2002 GMC SONOMA service

6-52 Uniform Tire Quality Grading
Quality grades can be found where applicable on the tire
sidewall between tread shoulder and maximum section
width. For example:
Treadwear 200 Traction AA Temperature A
The following information relates to the system
developed by the United States National Highway
Traffic Safety Administration, which grades tires by
treadwear, traction and temperature performance. (This
applies only to vehicles sold in the United States.) The
grades are molded on the sidewalls of most passenger
car tires. The Uniform Tire Quality Grading system does
not apply to deep tread, winter
-type snow tires,
space
-saver or temporary use spare tires, tires with
nominal rim diameters of 10 to 12 inches (25 to 30 cm),
or to some limited
-production tires.
While the tires available on General Motors passenger
cars and light trucks may vary with respect to these
grades, they must also conform to federal safety
requirements and additional General Motors Tire
Performance Criteria (TPC) standards.Treadwear
The treadwear grade is a comparative rating based on
the wear rate of the tire when tested under controlled
conditions on a specified government test course.
For example, a tire graded 150 would wear one and
a half (1 1/2) times as well on the government course
as a tire graded 100. The relative performance of tires
depends upon the actual conditions of their use,
however, and may depart significantly from the norm
due to variations in driving habits, service practices and
differences in road characteristics and climate.
Traction
-- AA, A, B, C
The traction grades, from highest to lowest, are AA, A,
B, and C. Those grades represent the tire's ability to stop
on wet pavement as measured under controlled
conditions on specified government test surfaces of
asphalt and concrete. A tire marked C may have poor
traction performance. Warning: The traction grade
assigned to this tire is based on straight
-ahead braking
traction tests, and does not include acceleration,
cornering, hydroplaning, or peak traction characteristics.

6-63
Finish Damage
Any stone chips, fractures or deep scratches in the finish
should be repaired right away. Bare metal will corrode
quickly and may develop into a major repair expense.
Minor chips and scratches can be repaired with touch
-up
materials available from your dealer or other service
outlets. Larger areas of finish damage can be corrected
in your dealer's body and paint shop.
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.

6-65
Vehicle Identification Number (VIN)
This is the legal identifier for your vehicle. It appears on
a plate in the front corner of the instrument panel, on the
driver's side. You can see it if you look through the
windshield from outside your vehicle. The VIN also
appears on the Vehicle Certification and Service Parts
labels and the certificates of title and registration.
Engine Identification
The 8th character in your VIN is the engine code.
This code will help you identify your engine,
specifications and replacement parts.
Service Parts Identification Label
You'll find this label on the inside of the glove box.
It's very helpful if you ever need to order parts. On this
label is:

your VIN,

the model designation,

paint information and

a list of all production options and special
equipment.
Be sure that this label is not removed from the vehicle.

6-73
Automatic Transmission
Drain and Refill 5.0 quarts (4.7 L). . . . . . . . . . . . . .
Differential Fluid
Rear Axle 4.0 pints (1.9 L). . . . . . . . . . . . . . . . . . .
Front Axle 2.6 pints (1.2 L). . . . . . . . . . . . . . . . . . .
All capacities are approximate. After refill, the level
must be checked.
All capacities are approximate. When adding, be sure to
fill to the appropriate level or as recommended in this
manual. See ªRecommended Fluids and Lubricantsº in
the Index.
ªVORTECº 2200 L4 (VIN Code 5)
Engine Specifications
Type L4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Firing Order 1
-3-4-2 . . . . . . . . . . . . . . . . . . . . . . . . . .
Spark Plug Gap 0.040 inches (1.01 mm). . . . . . . . . .
ªVORTECº 4300 V6 (VIN Code W)
Engine Specifications
Type V6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Firing Order 1
-6-5-4-3-2 . . . . . . . . . . . . . . . . . . . . . .
Spark Plug Gap 0.060 inches (1.52 mm). . . . . . . . . .
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.
Air Conditioning
Refrigerant R134a 1.8 lbs (.79 kg). . . . . . . . . . . .
Use Refrigerant Oil, R134a Systems

7-
7-1
Section 7 Maintenance Schedule
This section covers the maintenance required for your vehicle. Your vehicle needs these services to retain its safety,
dependability and emission control performance.
7
-2 Introduction
7
-4 Part A: Scheduled Maintenance Services
7
-8 Short Trip/City Scheduled Maintenance
7
-32 Long Trip/Highway Scheduled Maintenance7
-45 Part B: Owner Checks and Services
7
-51 Part C: Periodic Maintenance Inspections
7
-53 Part D: Recommended Fluids and Lubricants
7
-56 Part E: Maintenance Record

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.

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.

are driven off
-road in the recommended manner. See
ªOff
-Road Driving With Your Four-Wheel-Drive
Vehicleº in the Index.

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:

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).

Your vehicle has the 2200 L4 (Code 5) flexible
fuel engine and you have used ethanol fuel
(85% Ethanol/E
-85).

You frequently tow a trailer.

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 Service.
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
(4.3L V6 engine only).
Every 50,000 Miles (83 000 km): Automatic
Transmission Service (normal conditions).
Every 60,000 Miles (100 000 km): Engine Accessory
Drive Belt Inspection.
(Continued)