steering MERCEDES-BENZ GL320CDI 2007 X164 Repair Manual

396 Operation
Tires and wheels
Tire inflation pressure changes by approxi-
mately 1.5 psi (0.1 bar) per 18°F (10°C) of
air temperature change. Keep this in mind
when checking tire inflation pressure
where the temperature is different from
the outside temperature.
Checking tire inflation pressure
Regularly check your tire inflation pressure
at least once a month.
Check and adjust the tire inflation
pressure when the tires are cold. The tires
can be considered cold if the vehicle has
been parked for at least 3 hours or driven
less than 1 mile (1.6 km).
If you check the tire inflation pressure
when the tires are warm (the vehicle has
been driven for several miles or sitting less
than 3 hours), the reading will be
approximately 4 psi (0.3 bar) higher than
the cold reading. This is normal. Do not let
air out to match the specified cold tire
inflation pressure. Otherwise, the tire will
be underinflated.Checking tire inflation pressure
manually
Follow the steps below to achieve correct
tire inflation pressure:
Remove the cap from the valve on one
tire.
Firmly press a tire gauge onto the
valve.
Read tire inflation pressure on tire
gauge and check against the recom-
mended tire inflation pressure on the
Tire and Loading Information placard
on the driver’s door B-pillar
(
page 389) or, if available, the inside
of the fuel filler flap. If necessary, add
air to achieve the recommended tire in-
flation pressure.
Warning!G
Follow recommended tire inflation
pressures.
Do not underinflate tires. Underinflated tires
wear excessively and/or unevenly,
adversely affect handling and fuel economy,
and are more likely to fail from being over-
heated.
Do not overinflate tires. Overinflated tires
can adversely affect handling and ride
comfort, wear unevenly, increase stopping
distance, and result in sudden deflation
(blowout) because they are more likely to
become punctured or damaged by road
debris, potholes etc.
Do not overload the tires by exceeding the
specified load limit as indicated on the Tire
and Loading Information placard on the
driver’s door B-pillar. Overloading the tires
can overheat them, possibly causing a
blowout. Overloading the tires can also
result in handling or steering problems, or
brake failure.

398 Operation
Tires and wheels
Reactivating the Run Flat Indicator
The tire inflation pressure monitor must be
reactivated in the following situations:

If you have changed the tire inflation
pressure

If you have replaced the wheels or tires

If you have installed new wheels or
tires
Using the Tire and Loading Information
placard on the driver’s door B-pillar or,
if available, the tire inflation pressure
label on the inside of the fuel filler flap,
make sure the tire inflation pressure of
all four tires is correct.
Switch on the ignition (page 42).
Make sure the standard display menu
appears in the multifunction display
(
page 157).
Press buttonk orj repeatedly
until the following message appears in
the multifunction display:
Press the reset button on the instru-
ment cluster (
page 155).
The following message will appear in
the multifunction display:
Restart
Run Flat Indicator?
Yes
Cancel
Warning!G
The Run Flat Indicator does not provide a
warning for wrongly selected tire inflation
pressures. Always adjust tire inflation pres-
sure according to the Tire and Loading
Information placard on the driver’s door
B-pillar (
page 389) or, if available, on the
tire inflation pressure label located on the
inside of the fuel filler flap (
page 375).
The Run Flat Indicator does not replace
regular checks of the tire inflation pressures
since a gradual pressure loss in more than
one tire cannot be detected by the Run Flat
Indicator.
The Run Flat Indicator is not able to issue a
warning due to a sudden dramatic loss of
tire inflation pressure (e.g. tire blowout
caused by a foreign object). In this case
bring the vehicle to a halt by carefully apply-
ing the brakes and avoiding abrupt steering
maneuvers.
Warning!G
The Run Flat Indicator can only warn you in
a reliable manner if you have set the correct
tire inflation pressures for each tire.
If an incorrect tire inflation pressure was set,
the system will monitor the pressure ac-
cording to the incorrect value.

400 Operation
Tires and wheels
Warning!G
The TPMS does not indicate a warning for
wrongly selected inflation pressures. Always
adjust tire inflation pressure according to
the Tire and Loading Information placard on
the driver’s door B-pillar or, if available, the
supplemental tire inflation pressure infor-
mation on the inside of the fuel filler flap.
The TPMS is not able to issue a warning due
to a sudden dramatic loss of pressure (e.g.
tire blowout caused by a foreign object). In
this case bring the vehicle to a halt by care-
fully applying the brakes and avoiding
abrupt steering maneuvers.
Warning!G
Each tire, including the spare (if provided),
should be checked monthly when cold and
inflated to the inflation pressure recom-
mended by the vehicle manufacturer on the
Tire and Loading Information placard on the
driver’s door B-Pillar or, if available, the tire
inflation pressure label on 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 inflation pressure label, you should
determine the proper tire inflation 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 is significantly underinflated. Accord-
ingly, when the low tire pressure telltale illu-
minates, you should stop and check your
tires as soon as possible, and inflate them to
the proper pressure. Driving on a significant-
ly 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
driver’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 com-
bined with the low tire pressure telltale.
When the system detects a malfunction, the
telltale will flash for approximately 1 minute
and then remain continuously illuminated.
This sequence will continue upon subse-
quent vehicle start-ups as long as the
malfunction exists. When the malfunction
indicator is illuminated, the system may not
be able to detect or signal low tire pressure
as intended.

401 Operation
Tires and wheels
Reactivating the TPMS
The TPMS must be reactivated when you
have adjusted the tire inflation pressure to
a new level (e.g. because of different load
or driving conditions). The TPMS is then
recalibrated to the current tire inflation
pressures.
Using the Tire and Loading Information
placard on the driver’s door B-pillar
(
page 389) or, if available, the
supplemental tire inflation pressure
information on the inside of the fuel
filler flap (
page 375), make sure the
tire inflation pressure of all four tires is
correct.
Press buttonè orÿ on the mul-
tifunction steering wheel repeatedly
until the standard display menu ap-
pears in the multifunction display
(
page 157).
Press thej or kbutton repeat-
edly until you see the following
message:
Tire pressure monitor
active
Menu: R-Button
TPMS malfunctions may occur for a variety
of reasons, including the installation of in-
compatible 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.
iIf a condition causing the TPMS to malfunc-
tion develops, it may take up to 10 minutes for
the system to signal a malfunction using the
TPMS telltale flashing and illumination se-
quence.
The telltale extinguishes after a few minutes driv-
ing if the malfunction has been corrected.
iOperating radio transmission equipment
(e.g. wireless headsets, two-way radios) in or
near the vehicle could cause the TPMS to mal-
function.
Warning!G
It is the driver’s responsibility to calibrate
the TPMS on the recommended cold infla-
tion pressure. Underinflated tires affect the
ability to steer or brake the vehicle. You
might lose control over the vehicle.
iReactivate the TPMS after adjusting the tire
inflation pressure to the inflation pressure rec-
ommended for the vehicle operating condition.
Tire pressure should only be adjusted on cold
tires. Observe the recommended tire inflation
pressure on the Tire and Loading Information
placard on the driver’s door B-pillar
(
page 389). Some vehicles may have supple-
mental tire inflation pressure information for
driving at high speeds (
page 395) or for vehi-
cle loads less than the maximum loaded vehicle
condition (
page 395). If such information is
provided, it can be found on the inside of the fuel
filler flap.


402 Operation
Tires and wheels
Press the reset button (page 155).
The following message will appear in
the multifunction display:
Restart tire
pressure monitor?
Press the æbutton.
The following message will appear in
the multifunction display:
Tire pressure monitor
restarted
After driving a few minutes the system
verifies that the current tire inflation
pressures are within the system’s
specified range. Afterwards the current
tire inflation pressures are accepted as
reference pressures and then moni-
tored.
If you wish to cancel activation:
Press the çbutton.Checking tire pressure electronically
with the Advanced Tire Pressure Moni-
toring System (Advanced TPMS)*,
(Canada only)
The TPMS only functions on wheels that
are equipped with the proper electronic
sensors. It monitors the tire inflation pres-
sure, as selected by the driver, in all four
tires. A warning is issued to alert you to a
decrease in pressure in one or more of the
tires.
Tire pressure inquiries are made using the
multifunction display. The present inflation
pressures are displayed only after a few
minutes’ travel time.
Switch on the ignition (page 42).
Press thej or kbutton on the
multifunction steering wheel until the
current inflation pressures for each tire
appear in the multifunction display.
iThis device complies with RSS-210 of Indus-
try Canada. Operation is subject to the following
two conditions:
(1) This device may not cause interference, and
(2) this device must accept any interference
received, including interference that may
cause undesired operation of the device.
Any unauthorized modification to this device
could void the user’s authority to operate the
equipment.
iPossible differences between the readings
of a tire pressure gauge of an air hose, e.g. gas
station equipment, and the vehicle’s control
system can occur. Usually the readings issued by
the control system are more precise.
iWhen the message Tire pressure
displayed after driving for a few
minutes
appears in the multifunction display,
the individual inflation pressure values are
matched with the tires. The individual values are
displayed after a few minutes driving.


403 Operation
Tires and wheels
Warning!G
It is the driver’s responsibility to calibrate
the TPMS on the recommended cold infla-
tion pressure. Underinflated tires affect the
ability to steer or brake the vehicle. You
might lose control over the vehicle.
iWith a spare wheel without wheel sensor
mounted, the system may still indicate the tire
inflation pressure of the removed wheel for some
minutes. If this happens, keep in mind that the
indicated value where the spare wheel is mount-
ed does not reflect the actual spare tire inflation
pressure.
Warning!G
The TPMS does not indicate a warning for
wrongly selected inflation pressures. Always
adjust tire inflation pressure according to
the Tire and Loading Information placard on
the driver’s door B-pillar or, if available, the
supplemental tire inflation pressure infor-
mation on the inside of the fuel filler flap.
The TPMS is not able to issue a warning due
to a sudden dramatic loss of pressure (e.g.
tire blowout caused by a foreign object). In
this case bring the vehicle to a halt by care-
fully applying the brakes and avoiding
abrupt steering maneuvers.
Warning!G
Each tire, including the spare (if provided),
should be checked monthly when cold and
inflated to the inflation pressure recom-
mended by the vehicle manufacturer on the
Tire and Loading Information placard on the
driver’s door B-Pillar or, if available, the tire
inflation pressure label on the fuel filler flap.
If your vehicle has tires of a different size
than the size indicated on the vehicle plac-
ard or the tire inflation pressure label, you
should determine the proper tire inflation
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 illu-
minates, you should stop and check your
tires as soon as possible. Driving on a signif-
icantly underinflated tire causes the tire to
overheat and can lead to tire failure.


404 Operation
Tires and wheels
Reactivating Advanced TPMS*
The TPMS must be reactivated when you
have adjusted the tire inflation pressure to
a new level (e.g. because of different load
or driving conditions). The TPMS is then
recalibrated to the current tire inflation
pressures.
Using the Tire and Loading Information
placard on the driver’s door B-pillar
(
page 389) or, if available, the sup-
plemental tire inflation pressure
information on the inside of the fuel
filler flap (
page 375), make sure the
tire inflation pressure of all four tires is
correct.
Press buttonè orÿ on the mul-
tifunction steering wheel repeatedly
until the standard display menu
appears in the multifunction display
(
page 157).
Press thej or kbutton repeat-
edly until you see the current inflation
pressures for each tire appear in the
display or the following message ap-
pears in the display
Underinflation also reduces fuel efficiency
and tire tread life, and may effect 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 under-inflation has not
reached the level to trigger illumination of
the TPMS low tire pressure telltale.
iOperating radio transmission equipment
(e.g. wireless headsets, two-way radios) in or
near the vehicle could cause the TPMS to mal-
function.
Warning!G
It is the driver’s responsibility to calibrate
the TPMS on the recommended cold infla-
tion pressure. Underinflated tires affect the
ability to steer or brake the vehicle. You
might lose control over the vehicle.
iReactivate the TPMS after adjusting the tire
inflation pressure to the inflation pressure rec-
ommended for the vehicle operating condition.
Tire pressure should only be adjusted on cold
tires. Observe the recommended tire inflation
pressure on the Tire and Loading Information
placard on the driver’s door B-pillar
(
page 389). Some vehicles may have supple-
mental tire inflation pressure information for
driving at high speeds (
page 395) or for vehi-
cle loads less than the maximum loaded vehicle
condition (
page 395). If such information is
provided, it can be found on the inside of the fuel
filler flap.


408 Operation
Tires and wheels
For additional information on tire load
rating, see “Load identification”
(
page 410).
Tire speed rating
The tire speed rating6 (
page 406)
indicates the approved maximum speed
for the tire.Summer tires
Warning!G
The tire load rating must always be at least
half of the GAWR (
page 416) of your
vehicle. Otherwise, tire failure may be the
result which may cause an accident and/or
serious personal injury to you or others.
Always replace rims and tires with the same
designation, manufacturer and type as
shown on the original part.
Warning!G
Do not overload the tires by exceeding the
specified load limit as indicated on the Tire
and Loading Information placard located on
the driver’s door B-pillar. Overloading the
tires can overheat them, possibly causing a
blowout. Overloading the tires can also
result in handling or steering problems, or
brake failure.
iTire load rating5 (page 406) and Tire
speed rating6 (
page 406) are also referred
to as “service description”.
Warning!G
Even when permitted by law, never operate
a vehicle at speeds greater than the
maximum speed rating of the tires.
Exceeding the maximum speed for which
tires are rated can lead to sudden tire
failure, causing loss of vehicle control and
possibly resulting in an accident and/or
personal injury and possible death, for you
and for others.
iTire load rating5 (page 406) and Tire
speed rating6 (
page 406) are also referred
to as “service description”.
IndexSpeed rating
Qup to 100 mph (160 km/h)
Rup to 106 mph (170 km/h)
Sup to 112 mph (180 km/h)
Tup to 118 mph (190 km/h)
Hup to 130 mph (210 km/h)
Vup to 149 mph (240 km/h)
Wup to 168 mph (270 km/h)
Yup to 186 mph (300 km/h)
(Y)above 186 mph (300 km/h)
ZRabove 149 mph (240 km/h)

412 Operation
Tires and wheels
Maximum tire load
1Maximum tire load rating
The maximum tire load is the maximum
weight the tires are designed to support.For more information on tire load rating
(
page 407).
For information on calculating total and
cargo load capacities (
page 390).
Maximum tire inflation pressure
1Maximum permissible tire inflation
pressure
This is the maximum permissible tire
inflation pressure for the tire.
iFor illustration purposes only. Actual data
on tires are specific to each vehicle and may vary
from data shown in above illustration.
Warning!G
Do not overload the tires by exceeding the
specified load limit as indicated on the Tire
and Loading Information placard located on
the driver’s door B-pillar. Overloading the
tires can overheat them, possibly causing a
blowout. Overloading the tires can also
result in handling or steering problems, or
brake failure.
iFor illustration purposes only. Actual data
on tires are specific to each vehicle and may vary
from data shown in above illustration.

415 Operation
Tires and wheels
Tire ply material
1Plies in sidewall
2Plies under tread
This marking tells you about the type of
cord and number of plies in the sidewall
and under the tread.Tire and loading terminology
Accessory weight
The combined weight (in excess of those
standard items which may be replaced) of
automatic transmission, power steering,
power brakes, power windows, power
seats, radio, and heater, to the extent that
these items are available as
factory-installed equipment (whether
installed or not).
Air pressure
The amount of air inside the tire pressing
outward on each square inch of the tire.
Air pressure is expressed in pounds per
square inch (psi), or kilopascal (kPa) or
bars.
Aspect ratio
Dimensional relationship between tire
section height and section width
expressed in percentage.
Warning!G
The temperature grade for this tire is estab-
lished for a tire that is properly inflated and
not overloaded. Excessive speed, underin-
flation, or excessive loading, either sepa-
rately or in combination, can cause
excessive heat build-up and possible tire
failure.
iFor illustration purposes only. Actual data
on tires are specific to each vehicle and may vary
from data shown in above illustration.