2020 AUDI A4 check engine light

Checking and Filling


compartment. This increases the risk of
burns. The cooling system is under pressure.
When you no longer see or hear steam or
coolant escaping, you may open the engine
compartment with caution.
— 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.
— Coolant additive and coolant can be danger-
ous to your health. For this reason, store the
coolant in the original container and away
from children. There is a risk of poisoning.
@ Note
Do not continue driving if the coolant expan-
sion tank is empty. Do not add any coolant,
because air could enter the cooling system
and damage the engine. See an authorized
Audi dealer or authorized Audi Service Facility
for assistance.


Brake fluid

BFV-0229)


Fig. 165 Engine compartment: cap on brake fluid reservoir
Follow the safety precautions > page 214, Gener-
al information.
Checking the brake fluid level
Read the brake fluid level on the brake fluid res-
ervoir > page 216, fig. 162. The brake fluid level
must be between the MIN and MAX markings
SA.
The brake fluid level is monitored automatically.
Message
Ga y @ Brakes: stop vehicle and check brake
fluid level
222
Stop the vehicle and check the brake fluid level.
See an authorized Audi dealer or authorized Audi
Service Facility for assistance.
Changing the brake fluid
Brake fluid should be changed at regular inter-
vals. Have the brake fluid changed by an author-
ized Audi dealer or authorized Audi Service Facili-
ty. The authorized Audi dealer or authorized Audi
Service Facility will inform you of the replace-
ment intervals.

Z\ WARNING
— If the brake fluid level is below the MIN
marking, it can impair the braking effect and
driving safety, which increase the risk of an
accident. Do not continue driving. See an au-
thorized Audi dealer or authorized Audi
Service Facility for assistance.
— If the brake fluid is old, bubbles may form in
the brake system during heavy braking. This
could impair braking performance and driv-
ing safety, which increases the risk of an ac-
cident.
— The brake fluid in your vehicle must meet
the standard VW 501 14 and is available at
an authorized Audi dealer or authorized
Audi Service Facility. If this brake fluid is not
available, another high-grade brake fluid of
equivalent quality may be used, and it must
meet
the U.S. Federal Motor Vehicle Stand-
ard (FMVSS) 116 DOT 4, Class 6.

@) Note
— If the brake fluid level is above the MAX
marking, brake fluid may leak out over the
edge of the reservoir and result in damage
to the vehicle.
— Do not allow any brake fluid to come into
contact with the vehicle paint, because it
will corrode the paint.
Electrical system
If the =z or fm] indicator light turns on, there is a
malfunction in the generator, the battery, or the
vehicle electrical system.

8W1012721BB
Checking and Filling

a Electrical system: malfunction! Safely stop
vehicle
Do not continue driving and switch the engine off
=> AX. See an authorized Audi dealer or authorized
Audi Service Facility for assistance.
= Electrical system: malfunction! Restart not
possible. Please contact Service
If you switch the ignition off, you will not be able
to restart the vehicle. Vehicle functions/driving
stability may be limited. Drive to an authorized
Audi dealer or authorized Audi Service Facility im-
mediately.
= Electrical system: malfunction! Please con-
tact Service
Switch off all electrical equipment that is not
needed. Vehicle functions/driving stability may
be limited. Drive to an authorized Audi dealer or
authorized Audi Service Facility immediately.
= Electrical system: low battery charge. Bat-
tery will be charged while driving
The starting ability may be impaired.
If this message turns off after a little while, the
vehicle battery has charged enough while driving.
If this message does not turn off, drive immedi-
ately to an authorized Audi dealer or authorized
Audi Service Facility.

ZA WARNING
When there is an electrical system malfunc-
tion, vehicle functions may not work and driv-
ing stability may be limited, which increases
the risk of an accident. Stop driving and
switch the engine off. See an authorized Audi
dealer or authorized Audi Service Facility for
assistance.

Battery
Peale mee eee scl)
Because of the complex power supply, all work on
batteries such as disconnecting, replacing, etc.,
should only be performed by an authorized Audi
dealer or authorized Audi Service Facility > A\.
Multiple batteries with different technologies
may be installed in your vehicle:
— Vehicle battery (for example, for starting the
engine, basic power supply) > page 224, Lead
battery or > page 224, Other battery types
— Auxiliary battery (for example, for recuperation
or optional equipment) > page 224, Other bat-
tery types
Not running the vehicle for long periods of
time
The battery will gradually drain if the vehicle
does not run for long periods of time. To ensure
that the vehicle can still be started, the electrical
equipment will be reduced or switched off
= page 99. Some convenience functions, such as
interior lighting or power seat adjustment, may
not be available under certain circumstances.
These convenience functions will be available
again once you switch the ignition on and start
the
engine.
Even when electrical equipment is switched off,
the equipment can still drain the battery if the
vehicle is not driven for long periods of time.
Deep draining results in a chemical reaction that
destroys the inside of the battery. The battery
must be charged every month to prevent this
= page 225. Contact an authorized Audi dealer or
authorized Audi Service Facility for more infor-
mation.
Winter operation
Cold weather places higher demands on the bat-
tery. This results in reduced starting ability. Have
the battery checked by an authorized Audi dealer
or authorized Audi Service Facility before cold
weather begins.

Z\ WARNING
— 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.
— Never connect the charging cable or jump
start cable directly to your vehicle battery. >

223

8W1012721BB
Checking and Filling

a ing the battery

Fig. 166 Engine compartment: connectors for a charger or
jump start cables
Note the safety precautions > page 214, General
information, > A\ in Battery general informa-
tion on page 223 and > /\.
Requirement: only use chargers with a maximum
charging current of 14.8 volts. The battery ca-
bles remain connected.
The battery is located in the engine compart-
ment. The ground point ©) is always located on
the vehicle body.
> Switch off the ignition and all electrical equip-
ment.
> Open the hood > page 215.
> Press the release lever on the positive terminal
and fold the cover upward > fig. 166.
> Clamp the charger terminal clamps to the jump
start pins according to the instructions. (Pin un-
der the cover = “positive”).
> Insert the power cable for the charging device
into the socket and switch the device on.
> At the end of the charging process, switch the
charger off and pull the power cable out of the
socket.
» Remove the charging device terminal clamps.
> Close the cover on the positive terminal.
> Close the hood > page 215.

ZX WARNING
— Never connect the charging cable directly to
your vehicle battery. Only use the connec-
tions in the engine compartment
=> page 225.

— A highly explosive mixture of gases can form
when charging batteries. Only charge the
battery in well-ventilated areas.
— A drained battery can freeze at tempera-
tures around 32 °F (0 °C). Do not charge or
use a frozen or thawed battery. If ice forms,
the battery housing can crack and battery
electrolyte can leak out, which increases the
risk of an explosion and chemical burns.
Contact an authorized Audi dealer or author-
ized Audi Service Facility for more informa-
tion.
— Do not connect or disconnect the charging
cable while charging because this increases


the risk of an explosion.

G) Tips
Read all of the manufacturer's instructions
for the charger before charging the battery.
Windshield washer
system

B8W-0125


Fig. 167 Engine compartment: washer fluid reservoir cap
Follow the safety precautions > page 214, Gener-
al information.
The windshield washer fluid reservoir © contains
the cleaning solution for the windshield and the
headlight washer system > fig. 167, > page 216.
The reservoir capacity can be found in
=> page 278.
To reduce the risk of lime scale deposits on the
spray nozzles, use clean water with low amounts
of calcium. Always add window cleaner to the wa-
ter. When the outside temperatures are cold, an
anti-freezing agent should be added to the water
so that it does not freeze.
225
>

Checking and Filling

Messages
3 Please add washer fluid
Fill the washer fluid for the windshield washer
system and the headlight washer system* when
the ignition is switched off.
@) Note
— The concentration of anti-freezing agent
must be adjusted to the vehicle operating
conditions and the climate. A concentration
that is too high can lead to vehicle damage.
— Never add radiator anti-freeze or other addi-
tives to the washer fluid.
— Do not use a glass cleaner that contains
paint solvents, because this could damage
the paint.
Service interval display
The service interval display detects when your ve-
hicle is due for service.
The service interval display works in two stages:
— Inspection or oil change reminder: after driv-
ing acertain distance, a message appears in the
instrument cluster display each time the igni-
tion is switched on or off. The remaining dis-
tance or time is displayed briefly.
— Inspection or oil change due: if your vehicle
has reached an inspection or oil change interval
or both intervals at the same time, the mes-
sage Inspection due! or Oil change due! or Oil
change and inspection due! will appear briefly
after switching the ignition on or off.
Checking service intervals
You can check the remaining distance or time un-
til the next oil change or next inspection in the
Infotainment system.
Select on the home screen: VEHICLE > Settings
& Service > Service intervals.
Resetting the indicator
An authorized Audi dealer or authorized Audi
Service Facility will reset the service interval dis-
play after performing service.
226
If you have changed the oil yourself, you must re-
set the oil change interval.
Select on the home screen: VEHICLE > Settings
& Service > Service intervals > Reset oil change
interval.
@) Note
— Only reset the oil change indicator if the oil
was changed.
— Following the service intervals is critical to
maintaining the service life and value of
your vehicle, especially the engine. Even if
the mileage on the vehicle is low, do not ex-
ceed the time for the next service.

8W1012721BB
Fuses and bulbs

@) Note
If a new fuse burns out again shortly after you
have installed it, have the electrical system
checked as soon as possible by an authorized
Audi dealer or authorized Audi Service Facili-
it y.
G@) Tips
— The following table does not list fuse loca-
tions that are not used.
— Some of the equipment listed in the follow-
ing tables applies only to certain model ver-
sions or certain optional equipment.

Fig. 187 Driver's footwell (left-hand drive vehicle): fuse
panel with plastic clip
3
=f
= & a

x
Ss $ 2 8

Fig. 188 Front passenger's footwell (right-hand drive vehi-
cle): fuse panel with plastic clip


) (brown)
No. | Equipment

2 |Engine components

Exhaust doors, fuel injectors, radiator in-
let, crankcase housing heating

Vacuum pump, hot water pump, NOx sen-
4 |sor, particulate sensor, biodiesel sensor,
exhaust doors

Brake light sensor

6 | Engine valves, camshaft adjustment

Heated oxygen sensors, mass airflow sen-
sor, water pump

Water pump, high pressure pump, high
8 |pressure regulator valve, temperature
valve, engine mount

9 |Hot water pump, engine relay

10 | Oil pressure sensor, oil temperature sensor

Clutch pedal position sensor, engine start,
water pump
i

12 | Engine valves, engine mount

13 | Radiator fan


14 | Fuel injectors, engine control module

265

Index


Driving:down HWS: sccies 2 vives ev eee = 2 eevee 104
Driving programms « «sisi. & 2 owes a 0 wasn 2 2 ime 133
Driving through water...............005 105
DIIVIGSCUTISss « = eee x & eee « nanewE s eRe a se LS
Driving tips
Driving through water................- 105
Efficient driving
Offroad driving....
Uphilland downhill. « & ssceiie ee cvawise wo sway 104
Driving up hills:; ; « s0«s : 2 sees se eee = 2 es 104
Dust filter
refer to Pollutant filter..............0.. 87
DYNAMISStEETING « wes ¢ v mews 2 exes 6 were 107
E
E-mail
Message:Optiomstan. + + ssc a 6 seca w 6 ossen 167
Settings........ 0.0... cece eee eee 167
EDL
refer to Electronic Differential Lock...... 109
EDR
Event Data Recorder iis ss ccs scana es 269
Efficiency BSSisties « a cawy xv wows vv maw a es 124
Electrical SySte@il's s s sees ¢ 2 exes i rama i re 222
Electromechanical parking brake......... 102
Electronic Differential Lock.............. 109
Electronic immobilizer.............00000. 34
Electronic Stabilization Control........... 109
Embedded SIM ear « essicscs os soci v a ssteine wo 0 170
Emergency assistance wcscs os caw s eeea a eo 253
Emergency braking function............. 103
Emergency Callies s & css s ¢ weiss s nae 165,174
Emergency flashers...............000005 50
Emergency mode......... 02. eee eee 97
Emergency operation
DOOIS « snay ¢ © agay ae eee aH eee 2 He gE 32
Fuelsilleridoorin: « suiccs ov saws x aracne <0 ans 213
Luggage compartment lid............... 40
Panoramic glass roof................--. 44
Sliding/tilting SUNTOOF wos... vee se eon ss 43
Emissions control system..............- 213
Energy CONSUMEIS:: « s svse so ee ee Hewes ewe 15
Energy management.................085 99
282

Engine
Breakingin....... eee eee eee eee eee ee 98
GOOlaNE 2 snow 4 « meay ¢ e meme 2 x eee d RoE 220
Emiengeney tpt 3 seas vx wns o siemens a ¥ a 92
Jump starting. ......... 0. cee eee eee 260
Start/Stop system............--000 eee 99
Starting/Stopping wc « «esse se enews wees 92
Engine compartment
Opening and closing the hood.......... 215
Overview... .... 2. eee eee eee 216
Safety precautions..............0e00es 214
Engine oil
AGING o cweses oo eeeirece a emeners aw onemeiee vw eeSoes
Changing
Checking oil level... sca ss yeen ee reuse: 216
CONSUMPTION bss ¢ & saves & o ceawers © 8 ere 6 0 ws 216
Indicator light..............00.000 00 217
Replacement interval................. 226
Temperature display................... 14
Engine sound
Audi drive select.............002-.00. 106
Engine Start/Stop mode
refer to Start/Stop system............55 99
Engine start system.............000 000s 93
Engine stop
refer to Start/Stop system.............. 99
Entry/exit lighting..............0.-.. eee 50
Entry assistance ....... cece eee eee eee ee 62
also refer to Exit assistance............. 62
Environment
Unleaded gasoline................200. 210
ESC Offfad sec so seus 5 vere so eae ov os 110
ESC Sport.............0 0.00.0 .000000. 110
eSIM
refer to Embedded SIM card............ 170
Event Data Recorder (EDR).............. 269
Exit assistance... 2... eee eee eee eee
Exit warning..............0..0.0000005
Exterior antenna...............0..000.
Exterior lighting.................022-00
EXCe@niO MIPKONS secs ws wasos © w cess vem a OY
Folding settings

External voice operation................. 25