2019 MERCEDES-BENZ GLC warning

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
Z

Maximum tire pressures
CExample: maximum permissible tire pres-sure
Never exceed the maximum permissible tireinflation pressure. Always observe the recom-mended tire pressure for your vehicle whenadjusting the tire pressure (Ypage 333).
iThe actual values for tires are vehicle-spe-cific and may deviate from the values in theillustration.
Checking the tire pressures
Important safety notes
Observe the notes on tire pressure(Ypage 333).
Information on air pressure for the tires on yourvehicle can be found:
Ron the vehicle's Tire and Loading Informationplacard on the B-pillar
Rin the tire pressure table in the fuel filler flap(Ypage 333)
Rin the "Tire pressure" section
Checking tire pressures manually
To determine and set the correct tire pressure,proceed as follows:
XRemove the valve cap of the tire that is to bechecked.
XPress the tire pressure gauge securely ontothe valve.
XRead the tire pressure and compare it to therecommended value on the Tire and LoadingInformation placard or the tire pressure table(Ypage 333).
XIf the tire pressure is too low, increase the tirepressure to the recommended value.
XIf the tire pressure is too high, release air. Todo so, press down the metal pin in the valve,using the tip of a pen for example. Then checkthe tire pressure again using the tire pressurechecker.
XScrew the valve cap onto the valve.
XRepeat these steps for the other tires.
Tire pressure loss warning system
General notes
While the vehicle is in motion, the tire pressureloss warning system monitors the set tire pres-sure using the rotational speed of the wheels.This enables the system to detect significantpressure loss in a tire. If the speed of rotation ofa wheel changes as a result of a loss of pressure,a corresponding warning message will appear inthe multifunction display.
You can recognize the tire pressure loss warningby theRun Flat Indicator ActiveRun Flat Indicator ActivePressPress'OK' to Restart'OK' to Restartmessage which appears intheServiceServicemenu of the multifunction display.Information on the message display can befound in the "Restarting the tire pressure losswarning system" section (Ypage 337).
Important safety notes
The tire pressure warning system does not warnyou of an incorrectly set tire pressure. Observethe notes on the recommended tire pressure(Ypage 333).
The tire pressure loss warning does not replacethe need to regularly check the tire pressure. Aneven loss of pressure on several tires at thesame time cannot be detected by the tire pres-sure loss warning system.
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 function of the tire pressure loss warningsystem is limited or delayed if:
Rsnow chains are mounted on your vehicle'stires.
Rroad conditions are wintry.
336Tire pressure
Wheels and tires

Ryou are driving on sand or gravel.
Ryou adopt a very sporty driving style (corner-ing at high speeds or driving with high rates ofacceleration).
Ryou are towing a very heavy or large trailer.
Ryou are driving with a heavy load (in the vehi-cle or on the roof).
Restarting the tire pressure loss warn-
ing system
Restart the tire pressure loss warning system ifyou have:
Rchanged the tire pressure
Rchanged the wheels or tires
Rmounted new wheels or tires
XBefore restarting, make sure that the tirepressures are set properly on all four tires forthe respective operating conditions.
The recommended tire pressure can be foundon the Tire and Loading Information placardon the B-pillar. Additionally, a tire pressuretable is attached to the fuel filler flap. The tirepressure loss warning system can only givereliable warnings if you have set the correcttire pressure. If an incorrect tire pressure isset, these incorrect values will be monitored.
XAlso observe the notes in the section on tirepressures (Ypage 333).
XMake sure that the SmartKey is in positionHin the ignition lock (Ypage 131).
XPress

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

too low. The tire pressure monitor is not mal-functioning.
Rif the warning lamp flashes for around aminute and then remains lit constantly, thetire pressure monitor is malfunctioning.
In addition to the warning lamp, a messageappears in the multifunction display. Observethe information on display messages(Ypage 250).
It may take up to ten minutes for a malfunctionof the tire pressure monitor to be indicated. Amalfunction will be indicated by the tire pres-sure warning lamp flashing for approximatelyone minute and then remaining lit. When themalfunction has been rectified, the tire pressurewarning lamp goes out after a few minutes ofdriving.
The tire pressure values indicated by the on-board computer may differ from those meas-ured at a gas station with a pressure gauge. Thetire pressures shown by the on-board computerrefer to those measured at sea level. At highaltitudes, the tire pressure values indicated by apressure gauge are higher than those shown bythe on-board computer. In this case, do notreduce the tire pressures.
The operation of the tire pressure monitor canbe affected by interference from radio transmit-ting equipment (e.g. radio headphones, two-wayradios) that may be being operated in or near thevehicle.
Checking the tire pressure electroni-
cally
XMake sure that the SmartKey is in positionH(Ypage 131) in the ignition lock.
XPress

iThe actual values for tires are vehicle-spe-cific and may deviate from the values in theillustration.
Treadwear
The treadwear grade is a comparative ratingbased on the wear rate of the tire when testedunder controlled conditions on a specified U.S.government course. For example, a tire graded150 would wear one and one-half times as wellon the government course as a tire graded 100.
The relative performance of tires depends uponthe actual conditions of their use, however, andmay depart significantly from the norm due tovariations in driving habits, service practicesand differences in road characteristics and cli-mate.
Traction
GWARNING
The traction grade assigned to this tire is
based on straight-ahead braking traction
tests, and does not include acceleration, cor-
nering, hydroplaning, or peak traction char-
acteristics.
!Avoid wheelspin. This can lead to damage tothe drive train.
The traction grades – from highest to lowest –are AA, A, B and C. Those grades represent thetire's ability to stop on wet pavement as meas-ured under controlled conditions on specifiedgovernment test surfaces of asphalt and con-crete. A tire marked C may have poor tractionperformance.
The safe speed on a wet, snow covered or icyroad is always lower than on dry road surfaces.
You should pay special attention to road condi-tions when temperatures are around freezingpoint.
Mercedes-Benz recommends a minimum treaddepth of

Lowering the vehicle
GWARNING
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.
XPlace the ratchet wrench onto the hexagonnut of the jack so that the lettersABare visi-ble.
XTurn the ratchet wrench until the vehicle isonce again standing firmly on the ground.
XPlace the jack to one side.
XTighten the wheel bolts evenly in a crosswisepattern in the sequence indicated (Cto

Information regarding technical data
iThe data stated here specifically refers to avehicle with standard equipment. Consult anauthorized Mercedes-Benz Center for thedata for all vehicle variants and trim levels.
Vehicle electronics
Installing wireless devices and mobile
phones
GWARNING
The electromagnetic radiation from two-way
radios can interfere with the vehicle electron-
ics if two-way radios are manipulated or ret-
rofitted incorrectly. This could jeopardize the
operating safety of the vehicle. There is a risk
of an accident.
You should have all work on electrical and
electronic components carried out at a quali-
fied specialist workshop.
GWARNING
If you incorrectly operate two-way radios in
the vehicle, the electromagnetic radiation
may interfere with the vehicle electronics, for
example if:
Rthe two-way radio is not connected to an
exterior antenna
Rthe exterior antenna is not correctly moun-
ted or is not low-reflection
This could jeopardize the operating safety of
the vehicle. There is a risk of an accident.
Have the low-reflection exterior antenna
installed at a qualified specialist workshop.
Always connect two-way radios to the low-
reflection exterior antenna when operating in
the vehicle.
!The operating permit may be invalidated ifthe instructions for installation and use oftwo-way radios are not observed.
In particular, the following conditions must becomplied with:
Ronly approved wavebands may be used.
Robserve the maximum permissible outputin these wavebands.
Ronly approved antenna positions may beused.
Excessive levels of electromagnetic radiationmay cause damage to your health and the healthof others. Using an exterior antenna takes intoaccount current scientific discussions relatingto the possible health hazards that may resultfrom electromagnetic fields.
Approved antenna positions
CFront roof area
DRear roof area