2003 GMC ENVOY octane

Have you recently changed brands of fuel?
If so, be sure to fuel your vehicle with quality fuel. See
Gasoline Octane on page 5-4. Poor fuel quality will
cause your engine not to run as efficiently as designed.
You may notice this as stalling after start-up, stalling
when you put the vehicle into gear, mis®ring, hesitation
on acceleration or stumbling on acceleration. (These
conditions may go away once the engine is warmed up.)
This will be detected by the system and cause the
light to turn on.
If you experience one or more of these conditions,
change the fuel brand you use. It will require at least
one full tank of the proper fuel to turn the light off.
If none of the above steps have made the light turn off,
your dealer can check the vehicle. Your dealer has
the proper test equipment and diagnostic tools to ®x any
mechanical or electrical problems that may have
developed.
Emissions Inspection and Maintenance
Programs
Some state/provincial and local governments have or
may begin programs to inspect the emission control
equipment on your vehicle. Failure to pass this
inspection could prevent you from getting a vehicle
registration.
Here are some things you need to know to help your
vehicle pass an inspection:
Your vehicle will not pass this inspection if the SERVICE
ENGINE SOON or CHECK ENGINE light is on or not
working properly.
Your vehicle will not pass this inspection if the OBD
(on-board diagnostic) system determines that critical
emission control systems have not been completely
diagnosed by the system. The vehicle would be
considered not ready for inspection. This can happen if
you have recently replaced your battery or if your
battery has run down. The diagnostic system is
designed to evaluate critical emission control systems
during normal driving. This may take several days
of routine driving. If you have done this and your vehicle
still does not pass the inspection for lack of OBD
system readiness, your GM dealer can prepare the
vehicle for inspection.
3-44

Service............................................................5-3
Doing Your Own Service Work.........................5-3
Adding Equipment to the Outside of Your
Vehicle......................................................5-4
Fuel................................................................5-4
Gasoline Octane............................................5-4
Gasoline Speci®cations....................................5-5
California Fuel...............................................5-5
Additives.......................................................5-6
Fuels in Foreign Countries...............................5-7
Filling Your Tank............................................5-7
Filling a Portable Fuel Container.......................5-9
Checking Things Under the Hood....................5-10
Hood Release..............................................5-10
Engine Compartment Overview.......................5-12
Engine Oil...................................................5-15
Engine Air Cleaner/Filter................................5-20
Automatic Transmission Fluid.........................5-21
Engine Coolant.............................................5-24
Radiator Pressure Cap..................................5-26
Engine Overheating.......................................5-27
Cooling System............................................5-29
Engine Fan Noise.........................................5-35
Power Steering Fluid.....................................5-36
Windshield Washer Fluid................................5-37Brakes........................................................5-38
Battery........................................................5-41
Jump Starting...............................................5-42
Rear Axle.......................................................5-48
Four-Wheel Drive............................................5-48
Bulb Replacement..........................................5-50
Halogen Bulbs..............................................5-50
Headlamps..................................................5-50
Front Turn Signal and Sidemarker Lamps........5-51
Taillamps and Turn Signal Lamps...................5-51
Replacement Bulbs.......................................5-52
Windshield Wiper Blade Replacement..............5-52
Tires..............................................................5-54
In¯ation -- Tire Pressure................................5-55
Tire Inspection and Rotation...........................5-55
When It Is Time for New Tires.......................5-57
Buying New Tires.........................................5-58
Uniform Tire Quality Grading..........................5-59
Wheel Alignment and Tire Balance..................5-60
Wheel Replacement......................................5-60
Tire Chains..................................................5-62
Accessory In¯ator.........................................5-62
If a Tire Goes Flat........................................5-64
Changing a Flat Tire.....................................5-64
Section 5 Service and Appearance Care
5-1

CAUTION: (Continued)
·
Be sure to use the proper nuts, bolts and
other fasteners. ªEnglishº and ªmetricº
fasteners can be easily confused. If you
use the wrong fasteners, parts can later
break or fall off. You could be hurt.
Adding Equipment to the Outside of
Your Vehicle
Things you might add to the outside of your vehicle can
affect the air¯ow around it. This may cause wind
noise and affect windshield washer performance. Check
with your dealer before adding equipment to the
outside of your vehicle.
Fuel
Use of the recommended fuel is an important part of the
proper maintenance of your vehicle.
Gasoline Octane
Use regular unleaded gasoline with a posted octane
of 87 or higher. If the octane is less than 87, you may
get a heavy knocking noise when you drive. If this
occurs, use a gasoline rated at 87 octane or higher as
soon as possible. Otherwise, you might damage
your engine. A little pinging noise when you accelerate
or drive uphill is considered normal. This does not
indicate a problem exists or that a higher-octane fuel is
necessary. If you are using 87 octane or higher-octane
fuel and hear heavy knocking, your engine needs
service.
5-4

Additives
To provide cleaner air, all gasolines in the United States
are now required to contain additives that will help
prevent engine and fuel system deposits from forming,
allowing your emission control system to work
properly. You should not have to add anything to your
fuel. Gasolines containing oxygenates, such as
ethers and ethanol, and reformulated gasolines may be
available in your area to contribute to clean air.
General Motors recommends that you use these
gasolines, particularly if they comply with the
speci®cations described earlier.
Notice:Your vehicle was not designed for fuel that
contains methanol. Don't use fuel containing
methanol. It can corrode metal parts in your fuel
system and also damage the plastic and rubber
parts. That damage wouldn't be covered under your
warranty.Some gasolines that are not reformulated for low
emissions may contain an octane-enhancing additive
called methylcyclopentadienyl manganese tricarbonyl
(MMT); ask the attendant where you buy gasoline
whether the fuel contains MMT. General Motors does
not recommend the use of such gasolines. Fuels
containing MMT can reduce the life of spark plugs and
the performance of the emission control system may
be affected. The malfunction indicator lamp may turn on.
If this occurs, return to your authorized GM dealer for
service.
5-6

Part A: Scheduled Maintenance
Services
This part contains engine oil scheduled maintenance
which explains the engine oil life system and how
it indicates when to change the engine oil and ®lter.
Also, listed are scheduled maintenance services which
are to be performed at the mileage intervals speci®ed.
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 to schedule them.
When 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 ¯uids 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.
This schedule is for vehicles that:·carry passengers and cargo within recommended
limits. You will ®nd these limits on your vehicle's
Certi®cation/Tire label. See
Loading Your Vehicle on
page 4-47.
·are driven on reasonable road surfaces within legal
driving limits.
·are driven off-road in the recommended manner.
See
Off-Road Driving with Your Four-Wheel-Drive
Vehicle on page 4-15.
·use the recommended fuel. SeeGasoline Octane
on page 5-4
.
6-4

Extender, Safety Belt.......................................1-29
Exterior Lamps...............................................3-15
F
Filter.............................................................5-20
Engine Air Cleaner......................................5-20
Finding a PTY Station.....................3-67, 3-75, 3-84
Finding a Station............................3-65, 3-72, 3-82
Finish Care....................................................5-84
Finish Damage...............................................5-86
Fixed Mast Antenna.......................................3-107
Flash-to-Pass................................................... 3-9
Flat Tire, Changing.........................................5-64
Flat Tire........................................................5-64
Fluid.............................................................5-21
Automatic Transmission................................5-21
Power Steering...........................................5-36
Windshield Washer......................................5-37
FM ..............................................................3-105
Fog Lamps....................................................3-17
Following Distance..........................................4-57
Footnotes........................................................ 6-5
Four-Wheel Drive....................................2-25, 5-48
Front Axle......................................................5-49
Front Storage Area.........................................2-45
Fuel Information..............................................3-52
FUEL LEVEL LOW.........................................3-61
Fuel............................................................... 5-4Additives...................................................... 5-6
California Fuel.............................................. 5-5
Filling a Portable Fuel Container..................... 5-9
Filling Your Tank........................................... 5-7
Fuels in Foreign Countries.............................. 5-7
Gage.........................................................3-49
Gasoline Octane........................................... 5-4
Gasoline Speci®cations.................................. 5-5
Low Warning Light.......................................3-50
System Inspection.......................................6-16
Fuses...........................................................5-90
Fuses and Circuit Breakers...........................5-90
Windshield Wiper.........................................5-89
G
Gage............................................................3-48
Check Gages Warning Light..........................3-48
Engine Coolant Temperature.........................3-41
Fuel..........................................................3-49
Oil Pressure...............................................3-45
Speedometer..............................................3-36
Tachometer.................................................3-36
Voltmeter Gage...........................................3-39
Garage Door Opener.......................................2-40
Gasoline......................................................... 5-4
Octane........................................................ 5-4
Speci®cations............................................... 5-5
Gate Ajar Light...............................................3-49
6