lights MERCEDES-BENZ GLA 2019 Workshop Manual

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