2001 GMC YUKON XL DENALI ignition

3-21 Theft-Deterrent Feature (If Equipped)
THEFTLOCK
is designed to discourage theft of your
radio. It works by using a secret code to disable all radio
functions whenever battery power is removed.
The THEFTLOCK feature for the radio may be used or
ignored. If ignored, the system plays normally and the
radio is not protected by the feature. If THEFTLOCK
is activated, your radio will not operate if stolen.
When THEFTLOCK is activated, the radio will display
LOC to indicate a locked condition anytime battery
power has been interrupted. If your battery loses power
for any reason, you must unlock the radio with the secret
code before it will operate.
Activating the Theft
-Deterrent Feature
The instructions which follow explain how to enter your
secret code to activate the THEFTLOCK system. It is
recommended that you read through all nine steps
before starting the procedure.
If you allow more than 15 seconds to elapse between
any steps, the radio automatically reverts to time and
you must start the procedure over at Step 4.1. Write down any three or four
-digit number from
000 to 1999 and keep it in a safe place separate from
the vehicle.
2. Turn the ignition to ACCESSORY or RUN.
3. Turn the radio off.
4. Press the 1 and 4 buttons together. Hold them down
until
--- shows on the display. Next you will use the
secret code number which you have written down.
5. Press MN and 000 will appear on the display.
6. Press MN again to make the last two digits agree
with your code.
7. Press HR to make the first one or two digits agree
with your code.
8. Press AM
-FM after you have confirmed that the
code matches the secret code you have written down.
The display will show REP to let you know that you
need to repeat Steps 5 through 7 to confirm your
secret code.
9. Press AM
-FM and this time the display will show
SEC to let you know that your radio is secure. The
LED indicator by the volume control will begin
flashing when the ignition is turned off.

3-22
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 buttons together. 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.

3-25 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 using a scrubbing action, non
-abrasive cleaning
cassette, it is normal for the cassette to eject because
your unit is equipped with a cut tape detection feature
and a cleaning cassette may appear 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.

4-26
This has an effect on steering, accelerating and
braking. You may want to reduce the air pressure in
your tires slightly when driving on sand. This will
improve traction.
Hard packed snow and ice offer the worst tire traction.
On these surfaces, it's very easy to lose control. On wet
ice, for example, the traction is so poor that you will
have difficulty accelerating. And if you do get moving,
poor steering and difficult braking can cause you to slide
out of control.
CAUTION:
Driving on frozen lakes, ponds or rivers can be
dangerous. Underwater springs, currents under
the ice, or sudden thaws can weaken the ice. Your
vehicle could fall through the ice and you and
your passengers could drown. Drive your vehicle
on safe surfaces only.
Driving in Water
Light rain causes no special off-road driving problems.
But heavy rain can mean flash flooding, and flood
waters demand extreme caution.
Find out how deep the water is before you drive through
it. If it's deep enough to cover your wheel hubs, axles or
exhaust pipe, don't try it
-- you probably won't get
through. Also, water that deep can damage your axle
and other vehicle parts.
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.

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 ªOff
-Road
Drivingº 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.

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.
3. Turn off the ignition on both vehicles. Unplug
unnecessary accessories plugged into the cigarette
lighter or accessory power outlets. Turn off all lamps
that aren't needed as well as radios. This will avoid
sparks and help save both batteries. In addition, it
could save your radio!
NOTICE:
If you leave your radio on, it could be badly
damaged. The repairs wouldn't be covered by
your warranty.
4. Open the hoods and locate the positive (+) and
negative (
-) terminal locations on the other vehicle.
Your vehicle has a remote positive (+) jump starting
terminal and a remote negative (
-) jump starting
terminal. The remote positive (+) terminal is located
behind a red plastic cover near the engine accessory
drive bracket on the driver's side of the vehicle. To
uncover the remote positive (+) terminal, open the
red plastic cover.
The remote negative (
-) terminal is located on the
engine accessory drive bracket. It is marked ªGND.º
You should always use the remote positive (+) and
the remote negative (
-) terminals instead of the
positive (+) and negative (
-) terminals on
your battery.

5-21
A. Hoist Assembly
B. Wheel Wrench
C. Jack
Handle Extensions
D. Hoist Shaft
E. Valve Stem,
Pointed Up
F. Spare TireG. Tire Retainer
H. Hoist Cable
I. Hoist Lock
J. Hoist Shaft
Access Hole
K. Hoist End of
Extension ToolFollow these instructions to lower the spare tire:
1. If the vehicle is equipped with a hoist lock (I), open
the spare tire lock cover on the bumper and use the
ignition key to remove the lock.
2. Assemble the wheel wrench (B) and the two jack
handle extensions (C) as shown. Insert the hoist
end (K) (open end) of the extension through the
hole (J) in the rear bumper. Be sure the hoist end
of the extension connects into the hoist shaft (D)
(the ribbed square end of the extension is used to
lower the spare tire).
3. Turn the wheel wrench counterclockwise to lower
the spare tire (F) to the ground. Continue to turn the
wheel wrench until the spare tire can be pulled out
from under the vehicle. The wheel wrench has a
hook that allows you to pull the hoist cable (H)
towards you, to assist in reaching the spare tire.
4. When the tire has been lowered, tilt the retainer at
the end of the cable so it can be pulled up through
the wheel opening.
5. Put the spare tire near the flat tire.

6-14
How to Reset the CHANGE ENGINE OIL Message
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. If the CHANGE
ENGINE OIL message flashes for five seconds, the
system is reset.What to Do with Used Oil
Did you know that 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 real threat to the environment. If you
change your own oil, be sure to drain all free
-flowing oil
from the filter before disposal. Don't ever 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.