ­
sary weight .
When not be ing used , a roof rack should be re­
moved to decrease the wind resistance of the ve­
hicle. This will save you approximately 12% fuel
at speeds from 62 -75 mph (100 - 120 km/h) .
Save energy
The eng ine drives the generator, which generates
electric ity; the fuel consumpt io n also incr eases
with the demand for electr icity. The refore, switch
electrical eq uipment off when you no longer
need it . Examples of equipment that uses a lo t of
energy are air blowers at a high setting, the rear
window defogger and seat heating* .
@ Note
Do not leave engine idling unattended after
starting. If warning lights shou ld come on to
indicate improper operation, they would go
81

Driving
-The driver's door must be closed, the driver's
safety belt must be fastened, and the brake peda l (automat ic transmission) or the clutch
pedal (manua l transmission) must be pressed.
Or:
-The driver's door must be closed, the brake
pedal (automat ic transmission) or the clutch
pedal (manua l transmission) must be pressed,
and a gear must be engaged.
(D Note
Always sw itch the Start/Stop system off when
driving through water
q page 85.
@ Tips
The engine stops shortly before the vehicle
comes to a stop
1) .
Stopping/starting the engine
Appl ies to: ve hicl es w ith Sta rt/Stop system
F ig . 95 Instrument cluste r: e ng ine sw itched off (stop
phase)
A ppl ies to: ve hicles w ith manu al transmiss ion
• When the vehicle is stat ionary, shift to neut ral
and release the clutch pedal. The eng ine will
switch off . The
II indicator light appears in the
information line at the bottom of the instru­
ment cluster d isp lay. The needle in the tachom­
eter also moves into the
R EADY position .
• The engine will resta rt if you press the clutch
pedal. The ind icator light turns off.
A ppl ies to: ve hicles w ith a uto mat ic t ra nsmi ssio ns
• B rake the vehicle to a stop . The engine stops
shortly before the vehicle comes to a stop or if
the ve hicle is stationary
l). Keep yo ur foot on
l) Ma rket -spe cifi c
86
the brake peda l. The II indica tor light appears
in the status line at the bottom of the instru ­
ment cluste r display. The need le in the tachom ­
eter also moves into the
READY1> posit ion.
• The engine starts again when you take your
foot off the brake pedal. The indicator light
turns off .
Additional information for automatic
transmissions
The eng ine stops in the P, N and D selector lever
pos itions.
If you se lect the R posit ion du ring a Stop phase,
the engine will start aga in.
Se lect the P position quickly to prevent the e n­
gine from starting u nintent ionally when shifting
through R .
You can determine for yourse lf if the engine wi ll
stop o r not by red ucing or inc reasing the amount
of force you use to press t he brake peda l. For ex­
amp le, if yo u only lightly press on the brake ped­
al in stop-and-go traffic or when turning, the en­
gine w ill not switch off when the vehicle is sta ­
tiona ry . A s soon as you press the b rake down
harde r, the engine wi ll swi tch off .
(0 Tips
-Press the brake peda l during a Stop phase
to keep the vehicle from rolling .
-The ignitio n will turn off if yo u press the
! S TART ENGINE STOPI butto n du ring a stop
phase. The needle in the tachomet er moves
into the
OFF position.
General information
App lies to: vehicles wi th Start/S top sys te m
The standard Start/Stop mode can be canceled
for various system-related reasons.
Engine does not switch off
Before and dur ing each stop phase, the system
checks if certain conditions have been met. If the
lilJ.

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Trailer towing Driving with a trailer
General information
Your Audi was designed primarily for passenger
transportation .
If you plan to tow a trailer, please remember that
the additional load will affect durability, econo­ my and performance.
Trailer towing not only places more stress on the
vehicle, it also calls for more concentration from
the driver.
For this reason, always follow the operating and
driving instructions provided and use common
sense.
Technical requirements
Trailer hitch
Use a weight-carrying hitch conforming to the
gross trailer weight. The hitch must be suitable
for your vehicle and trailer and must be mounted
securely on the vehicle's chassis at a technically
sound
location . Use only a trailer hitch with a re­
movable ball mount . Always check with the trail­
er hitch manufacturer to make sure that you are
using the correct hitch.
Do not use a bumper hitch.
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 mounting
bo lts remain securely fastened.
When you are not towing a trailer,
remove the
tra iler hitch ball mount . This prevents the hitch
from causing damage shou ld your vehicle be
struck from beh ind ¢
,&. .
Trailer brakes
If your trailer is equipped with a braking system,
check to be sure that it conforms to all regula­
tions .
Trailer towing
The trailer hydraulic brake system must not be
directly connected to the vehicle's hydraulic
brake
system ¢.&. .
Safety chains
Always use safety chains between your vehicle
and the trailer.
Trailer lights
T ra iler lights must meet all regulations . Be sure
to check w ith your author ized Audi dealer for cor­
rect wiring, switches and relays.
Mirrors
If you are unable to see the traffic behind you us­
ing the regular outside mirrors, then you
must in­
stall extended mirrors. It is important that you
always have clear vision to the rear.
,8. WARNING
After removing the traile r hitch, do not store
it in your vehicle. In case of sudden braking,
the hitch could fly forward and injure you or
your passengers.
Operating instructions
Maximum trailer weight
A trailer for your vehicle is limited to a typical
class 1 or class 2 trailer.
Trailer load distribution
Be sure the load in the trailer is held securely in
place to prevent it from shifting forward, back­
ward or sideways.
Never allow a passenger to ride in a trailer ¢.&.
in Driver messages on page 100 .
Engine cooling system
Towing a trailer makes the engine work harder. It
is important that the cooling system's perform ­
ance is up to the additional load. Make sure that
the cooling system has enough fluid.
Tire pressure
When towing a trailer, inflate the tires of your
vehicle to the tire pressure listed under "Full
load" on the label ¢ page 344. Inflate trailer
99

Trailer towing
tires to tra iler and tire manufacturers ' specifica­
tions.
Lights
The headlig ht settings should be chec ked with
the t railer at tached before d riving off. Check to
make su re both vehicle and trailer lights are
wo rking properly.
Safety chains
Be sure t railer safety chains are properly connect­
ed from the trai le r to the h itch on the veh icle.
L eave enough sla ck in the c ha ins to permi t turn­
ing corners . When you install safety chains, ma ke
sure they wi ll not drag on the road when yo u are
driv ing .
The cha ins shou ld cross u nder the trailer tongue
to prevent it from dropp ing in case of separation
from the h itch .
Driver messages
Driving with a trailer requires extra caution.
Weight d istribution
Towing a loaded trailer w ith an empty car resu lts
in a hig hly unstable dist ribution of weight . If this
cannot be avo ided, drive at very low speeds on ly
to avoid the risk of losing s teering con trol.
A "balanced " rig is eas ier to operate and control.
This means that the tow vehicle should be loaded
to the extent possible and permissible , while
keep ing the tra ile r as lig ht as possib le under t he
circumstances . Whenever possible, t ransfer
some cargo to the l uggage compartment of the
tow vehicle whi le observ ing tongue load req uire­
ments and ve hicle loading conside rat ions.
Speed
The h igher the speed, the more d ifficult i t be­
comes for the drive r to contro l the rig. Do not
d rive at the maximum permissible speed. Reduce
your speed even more if load, weath er or w ind
conditions are unfavorable
-part icularly when
going downhill.
100
Reduce vehicle speed immediately if the trailer
shows the slightest sign of swaying.
Do not try
to stop the swa ying by a ccelerating.
Observe speed limits. In some a reas, speeds fo r
vehicles towing tra ilers are lower than for regular
vehicles .
Always apply bra kes early. Whe n driving down­
hill, shift in to a lower gea r to use the eng ine
b raking effect to slow the vehicle . Use of the
bra kes alone can cause them to overheat and fai l.
Coolant temperature
The coo lant tempe rat ure gauge 9 page 11 must
be obse rved caref ully. The coolant temperature
can increase i f you drive o n long inclines in a low
gear at high engine speeds . Reduce your speed
immediately if the LEDs in th e top part of the dis­
play turn on.
For more info rmation abou t indicator lig hts, re­
fer
to . ~page 30 .
A WARNING
Anyone not prope rly restrained in a moving
vehicle is at a much greater risk in an acci­
dent. Never let anyone ride in your car who is
not properly wear ing the restraints provided
by Aud i.
Trailer towing
information
' Important to know
-
Your vehicle handles differently when towing a
trailer because of the addit ional weight and dif­
ferent weight distribution . Safety, performance
and economy will greatly depend on how ca refu l­
l y you load your tra ile r and ope rate yo ur rig.
Before you actually tow your trailer, pract ice
turning, stopping and backing up in an area away
from traffic . Keep pract icing u ntil you have be­
come complete ly familiar w ith the way yo ur vehi­
cl e- tra ile r combination behaves and respo nds.

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Checking and Filling
Gasoline
Fuel supply
Applies to: veh icles with gaso line engine
Using the right fuel helps keep the environment
clean and prevents engine damage .
Fuel recommendation
The fuel recommended for your vehicle is unlead­
ed premium
grade gasoline. Audi recommends
using TOP TIER Detergent Gasoline with a mini­
mum octane rating of 91 AKI (95 RON). For more
information on TOP TIER Detergent Gasoline,
p lease go to the official website
(www.toptiergas .com) .
The recommended gasoline octane rating for
your engine can also be found on a label located
on the inside of the fuel filler flap . This rating
may be specified as AKI or RON.
Your vehicle may also be operated using unlead­
ed regular gasoline with a min imum octane rat ­
ing of 87 AKl/91 RON. However, using 87 AKl/91
RON octane fuel will slightly reduce engine pe r­
formance.
Use unleaded gasoline only. Unleaded gasoline
is available throughout the USA , Canada, and in
most European countries . We recommend that
you do not take your vehicle to areas or countries
where un leaded gasol ine may not be available.
For more information on refueling your vehicle,
see
c::> page 317 .
Octane rating
Octane rating indicates a gasoline's ability to re­
sist engine damaging "knock" caused by prema­
ture ignit ion and detonation . Therefore , buy ing
the correct grade of gasoline is very important to
h e lp prevent possible engine damage and a loss
of eng ine performance.
Gasoline most commonly used in the United
States and Canada has the following octane rat­
ings that can usually be found on the filler pump:
- Premium Grade: 91
-96 AKI
Checking and Filling
-Regu lar Grade: 87 -90 AKI
E xplanation of the abb reviations:
AKI =
Anti Knock Index = (R +M)/2 = (RON +MON)/
2
RON = R esearch Octane Number
MON = Motor Octane Number.
(D Note
- Do not use any fuel w ith octane ratings low­
er than 87 AKI or 91 RON otherwise expen­
sive engine damage w ill occur .
- Do
not us e leaded gasoline. The use of lead­
ed gasoline will severe ly damage your vehi­
cle's catalytic converter and its ability to
control exhaust emissions .
Blended gasoline
Applies to: vehicles with gasoline engine
Use of gasoline containing alcohol or MTBE
(methyl tertiary butyl ether)
You may use unleaded gasoline blended with al­
cohol or MTB E (commonly referred to as oxygen ­
ates) if the blended mixture meets the following
criteria:
Blend of gasoline methanol (wood alcohol or
methyl alcohol)
-Anti -knock index must be 87 AKI or higher.
- Blend must contain no more than 3% metha-
nol.
- Blend must contain more than 2% co-solvents.
Blend of gasoline and ethanol (grain alcohol or
ethyl alcohol)
- Anti-knock index must be 87 AKI or higher.
- Blend must not conta in more than 15% etha-
nol.
Blend of gasoline and MTBE
- Anti-knock index must be 87 AK I or higher.
- Blend must contain not more than 15% MTBE.
Seasonally adjusted gasoline
Many gasoline grades are blended to perform es­
pecially well for winter or summer dr iving . Dur-
ing seasonal change-over, we suggest that you
..,.
315

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.
,...

Check ing and F illing
I f you must add oi l between oi l changes, use an
oil that matches the Audi oi l quality standard
listed on the st icker. The sticker is located at the
front of the engine
compartment <=> page 325,
fig. 268.
Au di r ec omm end s
ocastrol i/g/g'fE:@t P'r(w.:::-..~J.D,'JAJ..
A udi r ecommends Longli fe high performa nce
e ngin e oil from Audi G enuin e Part s
Using the proper engine oil is important for the
functionality and service life of the eng ine. Your
engine was factory-filled with a h igh-quality oil
which can usually be used throughout the entire
yea r.
0 Note
Your Limited New Vehicle Warranty does not
cover damage o r malfunctions due to failure
to follow recommended maintenance and use
requirements as set fo rth in the Aud i Owner's
Man ual and Warranty
& Maintenance booklet.
- Use only a high qual ity eng ine oi l th at ex-
p ressly complies with the Audi oil q uality
standard specified for your vehicle's engine .
Using any other oil can cause se rious engine
damage .
- Do not mix any lubricants or other additives into the engine oil. Doing so can cause en­
gine damage.
(D Tips
If you need to add oil and there is none availa ­
ble that meets the Audi oi l quality standard
your engine requi res, you may add a total of
no more than 0.5 qt (0.5 l) of a h igh-quality
"synthet ic" o il that meets the following speci­
fications.
- Vehicles with gasoline eng ine: ACEA A3 or
API SM with a viscosity grade of SAE OW-30,
SAE 5W-30 or SAE 5W-40.
- Vehicles w ith diesel eng ine: ACEA C3 or
API CF with a v iscosity grade of SAE OW-30
or SAE 5W-30 .
- For more information about engine oi l that
has been approved for your vehicle, please
contact eithe r your authorized Aud i dealer
or Audi Custome r Relat ions at
326
1 (800) 822-2834 or visit our web site at
www.audi usa .com or www .audicanada .ca.
Engine oil consumption
The engine in your vehicle depends on an ade­
quate amount of oil to lubricate and cool all of
its moving ports.
In order to prov ide effect ive lub ricat ion and cool ­
ing of internal engine components, all internal
combustion engines consume a certain amount
of oil. Oil consumption var ies from engine to en­
gine and may change significantly over the life of
the engine. Typically, engines w ith a specified
break-in period
(see<=> page 80) consume more
o il dur ing the break-in per iod than they consume
after o il consumption has stabi lized .
U nder normal cond itions, the rate of oil con­
sumption depends on the quality and viscos ity of
the oil, the RPM (revolutions per m inute) at
wh ich the engine is operated, the amb ient tem­
perature and road condit ions. Furthe r facto rs a re
t h e amo unt of o il di lution from wate r condensa­
t ion or fue l residue a nd the oxidat ion level of the
oi l. As any engine is subject to wear as mileage
builds up, the oi l consumption may increase ove r
ti me until replacement of worn components may
become necessary.
With a ll these variab les coming into p lay, no
standard rate of oil cons umption can be estab ­
li shed or specified . There is no alternative to reg­
ular and frequent checking of the oil level, see
Note .
If the yellow engine oil leve l warning symbo l El
in the instrument cluster lights up, you should
check the o il level as soon as possible
<=> page 32 7. Top off the o il at your earliest con­
venience
<=> page 32 7.
A WARNING
Before you check anyth ing in the e ngine com­
partment, always read and heed all WARN­
I NGS<=> .&. in Working in the engine compart-
ment on page 323.
1iJ>,