brake GMC ENVOY 2004 Workshop Manual

Parking on Hills
{CAUTION:
You really should not park your vehicle, with a
trailer attached, on a hill. If something goes
wrong, your rig could start to move. People
can be injured, and both your vehicle and the
trailer can be damaged.
But if you ever have to park your rig on a hill, here’s
how to do it:
1. Apply your regular brakes, but don’t shift into
PARK (P) yet. When parking uphill, turn your wheels
away from the curb. When parking downhill, turn
your wheels into the curb.
2. Have someone place chocks under the trailer
wheels.
3. When the wheel chocks are in place, release the
regular brakes until the chocks absorb the load.
4. Reapply the regular brakes. Then apply your
parking brake, and then shift into PARK (P).
5. Release the regular brakes.
{CAUTION:
It can be dangerous to get out of your vehicle
if the shift lever is not fully in PARK (P) with
the parking brake rmly set. Your vehicle
can roll.
If you have left the engine running, the vehicle
can move suddenly. You or others could be
injured. To be sure your vehicle won’t move,
even when you’re on fairly level ground, use
the steps that follow.
Always put the shift lever fully in PARK (P)
with the parking brake rmly set.
If the transfer case on four-wheel drive
vehicles is in NEUTRAL, your vehicle will be
free to roll, even if your shift lever is in PARK
(P). So, be sure the transfer case is in a drive
gear — not in NEUTRAL.
See “Four-Wheel Drive (Automatic Transfer
Case)” in the Index.
4-64

When You Are Ready to Leave After
Parking on a Hill
1. Apply your regular brakes and hold the pedal down
while you:
start your engine,
shift into a gear, and
release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the
chocks.
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 uid (don’t overll),
engine oil, axle lubricant, belt(s), cooling system and
brake system. Each of these is covered in this manual,
and the Index will help you nd 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.
4-65

Trailer Wiring Harness
Your vehicle may be equipped with the seven-wire
trailer towing harness. This harness has a seven-pin
universal heavy-duty trailer connector that is attached to
a bracket on the hitch platform. The seven-wire
harness contains the following trailer circuits:
Yellow: Left Stop/Turn Signal
Dark Green: Right Stop/Turn Signal
Brown: Running Lamps
White: Ground
Light Green: Back-up Lamps
Red: Battery Feed
Dark Blue: Electric Brakes
If you need to tow a light-duty trailer with a standard
four-way round pin connector, an adapter connector is
available from your dealer.
Your vehicle may also be equipped with wiring for an
electric trailer brake controller. These wires are located
inside the vehicle on the driver’s side under the
instrument panel. These wires should be connected to
an electric trailer brake controller by your dealer or
a qualied service center.
4-66

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 Specications....................................5-5
California Fuel...............................................5-5
Additives.......................................................5-6
Fuels in Foreign Countries...............................5-6
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...................................................5-16
Engine Air Cleaner/Filter................................5-21
Automatic Transmission Fluid.........................5-22
Engine Coolant.............................................5-25
Radiator Pressure Cap..................................5-27
Engine Overheating.......................................5-28
Cooling System............................................5-29
Engine Fan Noise.........................................5-36Power Steering Fluid.....................................5-37
Windshield Washer Fluid................................5-38
Brakes........................................................5-39
Battery........................................................5-42
Jump Starting...............................................5-43
Rear Axle.......................................................5-49
Four-Wheel Drive............................................5-50
Front Axle......................................................5-51
Bulb Replacement..........................................5-52
Halogen Bulbs..............................................5-52
Headlamps..................................................5-52
Front Turn Signal and Sidemarker Lamps........5-52
Taillamps and Turn Signal Lamps...................5-52
Replacement Bulbs.......................................5-54
Windshield Wiper Blade Replacement..............5-54
Tires..............................................................5-57
Ination - Tire Pressure.................................5-65
Tire Inspection and Rotation...........................5-66
When It Is Time for New Tires.......................5-68
Buying New Tires.........................................5-68
Uniform Tire Quality Grading..........................5-69
Section 5 Service and Appearance Care
5-1

Checking Things Under
the Hood
{CAUTION:
Things that burn can get on hot engine parts
and start a re. These include liquids like fuel,
oil, coolant, brake uid, windshield washer and
other uids, and plastic or rubber. You or
others could be burned. Be careful not to drop
or spill things that will burn onto a hot engine.
Hood Release
1. To open the hood, rst
pull the handle located
inside the vehicle
on the lower driver’s
side of the instrument
panel.
5-10

A. Coolant Recovery Tank. SeeEngine Coolant on
page 5-25.
B. Engine Air Cleaner/Filter. SeeEngine Air
Cleaner/Filter on page 5-21.
C. Windshield Washer Fluid Reservoir. SeeWindshield
Washer Fluid on page 5-38.
D. Power Steering Fluid Reservoir. SeePower Steering
Fluid on page 5-37.
E. Automatic Transmission Dipstick. SeeAutomatic
Transmission Fluid on page 5-22.
F. Engine Oil Dipstick. SeeEngine Oil on page 5-16.G. Radiator Pressure Cap. SeeRadiator Pressure Cap
on page 5-27.
H. Engine Oil Fill Cap. SeeEngine Oil on page 5-16.
I. Remote Negative (-) Terminal Marked GND.
SeeJump Starting on page 5-43.
J. Brake Master Cylinder. SeeBrakes on page 5-39.
K. Battery. SeeBattery on page 5-42.
L. Engine Compartment Fuse Block. See “Engine
Compartment Fuse Block” underFuses and Circuit
Breakers on page 5-101.
5-13

A. Coolant Recovery Tank. SeeEngine Coolant on
page 5-25.
B. Engine Air Cleaner/Filter. SeeEngine Air
Cleaner/Filter on page 5-21.
C. Windshield Washer Fluid Reservoir. SeeWindshield
Washer Fluid on page 5-38.
D. Engine Oil Dipstick. SeeEngine Oil on page 5-16.
E. Automatic Transmission Dipstick. SeeAutomatic
Transmission Fluid on page 5-22.
F. Engine Oil Fill Cap. SeeEngine Oil on page 5-16.
G. Radiator Pressure Cap. SeeRadiator Pressure Cap
on page 5-27.H. Remote Negative (-) Terminal Marked GND. See
Jump Starting on page 5-43.
I. Power Steering Fluid Reservoir. SeePower Steering
Fluid on page 5-37.
J. Brake Master Cylinder. SeeBrakes on page 5-39.
K. Engine Compartment Fuse Block. See “Engine
Compartment Fuse block” underFuses and Circuit
Breakers on page 5-101.
L. Battery. SeeBattery on page 5-42.
5-15

Checking the Fluid Level
Prepare your vehicle as follows:
Park your vehicle on a level place. Keep the engine
running.
With the parking brake applied, place the shift lever
in PARK (P).
With your foot on the brake pedal, move the shift
lever through each gear range, pausing for about
three seconds in each range. Then, position the shift
lever in PARK (P).
Let the engine run at idle for three minutes or more.
Then, without shutting off the engine, follow these steps:
The automatic
transmission dipstick
handle with the
transmission and lock
symbol is located in the
engine compartment
on the passenger’s side of
the vehicle.SeeEngine Compartment Overview on page 5-12for
more information on location.
1. Flip the handle up and then pull out the dipstick
and wipe it with a clean rag or paper towel.
2. Push it back in all the way, wait three seconds and
then pull it back out again. Check both sides of the
dipstick, and read the lower level.
3. If the uid level is in the acceptable range, push the
dipstick back in all the way; then ip the handle
down to lock the dipstick in place.
5-24

Brakes
Brake Fluid
Your brake master cylinder reservoir is lled with DOT-3
brake uid. SeeEngine Compartment Overview on
page 5-12for the location of the reservoir.
There are only two reasons why the brake uid level in
the reservoir might go down. The rst is that the
brake uid goes down to an acceptable level during
normal brake lining wear. When new linings are put in,
the uid level goes back up. The other reason is
that uid is leaking out of the brake system. If it is, youshould have your brake system xed, since a leak
means that sooner or later your brakes will not work
well, or will not work at all.
So, it is not a good idea to “top off” your brake uid.
Adding brake uid will not correct a leak. If you add uid
when your linings are worn, then you will have too
much uid when you get new brake linings. You should
add (or remove) brake uid, as necessary, only when
work is done on the brake hydraulic system.
{CAUTION:
If you have too much brake uid, it can spill on
the engine. The uid will burn if the engine is
hot enough. You or others could be burned,
and your vehicle could be damaged. Add brake
uid only when work is done on the brake
hydraulic system. See “Checking Brake Fluid”
in this section.
Refer to the Maintenance Schedule to determine when
to check your brake uid. SeeScheduled Maintenance
on page 6-4.
5-39

Checking Brake Fluid
You can check the brake uid without taking off the cap.
Just look at the brake uid
reservoir. The uid level
should be above MIN. If it
is not, have your brake
system checked to
see if there is a leak.
After work is done on the brake hydraulic system,
make sure the level is above the MIN but not over the
MAX mark.
What to Add
When you do need brake uid, use only DOT-3 brake
uid. Use new brake uid from a sealed container
only. SeeRecommended Fluids and Lubricants on
page 6-12.Always clean the brake uid reservoir cap and the area
around the cap before removing it. This will help
keep dirt from entering the reservoir.
{CAUTION:
With the wrong kind of uid in your brake
system, your brakes may not work well, or
they may not even work at all. This could
cause a crash. Always use the proper brake
uid.
Notice:
Using the wrong uid can badly damage brake
system parts. For example, just a few drops of
mineral-based oil, such as engine oil, in your
brake system can damage brake system
parts so badly that they will have to be replaced.
Do not let someone put in the wrong kind of
uid.
If you spill brake uid on your vehicle’s painted
surfaces, the paint nish can be damaged.
Be careful not to spill brake uid on your
vehicle. If you do, wash it off immediately. See
Appearance Care on page 5-91.
5-40