2006 MERCEDES-BENZ R500 fuel pressure

375 Operation
Tires and wheels
Potential problems associated with
underinflated and overinflated tires
Underinflated tire inflation pressure
Underinflated tires can

cause excessive and uneven tire wear


adversely affect fuel economy


lead to tire failure from being
overheated


adversely affect handling
characteristicsOverinflated tire inflation pressure
Overinflated tires can:


adversely affect handling
characteristics


cause uneven tire wear


be more prone to damage from road
hazards


adversely affect ride comfort


increase stopping distance
Tire labeling
Besides tire name (sales designation) and
manufacturer name, a number of markings
can be found on a tire.
Following are some explanations for the
markings on your vehicle’s tires:
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
overheated.
Warning!
G
Follow recommended tire inflation
pressures.
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.

383 Operation
Tires and wheels
Always follow the recommended tire
inflation pressure (
page 363) for proper
tire inflation. Uniform Tire Quality Grading Standards
(U.S. vehicles)
Tire manufacturers are required to grade
tires based on three performance
factors: treadwear, traction and
temperature resistance.
1Treadwear
2Traction
3Temperature resistanceQuality grades can be found, where appli-
cable, on the tire sidewall between tread
shoulder and maximum section width. For
example:
All passenger car tires must conform to
federal safety requirements in addition to
these grades.
Warning!
G
Never exceed the max. tire inflation
pressure. Follow recommended tire inflation
pressures.
Do not underinflate tires. Underinflated tires
wear excessively and/or unevenly, adverse-
ly affect handling and fuel economy, and are
more likely to fail from being overheated.
Do not overinflate tires. Overinflated tires
can adversely affect handling and ride com-
fort, wear unevenly, increase stopping dis-
tance, and result in sudden deflation
(blowout) because they are more likely to
become punctured or damaged by road de-
bris, potholes etc.
iFor illustration purposes only. Actual
data on tires are specific to each vehi-
cle and may vary from data shown in
above illustration.
Treadwear
Traction
Temperature
200
AA
A

386 OperationTires and wheelsBar
Another metric unit for air pressure. There
are 14.5038 pounds per square inch (psi)
to 1 bar; there are 100 kilopascals (kPa)
to 1 bar.
Bead
The tire bead contains steel wires wrapped
by steel cords that hold the tire onto the
rim.
Cold tire inflation pressure
Tire inflation pressure when your vehicle
has been sitting for at least 3 hours or
driven no more than 1 mile (1.6 km).
Curb weight
The weight of a motor vehicle with stan-
dard equipment including the maximum
capacity of fuel, oil, and coolant, and, if so
equipped, air conditioning and additional
optional equipment, but without passen-
gers and cargo.DOT (D
epartment o
f T
ransportation)
A tire branding symbol which denotes the
tire meets requirements of the
U.S. Department of Transportation.
GAWR (G
ross A
xle W
eight R
ating)
The GAWR is the maximum permissible
axle weight. The gross vehicle weight on
each axle must never exceed the GAWR for
the front and rear axle indicated on the
Certification label located on the driver’s
door B-pillar.
GTW (G
ross T
railer W
eight)
The GTW is the weight of the trailer plus
the weight of all cargo, equipment, luggage
etc. loaded on the trailer. GVW (G
ross V
ehicle W
eight)
The GVW comprises the weight of the
vehicle including fuel, tools, spare wheel,
installed accessories, passengers and
cargo and, if applicable, trailer tongue
load. The GWV must never exceed the
GWVR indicated on the Certification label
located on the driver’s door B-pillar.
GVWR (G
ross V
ehicle W
eight R
ating)
This is the maximum permissible vehicle
weight of the fully loaded vehicle (weight of
the vehicle including all options, passen-
gers, fuel, and cargo and, if applicable,
trailer tongue load). It is indicated on
Certification label located on the driver’s
door B-pillar.
Kilopascal (kPa)
The metric unit for air pressure. There are
6.9 kPa to 1 psi; another metric unit for air
pressure is bars. There are 100 kilopascals
(kPa) to 1 bar.

408 Practical hintsWhat to do if …Problem
Possible cause/conse-
quence
Suggested solution
?
(USA only)
±
(Canada only)
The yellow engine malfunction
indicator lamp comes on while
driving.
A loss of pressure has been
detected in the fuel system.
The fuel cap may not be closed
properly or the fuel system
may be leaky.

Check the fuel cap (
page 342).
If it is not closed properly:

Close the fuel cap.
If it is closed properly:

Have the fuel system checked by an
authorized Mercedes-Benz Light Truck
Center.
Your fuel tank is empty.

After refueling start, turn off and
restart the engine three or four times in
succession.
The limp-home mode is canceled. You do
not need to have your vehicle checked.

413 Practical hints
What to do if …
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
vehicle placard or the tire inflation pressure
label. (If your vehicle has tires of a different
size than the size indicated on the vehicle
placard or the tire inflation pressure label,
you should determine the proper tire infla-
tion 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 over-
heat 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 under-inflation 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 mal-
function exists. When the malfunction
indicator is illuminated, 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 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.

439 Practical hints
What to do if …
Display symbol
Display messages
Possible cause/consequence
Possible solution
A
Check gas cap
See Operator’s Manual
A loss of pressure has been
detected in the fuel system. The
fuel cap may not be closed
properly or the fuel system may
be leaky.

Check the fuel cap (
page 342).
If it is not closed properly:

Close the fuel cap.
If it is closed properly:

Have the fuel system checked by an
authorized Mercedes-Benz Light Truck
Center.
a
Hood open
Trunk open
You are driving with the hood or
the tailgate open.

Close the hood (
page 345) or the
tailgate (
page 124).
You are trying to lock the vehicle
with the KEYLESS-GO* function
with a door or the tailgate open.

Close all doors and/or the tailgate
(page 124).

485 Practical hints
Flat tire

Detach the electric air pump.

Store the electrical plug and the air
hose behind the flap and place the
electric air pump back in the vehicle
tool kit storage well.Lowering the vehicle

Lower vehicle by turning crank coun-
terclockwise until vehicle is resting ful-
ly on its own weight.

Remove the jack.
1-5Wheel bolts6Wheel wrench

Tighten the five wheel bolts evenly, fol-
lowing the diagonal sequence illustrat-
ed (1 to 5), until all bolts are tight.
Observe a tightening torque of
110 lb-ft (150 Nm).
Warning!
G
Follow recommend tire inflation pressures.
Do not overinflate tires. Overinflating tires
can result in sudden deflation (blowout) be-
cause they are more likely to become punc-
tured or damaged by road debris, potholes,
etc.
Do not underinflate tires. Underinflated tires
wear unevenly, adversely affect handling
and fuel economy, and are more likely to fail
from being overheated.
Warning!
G
Inflate collapsible tire only after the wheel is
properly mounted.
Inflate the collapsible tire using the electric
air pump (
page 483) before
lowering the
vehicle.
Warning!
G
Have the tightening torque checked after
changing a wheel. The wheels could come
loose if they are not tightened to a torque of
110 lb-ft (150 Nm).


514 Technical dataRims and tires
!
Only use tires which have been tested
and approved for your vehicle by
Mercedes-Benz. Tires approved by
Mercedes-Benz are developed to pro-
vide best possible performance in con-
junction with the driving safety
systems on your vehicle such as ABS or
ESP
®. Tires specially developed for
your vehicle and tested and approved
by Mercedes-Benz can be identified by
finding the following on the tire’s side-
wall:


MO = M
ercedes-Benz O
riginal
equipment tires
Using tires other than those approved
by Mercedes-Benz may result in dam-
age that is not covered by the
Mercedes-Benz Limited Warranty.
!Using tires other than those approved
by Mercedes-Benz can have detrimen-
tal effects, such as

poor handling characteristics


increased noise


increased fuel consumption
Moreover, tires and rims not approved
by Mercedes-Benz may, under load,
exhibit dimensional variations and dif-
ferent tire deformation characteristics
that could cause them to come into
contact with the vehicle body or axle
parts. Damage to the tires or the vehi-
cle may be the result.
iFurther information on tires and rims is
available at any authorized
Mercedes-Benz Center. A placard with
the recommended tire inflation pres-
sures is located on the driver’s door
B-pillar (
page 510). Some vehicles
may have supplemental tire inflation
pressure information for driving at high
speeds (page 364) or for vehicle
loads less than the maximum loaded
vehicle condition (
page 364). If such
information is provided, it can be found
on the placard located on the inside of
the fuel filler flap. The tire inflation
pressure should be checked regularly
and should only be adjusted on cold
tires. Follow tire manufacturer’s main-
tenance recommendation included
with vehicle.