warning MERCEDES-BENZ SPRINTER 2006 Service Manual

INJECTOR CLASSIFICATION PROCEDURE
(1) Turn ignition switch ªONº.
(2) Using a DRB IIItand select ENGINE then
MISCELLANEOUS.
(3) Select LEARN INJECTORS.
(4) Using the up and down arrows, scroll to the
appropriate injector.
(5) Using the right and left arrows, set injector to
proper classification.
(6) Once injectors are classified, cycle ignition to
complete.
CLEANING FUEL INJECTORS
NOTE: Before cleaning the injector recesses, seal
the injector holes in the injector recesses with the
appropriate pin to prevent debris from falling into
the recesses and entering the motor.
(1) Seal the injector holes inside the cylinder head
recesses.
(2) Wipe out injector recesses with a non-woven
cloth, then clean with a cylinder brush.
(3) Clean the bottom of the cylinder recess with a
round brush.
(4) Blow out the recess and clean again with a
non-woven cloth and cover over.
(5) Perform these steps for each injector recess.
NOTE: DO NOT clean the tip of the injector with a
wire brush. Use a non - woven cloth.
(6) Clean injector body with a wire brush.
(7) Clean injector tips with a non-woven cloth.
NOTE: Do Not apply antiseize lubricant to the injec-
tor nozzle area.
(8) Grease injector body with anti seize lubricant.
NOTE: Always replace the seals that seal off the
injectors at the cylinder head to the combustion
chamber and replace the retaining screws.
REMOVAL
WARNING: NO SPARKS, OPEN FLAMES OR SMOK-
ING. RISK OF POISONING FROM INHALING AND
SWALLOWING FUEL. RISK OF INJURY TO EYES
AND SKIN FROM CONTACT WITH FUEL. POUR
FUELS ONLY INTO SUITABLE AND APPROPRI-
ATELY MARKED CONTAINERS. WEAR PROTECTIVE
CLOTHING.
NOTE: When removing injectors, the seal rings and
retaining stretch bolts must always be replaced.
Coat the injector body with the anti-seize com-pound before installing. Keep lubricant away from
the injector nozzle.
(1) Disconnect negative battery cable.
(2) Remove engine cover (Refer to 9 - ENGINE -
REMOVAL).
(3) Remove the fuel return hose locking clamps at
the injector and remove return hose.
(4) Disconnect the injector electrical connector
(Fig. 13).
NOTE: Counterhold injection lines with wrench
socket at threaded connections of injectors.
(5) Disconnect fuel injector high pressure line (Fig.
13).
(6) Remove fuel injector retaining bolt and tension
claw, then remove the injector and seal (Fig. 13).
NOTE: If injectors are tight, remove with extraction
claw in place of tensioning claw. If extraction claw
contacts cylinder head cover, remove cylinder head
cover. If necessary, remove injectors with threaded
adaptor and discard injector.
(7) Remove injectors (Fig. 13).
(8) Clean injectors and recesses (Refer to 14 -
FUEL SYSTEM/FUEL INJECTION/FUEL INJEC-
TOR - STANDARD PROCEDURE).Fig. 13 FUEL INJECTOR REMOVAL / INSTALLATION
1 - FUEL INJECTOR RETURN LINE
2 - RETAINING CLIP
3 - INJECTOR HIGH PRESSURE LINE
4 - INJECTOR SEAL
5 - FUEL INJECTOR
6 - TENSIONING CLAW
7 - SPECIAL TOOLS #8938 AND # 8937
14 - 38 FUEL INJECTIONVA

INSTALLATION
WARNING: NO SPARKS, OPEN FLAMES OR SMOK-
ING. RISK OF POISONING FROM INHALING AND
SWALLOWING FUEL. RISK OF INJURY TO EYES
AND SKIN FROM CONTACT WITH FUEL. POUR
FUELS ONLY INTO SUITABLE AND APPROPRI-
ATELY MARKED CONTAINERS. WEAR PROTECTIVE
CLOTHING.
NOTE: When removing injectors, the seal rings and
retaining stretch bolts must always be replaced.
Coat the injector body with the anti-seize com-
pound before installing. Keep lubricant away from
the injector nozzle.
(1) Clean injectors and recesses (Refer to 14 -
FUEL SYSTEM/FUEL INJECTION/FUEL INJEC-
TOR - STANDARD PROCEDURE).
(2) Coat injector body with anti seize lubricant
then install injectors with new seals.
(3) Install tensioning claws with new screws at
injectors. Tighten screws in two stages, 7 N´m (62
lbs. in.) then 90É (Fig. 13).
NOTE: If locking clamp has been pulled off at injec-
tor, the locking clamp must be replaced.
(4) Position fuel return line at injectors and secure
locking clamps (Fig. 13).
NOTE: Counterhold injection lines with wrench
socket at threaded connections of injectors. DO
NOT over tighten.
(5) Install high pressure injection lines (Refer to
14 - FUEL SYSTEM/FUEL DELIVERY/FUEL LINES
- INSTALLATION).
(6) Reconnect injector electrical connectors (Fig.
13).
(7) Connect negative battery cable.
NOTE: Fuel Injectors have different flow rates.
When injectors are removed, re-enter all injector six
digit codes.
(8) Program all injector codes into the ECM using
the scan tool.
(9) Start engine, allow to run, turn engine off and
inspect for leaks (Refer to 14 - FUEL SYSTEM -
WARNING).
CAUTION: Care must be taken when installing the
engine cover. Assure the proper routing of the fuel
injector return fuel hose to the banjo bolt fitting in
the left rear corner of the cover. Failure to do so
may pinch or damage the hose causing fuel leakage
or a driveability concern.(10) Install engine cover (Refer to 9 - ENGINE -
INSTALLATION)..
FUEL PRESSURE SENSOR
DESCRIPTION
The fuel rail pressure sensor measures the current
fuel rail pressure and supplies an appropriate voltage
signal to the ECM. The non-constant fuel system
pressure influences the position of the internal dia-
phragm. This results in a variation in the electrical
resistance which is analyzed by the ECM.
OPERATION
The fuel rail pressure sensor measures the current
fuel rail pressure and sends a voltage signal to the
ECM. The ECM then actuates the fuel rail pressure
control valve until the desired rail pressure is
achieved.
REMOVAL
(1) (Refer to 14 - FUEL SYSTEM/FUEL INJEC-
TION - WARNING) Disconnect the negative battery
cable.
(2) Remove the mixing housing.
(3) Unplug the sensor (Fig. 14).
(4) Counter-hold the threaded connection at the
fuel rail and unscrew the sensor (Fig. 14).
Fig. 14 FUEL RAIL PRESSURE SENSOR
1 - WIRING CONNECTOR
2 - FUEL RAIL PRESSURE SENSOR
3 - SEALING RING
4 - FUEL RAIL
VAFUEL INJECTION 14 - 39

INSTALLATION
(1) (Refer to 14 - FUEL SYSTEM/FUEL INJEC-
TION - WARNING) Install the sealing ring on to the
sensor (Fig. 14).
(2) Screw the sensor in to the fuel rail. Counter-
hold the threaded connection and tighten the sensor
to 18 lbs. ft. (25 N´m.) (Fig. 14).
(3) Connect the wiring harness to the sensor.
(4) Install the mixing housing.
CAUTION: Care must be taken when installing the
engine cover. Assure the proper routing of the fuel
injector return fuel hose to the banjo bolt fitting in
the left rear corner of the cover. Failure to do so
may pinch or damage the hose causing fuel leakage
or a driveability concern.
(5) Connect negative battery cable.
FUEL PRESSURE SOLENOID
DESCRIPTION
The fuel pressure solenoid is attached to the rear
of the fuel rail. A sealing metal disc seals the valve to
the rail. The seal is not serviceable and looses it's
sealing properties upon removal of the solenoid.
Therefore, the solenoid must be replaced when ever
it is removed from the rail. The solenoid controls and
maintains the rail pressure constant along with a
control current transmitted by the engine control
module (ECM) (Fig. 15).
OPERATION
High pressure which is present in the fuel rail
flows to the ball seat of the pressure solenoid (Fig.
16). The specified pressure required by the system is
built up in the rail by the fuel pressure solenoid
building up a magnetic force which corresponds to
this specific pressure by means of a control current
from the electronic control module (ECM) (Fig. 16).
This magnetic force equals a certain outlet cross sec-
tion at the ball seat of the valve. The rail pressure is
altered as a result of the quantity of fuel which flows
off (Fig. 16). The current fuel pressure is signaled by
the fuel rail pressure sensor to the engine control
module (ECM). The controlled fuel flows back along
the return fuel line, into the tank.
In a de-energized state, the fuel pressure solenoid
is closed as the spring force presses the ball into the
ball seat (Fig. 16). When driving, the fuel pressure
solenoid is constantly open (Fig. 16). When engine is
started, the fuel pressure solenoid is held closed by
magnetic force (Fig. 16). When driving, the pressure
of the fluid counteracts the magnetic force of the coil
and the slight spring force (Fig. 16).
Fig. 15 FUEL PRESSURE SOLENOID
1 - FUEL PRESSURE SENSOR
2 - FUEL RAIL
3 - FUEL PRESSURE SOLENOID
Fig. 16 FUEL PRESSURE SOLENOID OPERATION
1 - BALL SEAT
2 - SPRING FORCE
3 - MAGNETIC FORCE
4 - COIL
5 - FUEL PRESSURE SOLENOID
6 - HIGH PRESSURE SUPPLY
14 - 40 FUEL INJECTIONVA

STANDARD PROCEDURE - FUEL PRESSURE
SOLENOID TEST
(1) Disconnect the large fuel rail return hose at
the banjo fitting and clamp it off. Attach a jumper
hose to the banjo fitting and direct the hose into a
test vial. Crank the engine for 10 seconds (Fig. 17).
If return fuel is present in the test vial, replace the
fuel pressure solenoid.
REMOVAL
Review the high pressure fuel system warning before
beginning repair (Refer to 14 - FUEL SYSTEM - WARNING)
WARNING: NO SPARKS, OPEN FLAMES OR SMOK-
ING. RISK OF POISONING FROM INHALING AND
SWALLOWING FUEL. RISK OF INJURY TO EYES
AND SKIN FROM CONTACT WITH FUEL. POUR
FUELS ONLY INTO SUITABLE AND APPROPRI-
ATELY MARKED CONTAINERS. WEAR PROTECTIVE
CLOTHING.
(1) Disconnect negative battery cable.
(2) Remove fuel rail (Refer to 14 - FUEL SYSTEM/
FUEL INJECTION/FUEL INJECTOR - REMOVAL).
(3) Clamp fuel rail securely in vise with protective
jaws.
NOTE: Once removed, the solenoid must always be
replaced.
(4) Counterhold and unscrew the fuel pressure
solenoid and discard the sealing ring (Fig. 18).
INSTALLATION
Review the high pressure fuel system warning before
beginning repair (Refer to 14 - FUEL SYSTEM - WARNING)
WARNING: NO SPARKS, OPEN FLAMES OR SMOK-
ING. RISK OF POISONING FROM INHALING AND
SWALLOWING FUEL. RISK OF INJURY TO EYES
AND SKIN FROM CONTACT WITH FUEL. POUR
FUELS ONLY INTO SUITABLE AND APPROPRI-
ATELY MARKED CONTAINERS. WEAR PROTECTIVE
CLOTHING.
CAUTION: There is a special tightening procedure
for the fuel rail solenoid that must be followed
along with the proper use of a torque wrench.
Therefore the fuel rail must be removed before
installing the fuel pressure solenoid. Attention must
be paid to the sealing ring before assembly. If the
sealing ring is damaged when assembling, this
could result in a not so visible leak.
NOTE: Observe the alignment of the pressure sole-
noid. The electrical connection must point in the
same direction as the connection of the injection
line at the fuel rail.
(1) Screw the fuel pressure solenoid with new seal-
ing disc to the fuel rail until hand tight (Fig. 18).
(2) Tighten the fuel rail solenoid as follows :
Fig. 17 CHECKING FUEL RAIL PRESSURE
SOLENOID LEAKAGE
1 - CLAMP RUBBER FUEL RETURN HOSES
2 - ATTACH SEPARATE RUBBER FUEL HOSE
3 - CONTAINER TO MEASURE FUEL LEAKAGE
4 - DISCONNECT RUBBER RETURN HOSE
Fig. 18 FUEL PRESSURE SOLENOID
1 - FUEL PRESSURE SOLENOID
2 - METAL SEALING DISC
3 - FUEL RAIL
4 - VISE
VAFUEL INJECTION 14 - 41

²Tighten the nut to 60 N´m (44 ft. lbs.)
²Loosen the nut 90 degrees.
²Retighten the nut to 80 N´m (59 ft. lbs.).
(3) Install fuel rail (Refer to 14 - FUEL SYSTEM/
FUEL INJECTION/FUEL INJECTOR - INSTALLA-
TION).
(4) Connect negative battery cable.
(5) Start engine, allow to warm, turn engine off
and inspect for leaks (Refer to 14 - FUEL SYSTEM -
DIAGNOSIS AND TESTING).
FUEL TEMPERATURE SENSOR
DESCRIPTION
The fuel temperature sensor is integrated in the
high pressure fuel pump next to the fuel quantity
valve. The sensor detects the temperature of the fuel
and supplies that information to the ECM. The sen-
sor ranges from - 40ÉF (- 40C) to 284ÉF (140ÉC). If
the engine is cold, the actual value sent will read
ambient temperature. The value rises after the
engine has been started.
OPERATION
An negative temperature coefficient (NTC) resistor
integrated in the fuel temperature sensor alters it's
electrical resistance in line with the fuel temperature
(the resistance drops as the temperature rises). The
ECM uses this reading to calculate optimum engine
performance under all driving conditions. If the fuel
is to warm, the rail pressure in the system is low-
ered. The controller quantity of the pressure regulat-
ing valve is reduced and the fuel temperature is
lowered.
REMOVAL
NOTE: Capture and properly store all fluid seepage
in appropriately marked containers.
(1) Disconnect the negative battery cable.
(2) Remove the fuel temperature sensor from the
high pressure pump (Fig. 19).
INSTALLATION
(1) Clean sealing surfaces.
(2) Install new seal on sensor.
(3) Screw the sensor into the high pressure pump
and tighten to 18 lbs.ft. (25 N´m) (Fig. 19)
(4) Connect negative battery cable.
(5) Start engine, allow to warm, shut engine off
and inspect for leaks (Refer to 14 - FUEL SYSTEM/
FUEL INJECTION - WARNING).
INTAKE AIR TEMPERATURE
SENSOR
DESCRIPTION
The intake air temperature sensor is located
between the charge air pipe and the charge air dis-
tribution of the cylinders. The intake air temperature
sensor measures the temperature of the air as it is
supplied to the cylinders and transmits the value to
the ECM. This is required in order to determine the
density of the air being supplied for the combustion
process. The value range is from minus 40ÉF up to
302ÉF (minus 40ÉC to 150ÉC).
Fig. 19 HIGH PRESSURE FUEL PUMP
1 - HIGH PRESSURE PUMP
2 - FUEL SUPPY TO FUEL RAIL
3 - FUEL SUPPLY LINE
4 - FUEL RETURN LINE
5 - FUEL TEMPERATURE SENSOR
6 - FUEL QUANTITY CONTROL VALVE
7 - OIL LEVEL INDICATOR
8 - VACUUM PUMP
14 - 42 FUEL INJECTIONVA

PUMP
TABLE OF CONTENTS
page page
PUMP
DESCRIPTION.........................11
OPERATION...........................11
DIAGNOSIS AND TESTING - PUMP LEAKAGE . 11
STANDARD PROCEDURE
STANDARD PROCEDURE - POWER
STEERING PUMP - INITIAL OPERATION....11
STANDARD PROCEDURE - FLUSHING
POWER STEERING SYSTEM............12
REMOVAL.............................12
INSTALLATION.........................12
SPECIFICATIONS - TORQUE CHART........13
FLUID
STANDARD PROCEDURE
POWER STEERING PUMP FILL AND BLEED
PROCEDURE........................13FLUID COOLER TUBE
REMOVAL.............................13
INSTALLATION.........................13
HOSES
REMOVAL
REMOVAL - PRESSURE HOSE...........14
REMOVAL - RETURN LINE FROM PUMP TO
COOLER TUBE.......................14
REMOVAL - RETURN HOSE FROM GEAR
TO COOLER TUBE....................14
INSTALLATION
INSTALLATION - PRESSURE HOSE.......14
INSTALLATION - RETURN LINE FROM
PUMP TO COOLER TUBE...............14
INSTALLATION - RETURN HOSE FROM
GEAR TO COOLER TUBE...............14
PUMP
DESCRIPTION
CAUTION: Use approved fluid only in the power
steering system (Refer to LUBRICATION & MAINTE-
NANCE/FLUID TYPES - DESCRIPTION). No other
power steering or automatic transmission fluid is to
be used in the system. Damage may result to the
power steering pump and system if any other fluid
is used, and do not overfill.
The pump is connected to the steering gear via the
pressure hose and the return hose. The pump shaft
has a pressed-on pulley that is belt driven by the
crankshaft pulley.
All vehicles are equipped with a power steering
fluid cooler.
NOTE: Power steering pumps are not interchange-
able with pumps installed on other vehicles.
OPERATION
Hydraulic pressure is provided for the power steer-
ing gear by the belt driven power steering pump. The
power steering pumps are constant flow rate and dis-
placement, vane-type pumps.
DIAGNOSIS AND TESTING - PUMP LEAKAGE
The pump is serviced as an assembly and should
not be disassembled. The plastic pump reservoir and
the reservoir o-rings can be replaced.Check for leaks in the following areas:
²Pump shaft seal behind the pulley
²Pump to reservoir O-ring
²Reservoir cap
²Pressure and return lines
²Flow control valve fitting
STANDARD PROCEDURE
STANDARD PROCEDURE - POWER STEERING
PUMP - INITIAL OPERATION
WARNING: THE FLUID LEVEL SHOULD BE
CHECKED WITH ENGINE OFF TO PREVENT INJURY
FROM MOVING COMPONENTS.
CAUTION: Use approved fluid only in the power
steering system (Refer to LUBRICATION & MAINTE-
NANCE/FLUID TYPES - DESCRIPTION). No other
power steering or automatic transmission fluid is to
be used in the system. Damage may result to the
power steering pump and system if any other fluid
is used, and do not overfill.
Wipe filler cap clean, then check the fluid level.
The dipstick should indicateCOLDwhen the fluid is
at normal temperature.
(1) Turn steering wheel all the way to the left
(2) Fill the pump fluid reservoir to the proper level
and let the fluid settle for at least two (2) minutes.
(3) Raise the front wheels off the ground.
VAPUMP 19 - 11

CAUSES OF BURNT FLUID
Burnt, discolored fluid is a result of overheating
which has three primary causes.
1. Internal clutch slippage, usually caused by low
line pressure, inadequate clutch apply pressure, or
clutch seal failure.
2. A result of restricted fluid flow through the
main and/or auxiliary cooler. This condition is usu-
ally the result of a faulty or improperly installed
drainback valve, a damaged oil cooler, or severe
restrictions in the coolers and lines caused by debris
or kinked lines.
3. Heavy duty operation with a vehicle not prop-
erly equipped for this type of operation. Trailer tow-
ing or similar high load operation will overheat the
transmission fluid if the vehicle is improperly
equipped. Such vehicles should have an auxiliary
transmission fluid cooler, a heavy duty cooling sys-
tem, and the engine/axle ratio combination needed to
handle heavy loads.
FLUID CONTAMINATION
Transmission fluid contamination is generally a
result of:
²adding incorrect fluid
²failure to clean dipstick and fill tube when
checking level
²engine coolant entering the fluid
²internal failure that generates debris
²overheat that generates sludge (fluid break-
down)
²failure to replace contaminated converter after
repair
The use of non-recommended fluids can result in
transmission failure. The usual results are erratic
shifts, slippage, abnormal wear and eventual failure
due to fluid breakdown and sludge formation. Avoid
this condition by using recommended fluids only.
The dipstick cap and fill tube should be wiped
clean before checking fluid level. Dirt, grease and
other foreign material on the cap and tube could fall
into the tube if not removed beforehand. Take the
time to wipe the cap and tube clean before withdraw-
ing the dipstick.
Engine coolant in the transmission fluid is gener-
ally caused by a cooler malfunction. The only remedy
is to replace the radiator as the cooler in the radiator
is not a serviceable part. If coolant has circulated
through the transmission, an overhaul is necessary.
The torque converter should be replaced whenever
a failure generates sludge and debris. This is neces-
sary because normal converter flushing procedures
will not remove all contaminants.
STANDARD PROCEDURE
CHECK OIL LEVEL
(1) Verify that the vehicle is parked on a level sur-
face.
(2) Remove locking pin (1) (Fig. 149). Remove the
plate of the locking pin with a suitable tool and press
out the pin remaining in the cap downwards.
(3) Remove cap (2).
WARNING: Risk of accident from vehicle starting off
by itself when engine running. Risk of injury from
contusions and burns if you insert your hands into
the engine when it is started or when it is running.
Secure vehicle to prevent it from moving off by
itself. Wear properly fastened and close-fitting work
clothes. Do not touch hot or rotating parts.
(4) Actuate the service brake. Start engine and let
it run at idle speed in selector lever position ªPº.
(5) Shift through the transmission modes several
times with the vehicle stationary and the engine
idling
(6) Warm up the transmission, wait at least 2 min-
utes and check the oil level with the engine running.
Push the Oil Dipstick 8863A in up to the stop on the
electrohydraulic unit and pull out again, read off oil
level, repeat if necessary.
NOTE: The dipstick will protrude from the fill tube
approximately 75mm (3 inches) when installed.
Fig. 149 Remove Dipstick Tube Cap Lock
1 - LOCKING PIN
2 - TUBE CAP
3 - DIPSTICK TUBE
21 - 132 AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATIONVA

Radial-ply tires must always be used in sets of
four. Under no circumstances should they be used on
the front only. They may be mixed with temporary
spare tires when necessary. A maximum speed of 50
MPH is recommended while a temporary spare is in
use.
Radial-ply tires have the same load-carrying capac-
ity as other types of tires of the same size. They also
use the same recommended inflation pressures.
The use of oversized tires, either in the front or
rear of the vehicle, can cause vehicle drive train fail-
ure. This could also cause inaccurate wheel speed
signals when the vehicle is equipped with Anti-Lock
Brakes.
The use of tires from different manufactures on the
same vehicle is NOT recommended. The proper tire
pressure should be maintained on all four tires.
DESCRIPTION - TIRE PRESSURE FOR HIGH
SPEEDS
Where speed limits allow the vehicle to be driven
at high speeds, correct tire inflation pressure is very
important. For speeds up to and including 120 km/h
(75 mph), tires must be inflated to the pressures
shown on the tire placard. For continuous speeds in
excess of 120 km/h (75 mph), tires must be inflated
to the maximum pressure specified on the tire side-
wall.
Vehicles loaded to the maximum capacity should
not be driven at continuous speeds above 75 mph
(120 km/h).
For emergency vehicles that are driven at speeds
over 90 mph (144 km/h), special high speed tires
must be used. Consult tire manufacturer for correct
inflation pressure recommendations.
DESCRIPTION - REPLACEMENT TIRES
The original equipment tires provide a proper bal-
ance of many characteristics such as:
²Ride
²Noise
²Handling
²Durability
²Tread life
²Traction
²Rolling resistance
²Speed capability
It is recommended that tires equivalent to the orig-
inal equipment tires be used when replacement is
needed.
Failure to use equivalent replacement tires may
adversely affect the safety and handling of the vehi-
cle.The use of oversize tires may cause interference
with vehicle components. Under extremes of suspen-
sion and steering travel, interference with vehicle
components may cause tire damage.
WARNING: FAILURE TO EQUIP THE VEHICLE WITH
TIRES HAVING ADEQUATE SPEED CAPABILITY
CAN RESULT IN SUDDEN TIRE FAILURE.
DESCRIPTION - TIRE INFLATION PRESSURES
Under inflation will cause rapid shoulder wear, tire
flexing, and possible tire failure (Fig. 12).
Over inflation will cause rapid center wear and
loss of the tire's ability to cushion shocks (Fig. 13).
Improper inflation can cause:
²Uneven wear patterns
²Reduced tread life
²Reduced fuel economy
²Unsatisfactory ride
Fig. 12 Under Inflation Wear
1 - THIN TIRE THREAD AREAS
Fig. 13 Over Inflation Wear
1 - THIN TIRE THREAD AREA
22 - 8 TIRES/WHEELSVA

²Vehicle drift
For proper tire pressure specification refer to the
Tire Inflation Pressure Chart provided with the vehi-
cles Owners Manual. A Certification Label on the
drivers side door pillar provides the minimum tire
and rim size for the vehicle. The label also list the
cold inflation pressure for these tires at full load
operation
Tire pressures have been chosen to provide safe
operation, vehicle stability, and a smooth ride. Tire
pressure should be checked cold once a month. Tire
pressure decreases as the ambient temperature
drops. Check tire pressure frequently when ambient
temperature varies widely.
Tire inflation pressures are cold inflation pressure.
The vehicle must sit for at least 3 hours to obtain the
correct cold inflation pressure reading. Or be driven
less than one mile after sitting for 3 hours. Tire
inflation pressures may increase from 2 to 6 pounds
per square inch (psi) during operation. Do not reduce
this normal pressure build-up.
WARNING: OVER OR UNDER INFLATED TIRES CAN
AFFECT VEHICLE HANDLING AND TREAD WEAR.
THIS MAY CAUSE THE TIRE TO FAIL SUDDENLY,
RESULTING IN LOSS OF VEHICLE CONTROL.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - PRESSURE
GAUGES
A quality air pressure gauge is recommended to
check tire pressure. After checking the air pressure,
replace valve cap finger tight.
DIAGNOSIS AND TESTING - TIRE NOISE OR
VIBRATION
Radial-ply tires are sensitive to force impulses
caused by improper mounting, vibration, wheel
defects, or possibly tire imbalance.
To find out if tires are causing the noise or vibra-
tion, drive the vehicle over a smooth road at varying
speeds. Note the noise level during acceleration and
deceleration. The engine, differential and exhaust
noises will change as speed varies, while the tire
noise will usually remain constant.
DIAGNOSIS AND TESTING - TREAD WEAR
INDICATORS
Tread wear indicators are molded into the bottom
of the tread grooves. When tread depth is 1.6 mm
(1/16 in.), the tread wear indicators will appear as a
13 mm (1/2 in.) band (Fig. 14).Tire replacement is necessary when indicators
appear in two or more grooves or if localized balding
occurs.
DIAGNOSIS AND TESTING - TIRE WEAR PAT-
TERNS
Under inflation will cause wear on the shoulders of
tire. Over inflation will cause wear at the center of
tire.
Excessive camber causes the tire to run at an
angle to the road. One side of tread is then worn
more than the other (Fig. 15).
Excessive toe-in or toe-out causes wear on the
tread edges and a feathered effect across the tread
(Fig. 15).
Fig. 14 Tread Wear Indicators
1 - TREAD ACCEPTABLE
2 - TREAD UNACCEPTABLE
3 - WEAR INDICATOR
VATIRES/WHEELS 22 - 9

WHEELS
DESCRIPTION
Original equipment wheels are designed for the
specified Maximum Vehicle Capacity.
All models use steel or aluminum wheels.
Aluminum wheels require special balance weights
and alignment equipment.
(1) On vehicles equipped with dual rear wheels,
The slots in the wheel must be aligned to provide
access to the valve stem.
OPERATION
The wheel (Fig. 19) has raised sections between
the rim flanges and the rim well. Initial inflation of
the tire forces the bead over these raised sections. In
case of tire failure, the raised sections hold the tire
in position on the wheel until the vehicle can be
brought to a safe stop.
DIAGNOSIS AND TESTING
WHEEL INSPECTION
Inspect wheels for:
²Excessive run out
²Dents or cracks
²Damaged wheel lug nut holes
²Air Leaks from any area or surface of the rim
NOTE: Do not attempt to repair a wheel by hammer-
ing, heating or welding.
If a wheel is damaged an original equipment
replacement wheel should be used. When obtaining
replacement wheels, they should be equivalent in
load carrying capacity. The diameter, width, offset,pilot hole and bolt circle of the wheel should be the
same as the original wheel.
WARNING: FAILURE TO USE EQUIVALENT
REPLACEMENT WHEELS MAY ADVERSELY
AFFECT THE SAFETY AND HANDLING OF THE
VEHICLE. USED WHEELS ARE NOT RECOM-
MENDED. THE SERVICE HISTORY OF THE WHEEL
MAY HAVE INCLUDED SEVERE TREATMENT OR
VERY HIGH MILEAGE. THE RIM COULD FAIL WITH-
OUT WARNING.
STANDARD PROCEDURE
STANDARD PROCEDURE - WHEEL REPLACE-
MENT
The wheel stud/lugs are designed for specific appli-
cations. They must be replaced with equivalent parts.
Do not use replacement parts of lesser quality or a
substitute design.
Before installing the wheel, be sure to remove any
build up of corrosion on the wheel mounting surfaces.
Ensure wheels are installed with good metal-to-metal
contact. Improper installation could cause loosening
of wheel nuts. This could affect the safety and han-
dling of your vehicle.
To install the wheel, first position it properly on
the mounting surface. All wheel nuts should then be
tightened just snug. Gradually tighten them in
sequence to the proper torque specification.Never
use oil or grease on studs.
Wheels must be replaced if they have:
²Excessive runout
²Bent or dented
²Leak air through welds
²Have damaged bolt holes
Wheel repairs employing hammering, heating, or
welding are not allowed.
Original equipment wheels are available through
your dealer. Replacement wheels from any other
source should be equivalent in:
²Load carrying capacity
²Diameter
²Width
²Offset
²Mounting configuration
Failure to use equivalent replacement wheels may
affect the safety and handling of your vehicle.
Replacement withusedwheels is not recommended.
Their service history may have included severe treat-
ment.
STANDARD PROCEDURE - DUAL REAR WHEEL
INSTALLATION
The tires on both wheels must be completely raised
off the ground when tightening the lug nuts. This
Fig. 19 Safety Rim
1 - FLANGE
2 - RIDGE
3 - WELL
VATIRES/WHEELS 22 - 13