2003 GMC ENVOY fuel

SERVICE BRAKE SYSTEM
If a problem occurs with the brake system this message
will appear on the DIC. If this message appears, stop
as soon as possible and turn off the vehicle. Restart the
vehicle and check for the message on the DIC display.
If the message is still displayed, or appears again when
you begin driving, the brake system needs service.
TURN SIGNAL ON
If a turn signal is left on for 3/4 of a mile (1.2 km), this
message will appear on the display and you will
hear a chime. Move the turn signal/multifunction lever to
the off position. Pressing the select button will
acknowledge this message and clear it from the DIC
display.
REAR ACCESS OPEN
If the liftgate or liftglass is open while the ignition is in
RUN, this message will appear on the DIC and you will
hear a chime. Turn off the vehicle and check the
liftgate and liftglass. Restart the vehicle and check for
the message on the DIC display. Pressing the select
button will acknowledge this message and clear it from
the DIC display.
FUEL LEVEL LOW
If the fuel level is low in the vehicle's gas tank this
message will appear on the DIC and you will hear a
chime. Refuel as soon as possible. Pressing the select
button will acknowledge this message and clear it
from the DIC display.
CHECK WASHER FLUID
If the washer ¯uid level is low, this message will appear
on the DIC. Adding washer ¯uid will clear the message.
Pressing the select button will acknowledge this
message and clear it from the DIC display.
TRANS HOT IDLE ENGINE
If the transmission ¯uid in the vehicle gets hot, this
message will appear on the DIC. Driving with the
transmission ¯uid temperature high can cause damage
to the vehicle. Stop the vehicle and let it idle to allow
the transmission to cool. This message will clear when
the ¯uid temperature reaches a safe level.
3-61

Off-Road Driving with Your
Four-Wheel-Drive Vehicle
This off-road guide is for vehicles that have four-wheel
drive. Also, seeBraking on page 4-5. If your vehicle
doesn't have four-wheel drive, you shouldn't drive
off-road unless you're on a level, solid surface.
Off-road driving can be great fun. But it does have
some de®nite hazards. The greatest of these is
the terrain itself.
ªOff-roadingº means you've left the great North American
road system behind. Traffic lanes aren't marked.
Curves aren't banked. There are no road signs.
Surfaces can be slippery, rough, uphill or downhill. In
short, you've gone right back to nature.
Off-road driving involves some new skills. And that's
why it's very important that you read this guide.
You'll ®nd many driving tips and suggestions. These will
help make your off-road driving safer and more
enjoyable.
Before You Go Off-Roading
There are some things to do before you go out. For
example, be sure to have all necessary maintenance
and service work done. Check to make sure all
underbody shields (if so equipped) are properly
attached.
Be sure you read all the information about your
four-wheel-drive vehicle in this manual.
Is there enough fuel? Is the spare tire fully in¯ated? Are
the ¯uid levels up where they should be? What are
the local laws that apply to off-roading where you'll be
driving? If you don't know, you should check with
law enforcement people in the area. Will you be on
someone's private land? If so, be sure to get the
necessary permission.
4-15

After Off-Road Driving
Remove any brush or debris that has collected on the
underbody, chassis or under the hood. These
accumulations can be a ®re hazard.
After operation in mud or sand, have the brake linings
cleaned and checked. These substances can cause
glazing and uneven braking. Check the body structure,
steering, suspension, wheels, tires and exhaust
system for damage. Also, check the fuel lines and
cooling system for any leakage.
Your vehicle will require more frequent service due to
off-road use. Refer to the Maintenance Schedule
for additional information.
Driving at Night
Night driving is more dangerous than day driving.
One reason is that some drivers are likely to be
impaired Ð by alcohol or drugs, with night vision
problems, or by fatigue.
4-28

Once you are moving on the freeway, make certain you
allow a reasonable following distance. Expect to
move slightly slower at night.
When you want to leave the freeway, move to the
proper lane well in advance. If you miss your exit, do
not, under any circumstances, stop and back up. Drive
on to the next exit.
The exit ramp can be curved, sometimes quite sharply.
The exit speed is usually posted.
Reduce your speed according to your speedometer, not
to your sense of motion. After driving for any distance
at higher speeds, you may tend to think you are
going slower than you actually are.
Before Leaving on a Long Trip
Make sure you're ready. Try to be well rested. If you
must start when you're not fresh Ð such as after a day's
work Ð don't plan to make too many miles that ®rst
part of the journey. Wear comfortable clothing and shoes
you can easily drive in.Is your vehicle ready for a long trip? If you keep it
serviced and maintained, it's ready to go. If it needs
service, have it done before starting out. Of course,
you'll ®nd experienced and able service experts in GM
dealerships all across North America. They'll be
ready and willing to help if you need it.
Here are some things you can check before a trip:
·Windshield Washer Fluid:Is the reservoir full? Are
all windows clean inside and outside?
·Wiper Blades:Are they in good shape?
·Fuel, Engine Oil, Other Fluids:Have you checked
all levels?
·Lamps:Are they all working? Are the lenses clean?
·Tires:They are vitally important to a safe,
trouble-free trip. Is the tread good enough for
long-distance driving? Are the tires all in¯ated to the
recommended pressure?
·Weather Forecasts:What's the weather outlook
along your route? Should you delay your trip a
short time to avoid a major storm system?
·Maps:Do you have up-to-date maps?
4-35

{CAUTION:
Snow can trap exhaust gases under your
vehicle. This can cause deadly CO (carbon
monoxide) gas to get inside. CO could
overcome you and kill you. You can't see it or
smell it, so you might not know it is in your
vehicle. Clear away snow from around the
base of your vehicle, especially any that is
blocking your exhaust pipe. And check around
again from time to time to be sure snow
doesn't collect there.
Open a window just a little on the side of the
vehicle that's away from the wind. This will
help keep CO out.Run your engine only as long as you must. This saves
fuel. When you run the engine, make it go a little
faster than just idle. That is, push the accelerator
slightly. This uses less fuel for the heat that you get and
it keeps the battery charged. You will need a
well-charged battery to restart the vehicle, and possibly
for signaling later on with your headlamps. Let the
heater run for a while.
Then, shut the engine off and close the window almost
all the way to preserve the heat. Start the engine
again and repeat this only when you feel really
uncomfortable from the cold. But do it as little as
possible. Preserve the fuel as long as you can. To help
keep warm, you can get out of the vehicle and do
some fairly vigorous exercises every half hour or so until
help comes.
4-43

4. Shift the transfer case to NEUTRAL (N). See
ªFour-Wheel Driveº in the Index for the proper
procedure to select the NEUTRAL position for your
vehicle.
5. Release the parking brake only after the vehicle
being towed is ®rmly attached to the towing
vehicle.
6. Turn the ignition off and remove the key. If the key
is not removed, the battery will drain.
{CAUTION:
Shifting a four-wheel-drive vehicle's transfer
case into NEUTRAL can cause your vehicle to
roll even if the transmission is in Park (P). You
or others could be injured. Make sure the
parking brake is ®rmly set before you shift the
transfer case to NEUTRAL.
Dolly Towing
Your vehicle was not designed to be dolly towed. If you
need to tow your vehicle, see ªDinghy Towingº earlier
in this section.
Loading Your Vehicle
The Certi®cation/Tire label is found on the driver's door
edge, above the door latch. The label shows the
size of your original tires and the in¯ation pressures
needed to obtain the gross weight capacity of your
vehicle. This is called the Gross Vehicle Weight Rating
(GVWR). The GVWR includes the weight of the
vehicle, all occupants, fuel, cargo and trailer tongue
weight, if pulling a trailer.
The Certi®cation/Tire label also tells you the maximum
weights for the front and rear axles, called Gross
Axle Weight Rating (GAWR).
4-47

Trailering is different than just driving your vehicle by
itself. Trailering means changes in handling, durability
and fuel economy. Successful, safe trailering takes
correct equipment, and it has to be used properly.
That's the reason for this part. In it are many time-tested,
important trailering tips and safety rules. Many of
these are important for your safety and that of your
passengers. So please read this section carefully before
you pull a trailer.
If You Do Decide To Pull A Trailer
If you do, here are some important points:
·There are many different laws, including speed limit
restrictions, having to do with trailering. Make sure
your rig will be legal, not only where you live
but also where you'll be driving. A good source for
this information can be state or provincial police.
·Consider using a sway control if your trailer will
weigh 4,000 lbs. (1 816 kg) or less. You should
always use a sway control if your trailer will weigh
more than 4,000 lbs. (1 816 kg). You can ask a
hitch dealer about sway controls.
·Don't tow a trailer at all during the ®rst 500 miles
(800 km) your new vehicle is driven. Your engine,
axle or other parts could be damaged.
·Then, during the ®rst 500 miles (800 km) that you
tow a trailer, don't drive over 50 mph (80 km/h)
and don't make starts at full throttle. This helps your
engine and other parts of your vehicle wear in at
the heavier loads.
·With an automatic transmission, you can tow in
DRIVE (D). You may want to shift the transmission
to THIRD (3) or, if necessary, a lower gear
selection if the transmission shifts too often e.g.,
under heavy loads and/or hilly conditions.
Three important considerations have to do with weight:
·the weight of the trailer,
·the weight of the trailer tongue
·and the weight on your vehicle's tires.
4-51

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