2012 MERCEDES-BENZ A CLASS fuel pressure

G
WARNING
If you fit unsuitable accessories onto tyre
valves, the tyre valves may be overloaded and
malfunction, which can cause tyre pressure
loss. Due to their design, retrofitted tyre pres-
sure monitors keep the tyre valve open. This
can also result in tyre pressure loss. There is
a risk of accident.
Only screw standard valve caps or valve caps
specifically provided by Mercedes-Benz for
your vehicle onto the tyre valve. G
WARNING
If the tyre pressure drops repeatedly, the
wheel, valve or tyre may be damaged. Tyre
pressure that is too low may result in a tyre
blow-out. There is a risk of accident.
R Check the tyre for foreign objects.
R Check

whether the wheel is losing air or the
valve is leaking.
If you are unable to rectify the damage, con-
tact a qualified specialist workshop. H
Environmental note
Check the tyre pressure regularly, at least
every 14 days
.
You will find a table of tyre pressures for var-
ious operating conditions on the inside of
your vehicle's fuel filler flap.
Operation with an emergency spare
wheel (Y page 332).
Operation with a trailer: the applicable
value for the rear tyres is the maximum tyre
pressure value stated in the table inside the
fuel filler flap.
The table inside the fuel filler flap may state
tyre pressures for different load conditions.
These are defined in the table as different
numbers of passengers and amounts of lug-
gage. The actual number of seats may vary;
for more information, please refer to the vehi-
cle's registration documents.
If tyre sizes are not specified, the tyre pres-
sures stated on the tyre pressure information label apply for all tyres approved for this vehi-
cle.
If a tyre size precedes a tyre pressure, the
following tyre pressure information is only
valid for that tyre size.
Use a suitable pressure gauge to check the
tyre

pressure. The outer appearance of a tyre
does not permit any reliable conclusion about
the tyre pressure.
If possible, only correct tyre pressures when
the tyres are cold.
The tyres are cold:
R if the vehicle has been parked with the tyres
out of direct sunlight for at least three
hours and
R if the vehicle has not been driven further
than 1.6 km
Depending on the ambient temperature, the
speed at which you are driving and the load
on the tyres, the tyre temperature and thus
the tyre pressure change by approximately
10 kPa per 10 † (0.1 bar/1.5 psi). Take this
into account when checking the pressure of
warm tyres. Only correct the tyre pressure if
it is too low for the current operating condi-
tions.
Driving with tyre pressure that is too high or
too low can:
R shorten the service life of the tyres
R cause increased tyre damage
R have a negative effect on handling charac-
teristics and thus the driving safety (e.g.
aquaplaning)322
Tyre pressure
Wheels and tyres

i
The tyre pressure values given for low
loads are minimum values which offer you
good ride comfort characteristics.
However,
you can also use the values given
for higher loads. These are permissible and
will not adversely affect the running of the
vehicle. Tyre pressure loss warning system
Important safety notes While the vehicle is in motion, the tyre pres-
sure loss warning system monitors the set
tyre pressure using the rotational speed of
the

wheels. This enables the system to detect
significant pressure loss in a tyre. If the speed
of rotation of a wheel changes as a result of
a loss of pressure, a corresponding warning
message will appear in the multifunction dis-
play.
The tyre pressure warning system does not
warn you of an incorrectly set tyre pressure.
Observe the notes on the recommended tyre
pressure ( Y page 321).
The tyre pressure loss warning system does
not replace the need to regularly check your
vehicle's tyre pressures, since an even loss of
pressure on several tyres at the same time
cannot be detected by the tyre pressure loss
warning system.
The tyre pressure monitor is not able to warn
you of a sudden loss of pressure, e.g. if the
tyre is penetrated by a foreign object. In the
event of a sudden loss of pressure, bring the
vehicle to a halt by braking carefully. Avoid
abrupt steering manoeuvres.
The function of the tyre pressure loss warning
system is limited or delayed if:
R snow chains are fitted to your vehicle's
tyres.
R road conditions are wintry.
R you are driving on sand or gravel.
R you adopt a very sporty driving style (cor-
nering at high speeds or driving with high
rates of acceleration). R
you
are towing a very heavy or large trailer.
R you are driving with a heavy load (in the
vehicle or on the roof).
Restarting the tyre pressure loss warn-
ing system Restart the tyre pressure loss warning system
if you have:
R
changed the tyre pressure
R changed the wheels or tyres
R fitted new wheels or tyres
X Before restarting, make sure that the tyre
pressures

are set properly on all four tyres
for the respective operating conditions.
The recommended tyre pressures can be
found in the table on the fuel filler flap.
The tyre pressure loss warning system can
only give reliable warnings if you have set
the correct tyre pressure. If an incorrect
tyre pressure is set, these incorrect values
will be monitored.
X Observe the notes on tyre pressure
(Y page 321).
X Make sure that the key is in posi-
tion 2(Y page 143) in the ignition lock.
X Press the =
or ; button on the steer-
ing wheel to select the Service menu.
X Press the 9 or : button to select
Tyre pressure.
X Press the a button.
The Run Flat Indicator active
Restart

with OK message appears in the
multifunction display.
If you wish to confirm the restart:
X Press the a button.
The Tyre press. now OK? message
appears in the multifunction display.
X Press the 9 or : button to select
Yes.
X Press the a button.
The Run Flat Indicator restarted
message appears in the multifunction dis-
play. Tyre pressure
323
Wheels and tyres Z

X
Tighten the wheel bolts until they are fin-
ger-tight.
Lowering the vehicle G
WARNING
The wheels could work loose if the wheel nuts
and bolts are not tightened to the specified
tightening torque. There is a risk of accident.
Have the tightening torque immediately
checked at a qualified specialist workshop
after a wheel is changed. X
Place the ratchet ring spanner onto the
hexagon nut of the jack so that the letters
AB are visible.
X Turn the ratchet ring spanner until the vehi-
cle is once again standing firmly on the
ground.
X Place the jack to one side.
X Tighten the wheel bolts evenly in a cross-
wise pattern in the sequence indicated
(: to A). The tightening torque must be
130 Nm.
X Turn the jack back to its initial position.
X Stow the jack and the rest of the vehicle
tools in the vehicle again.
X Vehicles with AMG equipment: insert the
cover into the outer sill.
X Check the air pressure of the newly fitted
wheel and adjust accordingly.
Observe the recommended tyre pressure
(Y page 321). Wheel and tyre combinations
General notes
! For safety reasons, Mercedes-Benz rec-
ommends that you only use tyres and
wheels which have been approved by
Mercedes-Benz specifically for your vehi-
cle.
These are specially adapted to the control
systems, such as ABS or ESP ®
and are
marked as follows:
R MO = Mercedes-Benz Original
R MOE

= Mercedes-Benz Original Extended
(tyres featuring run-flat characteristics)
R MO1 = Mercedes-Benz Original (only cer-
tain AMG tyres)
Mercedes-Benz Original Extended tyres
may only be used on wheels that have been
specifically approved by Mercedes-Benz.
Only use tyres, wheels or accessories tes-
ted and approved by Mercedes-Benz. Cer-
tain characteristics, e.g. handling, vehicle
noise emissions or fuel consumption, may
otherwise be adversely affected. In addi-
tion, when driving with a load, tyre dimen-
sion variations could cause the tyres to
come into contact with the bodywork and
axle components. This could result in dam-
age to the tyres or the vehicle.
Mercedes-Benz accepts no liability for
damage resulting from the use of tyres,
wheels or accessories other than those tes-
ted and approved.
Further information about wheels, tyres
and approved combinations can be
obtained from any qualified specialist
workshop.
! Retreaded tyres are neither tested nor
recommended by Mercedes-Benz, since
previous damage cannot always be detec-
ted on retreaded tyres. As a result,
Mercedes-Benz cannot guarantee vehicle
safety if retreaded tyres are fitted. Do not
fit used tyres if you have no information
about their previous usage. Wheel and tyre combinations
329
Wheels and tyres Z

!
Large wheels: the lower the section width
for a certain wheel size, the lower the ride
comfort is on poor road surfaces. Roll com-
fort and suspension comfort are reduced
and the risk of damage to the wheels and
tyres as a result of driving over obstacles
increases.
Overview of abbreviations used in the follow-
ing tyre tables:
R BA: both axles
R FA: front axle
R RA: rear axle
You will find a table with recommended tyre
pressures for various operating conditions on
the inside of your vehicle's fuel filler flap. For
further information on tyre pressure, see
(Y page 321). Check tyre pressures regularly
and only when the tyres are cold.
Notes on the vehicle equipment – always fit
the vehicle:
R with tyres of the same size on a given axle
(left/right)
R with the same type of tyres at a given time
(summer tyres, winter tyres, MOExtended
tyres)
Exception: it is permissible to fit a different
type or make in the event of a flat tyre.
Observe the "MOExtended tyres (tyres with
run-flat characteristics)" section
(Y page 300).
Vehicles with MOExtended tyres are not
equipped with a TIREFIT kit at the factory. It
is therefore recommended that you addition-
ally equip your vehicle with a TIREFIT kit if you
fit tyres that do not feature run-flat charac-
teristics, e.g. winter tyres. A TIREFIT kit can
be obtained from a qualified specialist work-
shop. In the following table, the wheel/tyre combi-
nations are allocated to the vehicle models
through variants, e.g. V1, V2 etc.: V1
A 180
12 V2
A 180 CDI
12 V3
A 200
12
, A 220 CDI 12 V4
A 200 CDI
12 V5
A 250
12 V6 A 250 Sport
V7 A 45 AMG 4MATIC
i
Not all wheel/tyre combinations can be
fitted at the factory in all countries.
12 BlueEFFICIENCY330
Wheel and tyre combinations
Wheels and tyres

recommended fuel is not available, you
may also use unleaded petrol with an
octane rating of 93 RON/
83 MON.
All other models: as a temporary meas-
ure, if the recommended fuel is not availa-
ble, you may also use unleaded petrol with
an octane rating of 91 RON/82 MON. This
may reduce engine performance and
increase fuel consumption. Avoid driving at
full throttle and sudden acceleration. Never
refuel using fuel with a lower RON/MON.
i In some countries, the available petrol
may not be sufficiently low in sulphur. This
fuel can temporarily produce unpleasant
odours, especially on short journeys. As
soon as sulphur-free fuel (sulphur content
< 10 ppm) is used for refuelling, the odours
are reduced.
Information on refuelling (Y page 159).
Additives
! Operating the engine with fuel additives
can cause wear in the fuel high-pressure
pump and contaminate the entire fuel sys-
tem. The repair costs are high. This does
not include additives for the removal and
prevention of residue build-up. Petrol must
only be mixed with additives recommended
by Mercedes-Benz. More information about
recommended additives can be obtained
from any Mercedes-Benz Service Centre.
One of the major problems with low-grade
fuel is the creation of carbon deposits during
the process of burning fuel. Mercedes-Benz
recommends that you use fuel brands that
have additives.
If you use fuels without these additives for a
longer period of time, there may be a build-up
of carbon deposits. These will form especially
on the inlet valves and in the combustion
chamber.
This could lead to engine running problems,
e.g.:
R longer engine warm-up phase
R uneven idle R
engine noise
R misfiring
R loss of power
In areas where petrol with the required addi-
tives is not available, carbon deposits can
build
up. In this case, Mercedes-Benz recom-
mends the use of additives that have been
approved for Mercedes-Benz vehicles; see
http://bevo.mercedes-benz.com.
The quality of the fuel available in some coun-
tries may not be sufficient. Residue could
build up as a result. In such cases, and in
consultation with a Mercedes-Benz Service
Centre, the petrol may be mixed with the
additive recommended by Mercedes-Benz
(part no. A000989254512). You must
observe the notes and mixing ratios specified
on the container.
Consult a Mercedes-Benz Service Centre to
view a list of approved products. Observe the
instructions for use in the product descrip-
tion.
Do not mix other fuel additives with fuel. This
causes unnecessary costs and could damage
the engine.
Diesel (EN 590) Fuel grade
G
WARNING
If you mix diesel fuel with petrol, the flash
point
of this fuel mixture is lower than that of
pure diesel fuel. When the engine is running,
components in the exhaust system may over-
heat unnoticed. There is a risk of fire.
Never refuel with petrol. Never add petrol to
diesel fuel.
! When refuelling, only use diesel fuel that
conforms to the European standard EN 590
or is of equivalent quality. Fuel that does
not conform to EN 590 can lead to
increased wear as well as damage to the
engine and exhaust system. Service products and capacities
341
Technical data Z