ECU GMC ENVOY DENALI 2005 Service Manual

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.
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.
Problem Recommended Action
No power. The ignition might not be
in on or accessory.
The parental control
button might have been
turned on. The power
indicator light will ash.
Disc will not play. The system might be off.
The parental control
button might have been
turned on. The power
indicator light will ash.
The system might be in
auxiliary mode.
The disc is upside down
or is not compatible.
The picture does not ll
the screen. There are
black borders on the top
and bottom or on both
sides or it looks
stretched out.Check the display
mode settings in the
display menu.
The disc was ejected, but
it was pulled back into the
DVD player.The disc is being stored in
the DVD player. Press the
eject button again to eject
the disc.
3-131

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 equipped) are properly attached.
Be sure you read all the information about your
four-wheel-drive vehicle in this manual.
Is there enough fuel? Is the spare tire fully inated? 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.
{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.
SeeLoading Your Vehicle on page 4-44,Luggage
Carrier on page 2-55andTires on page 5-54.
4-17

Winter DrivingHere 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.
Also seeTires on page 5-54.
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 reective 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.
4-39

{CAUTION:
Do not load your vehicle any heavier than the
Gross Vehicle Weight Rating (GVWR), or either
the maximum front or rear Gross Axle Weight
Rating (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.
Using heavier suspension components to get added
durability might not change your vehicle’s weight ratings.
Ask your dealer to help you load your vehicle
the right way.
Notice:Overloading your vehicle may cause
damage. Repairs would not be covered by your
warranty. Do not overload your vehicle.
If you put things inside your vehicle — like suitcases,
tools, packages, or anything else — they will go as fast
as the vehicle goes. If you have to stop or turn
quickly, or if there’s a crash, they will 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 “Loading Your Vehicle
for Off-Road Driving” underOff-Road Driving with Your
Four-Wheel-Drive Vehicle on page 4-16.
4-49

Four-Wheel-Drive Vehicles
Four-wheel-drive vehicles can be dinghy towed if you
follow the proper procedures. The transmission has no
provisions for internal lubrication while being towed, so it
is important that you follow all the steps listed in this
manual to dinghy tow your four-wheel-drive vehicle.
Use the following procedure to tow your vehicle:
1. Shift the transmission to PARK (P).
2. Turn the engine off, but leave the ignition on.
3. Firmly set the parking brake.
4. Securely attach the vehicle being towed
to the tow vehicle.
{CAUTION:
Shifting a four-wheel-drive vehicle’s transfer
case into NEUTRAL can cause your vehicle to
roll even if the transmission is in PARK (P).
You or others could be injured. Make sure the
parking brake is rmly set before you shift the
transfer case to NEUTRAL.
5. Shift the transfer case to NEUTRAL (N). See
Four-Wheel Drive on page 2-26for the proper
procedure to select the NEUTRAL (N) position for
your vehicle.
6. Release the parking brake only after the vehicle
being towed is rmly attached to the towing vehicle.
7. Turn the ignition off.
After towing, see “Shifting Out of Neutral” under
Four-Wheel Drive on page 2-26.
4-53

Dolly Towing
Front Towing (Front Wheels Off
the Ground)
Two-Wheel-Drive Vehicles
Notice:If you tow a two-wheel-drive vehicle with
the rear wheels on the ground, the transmission
could be damaged. The repairs would not be
covered by your warranty. Never tow your vehicle
with the rear wheels on the ground.
Four-Wheel-Drive Vehicles
Four-wheel-drive vehicles can be dolly towed with the
rear wheels on the ground.
Use the following procedure to tow your vehicle:
1. Drive the vehicle onto the tow dolly.
2. Shift the automatic transmission to PARK (P).
3. Turn the engine off, but leave the ignition on.
4. Firmly set the parking brake.
5. Securely attach the vehicle being towed to the dolly.
{CAUTION:
Shifting a four-wheel-drive vehicle’s transfer
case into NEUTRAL can cause your vehicle to
roll even if the transmission is in PARK (P).
You or others could be injured. Make sure the
parking brake is rmly set before you shift the
transfer case to NEUTRAL.
6. Shift the transfer case to NEUTRAL (N). See
Four-Wheel Drive on page 2-26for the proper
procedure to select the NEUTRAL (N) position for
your vehicle.
7. Release the parking brake only after the vehicle
being towed is rmly attached to the towing vehicle.
8. Turn the ignition off.
After towing, see “Shifting Out of Neutral” under
Four-Wheel Drive on page 2-26.
4-54

Rear Towing
(Rear Wheels Off the Ground)
(Two-Wheel or Four-Wheel-Drive
Vehicles)Use the following procedure to tow your vehicle
from the rear:
1. Drive the vehicle onto the dolly.
2. Firmly set the parking brake. SeeParking Brake
on page 2-30for more information.
3. Shift the transmission in PARK (P).
4. Follow the dolly manufacturer’s instructions to attach
and secure the vehicle being towed to the dolly and
then the loaded dolly to the tow vehicle. Use an
adequate clamping device to ensure that the front
wheels are locked into the straight position.
5. Release the parking brake only after the vehicle
being towed is rmly attached to the towing vehicle.
6. Turn the ignition to LOCK.
If the tow vehicle will not be started or driven for
six weeks or more, remove the battery cable
from the negative terminal (post) of the battery.
4-55

Before you start, check all trailer hitch parts and
attachments, safety chains, electrical connection, 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.
Making Turns
Notice:Making very sharp turns while trailering
could cause the trailer to come in contact with the
vehicle. Your vehicle could be damaged. Avoid
making very sharp turns while trailering.
When you’re turning with a trailer, make wider turns than
normal. Do this so your trailer won’t strike soft shoulders,
curbs, road signs, trees or other objects. Avoid jerky or
sudden maneuvers. Signal well in advance.
4-64

Radiator Pressure Cap
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.
SeeEngine Compartment Overview on page 5-12for
information on location.
Engine Overheating
You will nd a coolant temperature gage on your
vehicle’s instrument panel. If your vehicle has a Driver
Information Center (DIC), the display will show an
Engine Coolant Hot or Engine Overheated message.
SeeDIC Warnings and Messages on page 3-55
for more information.
If Steam Is Coming From Your Engine
{CAUTION:
Steam from an overheated engine can burn
you badly, even if you just open the hood. Stay
away from the engine if you see or hear steam
coming from it. Just turn it off and get
everyone away from the vehicle until it cools
down. Wait until there is no sign of steam or
coolant before you open the hood.
If you keep driving when your engine is
overheated, the liquids in it can catch re. You
or others could be badly burned. Stop your
engine if it overheats, and get out of the
vehicle until the engine is cool.
Notice:If your engine catches re because you
keep driving with no coolant, your vehicle can
be badly damaged. The costly repairs would not be
covered by your warranty.
5-28

4. Unclip the wiring harness (A) and remove the
three socket retaining screws (B).
5. Remove the socket by releasing the retaining tabs.
6. Holding the socket, pull the bulb to release it from
the socket.
7. Push the new bulb into the socket until it clicks.
8. Reinstall the socket and screws.
9. Reconnect the wiring harness.
10. Reinstall the taillamp assembly and tighten
the screws.
11. Close the liftgate.
Back-Up Lamps
The back-up lamps are located in the rear bumper.
To replace a bulb, do the following:
1. Reach behind the rear bumper and locate
the bulb socket.
2. Turn it counterclockwise to remove from the bulb
assembly.
3. Pull the bulb from the bulb socket.
4. Push in a new bulb into the bulb socket.
5. Reinstall the bulb socket by lining up the tabs in the
lamp assembly and turn it clockwise to secure it.
Replacement Bulbs
Exterior Lamp Bulb Number
Back-up Lamps 3157
Front Sidemarker Lamps 194
Front Turn Signal Lamps 3457
Halogen Headlamps
High-Beam 9005 HB3
Low-Beam 9006 HB4
Rear Turn Signal, Stoplamp and
Taillamp3057
For replacement bulbs not listed here, contact
your dealer.
5-51