ECU GMC YUKON XL DENALI 2001 Owner's Guide

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.

4-15
Off-road driving involves some new skills. And that's
why it's very important that you read this guide. You'll
find 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. Is there
enough fuel? Is the spare tire fully inflated? Are the
fluid 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.
Loading Your Vehicle for Off-Road Driving
There are some important things to remember about
how to load your vehicle.

The heaviest things should be on the load floor and
forward of your rear axle. Put heavier items as far
forward as you can.

Be sure the load is secured properly, so driving on
the off
-road terrain doesn't toss things around.
CAUTION:

Cargo on the load floor piled higher than
the seatbacks can be thrown forward
during a sudden stop. You or your
passengers could be injured. Keep cargo
below the top of the seatbacks.

Unsecured cargo on the load floor can
be tossed about when driving over rough
terrain. You or your passengers can be
struck by flying objects. Secure the
cargo properly.

Heavy loads on the roof raise the vehicle's
center of gravity, making it more likely to
roll over. You can be seriously or fatally
injured if the vehicle rolls over. Put heavy
loads inside the cargo area, not on the roof.
Keep cargo in the cargo area as far forward
and low as possible.
You'll find other important information in this manual.
See ªVehicle Loading,º ªLuggage Carrierº and ªTiresº
in the Index.

4-37
Winter Driving
Here are some tips for winter driving:

Have your vehicle in good shape for winter.

You may want to put winter emergency supplies in
your vehicle.Include an ice scraper, a small brush or broom, a supply
of windshield washer fluid, a rag, some winter outer
clothing, a small shovel, a flashlight, a red cloth and
reflective warning triangles. And, if you will be driving
under severe conditions, include a small bag of sand, a
piece of old carpet or a couple of burlap bags to help
provide traction. Be sure you properly secure these
items in your vehicle.
Driving on Snow or Ice
Most of the time, those places where your tires meet
the road probably have good traction.
However, if there is snow or ice between your tires
and the road, you can have a very slippery situation.
You'll have a lot less traction or ªgripº and will need
to be very careful.

4-42
To find out the actual loads on your front and rear axles,
you need to go to a weigh station and weigh your vehicle.
Your dealer can help you with this. Be sure to spread out
your load equally on both sides of the centerline.
Never exceed the GVWR for your vehicle, or the GAWR
for either the front or rear axle.
And, if you do have a heavy load, you should spread it out.
CAUTION:
Do not load your vehicle any heavier than the
GVWR, or either the maximum front or rear
GAWR. If you do, parts on your vehicle can break,
and it can change the way your vehicle handles.
These could cause you to lose control and crash.
Also, overloading can shorten the life of your vehicle.
Your warranty does not cover parts or components that
fail because of overloading.
The label will help you decide how much cargo and
installed equipment your truck can carry.Using heavier suspension components to get added
durability might not change your weight ratings. Ask
your dealer to help you load your vehicle the right way.
If you put things inside your vehicle
-- like suitcases,
tools, packages, or anything else
-- they go as fast as
the vehicle goes. If you have to stop or turn quickly, or
if there is a crash, they'll keep going.
CAUTION:
Things you put inside your vehicle can strike and
injure people in a sudden stop or turn, or in a crash.

Put things in the cargo area of your vehicle.
Try to spread the weight evenly.

Never stack heavier things, like suitcases,
inside the vehicle so that some of them are
above the tops of the seats.

Don't leave an unsecured child restraint in
your vehicle.

When you carry something inside the vehicle,
secure it whenever you can.

Don't leave a seat folded down unless you
need to.

4-49
Towing a trailer requires a certain amount of experience.
Before setting out for the open road, you'll want to get
to know your rig. Acquaint yourself with the feel of
handling and braking with the added weight of the
trailer. And always keep in mind that the vehicle you
are driving is now a good deal longer and not nearly as
responsive as your vehicle is by itself.
Before you start, check the trailer hitch and platform
(and attachments), safety chains, electrical connector,
lamps, tires and mirror adjustment. If the trailer has
electric brakes, start your vehicle and trailer moving
and then apply the trailer brake controller by hand to be
sure the brakes are working. This lets you check your
electrical connection at the same time.
During your trip, check occasionally to be sure that the
load is secure, and that the lamps and any trailer brakes
are still working.Following Distance
Stay at least twice as far behind the vehicle ahead as you
would when driving your vehicle without a trailer. This
can help you avoid situations that require heavy braking
and sudden turns.
Passing
You'll need more passing distance up ahead when
you're towing a trailer. And, because you're a good
deal longer, you'll need to go much farther beyond
the passed vehicle before you can return to your lane.
Backing Up
Hold the bottom of the steering wheel with one hand.
Then, to move the trailer to the left, just move that hand
to the left. To move the trailer to the right, move your
hand to the right. Always back up slowly and, if
possible, have someone guide you.

5-25
Front Position
Rear Position
2. For the front position, make sure that the jack is
positioned where the sections of frame overlap.
For the rear, make sure the jack head is positioned
so that the rear axle is resting securely between the
grooves that are on the jack head. Turn the wheel
wrench clockwise to raise the vehicle. Raise the
vehicle far enough off the ground so there is enough
room for the spare tire to fit back underneath the rear
of the vehicle.

5-29 Storing a Flat or Spare Tire and Tools
CAUTION:
Storing a jack, a tire or other equipment in the
passenger compartment of the vehicle could
cause injury. In a sudden stop or collision, loose
equipment could strike someone. Store all these
in the proper place.
Store the tire under the rear of the vehicle in the spare
tire carrier. To store the tire do the following:
1. Put the tire on the ground at the rear of the vehicle
with the valve stem pointed upward.
2. Tilt the retainer downward and through the wheel
opening. Make sure the retainer is fully seated across
the underside of the wheel.
3. Attach the wheel wrench and extensions together.
Insert the hoist end through the hole in the rear
bumper and into the hoist shaft.
4. Raise the tire partway upward. Make sure the
retainer is seated in the wheel opening.5. Raise the tire fully against the underside of the
vehicle. Continue turning the wheel wrench until the
tire is secure and the cable is tight. The spare tire
hoist cannot be overtightened.
6. Make sure the tire is stored securely. Push, pull, and
then try to rotate or turn the tire. If the tire moves,
use the wheel wrench to tighten the cable.
Replace the jack, tools and spare tire lock.

5-31
Denali Models (Rear Access Panel)
A. Speaker
B. Bottle Jack
C. Wing Nut
D. Retaining Hook
E. Tire Blocks
F. Cover Panel1. Put the tool kit, with the jack tools and gloves, in the
tool bag and place in the retaining bracket under the
second row passenger's seat on the driver's side of
the vehicle.
2. Tighten down with the wing nut.
3. Then, assemble tire blocks (E) and bottle jack (B)
together with the wing nut and retaining hook (D).
4. Position behind the jack storage cover in the rear
side panel on the driver's side of the vehicle just
below the speaker (A) and tighten, adjusting
clockwise until the jack is secured tight in the
mounting bracket.

6-42 Tire Inspection and Rotation
Tires should be rotated every 6,000 to 8,000 miles
(10 000 to 13 000 km). Any time you notice unusual
wear, rotate your tires as soon as possible and check
wheel alignment. Also check for damaged tires or
wheels. See ªWhen It's Time for New Tiresº and
ªWheel Replacementº later in this section for more
information. Make sure the spare tire is stored securely.
Push, pull, and then try to rotate or turn the tire. If it
moves, use the wheel wrench to tighten the cable. See
ªStoring a Flat or Spare Tire and Toolsº in the Index.
The purpose of regular rotation is to achieve more
uniform wear for all tires on the vehicle. The first
rotation is the most important. See ªScheduled
Maintenance Servicesº in the Index for scheduled
rotation intervals.
When rotating your tires, always use the correct rotation
pattern shown here. Don't include the spare tire in your
tire rotation.
After the tires have been rotated, adjust the front
and rear inflation pressures as shown on the
Certification/Tire label. Make certain that all wheel
nuts are properly tightened. See ªWheel Nut Torqueº in
the Index.

7-17 At Least Twice a Year
Restraint System Check
Make sure the safety belt reminder light and all your
belts, buckles, latch plates, retractors and anchorages are
working properly. Look for any other loose or damaged
safety belt system parts. If you see anything that might
keep a safety belt system from doing its job, have it
repaired. Have any torn or frayed safety belts replaced.
Also look for any opened or broken air bag coverings,
and have them repaired or replaced. (The air bag system
does not need regular maintenance.)
Wiper Blade Check
Inspect wiper blades for wear or cracking. Replace blade
inserts that appear worn or damaged or that streak or
miss areas of the windshield. Also see ªWiper Blades,
Cleaningº in the Index.Spare Tire Check
At least twice a year, after the monthly inflation check
of the spare tire determines that the spare is inflated to
the correct tire inflation pressure, make sure that the
spare tire is stored securely. Push, pull, and then try
to rotate or turn the tire. If it moves, use the wheel
wrench/ratchet to tighten the cable. See ªStoring the
Spare Tire and Toolsº in the Index.
Engine Air Cleaner Filter Restriction
Indicator Check
Your vehicle has an indicator located on the air cleaner
in the engine compartment that lets you know when the
air cleaner filter is dirty and needs to be changed. Check
indicator at least twice a year or when your engine oil is
changed, whichever occurs first. See ªAir Cleanerº in
the Index for more information. Inspect your air cleaner
filter restriction indicator more often if the vehicle is
used in dusty areas or under off road conditions.