2017 AUDI A4 check engine light

Cockpit overview
If the light does not turn off after starting the
engine
or turns on while driving, this may indi·
cate that there is a malfunction in the eng ine. If
the indicator turns on , the catalytic converter
may be damaged.
Drive
with reduced engine performance (avoid
h ig h speeds for extended periods of time and/ or
fast acce leration) and have the malfunction cor­
rected. See an authorized Aud i dealer or author­
ized Audi Service Fac ility .
The electronic speed limiter may be faulty if the
indicator light turns on. For additional informa­
tion, refer to
¢ page 93, Electronic speed limit­
er .
The MIL indicator light may also turn on if the
fuel filler cap is not closed correctly
¢page 298.
On-Board Diagnostics
Fig . 24 Locat ion of Data Link Connector (D LC)
On-Board Diagnostics monitors the components
of your emission control system. Each monitored
component in your engine system has been as­
signed a code . In case of a malfunction, the com­
ponent w ill be identified and the fault stored as a
code in the control module memory.
The MIL light may also illuminate if there is a
leak in the on-board fuel vapor recovery system .
If the light illuminates after a refuel ing, stop the
veh icle and make sure the fue l filler cap is prop­
erly closed (on ly vehicles with gasol ine engine)
¢page 298.
In order to make an accurate d iagnosis, the stor­
ed data can only be disp layed using specia l diag­
nostic equipm ent (ge ne ric scan tool for OBD) .
26
In order to connect the special diagnostic equip­
ment, push the plug into the Data Link Connector
(DLC). The DLC is located to the r ight of the hood
release
¢ fig. 24.
Your authorized Audi dea le r or qualified work­
shop can interpret the code and perform the nec­
essary repair.
_& WARNING
Do not use the diagnostic connector for per­
sonal use. Incorrect usage can cause malfunc­
tions, which can increase the risk of a colli­
sion!
Indicator lights
Description
The indicator lights in the instrument cluster
blink or tur n on. They indicate functions or mal­
funct ions.
-
Messages may appear with some indicator lights .
A warning signal will sound at the same time.
The ind icator lights and messages in the instru­
ment cluster disp lay can be covered by other dis­
plays. To show them again, select the second tab
with the multifunction steering wheel ¢page 12.
If there are several ma lfunctions, you can display
them one at a time using the thumbwheel.
Some indicator lights in the display can display in
several colors.
& Central indicator lights
If
the . or Q indicator lig ht turns on, check
the message in the instrument cluster.
Overview
Some indicator lights turn on briefly as a function
check when you switch the ignition on. These sys ­
tems are marked with a ./ in the fo llow ing tables.
If one of these ind icator lights does not turn on,
there is a malfunction in that system.
Your vehicle has e ither a monoch rome display or
a multicolored display, depending on vehicle
equipment . Some indicator lights appear white
1111-

Cockpit over view
Do not cont inue driving . See an authorized Audi
dealer or a uthorized Audi Service Facility for as­
sistance ¢& .
1111 (U SA models ) / . (Cana da m od els) Park­
ing br ake: malfun ction! Safel y stop veh icle . See
owner 's manual
-If the indicato r light a nd the message appear
when the vehi cle is st ationary or aft er sw itch­
ing the ignition on ,
check if you can release the
parking brake . If you cannot re lease the park­
i ng brake, see yo ur authorized Aud i dea ler or
authori zed Aud i Serv ice Facility . If you can re­
lease the park ing brake and the message still
appears , see an authorized Audi dealer or au ­
thorized Aud i Serv ice Facility immediately to
have the malfunction corrected .
-If the indicator light and message appear w hile
driving ,
the hill start assist or emergency brak ­
ing function may be malfunctioning .
It may not
be possib le to set the pa rking brake or release
it once it has been set. Do not pa rk your veh icle
on h ills. See an author ized Audi dealer or au ­
thorized Audi Serv ice Facility fo r ass istance .
Brake servo: re strict ed . You can continue driv ­
ing . Pleas e contact Servic e
There is a malfunction in the brake booster . The
brake booster is available, but its effectiveness is
reduced . Braking behav ior may be diffe rent from
how it no rma lly fu nctions and t he b rake pedal
may v ibrate .
Dr ive to an authorized Aud i dea le r or authorized
Aud i Serv ice Facility immediately to have the
malfunct io n corrected.
_&. WARNING
- Read and follow the warn ings in
¢ page 304, Working in the engine com­
partment
before opening the hood and
check ing the brake fl uid level.
- If the brake system indicator light does no t
turn off o r it turns on while driving, the
brake fluid level in the reservoir is too low,
and this increases the risk of an accident.
Stop the vehicle and do not continue dr iv-
30
ing . See an autho rized Audi dea ler or au­
thorized A udi Service Fac ility for assistance.
- If the brake system indicator light turns on
together w ith the ABS and ESC indicator
lights, the ABS/ESC regu lating function may
be malfunct ion ing. Functions that stabilize
the vehicle are no longer available . This
could cause the vehicle to swerve, which in­
creases the risk that the vehicle will slide. Do not co ntin ue d rivi ng. See an autho rized
Aud i dea le r or a ut horized Audi Serv ice Facili­
ty fo r ass istance .
PARK/<®)/!®)' Electromechanical parking
brake
If the -(USA mode ls) I. (Canada models)
i ndicator l ight turns on, the parking brake was
set .
If the -(USA mode ls)/ . (Canada models) in­
dicator light blinks, the braking force is not build­
i ng up enough or not building up at a ll. Se lect the
P selector lever posit ion to help secure the vehi­
cle. Make sure the indicator light is off before you
start driving .
£dJ Parking brake: mal function! Please contact
S ervice
There is a ma lf u nction in the parking brake. Drive
to an authorized Aud i dea ler or authorized Audi
Service Facility immediate ly to have the malfunc­
tion corrected.
• (USA models )/ lC~) (Canada model s) Parking
brake: caution! Vehicle parked too steep
There is not eno ugh braking force to ho ld the ve ­
hicle in p lace . T he brakes have overheated. The
vehicle could roll away even on a small incline.
• (USA model s)/¢~) (C a nada model s) Parking
brake: applied
If this message appea rs, press the b rake pedal
first and then release the parking brake if ne ces­
sary .
II (USA model s)/¢~) (Canada mode ls) Parking
brake: emerg ency braking
The emergency braking funct ion was triggered . ..,.

<( a, .... N ,....
N .... 0 0
3 a,
Please relea se parking br ake
Re lease the par king brake if this message ap ­
pears .
Please press brak e pedal to r ele as e par king
brake
To release the parking brake, press the brake
pedal and press the~ button at the same time,
or start driv ing with hill start ass ist
¢ page 82,
Starting from a stop .
(D Tips
For additional information on the parking
brake, refer to ¢
page 81.
_L Cooling system
• Turn off engin e and che ck co olant le vel.
The coolant level is too low.
Do not continue driving and switch the engine
off. Check the coolant level ¢
page 310.
-If the coolant leve l is too low, add coolant
~ page 310. Only continue driv ing once the in­
dicator light turns off.
• Coolant temperature : to o high . Let engine
run with vehicle s tati onar y
Let the eng ine run at idle for a few minutes to
cool off, until the ind icator light tu rns off.
- If the indicator light does not turn off, do not continue driving the vehicle. See an author ized
Audi dealer or author ized A udi Se rvice Facility
for assistance.
_& WARNING
- Never open the hood if you ca n see or hear
steam o r coolant escaping from the engine
compartment. This increases the risk of
burns . Wait until you no longer see or hear
steam or coolant escap ing .
- The engine compartment in any veh icle can
be a dangerous area. Stop the engine and
allow it to cool before working in the engine
compartment. A lways follow the informa­
t io n found in
¢ page 304, Working in the
engine compartment.
Coc kpit o ve rv iew
(D Note
Do not continue driv ing if the . indicator
light turns on as this increases the risk of en­
gine damage.
~ -Safety belt
The . indicator light stays on until the dr iver 's
and front passenger's safety belts are fastened .
Above a certa in speed, there will also be a war n­
ing tone.
@ Tips
For additional informat ion on safety belts, re ­
fer to¢
page 245 .
0 Generator/battery
If the . or(•) indicator light t urns on , the re is a
malfunction in the generator or the vehicle e lec­
t rical system .
• Electric al sy stem: malfunction! Saf ely stop
v e hicle
Do not continue dr iving and switch the engine
off . See an authorized Audi dealer or authorized
Audi Se rvice Facility for assistance .
(•j Electrical system: mal function! Re start not
po ssible . Plea se co ntac t Se rvice
Disconnecting the vehicle battery from the elec­
trical system prevents it from d ischarging. Drive
to an authori zed Aud i dealer or authori zed Aud i
Service Facility immed iately .
Do not stop the engine, or you w ill not be able to
start it again. If you can no longer start the en­ gine, see an authori zed Audi dealer or autho riz ed
Audi Service Facility for assistance .
(•) Electri cal system: malfunction! Ple ase con­
tact Se rvice
Drive to an authori zed A udi dealer or authorized
A udi Service Facility immediate ly. Because the ve­
hicle battery is discharging, turn off a ll unneces­
sary electrical equipment such as the rad io. See
your authori zed Aud i dealer or authori zed Audi
Service Facility if the battery charge level is too
~w . ~
31

Cockpit overview
(•) Electrical system: low battery charge. Plea se
turn on ignition
The start ing ability may be impaired.
If th is message turns off after a little while , the
battery charged enough while driving.
If the message does not turn off and stay off
when dr iv ing, have an authorized Aud i dea ler or
author ized Audi Service Facility repair the mal­
function .
~ Engine oil pressure
• Turn off engine. Oil pressure too low
Stop the eng ine and do not continue driving .
Check the engine oil leve l¢
page 308 .
- If the engine oil level is too low, add engine o il
c=>page 308. Only cont inue driving once the in­
dicator light turns off.
- If the engine oil leve l is correct and the indica­
tor light st ill turns on, turn the eng ine off and
do not continue driving. See an authorized Audi
dealer or authorized Audi Service Fac ility for as­
sistance .
(D Tips
The oil pressure warning is not an o il level in­
dicator . Always check the o il level regularly .
~ Engine oil level (MIN)
• Please add oil immediately.
Add engine o il immed iate ly ¢page 308 .
l!I Please add max. x qt (l) oil. You can contin­
ue driving
Add the maximum amount of oil indicated in the
display as soon as possible
¢page 308.
~- Steering lock
• Steering : malfunction! Please stop vehicle
There is a malfunction in the elect ronic steering
lock . You cannot turn the ignition on.
32
Do not tow your vehicle because it cannot be
steered. See an authorized Audi dealer or author­
i zed Audi Service Facility for assistance.
1!11 Steering lock: malfunction! Please contact
Service
There is a malfunction in the electron ic steering
lo ck.
Drive to an authorized Audi dealer or authorized
Audi Service Facility immed iate ly to have the
malfunction corrected .
& WARNING
Do not tow your vehicle when there is a mal­
function in the electron ic steering lock -this
increases the risk of an accident .
-e Engine start system
• Engine start system: malfunction! Please
contact Service
-
Do not switch the ignition off, or you may not be
able to switch it back on.
Drive to an authorized Audi dealer or authorized
Audi Service Facility immediately to have the
malfunction corrected .
13 Engine start system: malfunction! Please
contact Service
There is a ma lfunction in the engine starting sys­
tem .
Drive to an authorized Audi dealer or authorized
Audi Service Facility immediate ly to have the
malfunction corrected.
f;. ![J Electronic Stabilization Control (ESC)
If the Ii) ind icator light blinks while driving, the
ESC or ASR (ant i-slip regu lation) is actively regu­
l ating.
If the
DJ ind icator light turns on, the system has
switched t he ESC off . In t his case, you can switch
the ignit ion off and then on to switch the ESC on
again. The indicator light turns off when the sys-
tem is functioning fu lly. .,..

<( a, .... N ,....
N .... 0 0
3 a,
If the II indicator light turns on, ESC was
switch ed off us ing the
!~0" 1 button ¢ page 134.
Stabili zation c ontrol (ESC / ABS) : malfun ction!
See owne r's manual
If the: G1 indicato r light and the~ (USA mod­
els)/ [iJ (Canada models) A BS i ndicator light tur n
on and the message appears, the re is a malf unc­
tion in the ABS or the elect ronic differen tial lock.
This a lso ca uses the ESC to malfunct ion . The
brakes still function with their norma l power, but
ABS is not active.
Drive to an autho rized Aud i dea ler o r a uthorized
Aud i Service Facility immediately to have the
malfunction corrected.
@ Tips
For addit ional information on ESC and A BS,
refer to ¢
page 134.
!f Safety systems
The El indicator light monitors the safety sys­
tems.
If the El indica tor light turns on or blinks, there
is a malfunction in a safety system .
Drive to an autho rized Aud i dea le r or a uthorized
Aud i Service Fac ility immediately to have the
malfunct ion corrected.
A WARNING
-
Have the safety systems inspecte d immedi­
ately. Otherwise, there is a risk that the sys­
tems may not activate during a collision,
which increases the risk of serious injury or
death .
(CD ) Brake system
[I] Brake s ov erheating . Plea se shift to D
T here was a heavy load on the b rakes. Place the
selector lever in the D/S posi tion in o rder to use
the eng ine braking e ffect and reduce the load on
the brakes .
Cockpit o ve rv iew
'IJ!t:t /(0) Brake pads
II (USA model s)/Ei] (Canada mod els ) Brake
pad s: wear limit rea ch ed. You can continue dri v­
ing . Pl ea se conta ct Service
T he brake pads are worn.
Drive to an au thorized Audi dealer or authorized
Audi Service Facility as soon as possible to have
the malfunc tion corrected .
~ Engine control
II Drive sy stem : malfun cti on! Pleas e contact
Servi ce
T here is an eng ine control malfunction .
Drive slowly to an a uthori zed Audi dea ler or a u­
thori zed Audi Serv ice Facility to have the engine
checked.
W Engine control (diesel engine)
App lies to : vehicles wit h diese l eng ines
The eng ine is preheating if the El ind icator light
turns on when the ignition is switched on .
If the indica tor light does not turn on or blinks
while driving, there is an engine control malfunc ­
t io n.
Immed iate ly drive s low ly to an authori zed Audi
dealer or au thorized Audi Service Fac ility to have
the malfunction corrected .
io Malfunction indicator lamp (MIL)
The malfunction indicator lamp (MIL) is part of
t h e On Board Diagnost ic system (OBD II) . T he
¢..ij c;ymbo l tur ns on when the igni tion is sw itched
o n a nd turns off aga in once the igni tion swi tc h es
on and running at a steady id le speed . This i ndi ­
cates that the MIL is functioning correctly.
T he ind icator light tu rns o n if there is a malfu nc­
t ion in the engine elec tronics . See an au thor ized
Audi dealer or authorized A udi Service Fac ility to
have the malfunction corrected. For additional
information, r efer to ¢
page 25 .
The ind icator light can also tu rn o n if the fuel fill­
er cap was not sealed correctly ¢
page 298.
33

Cockpit over view
~ Diesel particulate filter
Applies to: vehicles with diesel engine and diesel particulate
filter
II Particul ate filt er: malfunct ion! See own er' s
m anual
The diesel particulate f ilter requires regenera­
tion. To support the filter's self-cleaning func­
tion :
Drive for approximate ly 15 minutes at 37 mph
(60 km/h) or above in the S se lector lever posi­
tion. Keep the eng ine speed around 2,000 RPM.
The temperature increase that will result from
this can burn off the soot in the filter . The ind ica ­
tor light will turn off when the cleaning has com­
p leted successf ully.
H ave an authorized Audi dealer or authorized
Aud i Serv ice Facility repa ir the malfunction im ­
mediately if the ind icator light does
not turn off .
A WARNING
Always adapt your speed to the cu rrent
weather, road and traffic conditions . You
should never disobey traffic laws in order to
follow driving recommendations .
(D Tips
For addit iona l information on the diese l par­
t ic ulate fi lter, refer to~
page 303.
!?i Engine speed limitation
II! Ma ximum engine spe ed: XXXX rpm
The engine speed is automat ica lly lim ited to the
speed d isplayed in the instrument clus ter. Thi s
p rotects the engine from overheating.
The engine speed lim itation deactivates once the
eng ine is no longer in the cri tical temperature
range and you have released the acce le rato r ped­
al once.
If t he engine speed l imitation was activated by
an eng ine contro l ma lfunction, the
II indicator
light also turns on. Make su re the engine speed
does no t go above t he speed d isplayed, fo r exam­
p le w hen downsh ifting . Drive to an authorized
34
Audi dealer or authori zed A udi Service Fac ility im ­
mediate ly to have the ma lfunction corrected.
~ ... Engine oil sensor
• Oil le vel system: malfu nction! Please con­
tact S ervice
The sensor to check the engine oi l level has
failed. Drive to an authorized Audi dealer or au­
thorized Audi Serv ice Facility immediately to have
the malfunct ion corrected.
• Oil level sensor: oil change neces sary. Please
contact Service
Fuel has e ntered the engine oil as a result of fre ­
quent short drives. Avo id high engine speeds, full
acce leration and heavy engine loads. D rive to an
authorized Audi dea ler or a uthorized Audi Service
Facility immediate ly to have the o il changed.
• Oil pre ssure sensor: malfunct ion! Plea se
contact Ser vice
There is a ma lf u nction in the oi l pressure senso r.
D rive to an authori zed A udi dealer or au tho riz ed
Audi Service Facility immediate ly to have the
malfunction corrected.
f Engine warm-up request
n Please warm up engine
Fuel has entered the engine oil, eithe r from low
outside temperatures or frequent short drives.
Drive until the eng ine is warm so that the fuel in
the engine o il w ill evaporate. Avoid high engine
speeds, full accelerating and heavy engine loads
when doing this .
E@ Tank system
liD Please refuel
If the indicator light turns on for the first time
and the message appears, there are about 2.1
gallons (8 liters) of fuel left in the tank .
(iD Please refuel immediately
If the indic ator ligh t turns on the message ap ­
pears, the fuel tank is a lmost empty. Refue l the
vehicle immediately .
...

Driving
next traffic light is red . This produces an engine
braking effect, which helps to protect the brakes
and tires and reduces the emissions and fue l con ­
sumpt ion to zero (fuel shut-off during decelera­
t ion).
Shift effici ently
An effective way to save fuel is to upshift earlier.
Staying in a gear too long uses fue l unnecessari ­
ly .
P ress down o n the acce lerator peda l slowly and
avoid "kick -down".
Avoid full acceleration
You shou ld rare ly t rave l at the maximum vehicle
speed. High speeds cause a disp roportiona tely
h igh inc rease in fuel consump tion, emissions and
traffic no ise . Slower driving saves fuel.
Reduce idling time
The Start/Stop system* he lps to reduce the idling
time automatically. In vehicles witho ut the Start/
S top system* , it is efficient to swit ch the eng ine
off when stopped at r,;1ilro,;1d crossi ngs and long
red lights . Stopping the engine for 30 -40 sec ­
onds already saves more fuel than the amount of
extra fuel needed to restart the engine.
It t akes a very long time in idle to war m the en ­
g ine up to opera ting tempera ture . Wea r and
emissions are especially high in the warm -up
p hase . Therefore, yo u should begin driving im ­
mediately after starting the engine. Avoid high
RPMs while do ing th is.
Have maintenance performed regularly
By having ma intenance performed regularly on
your vehicle, you can help to reduce f uel con­
sumpt ion befo re yo u even start to dr ive. The
maintenance condition of your vehicle not only
affects t raffic safety and long-term value but a l­
so impacts
fuel consumpt ion . A poorly main ­
tained engine can lead to f uel consumption that
is 10% higher than normal.
Avoid short trips
The engine and exhaust cleaning system m ust
reach the ir opt imal
operating temperature to ef­
fectively reduce consumption and em iss ions.
74
A cold engine uses a d isproportionately high
amount of fue l. The engine reaches operating
temperat ure and cons umption norma lizes on ly
after approximate ly
four ki lometers.
Check the tire pres sure
To save fue l, make sure the t ires are always in­
flated to the correct press ure
¢ page 32 7. The
fuel consumpt ion can increase by S% if the pres ­
s u re is only 0.5 bar too low. Due to the increased
roll ing resistance, low tire pressures w ill also
l ead to greater tire
wear and will affect dr iving
behavior.
Do not drive on
winter tires year-round, as this
will consume up to 10% more f uel.
Eliminate unnecessary we ight
Since eve ry kil og ram o f extra weight in creases
fuel consumption, a quick inspection of the lug­
gage compartment may be worth it to avoid un­
necessary we ight.
When no t be ing used, a roof rack sho uld be re ­
moved to decrease the wind resistance of the ve­
hicle . You will save approx imately
12% of your
fuel when at speeds from 62-75 mph (100-120 km/h).
Save energy
The eng ine drives the generator, which generates
electricity; the fuel consumption also inc reases
with the demand for e lectricity. Therefore, switch
e lectrical equ ipment off when you no longer
need it. Examples of eq uipment that uses a lot of
energy are air blowers at a high setting, the rear
window defogger and seat heating* .
(D Note
Do not leave engine idling unattended after
starting . If warning lights shou ld come on to
i ndica te improper operation, they would go
unheeded . Extended idling also prod uces
h eat, w hic h could result i n overheating o r
o ther damage to the veh icle o r othe r prope r­
ty .

Stopping and starting the engine
Applies to: vehicles with Start-Stop system
Fig. 79 Instrument cluster : eng ine sw itched off (s top
p hase)
~ B rake the ve hicle to a stop. The engine stops
shortly before the vehicle comes to a stop or if
the vehicle is stationa ry
1l. Keep your foot on
the brake pedal. The
II indicator light appears
in the stat us line at the bottom of the instru­
ment cluster d isplay. The needle in the tachom­
eter also moves into the READY
1l position .
~ The engine starts aga in when you take your
foot off the b rake pedal.
If the park ing brake is
set, the engine w ill only start aga in when the
a cce le rator pedal is p ressed
1>. The indica tor
li gh t turns off.
Additional information The engine stops i n the P, N and D selector lever
positions .
If you select the R pos ition dur ing a Stop phase ,
the eng ine will start again .
Select the P pos ition quickly to p revent the en­
g ine from starting unintentionally when sh ift ing
through R.
You can determine for yourself if the engine will
stop or not by reducing or increasing the amount
of force you use to press the brake pedal. For ex­
ample, if you only lig htly press on the brake ped­
al in stop-and-go traff ic or when turning, the en­
g ine will not switch off when the vehicle is sta­
tionary . As soon as you press the brake down
ha rder, the eng ine will switch off.
l l Ma rket -spe cific
Drivi ng
(D Tips
- Press the bra ke peda l during a Stop phase
to keep the vehicle from rolling.
- The ignition will turn off if yo u press the
!START ENGINE STOPI butto n dur ing a stop
phase. The needle in the tachometer moves
into the
OFF position.
General information
Applies to: vehicles with Start-Stop system
The standard Start/Stop mode con be canceled
for different system-related reasons.
F ig. 80 Instrument cluste r: eng ine stop temporarily un­
ava ilable
Engine does not switch off
Before and dur ing each stop phase, the system
checks if certain conditions have been met. For
example, the eng ine will not switch off in the fol­
lowing situations:
- The engine has not reached the minim um re­
quired temperature for Start/Stop mode.
- The inte rior temperature selected by the A/C
system has not been reached.
- The outside temperature is extremely high/low.
- The windsh ield is being defrosted .
- The battery charge level is too low .
- The steering wheel is turned at a sharp angle o r
is moving .
- After engaging the reverse gear .
- On sharp incl ines.
- At high altitudes .
r,jj also appears in the instrument cl uster d is­
play.
79