2002 GMC YUKON XL DENALI ignition

3-23
Unlocking the Theft-Deterrent Feature After a
Power Loss
Enter your secret code as follows; pause no more than
15 seconds between steps:
1. Turn the ignition on. LOC will appear on the display.
2. Press MN and 000 will appear on the display.
3. Press MN again to make the last two digits agree
with your code.
4. Press HR to make the first one or two digits agree
with your code.
5. Press AM FM after you have confirmed that the code
matches the secret code you have written down. The
display will show SEC, indicating the radio is now
operable and secure.
If you enter the wrong code eight times, INOP will
appear on the display. You will have to wait an hour
with the ignition on before you can try again. When you
try again, you will only have three chances to enter the
correct code before INOP appears.
If you lose or forget your code, contact your dealer.Disabling the Theft-Deterrent Feature
Enter your secret code as follows; pause no more than
15 seconds between steps:
1. Turn the ignition to ACCESSORY or RUN.
2. Turn the radio off.
3. Press the 1 and 4 pushbuttons at the same time. Hold
them down until SEC shows on the display.
4. Press MN and 000 will appear on the display.
5. Press MN again to make the last two digits agree
with your code.
6. Press HR to make the first one or two digits agree
with your code.
7. Press AM FM after you have confirmed that the code
matches the secret code you have written down. The
display will show
---, indicating that the radio is no
longer secured.
If the code entered is incorrect, SEC will appear on the
display. The radio will remain secured until the correct
code is entered.
When battery power is removed and later applied to a
secured radio, the radio won't turn on and LOC will
appear on the display.
To unlock a secured radio, see ªUnlocking the
Theft
-Deterrent Feature After a Power Lossº earlier in
this section.

3-26 Care of Your Cassette Tape Player
A tape player that is not cleaned regularly can cause
reduced sound quality, ruined cassettes or a damaged
mechanism. Cassette tapes should be stored in their
cases away from contaminants, direct sunlight and
extreme heat. If they aren't, they may not operate
properly or may cause failure of the tape player.
Your tape player should be cleaned regularly after every
50 hours of use. Your radio may display CLN to indicate
that you have used your tape player for 50 hours without
resetting the tape clean timer. If this message appears on
the display, your cassette tape player needs to be
cleaned. It will still play tapes, but you should clean it as
soon as possible to prevent damage to your tapes and
player. If you notice a reduction in sound quality, try a
known good cassette to see if it is the tape or the tape
player at fault. If this other cassette has no improvement
in sound quality, clean the tape player.
The recommended cleaning method for your cassette
tape player is the use of a scrubbing action,
non
-abrasive cleaning cassette with pads which scrub
the tape head as the hubs of the cleaner cassette turn.
The recommended cleaning cassette is available through
your dealer (GM Part No. 12344789).When cleaning the cassette tape player with the
recommended non
-abrasive cleaning cassette, it is
possible that the cassette may eject, because the cut tape
detection feature on your radio may recognize it as a
broken tape. To prevent the cleaning cassette from being
ejected, use the following steps:
1. Turn the ignition to RUN or ACCESSORY.
2. Turn the radio off.
3. Press and hold the CD TAPE button for five seconds.
The tape symbol on the display will flash for
two seconds.
4. Insert the scrubbing action cleaning cassette.
5. Eject the cleaning cassette after the manufacturer's
recommended cleaning time.
When the cleaning cassette has been ejected, the cut tape
detection feature is active again.
You may also choose a non
-scrubbing action, wet-type
cleaner which uses a cassette with a fabric belt to clean
the tape head. This type of cleaning cassette will not
eject on its own. A non
-scrubbing action cleaner may
not clean as thoroughly as the scrubbing type cleaner.
The use of a non
-scrubbing action, dry-type cleaning
cassette is not recommended.

4-27
If the water isn't too deep, then drive through it slowly. At
fast speeds, water splashes on your ignition system and
your vehicle can stall. Stalling can also occur if you get
your tailpipe under water. And, as long as your tailpipe is
under water, you'll never be able to start your engine.
When you go through water, remember that when your
brakes get wet, it may take you longer to stop.
CAUTION:
Driving through rushing water can be dangerous.
Deep water can sweep your vehicle downstream
and you and your passengers could drown. If it's
only shallow water, it can still wash away the
ground from under your tires, and you could lose
traction and roll the vehicle over. Don't drive
through rushing water.
See ªDriving Through Waterº in the Index for more
information on driving through water.
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 fire 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.

4-36
If you drive regularly in steep country, or if you're
planning to visit there, here are some tips that can make
your trips safer and more enjoyable. See ªOperating
Your Vehicle Off Paved Roadsº in the Index for
information about driving off
-road.

Keep your vehicle in good shape. Check all fluid
levels and also the brakes, tires, cooling system and
transmission. These parts can work hard on
mountain roads.

Know how to go down hills. The most important
thing to know is this: let your engine do some of the
slowing down. Shift to a lower gear when you go
down a steep or long hill.
CAUTION:
If you don't shift down, your brakes could get
so hot that they wouldn't work well. You would
then have poor braking or even none going
down a hill. You could crash. Shift down to let
your engine assist your brakes on a steep
downhill slope.
CAUTION:
Coasting downhill in NEUTRAL (N) or with the
ignition off is dangerous. Your brakes will have to
do all the work of slowing down. They could get
so hot that they wouldn't work well. You would
then have poor braking or even none going down
a hill. You could crash. Always have your engine
running and your vehicle in gear when you
go downhill.

Know how to go uphill. You may want to shift down
to a lower gear. The lower gears help cool your engine
and transmission, and you can climb the hill better.

Stay in your own lane when driving on two
-lane
roads in hills or mountains. Don't swing wide or cut
across the center of the road. Drive at speeds that let
you stay in your own lane.

As you go over the top of a hill, be alert. There could be
something in your lane, like a stalled car or an accident.

You may see highway signs on mountains that warn of
special problems. Examples are long grades, passing or
no
-passing zones, a falling rocks area or winding
roads. Be alert to these and take appropriate action.

4-44 Trailer Recommendations
You must subtract your hitch loads from the Cargo
Weight Rating (CWR). CWR is the maximum weight of
the load your vehicle can carry. It doesn't include the
weight of the people inside. But you can figure about
150 lbs. (68 kg) for each seat. The total cargo load must
not be more than your vehicle's CWR.
Weigh your vehicle with the trailer attached, so that you
won't go over the GVWR or GAWR. If you are using a
weight
-distributing hitch, weigh the vehicle without the
equalizer bars in place.
You'll get the best performance if you spread out the
weight of your load the right way, and if you choose the
correct hitch and trailer brakes.
For more information, see ªTrailer Towingº in
the Index.
Automatic Level Control
The automatic level control rear suspension comes as a
part of the Autoride
suspension. See ªAutoride
º in
the Index for more information.
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
10 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 weight
-distributing hitch is being used, it is
recommended to allow the shocks to inflate, thereby
leveling the vehicle prior to adjusting the hitch.

5-4
2. Get the vehicles close enough so the jumper cables
can reach, but be sure the vehicles aren't touching
each other. If they are, it could cause a ground
connection you don't want. You wouldn't be able to
start your vehicle, and the bad grounding could
damage the electrical systems.
To avoid the possibility of the vehicles rolling, set
the parking brake firmly on both vehicles involved
in the jump start procedure. Put an automatic
transmission in PARK (P) or a manual transmission
in NEUTRAL before setting the parking brake.
NOTICE:
If you leave your radio on, it could be badly
damaged. The repairs wouldn't be covered by
your warranty.
3. Turn off the ignition on both vehicles. Unplug
unnecessary accessories plugged into the cigarette
lighter or accessory power outlets. Turn off the radio
and all lamps that aren't needed. This will avoid
sparks and help save both batteries. And it could
save your radio!
4. Open the hoods and locate the positive (+) and
negative (
-) terminal locations of the other vehicle.
Your vehicle has a remote positive (+) jump starting
terminal and a remote negative (
-) jump starting
terminal. You should always use these remote
terminals instead of the terminals on the battery.
The remote positive (+) terminal is located under a
red plastic cover near the engine accessory drive
bracket. To access the remote positive (+) terminal,
open the red plastic cover.
The remote negative (
-) terminal is located on
the engine accessory drive bracket and is
marked ªGNDº.
See ªEngine Compartment Overviewº in the Index
for more information on location.

5-23
A. Spare Tire (Valve
Stem Pointed Up)
B. Hoist Assembly
C. Hoist Cable
D. Tire Retainer
E. Hoist Shaft
F. Hoist End of
Extension ToolG. Hoist Shaft
Access Hole
H. Wheel Wrench
I. Jack Handle
Extensions
J. Hoist Lock1. Your vehicle is equipped with a hoist lock (J).
To unlock it, open the spare tire lock cover on the
bumper and use the ignition key to remove the lock.
2. Assemble the wheel wrench (H) and the two jack
handle extensions (I) as shown.

6-16
How to Reset the CHANGE ENGINE OIL Message
The GM Oil Life System
calculates when to change
your engine oil and filter based on vehicle use. Anytime
your oil is changed, reset the system so it can calculate
when the next oil change is required. If a situation
occurs where you change your oil prior to a CHANGE
ENGINE OIL message being turned on, reset
the system.
To reset the CHANGE ENGINE OIL message, do
the following:
1. Turn the ignition key to RUN with the engine off.
2. Fully press and release the accelerator pedal three
times within five seconds.
3. If the CHANGE ENGINE OIL message flashes for
five seconds, the system is reset.
If the system does not reset, try the procedure
once again. If it still does not reset, see your dealer
for service.What to Do with Used Oil
Used engine oil contains certain elements that may be
unhealthy for your skin and could even cause cancer.
Don't let used oil stay on your skin for very long. Clean
your skin and nails with soap and water, or a good hand
cleaner. Wash or properly throw away clothing or rags
containing used engine oil. See the manufacturer's
warnings about the use and disposal of oil products.
Used oil can be a threat to the environment. If you
change your own oil, be sure to drain all the oil from the
filter before disposal. Never dispose of oil by putting it
in the trash, pouring it on the ground, into sewers, or
into streams or bodies of water. Instead, recycle it by
taking it to a place that collects used oil. If you have a
problem properly disposing of your used oil, ask your
dealer, a service station or a local recycling center
for help.