ECU MERCEDES-BENZ GLC 2017 Repair Manual

Overinflated tires may: R
increase the braking distance R
adversely affect handling R
wear excessively and/or unevenly R
have an adverse effect on ride comfort R
be more susceptible to damage
Maximum tire pressures
C
Example: maximum permissible tire pres-
sure
Never exceed the maximum permissible tire
inflation pressure. Always observe the recom-
mended tire pressure for your vehicle when
adjusting the tire pressure ( Y
page 339).
i The actual values for tires are vehicle-spe-
cific and may deviate from the values in the
illustration.
Checking the tire pressures
Important safety notes Observe the notes on tire pressure
( Y
page 339).
Information on air pressure for the tires on your
vehicle can be found: R
on the vehicle's Tire and Loading Information
placard on the B-pillar R
in the tire pressure table in the fuel filler flap
( Y
page 149)R
in the "Tire pressure" section Checking tire pressures manually To determine and set the correct tire pressure,
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 339). 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 pressure
loss warning system monitors the set tire pres-
sure 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 display.
You can recognize the tire pressure loss warning
by the Run Flat Indicator Active Press
'OK' to Restart message which appears in
the Service menu of the multifunction display.
Information on the message display can be
found in the "Restarting the tire pressure loss
warning system" section ( Y
page 343).
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 339).
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 the342
Tire pressure
Wheels and tires

Speed rating The speed rating is part of the tire identification.
It specifies the speed range for which the tire is
approved.
GVW (Gross Vehicle Weight) The gross vehicle weight includes the weight of
the vehicle including fuel, tools, the spare wheel,
accessories installed, occupants, luggage and
the drawbar noseweight, if applicable. The gross
vehicle weight must not exceed the gross vehi-
cle weight rating GVWR as specified on the vehi-
cle identification plate on the B-pillar on the
driver's side.
GVWR (Gross Vehicle Weight Rating) The GVWR is the maximum permissible gross
weight of a fully loaded vehicle (the weight of the
vehicle including all accessories, occupants,
fuel, luggage and the drawbar noseweight, if
applicable). The gross vehicle weight rating is
specified on the vehicle identification plate on
the B-pillar on the driver's side.
Maximum loaded vehicle weight The maximum weight is the sum of: R
the curb weight of the vehicle R
the weight of the accessories R
the load limit R
the weight of the factory installed optional
equipment
Kilopascal (kPa) Metric unit for tire pressure. 6.9 kPa corre-
sponds to 1 psi. Another unit for tire pressure is
bar. 100 kilopascals (kPa) are the equivalent of
1 bar.
Load index
In addition to the load-bearing index, the load
index may also be imprinted on the sidewall of
the tire. This specifies the load-bearing capacity
more precisely.
Curb weight
The weight of a vehicle with standard equipment
including the maximum capacity of fuel, oil and
coolant. It also includes the air-conditioning sys-
tem and optional equipment if these are instal-
led in the vehicle, but does not include passen-
gers or luggage. Maximum load rating The maximum tire load is the maximum permis-
sible 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 out-
ward force to each square inch of the tire's sur-
face. 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 with the tires
out of direct sunlight 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.All about wheels and tires 355
Wheels and tires Z

must be positioned vertically, directly under
the jacking point of the vehicle.
! Only position the jack at the appropriate
jacking point of the vehicle. Otherwise, you
could damage the vehicle.
Observe the following when raising the vehi-
cle: R
To raise the vehicle, only use the vehicle-spe-
cific jack that has been tested and approved
by Mercedes-Benz. If used incorrectly, the
jack could tip over with the vehicle raised. R
The jack is designed only to raise and hold the
vehicle for a short time while a wheel is being
changed. It must not be used for performing
maintenance work under the vehicle. R
Avoid changing the wheel on uphill and down-
hill slopes. R
Before raising the vehicle, secure it from roll-
ing away by applying the parking brake and
inserting wheel chocks. Do not disengage 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
Do not place your hands or feet under the
raised vehicle. R
Do not lie under the vehicle. R
Do not start the engine when the vehicle is
raised. R
Never open or close a door or the tailgate
when the vehicle is raised. R
Make sure that no persons are present in the
vehicle when the vehicle is raised. X
Using lug wrench C , loosen the bolts on the
wheel you wish to change by about one full
turn. Do not unscrew the bolts completely.
The jacking points are located just behind the
front wheel housings and just in front of the rear
wheel housings (arrows). X
Take the ratchet wrench out of the tire-chang-
ing tool kit and place it on the hexagon nut of
the jack so that the letters AUF are visible.
X
Position jack