ECU GMC YUKON DENALI 2004 Service Manual

Security Light
This light will come on
brie¯y when you turn the
key toward START.
The light will stay on until
the engine starts.
If the light ¯ashes, the Passlock
žsystem has entered a
tamper mode. If the vehicle fails to start, seePasslockž
on page 2-18.
If the light comes on continuously while driving and
stays on, there may be a problem with the Passlock
ž
system. Your vehicle will not be protected by Passlockž,
and you should see your dealer.
Also, see
Content Theft-Deterrent on page 2-16for
additional information regarding the security light.
Cruise Control Light
The cruise light comes on
whenever you set your
cruise control. See
Cruise
ControlunderTurn
Signal/Multifunction Lever
on page 3-7
.
Tow/Haul Mode Light
This light is displayed
when the Tow/Haul mode
has been activated.
For more information, see
Towing a Trailer on
page 4-51.
3-44

XMŸ Radio Messages (cont'd)
Radio Display
MessageCondition Action Required
No Info Category Name not
availableNo category information is available at this time on this
channel. Your system is working properly.
No Info No Text/Informational
message availableNo text or informational messages are available at this
time on this channel. Your system is working properly.
Not Found No channel available for
the chosen categoryThere are no channels available for the category you
selected. Your system is working properly.
XM Locked Theft lock active The XM receiver in your vehicle may have previously been
in another vehicle. For security purposes, XM receivers
cannot be swapped between vehicles. If you receive this
message after having your vehicle serviced, check with the
servicing facility.
Radio ID Radio ID label
(channel 0)If you tune to channel 0, you will see this message
alternating with your XM Radio 8 digit radio ID label. This
label is needed to activate your service.
Unknown Radio ID not known
(should only be if
hardware failure)If you receive this message when you tune to channel 0,
you may have a receiver fault. Consult with your dealer.
Chk XMRcvr Hardware failure If this message does not clear within a short period of time,
your receiver may have a fault. Consult with your retail
location.
3-74

q(Return):Press this button to exit the current
active menu and return to the previous menu. This
button will operate only when a DVD is being played
and a menu is active.
|(Camera Angle):This button changes camera
angles on DVDs that have this feature when a DVD is
playing. The format and content of this function is
dependent on the disc.
{(Subtitle):This button turns on subtitles and moves
through subtitle options when a DVD is playing. The
format and content of this function is dependent on
the disc.
[(Fast Forward):Press this button to fast forward
the DVD or CD. To stop fast forwarding, press this
button again. This button may not work when the DVD
is playing the copyright information or the previews.
s(Play/Pause):Press this button to start play of a
DVD or CD. Press this button while a DVD or CD is
playing to pause it. Press this button again to continue
the play of the DVD or CD.
Slow Play:When the DVD is playing, press the pause
button then press the fast forward button. The DVD
will continue playing in a slow play mode. To cancel slow
play mode, press the play/pause button.
u(Next Track/Chapter):Press this button to advance
to the beginning of the next track or chapter. This
button may not work when the DVD is playing the
copyright information or the previews.
Battery Replacement
To change the batteries, do the following:
1. Remove the battery compartment door located on
the bottom of the remote control.
2. Replace the two AA batteries in the compartment.
Make sure that they are installed correctly, using
the diagram on the inside of the battery
compartment.
3. Close the battery door securely.
Notice:Do not store the remote control in heat or
direct sunlight. This could damage the remote
control and it would not be covered by your vehicles
warranty. Keep the remote control stored in a
cool, dry place.
If the remote control is to be stored for a long period of
time, remove the batteries and keep them in a cool,
dry place.
3-86

Operating Your All-Wheel-Drive
Vehicle Off Paved Roads
Many of the same design features that help make your
vehicle responsive on paved roads during poor weather
conditions Ð features like all-wheel drive Ð help make it
much better suited for off-road use than a conventional
passenger car. Its higher ground clearance also helps
your vehicle step over some off-road obstacles. But your
vehicle does not have features like special underbody
shielding and a transfer case low gear range, things that
are usually thought necessary for extended or severe
off-road service. This guide is for operating your vehicle
off paved roads.
Also, see
Braking on page 4-6.
Off-road driving can be great fun. But it does have
some de®nite hazards. The greatest of these is
the terrain itself.
ªOff-roadingº means you have left the great North
American road system behind. Traffic lanes are not
marked. Curves are not banked. There are no
road signs. Surfaces can be slippery, rough, uphill or
downhill. In short, you have gone right back to nature.
Off-road driving involves some new skills. And that
is why it is very important that you read this guide.
You will ®nd 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
in¯ated? Are the ¯uid levels up where they should be?
What are the local laws that apply to off-roading
where you will be driving? If you do not 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 ¯oor 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 does not toss things around.
4-16

{CAUTION:
·Cargo on the load ¯oor 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 ¯oor can be
tossed about when driving over rough
terrain. You or your passengers can be
struck by ¯ying 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 will ®nd other important information in this manual.
See
Loading Your Vehicle on page 4-44andTires
on page 5-54.
Environmental Concerns
Off-road driving can provide wholesome and satisfying
recreation. However, it also raises environmental
concerns. We recognize these concerns and urge every
off-roader to follow these basic rules for protecting
the environment:
·Always use established trails, roads and areas that
have been specially set aside for public off-road
recreational driving; obey all posted regulations.
·Avoid any driving practice that could damage the
environment Ð shrubs, ¯owers, trees, grasses Ð or
disturb wildlife (this includes wheel-spinning,
breaking down trees or unnecessary driving through
streams or over soft ground).
·Always carry a litter bag Ð make sure all refuse is
removed from any campsite before leaving.
·Take extreme care with open ®res (where permitted),
camp stoves and lanterns.
·Never park your vehicle over dry grass or other
combustible materials that could catch ®re from the
heat of the vehicle's exhaust system.
4-17

·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.
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 ¯uid, a rag, some winter
outer clothing, a small shovel, a ¯ashlight, a red
cloth and a couple of re¯ective 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.
4-37

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.
·Do not leave an unsecured child restraint
in your vehicle.
·When you carry something inside the
vehicle, secure it whenever you can.
·Do not leave a seat folded down unless
you need to.
There's also important loading information for off-road
driving in this manual. See ªLoading Your Vehicle
for Off-Road Drivingº under
Operating Your
All-Wheel-Drive Vehicle Off Paved Roads on page 4-16.
4-49

Driving with a Trailer
{CAUTION:
If you have a rear-most window open and you
pull a trailer with your vehicle, carbon
monoxide (CO) could come into your vehicle.
You can not see or smell CO. It can cause
unconsciousness or death. See
Engine
Exhaust on page 2-30
. To maximize your safety
when towing a trailer:
·Have your exhaust system inspected for
leaks, and make necessary repairs before
starting on your trip.
·Keep the rear-most windows closed.
·If exhaust does come into your vehicle
through a window in the rear or another
opening, drive with your front, main
heating or cooling system on and with the
fan on any speed. This will bring fresh,
outside air into your vehicle. Do not use
the climate control setting for maximum air
because it only recirculates the air inside
your vehicle. See
Dual Automatic Climate
Control System on page 3-20.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 all trailer hitch parts 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.
4-58

Adding Coolant
If you need more coolant, add the proper DEX-COOLž
coolant mixtureat the surge tank, but only when the
engine is cool.
{CAUTION:
You can be burned if you spill coolant on hot
engine parts. Coolant contains ethylene glycol,
and it will burn if the engine parts are hot
enough. Do not spill coolant on a hot engine.
When replacing the pressure cap, make sure it is
hand-tight.
Coolant Surge Tank Pressure Cap
The coolant surge tank pressure cap must be fully
installed on the coolant surge tank. SeeEngine
Compartment Overview on page 5-12for more
information on location.
Notice:If the pressure cap is not tightly installed,
coolant loss and possible engine damage may
occur. Be sure the cap is properly and tightly
secured.
Engine Overheating
You will ®nd a coolant temperature gage on your
vehicle's instrument panel. SeeEngine Coolant
Temperature Gage on page 3-38. In addition, you will
®nd an ENGINE COOLANT HOT, ENGINE
OVERHEATED and a REDUCED ENGINE POWER
message in the DIC on the instrument panel. See
DIC
Warnings and Messages on page 3-57.
Overheated Engine Protection
Operating Mode
If an overheated engine condition exists and the
REDUCED ENGINE POWER message is displayed, an
overheat protection mode which alternates ®ring
groups of cylinders helps prevent engine damage. In
this mode, you will notice a loss in power and engine
performance. This operating mode allows your vehicle to
be driven to a safe place in an emergency. Driving
extended miles (km) and/or towing a trailer in the
overheat protection mode should be avoided.
Notice:After driving in the overheated engine
protection operating mode, to avoid engine damage,
allow the engine to cool before attempting any
repair. The engine oil will be severely degraded.
Repair the cause of coolant loss, change the oil and
reset the oil life system. See
Engine Oil on
page 5-13.
5-25

9. After hearing the con®rming horn chirp for the left
rear tire, check to see if the TPM warning light is
still ¯ashing. If yes, turn the ignition switch to OFF.
10. Set all four tires to the recommended air pressure
level as indicated on the Certi®cation/Tire label or
the Tire and Loading Information label.
11. Put the valve caps back on the valve stems
The spare tire does not have a TPM sensor. If you
replace one of the road tires with the spare, the CHECK
TIRE PRESSURE message will be displayed on the DIC
screen. This message should go off once you re-install
the road tire containing the TPM sensor. The SERVICE
TIRE MONITOR message is displayed when the TPM
system is malfunctioning. One or more missing or
inoperable TPM sensors will cause the service tire
monitor message to be displayed. See your dealer for
service.
Federal Communications Commission and
Industry and Science Canada
The TPM system operates on a radio frequency subject
to Federal Communications Commission (FCC) Rules
and with Industry and Science Canada.
This device complies with Part 15 of the FCC Rules and
with RSS-210 of Industry and Science Canada.
Operation is subject to the following two conditions:
(1) This device may not cause harmful interference, and(2) this device must accept any interference received
including interference that may cause undesired
operation of the device.
Changes or modi®cations to this system by other than
an authorized service facility could void authorization to
use this equipment.
Tire Inspection and Rotation
Tires should be rotated every 5,000 to 8,000 miles
(8 000 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
When It Is Time
for New Tires on page 5-68andWheel Replacement
on page 5-71for 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 ratchet/wheel wrench to tighten the cable.
See
Changing a Flat Tire on page 5-74.
The purpose of regular rotation is to achieve more
uniform wear for all tires on the vehicle. The ®rst rotation
is the most important. See
Scheduled Maintenance
on page 6-4.
5-66