Page 323 of 400

6-63
Underbody Maintenance
Chemicals used for ice and snow removal and dust
control can collect on the underbody. If these are
not removed, accelerated corrosion (rust) can occur
on the underbody parts such as fuel lines, frame,
floor pan and exhaust system even though they have
corrosion protection.
At least every spring, flush these materials from the
underbody with plain water. Clean any areas where mud
and other debris can collect. Dirt packed in closed areas
of the frame should be loosened before being flushed.
Your dealer or an underbody car washing system can
do this for you.
Chemical Paint Spotting
Some weather and atmospheric conditions can create a
chemical fallout. Airborne pollutants can fall upon and
attack painted surfaces on your vehicle. This damage
can take two forms: blotchy, ringlet
-shaped
discolorations, and small irregular dark spots etched
into the paint surface.
Although no defect in the paint job causes this,
GM will repair, at no charge to the owner, the surfaces
of new vehicles damaged by this fallout condition
within 12 months or 12,000 miles (20 000 km) of
purchase, whichever occurs first.
Page 331 of 400

6-71
Relay Usage
A/C Relay
(Rear Heat
and A/C)Rear Heat and
Air Conditioning
Upfitter
-ACCY
RelayUpfitter Accessory
Starter
Enable RelayStarter
A/C Enable Relay Air Conditioning
Headlamps Relay Headlamps
Fuel Pump Relay Fuel Pump
Fuse/Circuit
BreakerUsage
UPFITTER
-BATT Upfitter Battery Power Stud,
Trailer Wiring Harness
UPFITTER
-ACCY Upfitter Accessory Relay
Spare Not used
Spare Not used
Spare Not used
ECM
-1B Fuel Pump Relay and Motor,
VCM, Oil Pressure Switch/SenderFuse/Circuit
BreakerUsage
HORN Horn Relay and Horn
A/C COMP A/C Enable Relay and
Compressor
RR HTR/AC Rear Heater and A/C
ATC Active Transfer Case
-L Van
FRT HVAC Front Heater and A/C
ENG
-I Oxygen Sensors, Camshaft
Position Sensor, Mass Air Flow
Sensor, Evaporative Emission
Canister Vent Solenoid
IGN
-E A/C Enable Relay Coil
ECM
-I Fuel Injectors 1-6, Crankshaft
Position Sensor, VCM,
Coil Driver Module (EST),
Ignition Coil
Blank Not Used
RH HDLMP Right Headlamp
LH Headlamp Left Headlamp
Blank Not Used
Blank Not Used
Page 334 of 400

6-74
Air Conditioning Refrigerant Capacity
If you do your own service work, you'll need the proper
service manual. See ªDoing Your Own Service Workº in
the Index for additional information. It is recommended
that service work on your air conditioning system be
performed by a qualified technician.
Refrigerant Type 134a
Front A/C 2.25 lbs. (1.02 kg). . . . . . . . . . . . . . . . . .
Front and Rear A/C 3.0 lbs. (1.36 kg). . . . . . . . . . . .
Use Refrigerant Oil, R134a Systems
Normal Maintenance
Replacement Parts
Replacement part numbers listed in this section are
based on the latest information available at the time of
printing, and are subject to change. If a part listed in this
manual is not the same as the part used in your vehicle
when it was built, or if you have any questions, please
contact your GM truck dealer.
Engine Oil Filter PF47*. . . . . . . . . . . . . . . . . . . . . . .
Engine Air Cleaner/Filter A1163C*. . . . . . . . . . . . . . .
Positive Crankcase Ventilation
(PCV) Valve CV769C*. . . . . . . . . . . . . . . . . . . . . .
Spark Plugs 41
-932* . . . . . . . . . . . . . . . . . . . . . . . . . .
Spark Plug Gap 0.060 inches (1.52 mm). . . . . . . . . .
Fuel Filter GF481*. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Wiper Blades (Front) Trico 22110158, Pin Type. . . . .
18 inches (45.7 cm) Length
Wiper Blade (Rear) Trico 22154396, Pin Type. . . . .
14 inches (35.5 cm) Length
*ACDelco
part number
Page 336 of 400

7-2
Have you purchased the GM Protection Plan? The Plan
supplements your new vehicle warranties. See your
Warranty and Owner Assistance booklet or your dealer
for details.
Introduction
Your Vehicle and the Environment
Proper vehicle maintenance not only helps to keep your
vehicle in good working condition, but also helps the
environment. All recommended maintenance procedures
are important. Improper vehicle maintenance can even
affect the quality of the air we breathe. Improper fluid
levels or the wrong tire inflation can increase the level
of emissions from your vehicle. To help protect our
environment, and to keep your vehicle in good
condition, please maintain your vehicle properly.
Maintenance Requirements
Maintenance intervals, checks, inspections and
recommended fluids and lubricants as prescribed in
this manual are necessary to keep your vehicle in good
working condition. Any damage caused by failure to
follow recommended maintenance may not be covered
by warranty.
Page 337 of 400

7-3 How This Section is Organized
This maintenance schedule is divided into five parts:
ªPart A: Scheduled Maintenance Servicesº explains
what to have done and how often. Some of these services
can be complex, so unless you are technically qualified
and have the necessary equipment, you should let your
dealer's service department or another qualified service
center do these jobs.
CAUTION:
Performing maintenance work on a vehicle can
be dangerous. In trying to do some jobs, you can
be seriously injured. Do your own maintenance
work only if you have the required know
-how
and the proper tools and equipment for the job.
If you have any doubt, have a qualified
technician do the work.
If you want to get the service information, see ªService
and Owner Publicationsº in the Index.ªPart B: Owner Checks and Servicesº tells you
what should be checked and when. It also explains
what you can easily do to help keep your vehicle in
good condition.
ªPart C: Periodic Maintenance Inspectionsº explains
important inspections that your dealer's service
department or another qualified service center
should perform.
ªPart D: Recommended Fluids and Lubricantsº lists
some recommended products necessary to help keep
your vehicle properly maintained. These products, or
their equivalents, should be used whether you do the
work yourself or have it done.
ªPart E: Maintenance Recordº is a place for you
to record and keep track of the maintenance performed
on your vehicle. Keep your maintenance receipts.
They may be needed to qualify your vehicle for
warranty repairs.
Page 338 of 400

7-4
Part A: Scheduled
Maintenance Services
Using Your Maintenance Schedule
We at General Motors want to help you keep your
vehicle in good working condition. But we don't know
exactly how you'll drive it. You may drive very short
distances only a few times a week. Or you may drive
long distances all the time in very hot, dusty weather.
You may use your vehicle in making deliveries.
Or you may drive it to work, to do errands or in
many other ways.
Because of all the different ways people use their
vehicles, maintenance needs vary. You may need more
frequent checks and replacements. So please read the
following and note how you drive. If you have any
questions on how to keep your vehicle in good
condition, see your dealer.
This part tells you the maintenance services you should
have done and when you should schedule them. If you
go to your dealer for your service needs, you'll know
that GM
-trained and supported service people will
perform the work using genuine GM parts.The proper fluids and lubricants to use are listed in
Part D. Make sure whoever services your vehicle
uses these. All parts should be replaced and all
necessary repairs done before you or anyone else
drives the vehicle.
These schedules are for vehicles that:
carry passengers and cargo within recommended
limits. You will find these limits on your vehicle's
Certification/Tire label. See ªLoading Your Vehicleº
in the Index.
are driven on reasonable road surfaces within legal
driving limits.
use the recommended fuel. See ªFuelº in the Index.
Selecting the Right Schedule
First you'll need to decide which of the two schedules
is right for your vehicle. Here's how to decide which
schedule to follow:
Page 339 of 400

Scheduled Maintenance
7-5
Short Trip/City Definition
Follow the Short Trip/City Scheduled Maintenance if
any one of these conditions is true for your vehicle:
Most trips are less than 5 miles (8 km). This is
particularly important when outside temperatures are
below freezing.
Most trips include extensive idling (such as frequent
driving in stop
-and-go traffic).
You frequently tow a trailer or use a carrier on top of
your vehicle.
If the vehicle is used for delivery service, police, taxi
or other commercial application.
One of the reasons you should follow this schedule
if you operate your vehicle under any of these
conditions is that these conditions cause engine
oil to break down sooner.
Short Trip/City Intervals
Every 3,000 Miles (5 000 km): Engine Oil and
Filter Change (or 3 months, whichever occurs first).
Chassis Lubrication (or 3 months, whichever occurs
first). Drive Axle Fluid Check.
Every 6,000 Miles (10 000 km): Tire Rotation.
Every 15,000 Miles (25 000 km): Engine Air Cleaner
Filter Inspection, if driving in dusty conditions.
Front Wheel Bearing Repack (2WD only) (or at each
brake relining, whichever occurs first). Automatic
Transmission Service (severe conditions only).
Every 30,000 Miles (50 000 km): Engine Air Cleaner
Filter Replacement. Fuel Filter Replacement.
Every 50,000 Miles (83 000 km): Automatic
Transmission Service (normal conditions).
Transfer Case Fluid Change.
Every 60,000 Miles (100 000 km): Engine Accessory
Drive Belt Inspection.
Page 341 of 400

Scheduled Maintenance
7-7
Long Trip/Highway Intervals
Every 7,500 Miles (12 500 km): Engine Oil and Filter
Change (or every 12 months, whichever occurs first).
Chassis Lubrication (or every 12 months, whichever
occurs first). Drive Axle Fluid Check. Tire Rotation.
Every 15,000 Miles (25 000 km): Automatic
Transmission Service (severe conditions only).
Every 30,000 Miles (50 000 km): Fuel Filter
Replacement. Engine Air Cleaner Filter Replacement.
Front Wheel Bearing Repack (2WD only)
(or at each brake relining, whichever occurs first).
Every 50,000 Miles (83 000 km): Automatic
Transmission Service (normal conditions).
Transfer Case Fluid Change.
Long Trip/Highway Intervals
Every 60,000 Miles (100 000 km): Engine Accessory
Drive Belt Inspection.
Every 100,000 Miles (166 000 km): Spark Plug Wire
Inspection. Spark Plug Replacement. Positive
Crankcase Ventilation (PCV) Valve Inspection.
Every 150,000 Miles (240 000 km): Cooling System
Service (or every 60 months, whichever occurs first).
These intervals only summarize maintenance services.
Be sure to follow the complete scheduled maintenance
on the following pages.