ONBOARD DIAGNOSTIC SYSTEM (OBD II)
Vehicles equipped with California emissions controls
have a sophisticated onboard diagnostic system called
OBDII. This system monitors the performance of the
emissions, engine, and automatic transmission control
systems. When these systems are operating properly,
your vehicle will provide excellent performance and fuel
economy, as well as engine emissions well within current
government regulations.
If any of these systems require service, the OBD II system
will turn on the “Malfunction Indicator Light.” It will
also store diagnostic codes and other information to
assist your service technician in making repairs. Al-
though your vehicle will usually be driveable and not
need towing, see your dealer for service as soon as
possible.CAUTION!
Prolonged driving with the “Malfunction Indicator
Light” on could cause further damage to the emis-
sion control system. It could also affect fuel economy
and driveability. The vehicle must be serviced before
any emissions tests can be performed.
If the “Malfunction Indicator Light” is flashing,
severe catalytic converter damage and power loss
will soon occur. Immediate service is required.
REPLACEMENT PARTS
Use of genuine Moparparts for normal/scheduled
maintenance and repairs is highly recommended to in-
sure the designed performance. Damage or failures
caused by the use of non-Mopar parts for maintenance
and repairs will not be covered by the manufacturer’s
warranty.
MAINTAINING YOUR VEHICLE 375
7
CAUTION!
To maintain your vehicle safely follow these guide-
lines:
•Watch your vehicle’s mileage and check yourMainte-
nance Schedulesregularly for required servicing. Ex-
cessive wear or damage to certain vehicle components
can result if required services are not performed.
•If you have your vehicle undercoated, inspect for
undercoating material on the propeller shafts. Such
material could cause the shafts to become unbalanced
and result in drivetrain vibrations. Remove any under-
coating with solvent.
•If you have your vehicle undercoated, make sure no
undercoating material is sprayed on the exhaust sys-
tem or components of the seat belt system.NOTE:It is not possible for the manufacturer and
Cummins, Inc. to anticipate every possible circumstance
that can involve a potential hazard.
WARNING!
To maintain your vehicle safely and avoid personal
injury, follow these guidelines:
•Never spray or pour diesel fuel, flammable liquid or
starting fluids (ether) into the air cleaner assembly, air
intake piping or turbocharger inlet in an attempt to
start the vehicle.
•Do not use alcohol or gasoline as a fuel blending agent.
They can be unstable under certain conditions and be
hazardous or explosive when mixed with diesel fuel.
MAINTAINING YOUR VEHICLE 377
7
•Driving in dusty conditions.
•Frequent trailer towing.
•Taxi, police, or delivery service (commercial service).
•Off-road or desert operation.
•Extensive operation at high engine speeds (greater
than 2900 rpm) and loads (greater than 70% throttle).
IfANYof these apply to you, then change your engine oil
at every interval shown in scheduleBof theMainte-
nance Schedulessection of this manual.
If none of these apply to you, then change your engine oil
at every interval shown on scheduleAof theMainte-
nance Schedulessection of this manual.
NOTE:Most vehicles are operated under the conditions
listed for ScheduleB.
Engine Oil Selection
1. Engine Oil Quality
Use only oils conforming to API Ser-
vice CI-4. A sulfated ash limit is speci-
fied for lubrication oil used in Cum-
mins engines. Oils with a high ash
content may produce deposits on
valves that can progress to guttering
and valve burning. A maximum sul-
fated ash content of 1.85 mass % is recommended for all
oil used in the engine.
2. Engine Oil Viscosity (SAE Grade)
The proper SAE viscosity of engine oil for the expected
ambient temperature range should be selected, as indi-
cated in the following chart:
MAINTAINING YOUR VEHICLE 381
7
Front Prop Shaft Lubrication
Lubricate the front driveshaft grease fitting at each oil
change listed in the appropriate Maintenance Schedule
for your vehicle (Schedule “A” and “B”). Use Mopar
type MS-6560 (lithium based grease), or equivalent.
Front Axle Universal Drive Joints And Pivot
Bearings
The front axle universal joint and pivot bearings are
permanently lubricated and do not require servicing.
Body Lubrication
Locks and all body pivot points, including such items as
seat tracks, doors, liftgate and hood hinges, should be
lubricated periodically to assure quiet, easy operation
and to protect against rust and wear. Prior to the appli-
cation of any lubricant, the parts concerned should be
wiped clean to remove dust and grit; after lubricating
excess oil and grease should be removed. Particular
attention should also be given to hood latching compo-
nents to insure proper function. When performing other
underhood services, the hood latch, release mechanism
and safety catch should be cleaned and lubricated.
The external lock cylinders should be lubricated twice a
year, preferably in the fall and spring. Apply a small
Front Driveshaft Grease Fitting
394 MAINTAINING YOUR VEHICLE
Extremely cold ambient temperature may require the
addition of a “winter front” for effective operation of the
cab heating/cooling system. Make certain that a percent-
age of the radiator is exposed for adequate air flow
through the charge air cooler and automatic transmission
oil cooler. The percentage of opening must be increased
with the increasing ambient air temperature and/or
engine load. If the cooling fan can be heard cycling
frequently, increase the size of the opening in the winter
front.
Coolant bottle level check
The coolant reserve system provides a quick visual
method of determining that the coolant level is adequate.
With the engine idling, and warmed to the normal
operating temperature, the level of the coolant on the
coolant bottle should be between the fluid level marks.
Check the coolant level whenever the hood is raised.The radiator normally remains completely full, so there is
no longer a need to remove the coolant pressure cap
except for checking coolant freeze point or replacement
with new antifreeze coolant.
WARNING!
Never add coolant to the radiator when the engine is
overheated. Do not loosen or remove pressure cap to
cool overheated engine! The coolant is under pres-
sure and severe scalding could result.
Drain, Flush And Refill
At intervals shown on the Maintenance Schedules, the
system should be drained, flushed and refilled. Refer to
your dealer or consult a service manual for proper
procedures.
398 MAINTAINING YOUR VEHICLE
Drain And Refill
Vehicles operated in normal service do not have regularly
scheduled oil changes. If fluid has become contaminated
with water or subjected to severe service, follow the
recommended change intervals in Maintenance Schedule
“B” in Section 8 of this manual.
Lubricant Selection
Refer to Fluids, Lubricants and Genuine Parts for the
correct lubricant type.
NOTE:The presence of water in the gear lubricant will
result in corrosion and possible failure of differential
components. Operation of the vehicle in water, as may be
encountered in some off-highway types of service, will
require draining and refilling the axle to avoid damage.
Limited-Slip Differentialsin vehicles equipped with
10.5”/11.5” AxlesDO NOT REQUIREany limited slip
oil additive (friction modifiers).
Transfer Case — If Equipped
Fluid Level Check
This fluid level can be checked by removing the filler
plug. The fluid level should be to the bottom edge of the
filler plug hole with the vehicle in a level position.
Lubricant Selection
Refer to Fluids, Lubricants and Genuine Parts for the
correct lubricant type.
Manual Transmission — If Equipped
Fluid Level Check
This fluid level can be checked by removing the filler
plug. If the level of the lubricant is more than 1/4” below
the bottom of the filler hole while the vehicle is on level
ground, enough lubricant should be added to bring the
level to the bottom of the filler hole.
406 MAINTAINING YOUR VEHICLE
or suspected. Proper maintenance of the entire vehicle
will help the effectiveness of the noise control systems.
Exhaust System
Inspect the entire exhaust system for leaks and damaged
parts. Devices such as hangers, clamps, and U-bolts
should be tight and in good condition. Damaged compo-
nents, burned or blown out mufflers, burned or rusted
out exhaust pipes should be replaced according to the
procedures and specifications outlined in the appropriate
service manual.
Air Cleaner Assembly
Inspect air cleaner housing for proper assembly and fit.
Make certain that the air cleaner is properly positioned
and that the cover is tight. Check all hoses leading to the
air cleaner for tightness. The air filter element must also
be clean and serviced according to the instructions out-
lined in the Maintenance Schedule Section of this
manual.Tampering With Noise Control System Prohibited
Federal law prohibits the following acts or the causing
thereof: (1) the removal or rendering inoperative by any
person, other than for purposes of maintenance, repair, or
replacement, of any device or element of design incorpo-
rated into any new vehicle for the purpose of noise
control prior to its sale or delivery to the ultimate
purchaser or while it is in use, or (2) the use of the vehicle
after such device or element of design has been removed
or rendered inoperative by any person.
Among those acts presumed to constitute tampering are
the acts listed below.
•AIR CLEANER
Removal of the air cleaner.
Removal of the air cleaner filter element from the air
cleaner housing.
Removal of the air ducting.
412 MAINTAINING YOUR VEHICLE
EMISSION CONTROL SYSTEM MAINTENANCE
The “Scheduled” maintenance services, listed inbold
typein this section (Section 8) must be done at the times
or mileages specified to assure the continued proper
functioning of the emission control system. These, and all
other maintenance services included in this manual,
should be done to provide best vehicle performance and
reliability. More frequent maintenance may be needed for
vehicles in severe operating conditions such as dusty
areas and very short trip driving.
Inspection and service also should be done any time a
malfunction is suspected.
NOTE:Maintenance, replacement, or repair of the emis-
sion control devices and systems on your vehicle may be
performed by any automotive repair establishment or
individual using any automotive part which has been
certified pursuant to U.S. EPA or, in the State of Califor-
nia, California Air Resources Board regulations.
MAINTENANCE SCHEDULES — 24–VALVE
CUMMINS TURBO DIESEL
There are two maintenance schedules that show the
requiredservice for your vehicle.
First is Schedule“B”. It is for vehicles that are operated
under one or more of the following conditions that are
listed below and at the beginning of the schedule.
•Frequent short trips where the engine does not achieve
full operating temperature (operating temperature de-
fined as 190° F (66° C ) coolant temperature).
•Extensive engine idling (over 10 minutes per hour of
operation) at ambient temperatures less than 32° F (0°
C).
•Driving in dusty conditions.
•Frequent trailer towing.
•Taxi, police, or delivery service (commercial service).
442 MAINTENANCE SCHEDULES
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