ECU MERCEDES-BENZ A-CLASS HATCHBACK 2018 Owners Manual

Diagnostics connection
The diagnostics connection is on ly intended for
th e connection of diagnostic devices at a quali‐
fi ed specialist workshop. &
WARNING Risk of accident due tocon‐
necting devices tothe diagnostics con‐
nection
If yo u connect equipment toa diagnostics
connection in theve hicle, it may af fect the
operation of vehicle sy stems.
As a result, the operating saf ety of theve hi‐
cle could be af fected. #
Only connect equipment toa diagnos‐
tics connection in theve hicle which is
appr ovedfo ryo ur vehicle byMercedes-
Benz. &
WARNING Risk of accident due to
objects in the driver's foot we ll
Objects in the driver's foot we ll may impede
pedal tr avel or block a depressed pedal. This jeopardises
the operating and road
saf ety of theve hicle. #
Stow all objects in theve hicle securely
so that they cannot getinto the driver's
fo ot we ll. #
Alw aysfit th efloor mats securely and
as prescribed in order toensure that
th ere is alw ays suf ficient room forthe
pedals. #
Do not use loose floor mats and do not
place floor mats on top of one ano ther. *
NO
TEBattery discharging from using
devices connected tothe diagnostics
connection Using devices at
the diagnostics connection
drains the batter y. #
Check thech arge leve l of the batter y. #
Ifth ech arge leve l is lo w,charge the
batter y,e.g. bydriving a considerable
dis tance. Connecting equipment
tothe diagnostics con‐
nection can lead toemissions monitoring infor‐
mation being reset, forex ample. This may lead
to theve hicle failing tomeet therequ irements of
th e next emissions inspection during the main
inspection. Qualified specialist
workshop
A qu alified specialist workshop has the neces‐
sary special skills, tools and qualifications to
cor rectly car ryout any necessary workon your
ve hicle. This particularly applies tosaf ety-re le‐
va nt wo rks.
Alw ays ha vethefo llowing workcar ried out on
yo ur vehicle at a qualified specialist workshop:
R safety-re leva nt wo rks
R service and maintenance work
R repair work
R modifications as well as ins tallations and
con versions
R workon electronic components General no
tes25

yo
ur vehicle as well as on possible vehi‐
cle damage. QR code
forre scue card
The QR code is secured in the fuel filler flap and
on the opposite side on the B-pillar. In theeve nt
of an accident, rescue services can use the QR
code toquickly find the appropriate rescue card
fo ryo ur vehicle. The cur rent rescue card con‐
ta ins the most impor tant information about your
ve hicle in a compact form , e.g. thero uting of the
electric lines.
Fu rther information can be obtained at http://
www.mercedes-benz.de/qr-code. Data
storage Electronic control units
Elect
ronic control units are fitted in your vehicle.
Some of these are necessary forth e safe opera‐
tion of your vehicle, while some assist you when
driving (driver assis tance sy stems). In addition,
yo ur vehicle pr ovides com fort and enter tainment functions, which are also made possible
byelec‐
tronic control units.
Elect ronic control units contain da tamemories
which cantemp orarily or permanently store
te ch nical information about theve hicle's operat‐
ing state, component loads, main tenance
re qu irements and tech nical events or faults.
In general, this information documents thest ate
of a component part, a module, a sy stem or the
sur roundings such as:
R operating states of sy stem components (e.g.
fl uid le vels, battery status, tyre pressure)
R status messages concerning theve hicle or
its individual components (e.g. number of
wheel revo lutions/speed, decele ration in
mo vement, lateral accele ration, display of
fast ened seat belts)
R malfunctions or defects in impor tant sy stem
components (e.g. lights, brakes)
R information on events leading tovehicle
damage
R system reactions in special driving situations
(e.g. airbag deployment, inter vention of sta‐
bility control sy stems) R
ambient conditions (e.g. temp erature, rain
sensor)
In addition toprov iding the actual control unit
function, this data assists the manufacturer in
de tecting and rectifying faults and optimising
ve hicle functions. The majority of this data is
te mp orary and is only processed in theve hicle
itself. Only a small portion of the data is stored
in theeve nt or fault memor y.
When your vehicle is serviced, tech nical da ta
from theve hicle can be read out byservice net‐
wo rkemplo yees (e.g. workshops, manufactur‐
ers) or third parties (e.g. breakdown services).
Services include repair services, maintenance
processes, warranty cases and quality assurance
measures, forex ample. The read out is per‐
fo rm ed via the legally prescribed port forthe
diagnostics connection in theve hicle. The
re spective service network locations or third
parties collect, process and use the data. They
document tech nical statuses of theve hicle,
assist in finding faults and impr oving quality and
are transmit tedto the manufacturer, if neces‐
sar y.Fu rthermore, the manufacturer is subject General no
tes27

Manufacturer's services
Re
garding online services of the manufacturer,
th e individual functions are described bythe
manufacturer in a suita ble place (e.g. Owner's
Manual, website of the manufacturer) along with
th ere leva nt da taprotection information. Per‐
sonal data may be used forth e pr ovision of
online services. Data is exch anged via a secure
connection, e.g. the manufacturer's designated
IT sy stems. Personal data is collected, pro‐
cessed and used via the pr ovision of services
exc lusively on the basis of legal permissions or
with prior consent.
The services and functions (sometimes subject
to afe e) can usually be activated or deactivated.
In some cases, this also applies tothe entire
ve hicle's data connection. This excludes, in par‐
ticular, legally prescribed functions and services.
Third pa rty services
If it is possible touse online services from other
pr ov iders, these services are subject tothe data
pr otection and term s of use of there sponsible
pr ov ider. The manufacturer has no influence on
th e conte ntexc hanged. Please enquire,
therefore, about the type, scope
and purpose of the collection and use of per‐
sonal data as part of third party services from
th eir respective pr ovider. Copyright
Information on free and open-source software
licences foryo ur vehicle's software can be found
on the data storage medium in your vehicle
document wallet and on the Internet toget her
with updates at:
http://www.mercedes-benz.com/opensource General no
tes29

Re
stra int sy stem Pr
otection bythere stra int sy stem The
restra int sy stem includes thefo llowing com‐
ponents:
R Seat belt sy stem
R Airbags
R Child restra int sy stem
R Child seat securing sy stem
The restra int sy stem can reduce therisk of vehi‐
cle occupants coming into contact with parts of
th eve hicle's interior in theeve nt of an accident.
The restra int sy stem can also reduce thefo rc es
to which vehicle occupants are subjected in the
eve nt of an accident.
Only a seat belt which is worncor rectly can pro‐
vide the intended le vel of pr otection. Depending
on the de tected accident situation, seat belt ten‐
sioners and/or airbags supplement a cor rectly
wo rnseat belt. Seat belt tensioners and/or air‐
bags are not depl oyed in everyaccident. Fo
rth ere stra int sy stem toprov ide its full pr otec‐
tion, each occupant must obser vethefo llowing:
R Fasten the seat belt cor rectl y.
R Be in an almost up right position with their
back against the seat backrest.
R Sit with their feet resting on thefloor, if pos‐
sible.
R Alw ays secure persons under 1.50 m tall in
an additional restra int sy stem suitable for
Mercedes-Benz vehicles.
Ho wever,no sy stem available today can com‐
ple tely eliminate injuries and fata lities in every
accident situation. In particular, the seat belt
and airbag generally do not pr otect against
objects penetrating theve hicle from the outside.
The risk of an injury resulting from airbag
deployment also cannot be ruled out entirel y. Re
duced restra int sy stem pr otection &
WARNING Risk of inju ryor death from
modifications tothere stra int sy stem
The restra int sy stem can no longer function
cor rectly af ter alterations ha vebeen made.
The restra int sy stem may then not pr otect
th eve hicle occupants as intended byfailing
in an accident or triggering unexpec tedly, for
ex ample #
Never alter the parts of there stra int
sy stem. #
Neverta mp er with the wiring or any
electronic component parts or their
software. If it is necessary
tomodify theve hicle toaccom‐
modate a person with disabilities, con tact a
qu alified specialist workshop.
Mercedes-Benz recommends that you use driv‐
ing aids which ha vebeen appr ovedfo ryo ur vehi‐
cle byMercedes-Benz. 30
Occupant saf ety

#
Alw ays ensure that all vehicle occu‐
pants ha vetheir seat belts fastened
cor rectly and are sitting prope rly. Alw
ays obser vethe instructions about the cor‐
re ct driver's seat position and adjusting the seat
(→ page 88).
In order forth e cor rectly wornseat belt topro‐
vide the intended le vel of pr otection, each vehi‐
cle occupant must obser vethefo llowing infor‐
mation:
R The seat belt must not be twis ted and must
fi t tightly and snu gly across the body.
R The seat belt must be routed across the
centre of the shoulder and as low down
across the hips as possible.
R The shoulder section of the seat belt should
not touch your ne cknor be routed under
yo ur arm or behind your bac k.
R Avoid wearing bulky clo thing, e.g. a winter
coat.
R Push the lap belt down as far as possible
across your hips and pull tight with the shoul‐ der section of
the belt. Ne verro ute the lap
belt across your abdomen.
R Neverro ute the seat belt across sharp, poin‐
te d, abrasive or fragile objects.
R Only one person should use each seat belt at
any one time. Ne ver allow babies and chil‐
dren totrave l sitting on the lap of ano ther
ve hicle occupant.
R Never secure objects with a seat belt if the
seat belt is also being used byone of the
ve hicle's occupants. Alw ays obser vethe
instructions for loading theve hicle when
securing objects, luggage or loads
(→ page 101).
Also ensu rethat no objects, e.g. a cushion,
are ever placed between a person and the
seat.
If ch ildren are tra velling in theve hicle, be sure to
obser vethe instructions and saf ety no tes on
"Children in theve hicle" (→ page 46). Re
duced seat belt pr otection &
WARNING Risk of inju ryor death due to
incor rect seat position
The seat belt does not of ferth e intended
le ve l of pr otection if you ha venot mo vedthe
seat backrest toan almost vertical position.
When braking or in theeve nt of an accident,
yo u could slide underneath the seat belt and
sus tain abdominal or neck injuries, forex am‐
ple. #
Adjust the seat proper lybefore begin‐
ning your journe y. #
Alw ays ensure that the seat backrest is
in an almost vertical position and that
th e shoulder section of your seat belt is
ro uted across the cent reofyour shoul‐
der. Occupant saf
ety33

&
WARNING Risk of inju ryor death when
additional restra int sy stems are not used
fo r persons with a smaller build
Pe rsons under 1.50 m tall cannot wearthe
seat belt cor rectly wi thout a suitable addi‐
tional restra int sy stem.
If th e seat belt is not worncor rectly, it can‐
not per form its intended pr otective function.
In addition, an incor rectly fastened seat belt
can also cause injuries, forex ample, in the
ev ent of an accident or when braking or
ch anging direction sudden ly.#
Alw ays secure persons under 1.50 m
ta ll in a suitable restra int sy stem. &
WARNING Risk of inju ryor death due to
damaged or modified seat belts
Seat belts cann otprov ide pr otection in the
fo llowing situations:
R Ifth e seat belts are damaged, modified,
ex treme lydirty, bleached or dyed R
Ifth e seat belt buckle is damaged or
ex treme lydirty
R Ifth e seat belt tensioners, seat belt
anchorages or seat belt retractors ha ve
been modified
Seat belts may be damaged in an accident,
although the damage may not be visible, e.g.
due tosplinters of glass.
Modified or damaged seat belts may tear or
fa il, e.g. in an accident.
Modified seat belt tensioners could acciden‐
ta lly trigger or failto function as intended. #
Never modify the seat belts, seat belt
te nsioners, seat belt anchorages or seat
belt retractors. #
Makesure that the seat belts are
undamaged, not wornand clean. #
Alw ays ha vethe seat belts checked
immediately af ter an accident at a
qu alified specialist workshop. Mercedes-Benz
recommends that you use seat
belts which ha vebeen appr ovedfo ryo ur vehicle
by Mercedes-Benz.
The sport seat is designed forth est andard
th re e-point seat belt. If youfit a di fferent multi‐
point seat belt, e.g. sport or racing seat belts,
th ere stra int sy stem cann otprov ide the intended
le ve l of pr otection.
Depending on the type of seat, there may be
openings in the seat backrest. These openings
ha ve no function. &
WARNING Risk of inju ryor fata l injury
due tomodified seat belt sy stems
If yo ufe ed seat belts thro ugh the opening in
th e seat backrest, the seat backrest may be
damaged or may even break in theeve nt of
an accident. #
Only use thest andard thre e-point seat
belt. #
Never modify the seat belt sy stem. 34
Occupant saf ety

Ve
hicles with automatic front passen ger
front airbag shu toff:th e front passenger front
airbag can only be deplo yed in an accident if the
PA SSENGER AIR BAG OFF indicator lamp is off.
If th e front passenger seat is occupied, make
sure, bo thbefore and during the journe y,that
th est atus of the front passenger front airbag is
cor rect (→ page 41). Pr
otection bythe airbags Depending on
the accident situation, an airbag
may supplement the pr otection of fere dby a cor‐
re ctly fastened seat belt. &
WARNING Risk of inju ryor death due to
incor rect seat position
If yo u deviate from the cor rect seat position,
th e airbag cann otper form its intended pro‐
te ctive function and deployment may even
cause fur ther injuries. To
avoid hazardous situations, alw ays make
sure that all vehicle occupants:
R Have their seat belt fastened cor rectly,
including pregnant women.
R Are seated proper lyand keep as faraw ay
as possible from the airbags.
R Obser vethefo llowing information. #
Alw ays make sure that there are no
objects between the airbag and vehicle
occupant. To
avo idtherisks resulting from the deployment
of an airbag, each vehicle occupant must
obser vethefo llowing information:
R Before starting your journe y,adjust your seat
co rrectly ;th e driver's seat and front
passenger seat should be mo ved as far back
as possible.
When doing so, alw ays obser vethe informa‐
tion on the cor rect driver's seat position
(→ page 88). R
Only hold thesteering wheel bythesteering
wheel rim. This allow sth e airbag tobe fully
deplo yed.
R Alw ays lean against the seat backrest when
th eve hicle is in motion. Do not lean forw ards
or against the door or side windo w.You may
ot herwise be in the deployment area of the
airbags.
R Alw ayske ep your feet on thefloor. Do not
put your feet on the cockpit, forex ample.
Yo ur feet may otherwise be in the deploy‐
ment area of the airbag.
R Ifch ildren are tra velling in theve hicle,
obser vethe additional no tes (→ page 46).
R Alw aysstow and secure objects cor rectly.
Objects in theve hicle interior may pr event an
airbag from functioning cor rectly. Each vehicle
occupant must alw ays make sure of thefo llow‐
ing:
R There are no people, animals or objects
between theve hicle occupants and an air‐
bag. 38
Occupant saf ety

Ve
hicles without automatic front passenger front
airbag shutoff ha vea special sticke r af fixe dto
th e side of the cockpit on the front passenger
side (→ page 53).
Self-test of automatic front passenger front
airbag shutoff
When the ignition is switched on, a self-test is
per form ed during which the two PASSENGER
AIR BAG ON and OFF indicator lamps light up
simul taneously.
The status of the front passenger front airbag is
displa yed af terth e self-tes t:
R PASSENGER AIR BAG ON lights up for
60 seconds, subsequently bo thindicator
lamps are off (PASSENGER AIR BAG ON and
OFF): the front passenger front airbag is able
to deploy in theeve nt of an accident.
R PASSENGER AIR BAG OFF lights up continu‐
ously: the front passenger front airbag is dis‐
abled. It will then not be deplo yed in the
eve nt of an accident.
If th ePA SSENGER AIR BAG ON indicator lamp is
off, on lythePA SSENGER AIR BAG OFF indicator
lamp sho ws thest atus of the front passenger front airbag. The
PASSENGER AIR BAG OFF indi‐
cator lamp may be lit continuously or be off.
If th ePA SSENGER AIR BAG OFF indicator lamp
and the6 restra int sy stem warning lamp
light up simultaneousl y,the front passenger seat
may not be used. Also in this case, do not fit a
ch ild restra int sy stem tothe front passenger
seat. Ha veautomatic front passenger front air‐
bag shutoff checked and repaired immediately at
a qu alified specialist workshop.
St atus display
If th e front passenger seat is occupied, ensure,
bo th before and during the journe y,that thest a‐
tus of the front passenger front airbag is cor rect
fo rth e cur rent situation.
Af terfitting a rear wa rd-facing child restra int
sy stem tothe front passenger seat:
PA SSENGER AIR BAG OFF must be lit continu‐
ousl y. &
WARNING Risk of inju ryor death from
using a rear wa rd-facing child restra int
sy stem when the front passenger front
airbag is enabled
If yo u secure a child in a rear wa rd-facing
ch ild restra int sy stem on the front passenger
seat and thePA SSENGER AIR BAG OFF indi‐
cator lamp is off, the front passenger airbag
can deploy in theev ent of an accident.
The child could be stru ck bythe airbag.
Alw ays ensure that the front passenger air‐
bag is disabled. The PASSENGER AIR BAG
OFF indicator lamp must be lit.
NEVER use a rear wa rd-facing child restra int
sy stem on a seat pr otected byan ENABLED
FRONT AIRB AGin front of it, DE ATH or SERI‐
OUS INJU RYtotheCH ILD can occur. When
fitting a child restra int sy stem tothe front
passenger seat, obser vetheve hicle-specific
information (→ page 52).
Also, alw ays obser vethe no tes on rear wa rd-
fa cing or forw ard-facing child restra int sy stems
on the front passenger seat (→ page 53).42
Occupant saf ety

Depending on
thech ild restra int sy stem and the
st ature of thech ild, thePA SSENGER AIR BAG
OFF indicator lamp may be off. In this case, do
not fit th ere ar wa rd-facing child restra int sy stem
to the front passenger seat.
Ins tead, fit th ere ar wa rd-facing child restra int
sy stem toa suitable rear seat.
Af terfitting a forw ard-facing child restra int
sy stem tothe front passenger seat: depend‐
ing on thech ild restra int sy stem and thest ature
of thech ild, PASSENGER AIR BAG OFF may be lit
continuously or be off. Alw ays obser vethefo l‐
lowing information. &
WARNING Risk of inju ryor death due to
incor rect positioning of thefo rw ard-
fa cing child restra int sy stem
If yo u secure a child in a forw ard-facing child
re stra int sy stem on the front passenger seat
and you position the front passenger seat too
close tothe dashboard, in theev ent of an
accident, thech ild could:
R come into con tact wi thparts of theve hi‐
cle's interior if thePA SSENGER AIR BAG
OFF indicator lamp is lit, forex ample
R bestru ck bythe airbag if thePA SSENGER
AIR BAG OFF indicator lamp is off #
Alw ays mo vethe front passenger seat
as far back as possible and fully retract
th e seat cushion length adjustment.
Alw ays make sure that the shoulder belt
st ra p is cor rectly routed from the seat
belt outlet on theve hicle tothe shoul‐
der belt guide on thech ild restra int sys‐
te m. The shoulder belt stra p must be
ro uted forw ards and down wards from th
e seat belt outlet. If necessar y,adjust
th e front passenger seat according ly. #
Alw ays obser vethech ild restra int sys‐
te m manufacturer's ins tallation instruc‐
tions. When
fitting a child restra int sy stem tothe front
passenger seat, obser vetheve hicle-specific
information (→ page 53).
If a person is sitting on the front passenger
seat: PASSENGER AIR BAG OFF may be lit con‐
tinuously or be off, depending on the person's
st ature.
A person on the front passenger seat must
alw ays obser vethefo llowing information:
R Ifth e front passenger seat is occupied byan
adult or a person with a stature cor respond‐
ing tothat of an adult, thePA SSENGER AIR
BA G OFF indicator lamp must be off. This
indicates that the front passenger front air‐
bag is enabled.
If th ePA SSENGER AIR BAG OFF indicator
lamp is lit continuousl y,an adult or person Occupant saf
ety43

Child
ren in theve hicle Note
s onthe safe transportation of children &
WARNING Risk of accident and inju ry
due tochildren left unat tended in the
ve hicle
If yo u lea vechildren unat tended in theve hi‐
cle, they may be able toset theve hicle in
motion, forex ample by:
R releasing the parking brake.
R shifting the automatic transmission out of
park position jor shifting manual trans‐
mission into idle position.
R starting the engine.
In addition, they may operate vehicle equip‐
ment and become trapped. #
Never lea vechildren and animals unat‐
te nded in theve hicle. #
When leaving theve hicle, alw aysta ke
th eke y with you and lock theve hicle.
This also applies tothe digital vehicle ke
y if the "Digital Vehicle Key" function
is activated via Mercedes me connect. &
WARNING Risk offata l injury due to
ex posure toextreme heat or cold in the
ve hicle
If people –particularly children – are exposed
to extreme temp eratures over an extended
pe riod of time, there is a risk of serious or
ev en fata l injury! #
Never lea veanyone – pa rticularly chil‐
dren – unat tended in theve hicle. #
Never lea veanimals in theve hicle unat‐
te nded. &
WARNING Risk of bu rns when thech ild
seat is exposed todirect sunlight
If th ech ild restra int sy stem is exposed to
direct sunlight or heat, parts could heat up.
Children could suf fer burns on these parts,
particularly on me tallic parts of thech ild
re stra int sy stem. #
Alw ays make sure that thech ild
re stra int sy stem is not exposed to
direct sunlight. #
Protect it with a blank et,fo rex ample. #
Ifth ech ild restra int sy stem has been
ex posed todirect sunlight, allow it to
cool before secu ring a child into it. #
Never lea vechildren unat tended in the
ve hicle. To
impr oveprotection forch ildren younger than
12 years old or under 1.50 m in height,
Mercedes-Benz recommends you obse rvethe
fo llowing information:
R Only secure children using a child restra int
sy stem which is appropriate tothe height,
age and weight of thech ild and recommen‐
ded and suitable for Mercedes-Benz vehicles.
Be sure toobser vethe instructions for cor‐
re ct use of thech ild restra int sy stem.
R Alw aysfit a child restra int sy stem toare ar
seat if possible.
R Onlyuse thefo llowing securing sy stems for
ch ild restra int sy stems: 46
Occupant saf ety