ignition MERCEDES-BENZ A-CLASS HATCHBACK 2018 Workshop Manual

St
arting assi stance and charging the12 V
battery Re
quirements:
R The vehicle is secured with the electric park‐
ing brake.
R Automatic transmission: the transmission
is in position j.
R Manual transmission: the transmission is in
neutral.
R The ignition and all electrical consumers are
switched off.
R The bonn etis open. #
Slide co ver1 of positive clamp 2onthe
jump-s tarting connection point in the direc‐
tion of the ar row. #
Connect positive clamp 2onyour vehicle to
th e positive pole of the donor battery using
th e jump lead/charging cable. Alw ays begin
with positive clamp 2onyour ow nve hicle
fi rs t. #
During starting assi stance: start the
engine of the donor vehicle and run at idle
speed. #
Connect the negative pole of the donor bat‐
te ry and ear thpoint 3ofyour ow nve hicle
by using the jump lead/charging cable. Begin
with the donor battery firs t. #
During starting assi stance: start the
engine of your ow nve hicle. #
During thech arging process: start the
ch arging process. #
During starting assi stance: letthe engines
ru nfo r se veral minutes. #
During starting assi stance: before discon‐
necting the jump lead, switch on an electrical
consumer in your ow nve hicle, e.g. there ar
wind owheater or lighting.
When thest arting assis tance/charging process
is compl ete: #
First,re mo vethe jump lead/charging cable
from ear thpoint 3and negative pole of the
donor batter y,then from positive clamp 2
and positive pole of the donor batter y.Begin 448
Breakdown assis tance

each time with
the conta cts onyour own
ve hicle firs t. #
Afterre moving the jump lead/charging
cable, close co ver1 of positive clamp 2.
Fu rther information can be obtained at a quali‐
fi ed specialist workshop. Re
placing the 12V battery #
Obser vethe no tes on the12 V battery
(→ page 444).
Mercedes-Benz recommends that you ha vethe
12 V battery replaced at a qualified specialist
wo rkshop, e.g. at a Mercedes-Benz Service
Centre.
Obser vethefo llowing no tes if youwa ntto
re place the battery yourself:
R Alw aysre place a faulty bat tery with a battery
which meets the specific vehicle require‐
ments.
The vehicle is equipped with an AGMtech nol‐
ogy battery (Absorbent Glass Mat). Fullve hi‐ cle functionality is only guaranteed with an
AG M batter y.Fo r saf etyre asons, Mercedes-
Benz recommends that you on lyuse bat ter‐
ies which have been tested and appr ovedfor
yo ur vehicle byMercedes-Benz.
R Carryover de tach able parts, such as vent
hoses, elbow fittings or term inal co vers, from
th e battery being replaced.
R Make sure that theve nt hose is al ways con‐
nected tothe original opening on the side of
th e batter y.
Fit any existing or supplied cell caps.
Otherwise, gases or battery acid could
escape.
R Make sure that de tach able parts are recon‐
nected in the same way. To
w- starting or towing away Pe
rm itted towing me thods Mercedes-Benz
recommends transporting your
ve hicle in the case of a breakdown, rath er than
to wing it away. Fo
rto wing, use a tow rope or tow bar with bo th
axles on the ground. Do not use tow bar sys‐
te ms. &
WARNING Risk of accident when towing
with steering wheel lock
Yo u will no lon ger be able tosteer theve hicle
if th esteering wheel lock is engaged. #
Alw ays switch on the ignition when tow‐
ing theve hicle with a tow cable or a tow
bar. *
NO
TEDama getotheve hicle due to tow‐
ing away incor rectly #
Obser vethe instructions and no tes on
to wing away. Breakdown assis
tance 449

*
NO
TEDama gedue to to wing away at
exc essively high speeds or over long dis‐
ta nces The driv
etra in could be damaged when tow‐
ing at excessively high speeds or over long
dis tances. #
Atowing speed of 50 km/h must not
be exc eeded. #
Atowing dis tance of 50 km must not be
exc eeded. &
WARNING Risk of accident when towing
a ve hicle which is too heavy
If th eve hicle being tow- star ted or towed
aw ay is heavier than the permissible gross
mass, thefo llowing situations can occur:
R theto wing eye may become de tach ed.
R the car/t railer combination may swer ve
or eve nove rturn. #
If ano ther vehicle is tow- star ted or
to we daw ay, its weight must not exceed th
e permissible gross mass of your own
ve hicle. If a
vehicle must be tow star ted or towe daw ay,
its permissible gross mass must not exceed the
permissible gross mass of theto wing vehicle. #
Information on the permissible gross mass of
th eve hicle can be found on theve hicle iden‐
tification plate (→ page 483). #
Vehicles with automatic transmission: do
not open the driver's door or front passenger
door, otherwise the automatic transmission
automatically shifts toposition j. #
Fittheto wing eye (→ page 453). #
Fasten theto w bar.
* NO
TEDama gedue toincor rect connec‐
tion #
Only connect theto w rope or tow bar to
th eto wing eyes. #
Deactivate the automatic locking mechanism
(→ page 73). #
Do not activate the HOLD function. #
Deactivate tow- aw ay protection (→ page 86). #
Deactivate Active Brake Assi st (→page 196). #
Vehicles with automatic transmission:
shift the automatic transmission toposition
i. #
Vehicles with manual transmission: shift
to neutral i. #
Release the electric parking brake. #
Switch on the ignition, otherwise thesteering
wheel lock may engage. &
WARNING Risk of accident due tolimi‐
te d saf ety-re lated functions during the
to wing process
Saf ety-re lated functions are limited or no lon‐
ge rav ailable in thefo llowing situations:
R the ignition is switched off.
R the brake sy stem or po werst eering sys‐
te m is malfunctioning. Breakdown assi
stance 451

#
Vehicles with automatic transmission
must not be tow- star ted. #
Vehicles with automatic transmission must
not be tow- star ted.
Ve hicles with manual transmission #
Obser vethe no tes on towing away
( → page 450). #
If necessar y,allow the engine and exhaust
sy stem tocool down. #
Switch the ignition on. #
Enga gesecond gear. #
Release the electric parking brake. #
Tow- start theve hicle while the clutch pedal
is fully depressed. #
Slowly release the clutch pedal. #
Immediately shift toneutral if the engine
st arts. #
Pull over and stop theve hicle, paying atten‐
tion toroad and traf fic conditions. #
Remo vetheto w bar. #
Remo vetheto wing eye. #
Have theve hicle checked at a qualified spe‐
cialist workshop. Electrical fuses
Note
s on electrical fuses &
WARNING Risk of accident and inju ry
due to ov erloaded lines
If yo u manipulate or bridge a faulty fuse or if
yo ure place it with a fuse with a higher
amperage, the electric line could be overloa‐
ded.
This could result in a fire. #
Alw aysre place faulty fuses with speci‐
fi ed new fuses conta iningthe cor rect
amperage. *
NO
TEDama gedue toincor rect fuses Electrical components or sy
stems may be
damaged byincor rect fuses, or their func‐
tionality may be significant lyimpaired. #
Only use fuses that ha vebeen appr oved
by Mercedes-Benz and which ha vethe
cor rect fuse rating. Blown fuses mu
stbe replaced with fuses of the
same rating, which you can recognise bythe col‐
our and fuse rating. The fuse ratings and fu rther
information tobe obser ved are lis ted in the fuse
assignment diagram.
Fu se assignment diag ram: onthe fuse box in
th e engine compartment (→ page 455).
* NO
TEDama geor malfunctions caused
by moisture Moisture may cause dama
getothe electrical
sy stem or cause it tomalfunction. #
When the fuse box is open, make sure
th at no moisture can enter the fuse
box. #
When closing the fuse box, make sure
th at the seal of the lid is positioned cor‐
re ctly on the fuse box. 454
Breakdown assis tance

If
th e newly inser ted fuse also blo ws, ha vethe
cause traced and rectified at a qualified special‐
ist workshop, e.g. a Mercedes-Benz Service
Centre.
Ensure thefo llowing before replacing a fuse:
R The vehicle is secured against rolling away.
R All electrical consumers are switched off.
R The ignition is switched off.
The electrical fuses are located in various fuse
bo xes:
R Fuse box in the engine compartment on the
left-hand side of theve hicle, when vie wed in
th e direction of tr avel (→ page 455)
R Fuse box in the front passenger foot we ll
(→ page 456)
R Fuse box in the cent reofthe load compart‐
ment (→ page 457) Opening and closing
the fuse box in the
engine compa rtment Requ
irements:
R You need a dry clo thand a sc rewdriver. Obser
vethe no tes on electrical fuses
(→ page 454).
Opening &
WARNING Risk of inju ryfrom using the
windscreen wipers while the engine bon‐
net is open
When the engine bonn etis open, and the
windscreen wipers are set in motion, you can
be trapped bythe wiper linkage. #
Alw ays switch off the windscreen wip‐
ers and ignition before opening the
engine bonn et. #
Open the bonn et. #
Remo veany existing moisture from the fuse
box using a dry clo th. #
Loosen scr ews1. #
Press clamps 2and lift the fuse box lid up
and out.
The fuse assignment diagram is in a recess on
th e side of the fuse box. Breakdown assis
tance 455

If
th e preceding tyre sizes are complemented by
th e+ symbol, the tyre pressure information
fo llowing sho wsalternative tyre pressures.
These tyre pressures may impr oveyour vehicle's
ri de comfort. Fuel consum ption may then
increase slightl y.
The load conditions "partially laden" and "fully
laden" are defined in theta ble for dif fere nt num‐
be rs of passengers and amounts of luggage. The
actual number of seats may dif fer from this.
Be sure toalso obse rveth efo llowing fur ther
re lated subjects:
R Notes on tyre pressure (→ page 459)Ty
re pressure moni toring sy stem Fu
nction of the ty repressure moni toring sys‐
tem
The sy stem checks the tyre pressure and the
tyre temp erature of the tyres fitted totheve hicle
by means of a tyre pressu resensor.
New tyre pressure sensors, e.g. in winter tyres,
are automatically taught-in during thefirs t jour‐
ney they are used. The tyre pressure and
the tyre temp erature
appear in the multifunction display
(→ page 461).
If th ere is a subs tantial pressure loss or if the
tyre temp erature is excessive, you will be
wa rned in thefo llowing ways:
R via display messa ges (→ page 528)
R viatheh warning lamp in the instrument
clus ter (→ page 559)
The tyre pressu remonitoring sy stem is only an
aid. It is the driver's responsibility toset the tyre
pressure tothere commended cold tyre pressure
suitable forth e operating situation. Set the tyre
pressure for cold tyres using a tyre pressu re
ga uge. Notethat the cor rect tyre pressure for
th e cur rent operating situation mu stfirs t be
tau ght-in tothe tyre pressure monitoring sys‐
te m.
In most cases, the tyre pressure monitoring sys‐
te m will auto matically update the new refere nce
va lues af teryo u ha vechanged the tyre pressure.
Yo u can, ho wever,also update there fere nce val‐
ues byrestarting the tyre pressure monitoring
sy stem manually (→ page 462). Sy
stem limitations
The sy stem may be impaired or may not function
in thefo llowing situations:
R ifth e tyre pressure is set incor rectly
R ifth ere is a sudden pressure loss caused, for
ex ample, byafo re ign object penetrating the
tyre
R ifth ere is a malfunction caused byano ther
ra dio signal source
Make sure toobser vethefo llowing fur ther rela‐
te d subjec t:
R notes on tyre pressure (→ page 459)
Checking the ty repressure with the tyre
pressure moni toring sy stem
Requ irements:
R The ignition is switched on.
On-board computer: , Service .
Tyres
One of thefo llowing displa ysappears:
R Cur rent tyre pressure and tyre temp erature
of the individual wheels: Wheels and tyres
461

#
Remo vesticke r1 from the tyre inflation
compressor housing and af fix it tothe instru‐
ment clus ter within the driver's field of
vision. #
Pull filler hose 2and plug 4out of the tyre
inflation compressor housing. #
Insert plug 8offiller hose 2inthe soc ket
on the tyre inflation compressor and then
turn it until plug 8engages. #
Unscr ew the cap from theva lve on the emer‐
ge ncy spa rewheel. #
Screw union nut 3offiller hose 2onto the
va lve. #
Make sure on and off switch 5ofthe tyre
inflation compressor is set to0. #
Insert plug 4into a soc ket in your vehicle.
R Cigar ette lighter soc ket: ( → page 114)
R 12V soc ket: ( → page 115)
R Obse rveth e no tes on the cigar ette lighter:
(→ page 114)
R Obse rveth e no tes on soc kets: (→ page 115) #
Turn theke yto position 1inthe ignition
loc k. #
Press on and off switch 5onthe tyre infla‐
tion compressor toI.
The tyre inflation compressor is switched on.
The tyre is inflated. The tyre pressure is
shown on manome ter6. #
Pump the tyre tothe specified tyre pressure.
The specified tyre pressure is stated on the
label of the emer gency spa rewheel. #
When the specified tyre pressure has been
re ached, press on and off swit ch5 onthe
tyre inflation compressor to0.
The tyre inflation compressor is switched off. #
Turn theke yto position ginthe ignition
loc k. #
Ifth e tyre pressure is higher than the speci‐
fi ed pressure, press pressure release valve
bu tton 7until the cor rect tyre pressure has
been reached. #
Unscr ew union nut 3offiller hose 2from
th eva lve. #
Screw theva lve cap of the emer gency spa re
wheel onto theva lve again. Wheels and tyres
47 9

Fu
rther information on appr oved operating fluids
is available at thefo llowing locations:
R inthe Mercedes-Benz Specifications for
Operating Fluids byentering the designation
- at http://be vo.mercedes-benz.com
- inthe Mercedes-Benz BeVo App
R at a qualified specialist workshop &
WARNING Risk offire or explosion from
fuel
Fu els are highly flammable. #
Fire, naked flames, smoking and creat‐
ing spar ksmust be avoided. #
Swit choff the ignition and, if it has
been in use, switch off thest ationary
heater before youre fuel your vehicle. &
WARNING Risk of inju ryfrom fuels
Fu els are poisonous and hazardous to your
health. #
Do not swallow fuel or let it come into
contact with skin, eyes or clo thing. #
Do not inhale fuel vapour. #
Keep children away from fuel. #
Keep doors and windo wsclosed du ring
th ere fuelling process.
If yo u or other people come into contact with
fuel, obser vethefo llowing: #
Immediately rinse fuel off your skin with
soap and water. #
If fuel comes into contact with your
ey es, immediately rinse them thor‐
oughly with clean water.Seek medical
attention immediately. #
Ifyo u swallow fuel, seek medical atten‐
tion immediatel y.Do not induce vomit‐
ing. #
Change immediately out of clo thing that
has come into con tact wi thfuel. Fu
el Information on fuel
grades forve hicles with
petrol engines
Obser vethe no tes on operating fluids
(→ page 485).
* NO
TEDama gecaused bythe wrong fuel Even small amounts of
the wrong fuel could
re sult in damage tothe fuel sy stem, the
engine and the emission control sy stem. #
Only refuel using unleaded, sulphu r-free
fuel that con form sto European EN 228,
or an equi valent specification.
Fu el of this specification may con tain up to
10 %ethanol by volume. Your vehicle is suita‐
ble for use with E10 fuel.
Ne verre fuel with one of thefo llowing fuels:
R diesel
R regular petrol with an octane number
lo we rth an 91 RON 486
Tech nical da ta

R
petrol with more than 10%ethanol byvol‐
ume, e.g. E15, E20, E85, E100
R petrol with more than 3% me thanol by
vo lume, e.g. M15, M30
R petrol with additives con taining me tal
If yo u ha veacciden tally refuelled with the
wrong fuel: #
do not swit chon the ignition. #
consult a qualified specialist workshop. The
following compatibility indications for fuel
apply to yourvehicle: 1
For petrol with maximum 5% ethanol byvol‐
ume
2 For petrol with maximum 10%ethanol by vol‐
ume
Ac cording toEuropean standard EN 1694 2you
can find the compatibility indications at thefo l‐
lowing locations:
R onthe instruction label on the fuel filler flap
R onthe fuel pump or pump nozzle suitable for
yo ur vehicle thro ughout Europe
If th eav ailable fuel is not suf ficiently low in sul‐
phu r,th is can produce unpleasant odours. The
recommended octane number foryo ur vehi‐
cle can also be found on the instruction label in
th e fuel filler flap (→ page169).
As a temp orary measure, if there commended
fuel is not available, you may also use regular
unleaded petrol with at least 91RON. This may
re duce engine output and increase fuel con‐
sum ption.
Ne verre fuel using petrol with a lo werRO N.
Fu rther information on fuel can be obtained at a
fi lling station or a qualified specialist workshop.
Information on additives in petrol
Obser vethe no tes on operating fluids
(→ page 485).
* NO
TEDama gefrom use of unsuitable
additives Even small amounts of
the wrong additive
may lead tomalfunctions occur ring. #
Only add cleaning additives recommen‐
ded byMercedes-Benz tothe fuel. Te
ch nical da ta487

Mercedes-Benz
recommends that you use fuel
brands that ha veadditives.
In some countries, the fuel available may not
ha ve suf ficient additives. Residue could build up
in the fuel injection sy stem as a result. In this
case, in consultation with a Mercedes-Benz
service centre, the fuel may be mixed with the
cleaning additive recommended byMercedes-
Benz. Be sure toobser vethe no tes and mixing
ra tios speci fied on the conta iner.
Information on fuel grades forve hicles with
a diesel engine
Gene ral no tes
Obser vethe no tes on operating fluids
(→ page 485). &
WARNING Risk offire from fuel mixture
If yo u mix diesel fuel with petrol, theflash
point of the fuel mixture is lo werth an that of
pure diesel fuel.
While the engine is running, component
pa rts in theex haust sy stem may overheat
without warning. #
Neverre fuel using petrol in diesel
engines. #
Never mix petrol with diesel fuel. *
NO
TEDama gecaused bythe wrong fuel Even small amounts of
the wrong fuel could
re sult in damage tothe fuel sy stem, the
engine and the emission control sy stem. #
Only refuel using sulphu r-free diesel
fuel that con form sto European stand‐
ard EN 590, or an equivalent specifica‐
tion.
In countries without sulphur-f ree diesel
fuel, refuel using only lo w-sulphur diesel
fuel with a sulphur content less than
50 ppm. #
Vehicles without diesel particulate
fi lter: refuel using only diesel fuel with
a sulphur content less than 500 ppm.
Ne verre fuel with one of thefo llowing fuels:
R petrol R
marine diesel
R heating oil
R pure bio-diesel fuel or vege table oil
R paraf fin or kerosene
If yo u ha veacciden tally refuelled with the
wrong fuel: #
Do not swit ch the ignition on. #
Consult a qualified specialist workshop. The
following compatibility indication for fuel
applies to yourvehicle: 488
Tech nical da ta