Page 182 of 458
Oil Pressure Gage
The oil pressure gage shows the engine oil
pressure in psi (pounds per square inch) when the
engine is running. Canadian vehicles indicate
pressure in kPa (kilopascals).
Oil pressure may vary with engine speed, outside
temperature and oil viscosity, but readings
above the low pressure zone indicate the normal
operating range.A reading in the low pressure zone may be
caused by a dangerously low oil level or other
problem causing low oil pressure. Check your oil
as soon as possible.
{CAUTION:
Do not keep driving if the oil pressure is
low. If you do, your engine can become so
hot that it catches  re. You or others could
be burned. Check your oil as soon as
possible and have your vehicle serviced.
Notice:Lack of proper engine oil maintenance
may damage the engine. The repairs would
not be covered by your warranty. Always follow
the maintenance schedule in this manual for
changing engine oil.
United StatesCanada
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        Page 183 of 458

Change Engine Oil Light
This light is displayed
when your vehicle
needs to be serviced.
If your vehicle has a V8 engine and this light is
flashing, it indicates that the oil level is low.
When this light is on steady, your vehicle needs to
be serviced. SeeScheduled Maintenance
(Gasoline Engine) on page 405for more
information.
Once the engine oil has been changed, the
change engine oil light must be reset. Until it is
reset, the light will stay on for a while each time the
engine is started. For more information on
resetting the system, see “How to Reset the
Engine Oil Life System” underEngine Oil
Life System (Gasoline Engine) on page 306.
Security Light
The light will stay on until the engine starts. If the
light flashes, the Passlock®System has entered
a tamper mode. If the vehicle fails to start,
seePasslock
®on page 118.
If the light comes on continuously while driving
and stays on, there may be a problem with
the Passlock
®System. Your vehicle will not be
protected by Passlock®, and you should see your
GM dealer.
United StatesCanada
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        Page 286 of 458

Maintenance When Trailer Towing
Your vehicle will need service more often when
you’re pulling a trailer. See the Maintenance
Schedule for more on this. Things that are
especially important in trailer operation are
automatic transmission fluid (don’t overfill), engine
oil, axle lubricant, belt, cooling system and
brake system. Each of these is covered in this
manual, and the Index will help you find them
quickly. If you’re trailering, it’s a good idea
to review these sections before you start your trip.
Check periodically to see that all hitch nuts and
bolts are tight.
Trailer Wiring Harness
The optional heavy-duty trailer wiring package
includes a seven-wire harness assembly at the rear
of the vehicle and a four-wire harness assembly
under the left hand side of the instrument panel.
The seven-wire harness assembly is taped together
and located in a frame pocket at the driver side rear
left corner of the frame. The seven-wire harness
includes a 30-amp feed wire.Both harnesses come without connectors and
should be wired by a qualified electrical technician.
The technician can use the following color code
chart when connecting the wiring harness to your
trailer and trailer brake controller.
Seven-Wire Harness
•Light Green: Back-up lamps
•Brown: Parking lamps
•Yellow: Left stoplamp and turn signal
•Dark Green: Right stoplamp and turn signal
•Dark Blue: Use for electric trailer brakes
•Red/Black Stripe: Trailer accessory
•White (heavy gage): Ground wire
Four-Wire Harness (Trailer Brake Controller)
•Black: Ground
•Red/White Stripe: Fused Battery
•Dark Blue: Trailer Brake Feed
•Light Blue: Fused Stoplamp/CHMSL
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        Page 401 of 458

Maintenance Schedule................................ 402
Introduction............................................... 402
Maintenance Requirements........................ 402
Your Vehicle and the Environment............ 402
Using the Maintenance Schedule............... 403
Scheduled Maintenance
(Gasoline Engine).................................. 405
Additional Required Services
(Gasoline Engine).................................. 408
Maintenance Footnotes
(Gasoline Engine).................................. 409Owner Checks and Services..................... 411
At the First 100, 1,000 and 6,000 Miles
(160, 1 600 and 10 000 km).................. 411
At Each Fuel Fill....................................... 412
At Least Once a Month............................. 412
At Least Once a Year............................... 413
Recommended Fluids and Lubricants........ 415
Normal Maintenance
Replacement Parts................................. 417
Engine Drive Belt Routing......................... 418
Maintenance Record.................................. 419
Section 6 Maintenance Schedule
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        Page 404 of 458

The services inScheduled Maintenance (Gasoline
Engine) on page 405should be performed
when indicated. SeeAdditional Required Services
(Gasoline Engine) on page 408andMaintenance
Footnotes (Gasoline Engine) on page 409for
further information.
{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, see your GM
Goodwrench
®dealer to have a quali ed
technician do the work. SeeDoing Your
Own Service Work on page 291.
Some maintenance services can be complex.
So, unless you are technically qualified and have
the necessary equipment, you should have
your GM Goodwrench
®dealer do these jobs.When you go to your GM Goodwrench
®dealer for
your service needs, you will know that GM-trained
and supported service technicians will perform
the work using genuine GM parts.
If you want to purchase service information, see
Service Publications Ordering Information on
page 440.
Owner Checks and Services on page 411tells you
what should be checked, when to check it, and
what you can easily do to help keep your vehicle in
good condition.
The proper replacement parts, fluids, and
lubricants to use are listed inRecommended
Fluids and Lubricants on page 415andNormal
Maintenance Replacement Parts on page 417.
When your vehicle is serviced, make sure these
are used. All parts should be replaced and all
necessary repairs done before you or anyone else
drives the vehicle. We recommend the use of
genuine GM parts.
404 
     
        
        Page 405 of 458

Scheduled Maintenance
(Gasoline Engine)
This maintenance section applies to vehicles with
a gasoline engine. If your vehicle has a diesel
engine, see the maintenance schedule section in
the DURAMAX
®Diesel Engine Supplement.
When the change engine oil light comes on, it
means that service is required for your vehicle.
Have your vehicle serviced as soon as possible
within the next 600 miles (1 000 km). It is possible
that, if you are driving under the best conditions, the
engine oil life system may not indicate that vehicle
service is necessary for over a year. However, your
engine oil and filter must be changed at least once
a year and at this time the system must be reset.
Your dealer/retailer has trained service technicians
who will perform this work using genuine parts and
reset the system.If the engine oil life system is ever reset
accidentally, you must service your vehicle within
3,000 miles (5 000 km) since your last service.
Remember to reset the oil life system whenever
the oil is changed. SeeEngine Oil Life System
(Gasoline Engine) on page 306for information
on the Engine Oil Life System and resetting the
system.
When the change engine oil light appears, certain
services, checks, and inspections are required.
Required services are described in the following
for “MaintenanceI” and “MaintenanceII.”
Generally, it is recommended that your first
service be MaintenanceI, your second service
be MaintenanceII, and that you alternate
MaintenanceIand MaintenanceIIthereafter.
However, in some cases, MaintenanceIImay
be required more often.
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        Page 406 of 458

MaintenanceI— Use MaintenanceIif the
change engine oil light comes on within 10 months
since the vehicle was purchased or MaintenanceII
was performed.MaintenanceII— Use MaintenanceIIif the
previous service performed was MaintenanceI.
Always use MaintenanceIIwhenever the message
comes on 10 months or more since the last
service or if the message has not come on at
all for one year.
Scheduled Maintenance
Service MaintenanceIMaintenanceII
Change engine oil and filter. SeeEngine Oil (Gasoline Engine) on page 303.
Reset oil life system. SeeEngine Oil Life System (Gasoline Engine) on
page 306.An Emission Control Service.••
Lubricate chassis components.See footnote #.••
Visually check for any leaks or damage.See footnote (j).••
Inspect engine air cleaner filter. If necessary, replace filter. SeeEngine
Air Cleaner/Filter on page 308.See footnote (l).•
Rotate tires and check inflation pressures and wear. SeeTire Inspection and
Rotation on page 356and “Tire Wear Inspection” inAt Least Once a Month
on page 412.••
Inspect brake system.See footnote (a).••
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        Page 407 of 458
Scheduled Maintenance (cont’d)
Service MaintenanceIMaintenanceII
Check engine coolant and windshield washer fluid levels and add fluid as
needed.••
Perform any needed additional services. See “Additional Required Services”
in this section.••
Inspect suspension and steering components.See footnote (b).•
Inspect engine cooling system.See footnote (c).•
Inspect wiper blades.See footnote (d).•
Inspect restraint system components.See footnote (e).•
Lubricate body components.See footnote (f).•
Check transmission fluid level and add fluid as needed.•
Inspect shields, vehicles with GVWR above 10,000 lbs (4 536 kg) only.
See footnote (g).•
Inspect throttle system.See footnote (m).•
407