2002 GMC YUKON ABS

2-32
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 firmly set. Your vehicle can roll.
Don't leave your vehicle when the engine is
running unless you have to. If you've 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, always set your parking brake and
move the shift lever to PARK (P).
Four-wheel drive vehicles with the transfer case
in NEUTRAL will allow the vehicle 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. Always set your parking brake.
Follow the proper steps to be sure your vehicle won't
move. See ªShifting Into PARK (P)º in the Index.
If you're pulling a trailer, see ªTowing a Trailerº in
the Index.
Level Control (If Equipped)
Self-Adjusting
The self
-adjusting rear suspension is available on
C/K 1500 vehicles and is available with the premium
smooth ride suspension package.
This type of level control will provide a leveled riding
position as well as improved handling under a variety
of passenger and loading conditions. A hydraulic pump
inside each rear shock absorber raises the rear of the
vehicle to the proper height, based on inputs from the
road surface, while the vehicle is being driven. It takes
approximately 2 miles (3.2 km) of driving for the
leveling to complete, depending on the road
surface conditions.
If the loaded vehicle is not moved for approximately
twelve hours, the leveling system may bleed down to a
lower height. This can be especially apparent if a trailer
is left attached to a parked vehicle for long periods of
time. The vehicle must be driven to re
-level the vehicle.
If a self
-equalizing hitch is being used, the vehicle
should be driven approximately 2 miles (3.2 km) with
the trailer prior to adjusting (leveling) the hitch.

2-33
Automatic Level Control
The automatic level control rear suspension is available
on C/K 1500 vehicles and comes as a part of the
Autoride
suspension.
This type of level control is fully automatic and will
provide a better leveled riding position as well as better
handling under a variety of passenger and loading
conditions. An air compressor connected to the rear
shocks will raise or lower the rear of the vehicle to
maintain proper vehicle height. The system is activated
when the ignition key is turned to RUN and will
automatically adjust vehicle height thereafter. The
system may exhaust (lower vehicle height) for up to ten
minutes after the ignition key has been turned to OFF.
You may hear the air compressor operating when the
height is being adjusted.
If a self
-equalizing hitch is being used, it is
recommended to allow the shocks to inflate, thereby
leveling the vehicle prior to adjusting the hitch.
Autoride
(If Equipped)
The Autoride feature will provide a superior vehicle
ride and handling under a variety of passenger and
loading conditions.
The system is fully automatic and uses a computer
controller to continuously monitor vehicle speed, wheel
to body position, lift/drive and steering position of the
vehicle. The controller then sends signals to each shock
absorber to independently adjust the damping level to
provide the optimum vehicle ride.
Autoride also interacts with the tow/haul switch that,
when engaged, will provide additional control of the
shock absorbers. This additional control results in better
ride and handling characteristics when the vehicle is
loaded or towing a trailer. See ªTow/Haul Modeº in the
Index for more information.
Locking Rear Axle (If Equipped)
If your vehicle has this feature, your locking rear axle
can give you additional traction on snow, mud, ice, sand
or gravel. It works like a standard axle most of the time,
but when one of the rear wheels has no traction and the
other does, this feature will allow the wheel with
traction to move the vehicle.

4-7
Avoid needless heavy braking. Some people drive
in spurts
-- heavy acceleration followed by heavy
braking
-- rather than keeping pace with traffic. This
is a mistake. Your brakes may not have time to cool
between hard stops. Your brakes will wear out much
faster if you do a lot of heavy braking. If you keep pace
with the traffic and allow realistic following distances,
you will eliminate a lot of unnecessary braking. That
means better braking and longer brake life.
If your engine ever stops while you're driving, brake
normally but don't pump your brakes. If you do, the
pedal may get harder to push down. If your engine
stops, you will still have some power brake assist. But
you will use it when you brake. Once the power assist is
used up, it may take longer to stop and the brake pedal
will be harder to push.
Anti-Lock Brake System (ABS)
Your vehicle has anti-lock brakes. ABS is an advanced
electronic braking system that will help prevent a
braking skid.
When you start your engine and begin to drive away,
your anti
-lock brake system will check itself. You may
hear a momentary motor or clicking noise while this test
is going on. This is normal.
If there's a problem with the
anti
-lock brake system, this
warning light will stay on.
See ªAnti
-Lock Brake
System Warning Lightº
in the Index.

4-8
Let's say the road is wet and you're driving safely.
Suddenly, an animal jumps out in front of you. You slam
on the brakes and continue braking. Here's what
happens with ABS:
A computer senses that wheels are slowing down. If one
of the wheels is about to stop rolling, the computer will
separately work the brakes at each front wheel and at
both rear wheels.The anti
-lock system can change the brake pressure
faster than any driver could. The computer is
programmed to make the most of available tire and road
conditions. This can help you steer around the obstacle
while braking hard.
As you brake, your computer keeps receiving updates on
wheel speed and controls braking pressure accordingly.

4-17
A cornering skid and an acceleration skid are best
handled by easing your foot off the accelerator pedal.
A cornering skid is best handled by easing your foot off
the accelerator pedal. If you have the ªTraction Assist
System,º remember: It helps avoid only the acceleration
skid. If you do not have this system, or if the system is
off, then an acceleration skid is also best handled by
easing your foot off the accelerator pedal.
If your vehicle starts to slide, ease your foot off the
accelerator pedal and quickly steer the way you want the
vehicle to go. If you start steering quickly enough, your
vehicle may straighten out. Always be ready for a
second skid if it occurs.Of course, traction is reduced when water, snow, ice,
gravel or other material is on the road. For safety, you'll
want to slow down and adjust your driving to these
conditions. It is important to slow down on slippery
surfaces because stopping distance will be longer and
vehicle control more limited.
While driving on a surface with reduced traction, try
your best to avoid sudden steering, acceleration or
braking (including engine braking by shifting to a lower
gear). Any sudden changes could cause the tires to
slide. You may not realize the surface is slippery until
your vehicle is skidding. Learn to recognize warning
clues
-- such as enough water, ice or packed snow on
the road to make a ªmirrored surfaceº
-- and slow
down when you have any doubt.
Remember: Any anti
-lock brake system (ABS) helps
avoid only the braking skid.

4-67
You may also want to activate the tow/haul mode if the
transmission shifts too often. See ªTow/Haul Modeº in
the Index.
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a
lower temperature than at normal altitudes. If you turn
your engine off immediately after towing at high altitude
on steep uphill grades, your vehicle may show signs
similar to engine overheating. To avoid this, let the
engine run while parked (preferably on level ground)
with the automatic transmission in PARK (P) for a
few minutes before turning the engine off. If you do
get the overheat warning, see ªEngine Overheatingº
in the Index.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 brake, but don't shift into
PARK (P) yet.
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 shift into PARK (P).

6-75
Fuse Usage
STUD #1 Accessory Power/Trailer Wiring
Feed/Load Leveling
ABS Anti
-Lock Brakes
IGN A Ignition Switch
AIR A.I.R. System
RAP #1 Retained Accessory Power, Power
Mirrors, Power Door Locks,
Power Seat(s)
IGN B Ignition Switch
RAP #2 Retained Accessory Power/Rear
Power Windows, Sunroof, Radio
STUD #2 Accessory Power/Trailer Wiring
Brake Feed
TRL R TRN Right Turn Signal Trailer Wiring
TRL L TRN Left Turn Signal Trailer Wiring
IGN 1 Ignition, Fuel Controls
INJ B Ignition, Fuel Controls (Relay)
STARTER Starter (Relay)Fuse Usage
PARK LP Parking Lamps
FRT HVAC Climate Control System
STOP LP Exterior Lamps, Stoplamps
ECM I PCM
CHMSL Center High Mounted Stoplamp
VEH STOP Stoplamps, Cruise Control
TRL B/U Backup Lamps Trailer Wiring
INJ A Fuel Controls, Ignition
RR HVAC Rear HVAC
VEH B/U Vehicle Backup Lamps
ENG 1 Engine Controls, Canister Purge,
Fuel System
ETC Electronic Throttle Control
IGN E A/C Compressor Relay, Rear
Window Defogger, Daytime
Running Lamps, A.I.R. System
B/U LP Backup Lamps, Automatic
Transmission Shift Lock
Control System