light MERCEDES-BENZ GLA 2019 Owners Manual

If the tire pressures have been set to the lowervalues for lighter loads and/or lower roadspeeds, the pressures should be reset to thehigher values:
Rif you want to drive with an increased loadand/or
Rif you want to drive at higher speeds
iThe tire pressures for increased loadsand/or higher road speeds, shown in thetire pressure table, may have a negativeeffect on driving comfort.
If the tire pressure is not set correctly, this canlead to an excessive build-up of heat and asudden loss of pressure.
For more information, contact a qualified spe-cialist workshop.
Important notes on tire pressure
GWARNING
If the tire pressure drops repeatedly, the
wheel, valve or tire may be damaged. Tire
pressure that is too low may result in a tire
blow-out. There is a risk of an accident.
RCheck the tire for foreign objects.
RCheck 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.
GWARNING
If you fit unsuitable accessories onto tire
valves, the tire valves may be overloaded
and malfunction, which can cause tire pres-
sure loss. Due to their design, retrofitted tire
pressure 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 thetire pressure. The outer appearance of a tiredoes not permit any reliable conclusion aboutthe tire pressure. On vehicles equipped withthe electronic tire pressure monitor, the tire
pressure can be checked in the on-board com-puter.
The tire temperature and pressure increasewhen the vehicle is in motion. This is depend-ent on 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 been driven less than1 mile (1.6 km)
The tire temperature changes depending onthe outside temperature, the vehicle speedand the tire load. If the tire temperaturechanges by 18 ‡ (10 †), the tire pressurechanges by approximately 10 kPa (0.1 bar/1.5 psi). Take this into account when checkingthe pressure of warm tires. Only correct thetire pressure if it is too low for the currentoperating conditions. If you check the tirepressure when the tires are warm, the result-ing value will be higher than if the tires werecold. This is normal. Do not reduce the tirepressure to the value specified for cold tires.The tire pressure would otherwise be 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 in the fuel filler flap(Ypage 144)
Underinflated or overinflated tires
Underinflated tires
GWARNING
Tires with pressure that is too low can over-
heat and burst as a consequence. In addi-
tion, they also suffer from excessive and/or
irregular wear, which can severely impair the
braking properties and the driving character-
istics. There is a risk of an accident.
Avoid tire pressures that are too low in all
the tires, including the spare wheel.
Tire pressure309
Wheels and tires
Z

monitor warns you if the pressure drops in oneor more of the tires. The tire pressure monitoronly functions if the corresponding sensorsare installed in all wheels.
Information on tire pressures is displayed inthe multifunction display. After a few minutesof driving, the current tire pressure of each tireis shown in theServ.Serv.menu of the multifunc-tion display, see illustration (example).
For information on the message display, referto the "Checking the tire pressure electroni-cally" section (Ypage 313).
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 pres-
sure recommended by the vehicle manufac-
turer on the Tire and Loading Information
placard on the driver's door B-pillar or the
tire pressure label on the inside of the fuel
filler flap. If your vehicle has tires of a differ-
ent size than the size indicated on the Tire
and Loading Information placard or, if availa-
ble, 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 monitor-
ing system (TPMS) that illuminates a low tire
pressure telltale when one or more of your
tires are significantly underinflated. Accord-
ingly, 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 signifi-
cantly underinflated 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 vehi-
cle's handling and stopping ability. Please
note that the TPMS is not a substitute for
proper tire maintenance, and it is the driv-
er's responsibility to maintain correct tire
pressure, even if underinflation has not
reached the level to trigger illumination of
the TPMS low tire pressure 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
system 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 vehicle is started as long as the malfunc-
tion exists. When the malfunction indicator
is illuminated, the system may not be able to
detect or signal low tire pressure as inten-
ded.
TPMS malfunctions may occur for a variety
of reasons, including the installation of
incompatible 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 307). Note that the correct tire pres-sure for the current operating situation mustfirst be taught-in to the tire pressure monitor.If a substantial loss of pressure occurs, thewarning threshold for the warning message isaligned to the taught-in reference values.Restart the tire pressure monitor after adjust-ing the pressure of the cold tires(Ypage 314). The current pressures aresaved as new reference values. As a result, awarning message will appear if the tire pres-sure drops significantly.
312Tire pressure
Wheels and tires

The tire pressure monitor does not warn you ofan incorrectly set tire pressure. Observe thenotes on the recommended tire pressure(Ypage 307).
The tire pressure monitor is not able to warnyou of a sudden loss of pressure, e.g. if thetire is penetrated by a foreign object. In theevent of a sudden loss of pressure, bring thevehicle to a halt by braking carefully. Avoidabrupt steering movements.
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, thetire pressure on one or more tires is signifi-cantly too low. The tire pressure monitor isnot malfunctioning.
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 223).
It may take up to ten minutes for a malfunc-tion of the tire pressure monitor to be indica-ted. A malfunction will be indicated by the tirepressure warning lamp flashing for approx-imately one minute and then remaining lit.When the malfunction has been rectified, thetire pressure warning lamp goes out after afew minutes of driving.
The tire pressure values indicated by the on-board computer may differ from those meas-ured at a gas station with a pressure gauge.The tire pressures shown by the on-boardcomputer refer to those measured at sea level.At high altitudes, the tire pressure values indi-cated by a pressure gauge are higher thanthose shown by the on-board computer. In thiscase, do not reduce the tire pressures.
The operation of the tire pressure monitor canbe affected by interference from radio trans-mitting equipment (e.g. radio headphones,two-way radios) that may be being operated inor near the vehicle.
Checking the tire pressure electroni-
cally
XMake sure that the SmartKey is in positionHin the ignition lock (Ypage 125).
XPressYoreon the steering wheelto select theServ.Serv.menu.
XPress thecordbutton to selectTire PressureTire Pressure.
XPress thevbutton.The current tire pressure of each tire isshown in the multifunction display.
If the vehicle was parked for longer than20 minutes, theTire pressure will beTire pressure will bedisplayed after driving a few minutesdisplayed after driving a few minutesmessage is shown.
After a teach-in process, the tire pressuremonitor automatically detects new wheels ornew sensors. As long as a clear allocation ofthe tire pressure value to the individual wheelsis not possible, theTire Pressure MonitorTire Pressure MonitorActiveActivemessage is shown instead of the tirepressure display. The tire pressures arealready being monitored.
If an emergency spare wheel is mounted, thesystem may continue to show the tire pressureof the wheel that has been removed for a fewminutes. If this occurs, note that the value dis-played for the position where the spare wheelis fitted is not the same as the current tirepressure of the emergency spare wheel.
Tire pressure monitor warning mes-
sages
If the tire pressure monitor detects a pressureloss in one or more tires, a warning message isshown in the multifunction display. The yellowtire pressure warning lamp then lights up.
RIf thePlease Correct Tire PressurePlease Correct Tire Pressuremessage appears in the multifunction dis-play, the tire pressure in at least one tire istoo low. The tire pressure must be correctedwhen the opportunity arises.
RIf theCheck Tire PressureCheck Tire Pressuremessageappears in the multifunction display, the tirepressure in one or more tires has droppedsignificantly. The tires must be checked.
RIf theTire Pressure Warning TireTire Pressure Warning TireFailureFailuremessage appears, the tire pressurein one or more tires has dropped suddenly.The tires must be checked.
Tire pressure313
Wheels and tires
Z

If "LT" precedes the size description: these arelight truck tires according to U.S. manufactur-ing standards.
If "T" precedes the size description: compactemergency wheels with high tire pressure thatare only designed for temporary use in anemergency.
Tire width:tire widthCshows the nominaltire width in millimeters.
Aspect ratio:aspect ratioDis the size ratiobetween the tire height and tire width and isshown in percent. The aspect ratio is calcula-ted by dividing the tire width by the tire height.
Tire code:tire code

All-weather tires and winter tires
IndexSpeed rating
Q M+S1up to 100 mph (160 km/h)
T M+S1up to 118 mph (190 km/h)
H M+S1up to 130 mph (210 km/h)
V M+S1up to 149 mph (240 km/h)
iNot all tires with the M+S marking providethe driving characteristics of winter tires. Inaddition to the M+S marking, winter tiresalso have theMsnowflake symbol on thetire wall. Tires with this marking fulfill therequirements of the Rubber ManufacturersAssociation (RMA) and the Rubber Associa-tion of Canada (RAC) regarding the tire trac-tion on snow. They have been especiallydeveloped for driving on snow.
An electronic speed limiter prevents your vehi-cle from exceeding a speed of 130 mph(210 km/h).
The speed rating of tires mounted at the fac-tory may be higher than the maximum speedthat the electronic speed limiter permits.
Make sure that your tires have the requiredspeed rating, e.g. when buying new tires. Therequired speed rating for your vehicle can befound in the "Tires" section (Ypage 329).
Further information about reading tire datacan be obtained from any qualified specialistworkshop.
Load index
In addition to the load-bearing index, loadindexCmay be imprinted after the letters
that identify speed rating on the sidewall ofthe tire. Speed rating (Ypage 320).
RIf no specification is given: no text (as in theexample above), represents a standard load(SL) tire
RXL or Extra Load: represents a reinforcedtire
RLight Load: represents a light load tire
RC, D, E: represents a load range thatdepends on the maximum load that the tirecan carry at a certain pressure
iTire data is vehicle-specific and may devi-ate from 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 316).
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 tiremanufacturer or retreader must imprint a TINin or on the sidewall of each tire produced.
1Or M+SMfor winter tires.
322All about wheels and tires
Wheels and tires

pounds per square inch (psi), in kilopascal(kPa) or in bar. The tire pressure should onlybe corrected when the 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 furtherthan 1 mile (1.6 km)
Tread
The part of the tire that comes into contactwith the road.
Bead
The tire bead ensures that the tire sitssecurely on the wheel. There are several steelwires in the bead to prevent the tire from com-ing loose from the wheel rim.
Sidewall
The part of the tire between the tread and thebead.
Weight of optional extras
The combined weight of those optional extrasthat weigh more than the replaced standardparts and more than 2.3 kg (5 lbs). Theseoptional extras, such as high-performancebrakes, level control, a roof rack or a high-per-formance battery, are not included in the curbweight and the weight of the accessories.
TIN (Tire Identification Number)
This is a unique identifier which can be usedby a tire manufacturer to identify tires, forexample for a product recall, and thus identifythe purchasers. The TIN is made up of themanufacturer's identity code, tire size, tiretype code and the manufacturing date.
Load bearing index
The load bearing index (also load index) is acode that contains the maximum load bearingcapacity of a tire.
Traction
Traction is the result of friction between thetires and the road surface.
Treadwear indicators
Narrow bars (tread wear bars) that are distrib-uted over the tire tread. If the tire tread is levelwith the bars, the wear limit of