ECU GMC ENVOY DENALI 2007 Repair Manual

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).
SeeFour-Wheel Drive on page 122for
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 122.
357

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).
SeeFour-Wheel Drive on page 122for
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”
underFour-Wheel Drive on page 122.
358

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 126for 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.
359

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.
371

Add coolant mixture at the recovery tank, but be
careful not to spill it.
{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.
Occasionally check the coolant level in the
radiator. For information on how to add coolant to
the radiator, seeCooling System on page 411.
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 390
for information on location.
Engine Overheating
You will nd a coolant temperature gage on your
vehicle’s instrument panel. SeeEngine Coolant
Temperature Gage on page 208for more
information.
If your vehicle has a Driver Information Center
(DIC), the display will show an Engine Coolant
Hot/Engine Overheated message. SeeDIC
Warnings and Messages on page 222for more
information.
408

Headlamps
To replace one of these bulbs, do the following:
1. Open the hood.Hood Release on page 388
for more information.
2. Lift the two headlamp retaining clips.
3. Pull the headlamp assembly away from the
vehicle to access the electrical connectors.4. Remove the cover from the headlamp bulb.
5. Remove the bulb socket that needs to
be replaced by turning it counterclockwise.
6. Disconnect the electrical connector from the
old bulb.
7. Plug the electrical connector into the new bulb
using care not to touch the glass with your
ngers.
8. Install the new bulb into the socket and turn it
clockwise to secure.
9. Reinstall by reversing Steps 1 through 6.
10. Press down on the headlamp retaining clips to
secure the headlamp assembly.
431

Front Turn Signal, Sidemarker and
Parking Lamps
To replace one of these bulbs, do the following:
1. Follow Steps 1 through 3 underHeadlamps on
page 431to access the front turn signal,
sidemarker or parking lamp.
2. Turn the bulb socket counterclockwise and
remove it from the lamp assembly.
3. Holding the socket, pull the old bulb to
release it from the socket.
4. Push the new bulb into the socket until it
clicks.
5. Insert the bulb socket into the lamp assembly
and turn it clockwise to secure.
6. Reinstall the headlamp assembly by lining up
the headlamp assembly with the slots in the
headlamp retaining clips.
7. Press down on the headlamp retaining clips to
secure the headlamp assembly.
Taillamps, Turn Signal, and
Stoplamps
To replace a stoplamp/taillamp or turn signal bulb,
do the following:
1. Open the liftgate. SeeLiftgate/Liftglass on
page 106for more information.
2. Remove the
two screws from
the taillamp
assembly.
3. Pull the assembly away from the vehicle.
432

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
lamp assembly.3. Holding the socket, pull the old bulb to
release it from the socket.
4. Push in a new bulb into the bulb socket until it
clicks.
5. Reinstall the bulb socket into the lamp
assembly and turn it clockwise to secure.
434

Federal Communications Commission
(FCC) and Industry and Science Canada
The Tire Pressure Monitor System (TPMS)
operates on a radio frequency and complies with
Part 15 of the FCC Rules. Operation is subject
to the following two conditions:
1. This device may not cause harmful
interference.
2. This device must accept any interference
received, including interference that may
cause undesired operation.
The Tire Pressure Monitor System (TPMS)
operates on a radio frequency and complies with
RSS-210 of Industry and Science Canada.
Operation is subject to the following two conditions:
1. This device may not cause interference.
2. This device must accept any interference
received, including interference that may
cause undesired operation of the device.
Changes or modications 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.
SeeWhen It Is Time for New Tires on page 455
andWheel Replacement on page 460for
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.
For information on storing or removing the
spare tire, seeChanging a Flat Tire on page 465.
The purpose of regular rotation is to achieve
more uniform wear for all tires on the vehicle. The
rst rotation is the most important. SeeScheduled
Maintenance on page 507.
453

3. Make sure the valve stem is pointed up and
to the rear.
4. Pull the retainer (D) through the wheel.
5. Put the socket end of the extension (C)
through the hole just above the rear bumper
at a 45 degree angle downward. Connect
the socket end of the extension to the hoist
shaft (B).
6. Raise the tire fully against the underside of
the vehicle. Continue turning the wheel
wrench (A) clockwise until you hear two clicks
or feel it skip twice. This indicates that the
tire is secure and the cable is tight. The spare
tire hoist cannot be overtightened.7. Make sure the tire is stored securely. Push,
pull (A), and then try to turn (B) the tire. If the
tire moves, use the wheel wrench and socket
end of the extension to tighten the cable.
8. Return the equipment to the proper location in
the vehicle as shown next.
480