2019 MERCEDES-BENZ GLC light

GWARNING
If you fit unsuitable accessories onto tire
valves, the tire valves may be overloaded and
malfunction, which can cause tire pressure
loss. Due to their design, retrofitted tire pres-
sure monitors keep the tire valve open. This
can also result in tire pressure loss. There is a
risk of an accident.
Only screw the standard valve cap or other
valve caps approved by Mercedes-Benz for
your vehicle onto the tire valve.
Use a suitable pressure gauge to check the tirepressure. The outer appearance of a tire doesnot permit any reliable conclusion about the tirepressure. On vehicles equipped with the elec-tronic tire pressure monitor, the tire pressurecan be checked in the on-board computer.
The tire temperature and pressure increasewhen the vehicle is in motion. This is dependenton the driving speed and the load.
Therefore, you should only correct tire pres-sures when the tires are cold.
The tires are cold:
Rif the vehicle has been parked with the tiresout of direct sunlight for at least three hoursand
Rif the vehicle has not been driven further than1 mile (1.6 km)
The tire temperature changes depending on theoutside temperature, the vehicle speed and thetire load. If the tire temperature changes by18 ‡ (10 †), the tire pressure changes byapproximately 10 kPa (0.1 bar/1.5 psi). Takethis into account when checking the pressure ofwarm tires. Only correct the tire pressure if it istoo low for the current operating conditions. Ifyou check the tire pressure when the tires arewarm, the resulting value will be higher than ifthe tires were cold. This is normal. Do notreduce the tire pressure to the value specifiedfor cold tires. The tire pressure would otherwisebe too low.
Observe the recommended tire pressures forcold tires:
Ron the Tire and Loading Information placardon the B-pillar on the driver's side
Rin the tire pressure table on the fuel filler flap(Ypage 333)
Underinflated or overinflated tires
Underinflated tires
GWARNING
Tires with pressure that is too low can over-
heat and burst as a consequence. In addition,
they also suffer from excessive and/or irreg-
ular wear, which can severely impair the brak-
ing properties and the driving characteristics.
There is a risk of an accident.
Avoid tire pressures that are too low in all the
tires, including the spare wheel.
Underinflated tires may:
Roverheat, leading to tire defects
Radversely affect handling
Rwear excessively and/or unevenly
Rhave an adverse effect on fuel consumption
Overinflated tires
GWARNING
Tires with excessively high pressure can burst
because they are damaged more easily by
road debris, potholes etc. In addition, they
also suffer from irregular wear, which can
severely impair the braking properties and the
driving characteristics. There is a risk of an
accident.
Avoid tire pressures that are too high in all the
tires, including the spare wheel.
Overinflated tires may:
Rincrease the braking distance
Radversely affect handling
Rwear excessively and/or unevenly
Rhave an adverse effect on ride comfort
Rbe more susceptible to damage
Tire pressure335
Wheels and tires
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Information on the message display can befound in the "Checking the tire pressure elec-tronically" section (Ypage 339).
Important safety notes
GWARNING
Each tire, including the spare (if provided),
should be checked at least once every two
weeks when cold and inflated to the pressure
recommended by the vehicle manufacturer
on the Tire and Loading Information placard
on the driver's door B-pillar or the tire pres-
sure label on the inside of the fuel filler flap. If
your vehicle has tires of a different size than
the size indicated on the Tire and Loading
Information placard or, if available, the tire
pressure label, you should determine the
proper tire pressure for those tires.
As an added safety feature, your vehicle has
been equipped with a tire pressure monitoring
system (TPMS) that illuminates a low tire pres-
sure telltale when one or more of your tires
are significantly underinflated. Accordingly,
when the low tire pressure telltale lights up,
you should stop and check your tires as soon
as possible, and inflate them to the proper
pressure. Driving on a significantly underin-
flated tire causes the tire to overheat and can
lead to tire failure.
Underinflation also reduces fuel efficiency
and tire tread life, and may affect the vehicle's
handling and stopping ability. Please note that
the TPMS is not a substitute for proper tire
maintenance, and it is the driver's responsi-
bility to maintain correct tire pressure, even if
underinflation has not reached the level to
trigger illumination of the TPMS low tire pres-
sure telltale.
Your vehicle has also been equipped with a
TPMS malfunction indicator to indicate when
the system is not operating properly. The
TPMS malfunction indicator is combined with
the low tire pressure telltale. When the sys-
tem detects a malfunction, the warning lamp
will flash for approximately a minute and then
remain continuously illuminated. This
sequence will be repeated every time the vehi-
cle is started as long as the malfunction
exists. When the malfunction indicator is illu-
minated, the system may not be able to detect
or signal low tire pressure as intended.
TPMS malfunctions may occur for a variety of
reasons, including the installation of incom-
patible replacement or alternate tires or
wheels on the vehicle that prevent the TPMS
from functioning properly. Always check the
TPMS malfunction telltale after replacing one
or more tires or wheels on your vehicle to
ensure that the replacement or alternate Tires
and wheels allow the TPMS to continue to
function properly.
It is the driver's responsibility to set the tirepressure to that recommended for cold tireswhich is suitable for the operating situation(Ypage 333). Note that the correct tire pressurefor the current operating situation must first betaught-in to the tire pressure monitor. If a sub-stantial loss of pressure occurs, the warningthreshold for the warning message is aligned tothe taught-in reference values. Restart the tirepressure monitor after adjusting the pressure ofthe cold tires (Ypage 339). The current pres-sures are saved as new reference values. As aresult, a warning message will appear if the tirepressure drops significantly.
The tire pressure monitor does not warn you ofan incorrectly set tire pressure. Observe thenotes on the recommended tire pressure(Ypage 333).
The tire pressure monitor is not able to warn youof a sudden loss of pressure, e.g. if the tire ispenetrated by a foreign object. In the event of asudden loss of pressure, bring the vehicle to ahalt by braking carefully. Avoid abrupt steeringmovements.
The tire pressure monitor has a yellow warninglamp in the instrument cluster for indicatingpressure loss or a malfunction. Whether thewarning lamp flashes or lights up indicateswhether a tire pressure is too low or the tirepressure monitor is malfunctioning:
Rif the warning lamp is lit continuously, the tirepressure on one or more tires is significantly
338Tire pressure
Wheels and tires

The speed rating of tires mounted at the factorymay be higher than the maximum permissiblespeed permitted by the electronic speed limiter.
Make sure that your tires have the requiredspeed rating, e.g. when buying new tires. Youcan find information on this under "Tires"(Ypage 354).
Further information about reading tire data canbe obtained from any qualified specialist work-shop.
Load index
In addition to the load-bearing index, loadindexCmay also be imprinted on the sidewallof the tire. You will find this after the letter thatidentifies the speed rating (Ypage 345).
RIf no specification is given: no text (as in theexample above), represents a standard load(SL) tire
RXL or Extra Load: represents a reinforced tire
RLight Load: represents a light load tire
RC, D, E: represents a load range that dependson the maximum load that the tire can carry ata certain pressure
iTire data is vehicle-specific and may deviatefrom the data in the example.
Maximum load rating
Maximum tire loadCis the maximum permis-sible weight for which the tire is approved.
Do not overload the tires by exceeding thespecified load limit. The maximum permissibleload can be found on the vehicle's Tire andLoading Information placard on the B-pillar onthe driver's side (Ypage 340).
iThe actual values for tires are vehicle-spe-cific and may deviate from the values in theillustration.
DOT, Tire Identification Number (TIN)
US tire regulations stipulate that every tire man-ufacturer or retreader must imprint a TIN in or onthe sidewall of each tire produced.
The TIN is a unique identification number. TheTIN enables the tire manufacturers or retreadersto inform purchasers of recalls and other safety-relevant matters. It makes it possible for thepurchaser to easily identify the affected tires.
The TIN is made up of manufacturer identifica-tion codeD, tire size

Speed rating
The speed rating is part of the tire identification.It specifies the speed range for which the tire isapproved.
GVW (Gross Vehicle Weight)
The gross vehicle weight includes the weight ofthe vehicle including fuel, tools, the spare wheel,accessories installed, occupants, luggage andthe drawbar noseweight, if applicable. The grossvehicle weight must not exceed the gross vehi-cle weight rating GVWR as specified on the vehi-cle identification plate on the B-pillar on thedriver's side.
GVWR (Gross Vehicle Weight Rating)
The GVWR is the maximum permissible grossweight of a fully loaded vehicle (the weight of thevehicle including all accessories, occupants,fuel, luggage and the drawbar noseweight, ifapplicable). The gross vehicle weight rating isspecified on the vehicle identification plate onthe B-pillar on the driver's side.
Maximum loaded vehicle weight
The maximum weight is the sum of:
Rthe curb weight of the vehicle
Rthe weight of the accessories
Rthe load limit
Rthe weight of the factory installed optionalequipment
Kilopascal (kPa)
Metric unit for tire pressure. 6.9 kPa corre-sponds to 1 psi. Another unit for tire pressure isbar. 100 kilopascals (kPa) are the equivalent of1 bar.
Load index
In addition to the load-bearing index, the loadindex may also be imprinted on the sidewall ofthe tire. This specifies the load-bearing capacitymore precisely.
Curb weight
The weight of a vehicle with standard equipmentincluding the maximum capacity of fuel, oil andcoolant. 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 isapproved.
Maximum permissible tire pressure
Maximum permissible tire pressure for one tire.
Maximum load on one tire
Maximum load on one tire. This is calculated bydividing the maximum axle load of one axle bytwo.
PSI (pounds per square inch)
A standard unit of measure for tire pressure.
Aspect ratio
Relationship between tire height and tire widthin 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 persquare inch (psi), in kilopascal (kPa) or in bar.The tire pressure should only be corrected whenthe tires are cold.
Cold tire pressure
The tires are cold:
Rif the vehicle has been parked with the tiresout of direct sunlight for at least three hoursand
Rif the vehicle has not been driven further than1 mile (1.6 km)
Tread
The part of the tire that comes into contact withthe road.
Bead
The tire bead ensures that the tire sits securelyon the wheel. There are several steel wires in thebead to prevent the tire from coming loose fromthe wheel rim.
Sidewall
The part of the tire between the tread and thebead.
All about wheels and tires349
Wheels and tires
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