2015 MERCEDES-BENZ CLA-Class ECU

Checking the tire pressures
Important safety notes Observe the notes on tire pressure
(Y page 322).
Information on air pressure for the tires on
your vehicle can be found:
R on the vehicle's Tire and Loading Informa-
tion placard on the B-pillar
R on the tire pressure label on the fuel filler
flap (Y page 159)
R in the "Tire pressure" section
Checking tire pressures manually To determine and set the correct tire pres-
sure, proceed as follows:
X Remove the valve cap of the tire that is to
be checked.
X Press the tire pressure gauge securely onto
the valve.
X Read the tire pressure and compare it to
the recommended value on the Tire and
Loading Information placard or the tire
pressure table (Y page 322).
X If the tire pressure is too low, increase the
tire pressure to the recommended value.
X If the tire pressure is too high, release air.
To do so, press down the metal pin in the
valve, using the tip of a pen for example.
Then check the tire pressure again using
the tire pressure checker.
X Screw the valve cap onto the valve.
X Repeat these steps for the other tires. Tire pressure loss warning system
General notes While the vehicle is in motion, the tire pres-
sure loss warning system monitors the set
tire pressure using the rotational speed of the wheels. This enables the system to detect
significant pressure loss in a tire. 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.
You can recognize the tire pressure loss warn-
ing in the multifunction display in the Serv.
Serv.
menu, by the Run RunFlat
Flat Indicator
Indicator Active
Active
Press 'OK' to Restart
Press 'OK' to Restart message. Further
information on displaying this message can
be found under "Restarting the tire pressure
loss warning system" (Y page 326).
Important safety notes The tire pressure warning system does not
warn you of an incorrectly set tire pressure.
Observe the notes on the recommended tire
pressure (Y page 322).
The tire pressure loss warning does not
replace the need to regularly check the tire
pressure. An even loss of pressure on several tires at the same time cannot be detected by
the tire pressure loss warning system.
The tire pressure monitor is not able to warn
you of a sudden loss of pressure, e.g. if the
tire 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 maneuvers.
The function of the tire pressure loss warning system is limited or delayed if:
R snow chains are mounted on your vehicle's
tires.
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 driving with a heavy load (in the
vehicle or on the roof). Tire pressure
325Wheels and tires Z

Curb weight
The weight of a vehicle with standard equip-
ment including the maximum capacity of fuel, oil and coolant. It also includes the air-condi-
tioning system and optional equipment if
these are installed in the vehicle, but does not include passengers or luggage.
Maximum load rating
The maximum load rating is the maximum
permissible weight in kilograms or lbs for
which a tire is approved.
Maximum permissible tire pressure
Maximum permissible tire pressure for one
tire.
Maximum load on one tire
Maximum load on one tire. This is calculated
by dividing the maximum axle load of one axle by two.
PSI (pounds per square inch)
A standard unit of measure for tire pressure.
Aspect ratio
Relationship between tire height and tire
width in percent.
Tire pressure
This is pressure inside the tire applying an
outward force to each square inch of the tire's
surface. The tire pressure is specified in
pounds per square inch (psi), in kilopascal
(kPa) or in bar. The tire pressure should only
be corrected when the tires are cold.
Cold tire pressure
The tires are cold:
R if the vehicle has been parked without
direct sunlight on the tires for at least three
hours and
R if the vehicle has not been driven further
than 1 mile (1.6 km) Tread
The part of the tire that comes into contact
with the road.
Bead
The tire bead ensures that the tire sits
securely on the wheel. There are several steel
wires in the bead to prevent the tire from
coming loose from the wheel rim.
Sidewall
The part of the tire between the tread and the bead.
Weight of optional extras
The combined weight of those optional extras
that weigh more than the replaced standard
parts and more than 2.3 kg (5 lbs). These
optional extras, such as high-performance
brakes, level control, a roof rack or a high-
performance battery, are not included in the
curb weight and the weight of the accesso-
ries.
TIN (Tire Identification Number)
This is a unique identifier which can be used
by a tire manufacturer to identify tires, for
example for a product recall, and thus identify the purchasers. The TIN is made up of the
manufacturer's identity code, tire size, tire
type code and the manufacturing date.
Load bearing index
The load bearing index (also load index) is a
code that contains the maximum load bearing
capacity of a tire.
Traction
Traction is the result of friction between the
tires and the road surface.
Treadwear indicators
Narrow bars (tread wear bars) that are dis-
tributed over the tire tread. If the tire tread is level with the bars, the wear limit of áin
(1.6 mm) has been reached. 340
All about wheels and tiresWheels and tires

X
Vehicles without KEYLESS-GO: remove
the SmartKey from the ignition lock.
X Vehicles with KEYLESS-GO start-func-
tion or KEYLESS-GO: open the driver's
door.
The on-board electronics now have status
0. This is the same as the SmartKey having
been removed.
X Vehicles with KEYLESS-GO start-func-
tion or KEYLESS-GO: remove the Start/
Stop button from the ignition lock
(Y page 141).
X If included in the vehicle equipment,
remove the tire-change tool kit from the
vehicle.
X Safeguard the vehicle against rolling away
(Y page 160).
Securing the vehicle to prevent it from
rolling away If your vehicle is equipped with a wheel chock,
it can be found in the tire-change tool kit
(Y page 300).
The folding wheel chock is an additional
safety measure to prevent the vehicle from
rolling away, for example when changing a
wheel.
X Fold both plates upwards :.
X Fold out lower plate ;.
X Guide the lugs on the lower plate fully into
the openings in base plate =. Securing the vehicle on level ground
X On level ground: place chocks or other
suitable items under the front and rear of
the wheel that is diagonally opposite the
wheel you wish to change. Securing the vehicle on slight downhill gradients
X On light downhill gradients: place
chocks or other suitable items in front of
the wheels of the front and rear axle.
Raising the vehicle G
WARNING
If you do not position the jack correctly at the appropriate jacking point of the vehicle, the
jack could tip over with the vehicle raised.
There is a risk of injury.
Only position the jack at the appropriate jack-
ing point of the vehicle. The base of the jack
must be positioned vertically, directly under
the jacking point of the vehicle.
! The jack is designed exclusively for jack-
ing up the vehicle at the jacking points.
Otherwise, your vehicle could be damaged. 342
Changing a wheelWheels and tires

Observe the following when raising the
vehicle:
R To raise the vehicle, only use the vehicle-
specific jack that has been tested and
approved by Mercedes-Benz. If used incor-
rectly, the jack could tip over with the vehi- cle raised.
R The jack is designed only to raise and hold
the vehicle for a short time while a wheel
is being changed. It is not suited for per-
forming maintenance work under the vehi-
cle.
R Avoid changing the wheel on uphill and
downhill slopes.
R Before raising the vehicle, secure it from
rolling away by applying the parking brake
and inserting wheel chocks. Do not disen-
gage the parking brake while the vehicle is raised.
R The jack must be placed on a firm, flat and
non-slip surface. On a loose surface, a
large, flat, load-bearing underlay must be
used. On a slippery surface, a non-slip
underlay must be used, e.g. rubber mats.
R Do not use wooden blocks or similar
objects as a jack underlay. Otherwise, the
jack will not be able to achieve its load-
bearing capacity due to the restricted
height.
R Make sure that the distance between the
underside of the tires and the ground does
not exceed 1.2 in (3 cm).
R Never place your hands and feet under the
raised vehicle.
R Do not lie under the vehicle.
R Do not start the engine when the vehicle is
raised.
R Do not open or close a door or the trunk lid
when the vehicle is raised.
R Make sure that no persons are present in
the vehicle when the vehicle is raised.
Vehicles with steel wheels: the hub cap
covers the wheel bolts. Before you can
unscrew the wheel bolts, you must remove
the hub caps. Steel wheel with hub caps
X Using both hands, carefully reach into two
hub cap openings and remove the hub cap. X
Using lug wrench :, loosen the bolts on
the wheel you wish to change by about one full turn. Do not unscrew the bolts com-
pletely. Jacking points
The jacking points are located just behind the front wheel housings and just in front of the
rear wheel housings (arrows).
AMG vehicles and vehicles with AMG
equipment: to protect the vehicle body, the Changing a wheel
343Wheels and tires Z

!
To prevent damage to the paintwork, hold
the wheel securely against the wheel hub
while screwing in the first wheel bolt. X
Clean the wheel and wheel hub contact
surfaces.
X Place the new wheel on the wheel hub and
push it on.
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 wrench onto the hexagon
nut of the jack so that the letters ABare
visible.
X Turn the ratchet wrench until the vehicle 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 specified tightening torque is
96 lb-ft (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 AMG vehicles and vehicles with AMG
equipment: insert the cover into the outer
sill.
X Check the tire pressure of the newly moun-
ted wheel and adjust it if necessary.
Observe the recommended tire pressure
(Y page 322).
When you are driving with the collapsible
spare wheel mounted, the tire pressure loss
warning system or the tire pressure monitor
cannot function reliably. Only restart the tire
pressure loss warning system/the tire pres-
sure monitor when the damaged wheel has
been replaced with a new wheel.
Vehicles with a tire pressure control sys-
tem: all installed wheels must be equipped
with functioning sensors. Wheel and tire combinations
General notes
! For safety reasons, Mercedes-Benz rec-
ommends that you only use tires and
wheels which have been approved by
Mercedes-Benz specifically for your vehi-
cle. Wheel and tire combinations
345Wheels and tires Z