2007 MERCEDES-BENZ R320CDI fuel pressure

398 Operation
Tires and wheels
Maximum tire inflation pressure
1Maximum permissible tire inflation
pressure
This is the maximum permissible tire
inflation pressure for the tire.Always follow the recommended tire
inflation pressure (
page 380) 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 resistance
iFor illustration purposes only. Actual data
on tires are specific to each vehicle and may vary
from data shown in above illustration.
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 vehicle and may vary
from data shown in above illustration.

401 Operation
Tires and wheels
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.Bar
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 (Department of Transportation)
A tire branding symbol which denotes the
tire meets requirements of the
U.S. Department of Transportation.
GAWR (G
ross Axle Weight Rating)
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 Trailer Weight)
The GTW is the weight of the trailer plus
the weight of all cargo, equipment, luggage
etc. loaded on the trailer.

402 Operation
Tires and wheels
GVW (Gross Vehicle Weight)
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 GVW must never exceed the
GVWR indicated on the certification label
located on the driver’s door B-pillar.
GVWR (G
ross Vehicle Weight Rating)
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 certi-
fication 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.Maximum load rating
The maximum load in kilograms and
pounds that can be carried by the tire.
Maximum loaded vehicle weight
The sum of curb weight, accessory weight,
total load limit and production options
weight.
Maximum tire inflation pressure
This number is the greatest amount of air
pressure that should ever be put in the tire
under normal driving conditions.
Normal occupant weight
The number of occupants the vehicle is
designed to seat, multiplied by
68 kilograms (150 lbs).
Occupant distribution
The distribution of occupants in a vehicle
at their designated seating positions.Production options weight
The combined weight of those installed
regular production options weighing over
5 lbs (2.3 kilograms) in excess of those
standard items which they replace, not
previously considered in curb weight or
accessory weight, including heavy duty
brakes, ride levelers, roof rack, heavy duty
battery, and special trim.
PSI (P
ounds per square inch)
A standard unit of measure for air pressure
-> bar, kilopascal (kPa).
Recommended tire inflation pressure
Recommended tire inflation pressure
listed on placard located on driver’s door
B-pillar for normal driving conditions.
Provides best handling, tread life and
riding comfort.

424 Practical hints
What to do if …
ProblemPossible cause/conse-
quenceSuggested 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 360).
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.

429 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 underinflation has not
reached the level to trigger illumination of
the TPMS low tire pressure telltale.
USA only:
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.

460 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
c You are driving with one or more
doors open.Stop the vehicle in a safe location or as
soon as it is safe to do so.
Close the doors.
A Gas cap is openA 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 360).
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.
aYou are driving with the hood or
the tailgate open.Carefully bring the vehicle to a halt as
soon as it is safe to do so in a safe
location.
Close the hood (page 364) or the
tailgate (
page 125).
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 125).

503 Practical hints
Flat tire
Press 0 on electric air pump switch 2.
Turn the SmartKey in the starter switch
to position0.
Vehicles with KEYLESS-GO*:
Press the KEYLESS-GO start/stop
button twice without depressing
the brake pedal.
If the tire inflation pressure is above
the recommended tire inflation pres-
sure given in this Operator’s Manual,
release excess tire inflation pressure
using the vent screw.
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 bolts
!Please compare the recommended tire in-
flation pressure for your vehicle with the tire in-
flation pressure on the yellow label located on
the spare wheel rim.
If the tire inflation pressure on the yellow label
on the spare wheel rim differs from the values
given in this Operator’s Manual, inflate the tire to
the recommended tire inflation pressure given
on the yellow label on the spare wheel rim.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 501) before lowering the
vehicle.

532 Technical data
Rims and tires
!Only use tires which have been tested and
approved by Mercedes-Benz. Tires approved by
Mercedes-Benz are developed to provide best
possible performance in conjunction 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 sidewall:

MO = Mercedes-Benz Original equipment
tires
AMG vehicles:
Does not apply to all approved tires on AMG
vehicles. For information on tested and
approved tires for AMG vehicles, contact an
authorized Mercedes-Benz Center.
Using tires other than those approved by
Mercedes-Benz may result in damage that is
not covered by the Mercedes-Benz Limited
Warranty.
!Using tires other than those approved by
Mercedes-Benz can have detrimental effects,
such as

poor handling characteristics

increased noise

increased fuel consumption
Moreover, tires and rims not approved by
Mercedes-Benz may, under load, exhibit dimen-
sional variations and different tire deformation
characteristics that could cause them to come
into contact with the vehicle body or axle parts.
Damage to the tires or the vehicle may be the
result.
iFurther information on tires and rims is
available at any authorized Mercedes-Benz Light
Truck Center. A placard with the recommended
tire inflation pressures is located on the driver’s
door B-pillar (
page 376). Some vehicles may
have supplemental tire inflation pressure infor-
mation for driving at high speeds (
page 381)
or for vehicle loads less than the maximum
loaded vehicle condition (
page 382). 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 maintenance
recommendation included with vehicle.
iThe following pages also list the approved
wheel rim and tire sizes for equipping your vehi-
cles with winter tires. Winter tires are not avail-
able as standard or optional factory equipment,
but can be purchased from an authorized
Mercedes-Benz Light Truck Center.
Depending on vehicle model and the standard or
optional factory-equipped wheel rim/tire
configuration on your vehicle (Appearance
Package, Sport Package etc.), equipping your
vehicle with winter tires approved for your
vehicle model may also require the purchase of
two or four wheel rims of the recommended size
for use with these winter tires. See an authorized
Mercedes-Benz Light Truck Center for more
information.