engine GMC ENVOY DENALI 2009 User Guide

2. If the engine does not start after 5-10 seconds,
especially in very cold weather (below 0°F or−18°C),
it could be ooded with too much gasoline. Try
pushing the accelerator pedal all the way to the oor
and holding it there as you hold the key in START for
up to a maximum of 15 seconds. Wait at least
15 seconds between each try, to allow the cranking
motor to cool down. When the engine starts, let go of
the key and accelerator. If the vehicle starts briey
but then stops again, repeat these steps. This clears
the extra gasoline from the engine. Do not race the
engine immediately after starting it. Operate the
engine and transmission gently until the oil warms up
and lubricates all moving parts.
Notice:The engine is designed to work with the
electronics in the vehicle. If you add electrical parts
or accessories, you could change the way the
engine operates. Before adding electrical equipment,
check with your dealer/retailer. If you do not, the
engine might not perform properly. Any resulting
damage would not be covered by the vehicle
warranty.Adjustable Throttle and Brake Pedal
If the vehicle has this feature, you can change the
position of the throttle and brake pedals.
The vehicle must be in P (Park) for this feature to
operate.
The switch used to adjust
the pedals is located on
the steering column.
Press the switch forward or backward to move the
pedals closer or farther away from you.
2-23

Engine Coolant Heater
The engine coolant heater can provide easier starting
and better fuel economy during engine warm-up in cold
weather conditions at or below 0°F (−18°C). Vehicles
with an engine coolant heater should be plugged
in at least four hours before starting the vehicle. An
internal thermostat in the plug-end of the cord may exist
which will prevent engine coolant heater operation at
temperatures above 0°F (−18°C).
To Use the Engine Coolant Heater
1. Turn off the engine.
2. Open the hood and unwrap the electrical cord. The
cord is located on the driver side of the engine
compartment next to the battery box facing
the engine.
3. Plug it into a normal, grounded 110-Volt AC outlet.
{CAUTION:
Plugging the cord into an ungrounded outlet could
cause an electrical shock. Also, the wrong kind of
extension cord could overheat and cause a re.
You could be seriously injured. Plug the cord into
a properly grounded three-prong 110-volt AC
outlet. If the cord will not reach, use a heavy-duty
three-prong extension cord rated for at least
15 amps.
4. Before starting the engine, be sure to unplug and
store the cord as it was before to keep it away
from moving engine parts and prevent damage.
The length of time the heater should remain plugged in
depends on several factors. Ask a dealer/retailer in
the area where you will be parking the vehicle for the
best advice on this.
2-24

Active Fuel Management™
The vehicle’s V8 engine may have Active Fuel
Management™. This system allows the engine to
operate on either all or half of its cylinders, depending
on driving conditions.
When less power is required, such as cruising at a
constant vehicle speed, the system will operate in the
half cylinder mode, allowing the vehicle to achieve better
fuel economy. When greater power is required, such
as accelerating from a stop, passing, or merging onto a
freeway, the system will maintain full-cylinder operation.
Automatic Transmission Operation
There are several different
positions for the gear shift
lever.
2-25

P (Park):This position locks the rear wheels. It is the
best position to use when you start the engine because
the vehicle cannot move easily.
{CAUTION:
It is dangerous to get out of the vehicle if the shift
lever is not fully in P (Park) with the parking brake
rmly set. The vehicle can roll.
Do not leave the vehicle when the engine is
running unless you have to. If you have left the
engine running, the vehicle can move suddenly.
You or others could be injured. To be sure the
vehicle will not move, even when you are on fairly
level ground, always set the parking brake and
move the shift lever to P (Park). SeeShifting Into
Park on page 2-34. If you are pulling a trailer, see
Towing a Trailer on page 4-46.
{CAUTION:
If you have four-wheel drive, the vehicle will be free
to roll — even if the shift lever is in P (Park) — if the
transfer case is in Neutral. So, be sure the transfer
case is in a drive gear — not in Neutral. See
Four-Wheel Drive on page 2-28. SeeShifting Into
Park on page 2-34.
Make sure the shift lever is fully in P (Park) before
starting the engine. The vehicle has an automatic
transmission shift lock control system. You have to fully
apply the brake pedal, then press the shift lever
button before you can shift from P (Park) when the
ignition key is in ON/RUN. If you cannot shift out
of P (Park), ease pressure on the shift lever and push
the shift lever all the way into P (Park) as you maintain
brake application. Then press the shift lever button
and move the shift lever into another gear. SeeShifting
Out of Park on page 2-36.
2-26

R (Reverse):Use this gear to back up.
Notice:Shifting to R (Reverse) while the vehicle is
moving forward could damage the transmission.
The repairs would not be covered by the vehicle
warranty. Shift to R (Reverse) only after the vehicle
is stopped.
To rock the vehicle back and forth to get out of snow,
ice, or sand without damaging the transmission,
seeIf Your Vehicle is Stuck in Sand, Mud, Ice, or Snow
on page 4-30.
N (Neutral):In this position, the engine does not
connect with the wheels. To restart the engine when the
vehicle is already moving, use N (Neutral) only.
{CAUTION:
Shifting into a drive gear while the engine is
running at high speed is dangerous. Unless your
foot is rmly on the brake pedal, the vehicle could
move very rapidly. You could lose control and hit
people or objects. Do not shift into a drive gear
while the engine is running at high speed.Notice:Shifting out of P (Park) or N (Neutral) with
the engine running at high speed may damage
the transmission. The repairs would not be covered
by the vehicle warranty. Be sure the engine is
not running at high speed when shifting the vehicle.
D (Drive):This position is for normal driving. It provides
the best fuel economy. If you need more power for
passing, and you are:
Going less than about 35 mph (55 km/h), push the
accelerator pedal about halfway down.
Going about 35 mph (55 km/h) or more, push the
accelerator all the way down.
The vehicle will shift down to the next gear and have
more power.
Downshifting the transmission in slippery road conditions
could result in skidding, see “Skidding” underLoss of
Control on page 4-12.
D (Drive) can be used when towing a trailer, carrying a
heavy load, driving on steep hills, or for off-road driving.
You may want to shift the transmission to 3 (Third) or, if
necessary, a lower gear selection if the transmission
shifts too often.
3 (Third):This position is also used for normal driving. It
reduces vehicle speed more than D (Drive) without using
the brakes. You might choose 3 (Third) instead of
D (Drive) when driving on hilly, winding roads, when
towing a trailer, so there is less shifting between gears
and when going down a steep hill.
2-27

To shift to the 3 (Third) position, you must rst press the
large button on the shift handle. While the button is
pressed, move the shifter in the 3 (Third) position.
2 (Second):This position reduces vehicle speed even
more than 3 (Third) without using the brakes. You can
use 2 (Second) on hills. It can help you control vehicle
speed as you go down steep mountain roads, as you use
your brakes off and on.
To shift to the 2 (Second) position, you must rst press
the large button on the shift handle. While the button is
pressed, move the shifter in the 2 (Second) position.
You can also use 2 (Second) for starting the vehicle from
a stop on slippery road surfaces.
1 (First):This position reduces vehicle speed even
more than 2 (Second) without using the brakes. You can
use it on very steep hills, or in deep snow or mud. If
the shift lever is put in 1 (First) while the vehicle
is moving forward, the transmission will not shift into
rst gear until the vehicle is going slowly enough.
To shift to the 1 (First) position, you must rst press the
large button on the shift handle. While the button is
pressed, move the shifter in the 1 (First) position.Notice:Spinning the tires or holding the vehicle in
one place on a hill using only the accelerator pedal
may damage the transmission. The repair will not be
covered by the vehicle warranty. If you are stuck, do
not spin the tires. When stopping on a hill, use the
brakes to hold the vehicle in place.
Four-Wheel Drive
If the vehicle has four-wheel drive, the engine’s driving
power can be sent to all four wheels for extra traction.
Read the following before using four-wheel drive,
to become familiar with its operation. You should use
Two-Wheel High for most normal driving conditions.
Notice:Driving on clean, dry pavement in
Four-Wheel-Drive High or Four-Wheel-Drive Low for
an extended period of time may cause premature
wear on your vehicle’s powertrain. Do not drive on
clean, dry pavement in Four-Wheel-Drive High or
Four-Wheel-Drive Low for extended periods of time.
Notice:If you continually drive your vehicle with the
transfer case in AUTO or Four-Wheel Drive, you
could shorten the life of the transfer case or the
Four-Wheel Drive system. The selector switch should
be left in Two-Wheel Drive High mode. Only use
AUTO and Four-Wheel Drive when you need extra
traction such as in wet or slippery road conditions.
2-28

Shifting Into Two-Wheel High
Turn the knob to Two-Wheel High. This can be done at
any speed unless you are shifting out of Four-Wheel Low.
Shifting Into Four-Wheel Low
To shift to Four-Wheel Low, the vehicle’s engine must
be running and the vehicle must be stopped or moving
less than 2 mph (3.2 km/h) with the transmission in
N (Neutral). The preferred method for shifting into
Four-Wheel Low is to have your vehicle moving 1 or
2 mph (1.6 to 3.2 km/h). Turn the knob to Four-Wheel
Low. You must wait for the Four-Wheel Low indicator light
to stop ashing and stay on before shifting the
transmission into gear.
If you turn the knob to Four-Wheel Low when the
vehicle is in gear and/or moving, the Four-Wheel Low
indicator light will ash for 30 seconds and not complete
the shift unless the vehicle is moving less than 2 mph
(3.2 km/h) and the transmission is in N (Neutral).
After 30 seconds, the transfer case will return to the
setting last chosen.
Shifting Out of Four-Wheel Low
To shift from Four-Wheel Low to Four-Wheel High, Auto
Four-Wheel Drive, or Two-Wheel High, the vehicle
must be stopped or moving less than 2 mph (3.2 km/h)
with the transmission in N (Neutral) and the engine
running. The preferred method for shifting out of
Four-Wheel Low is to have your vehicle moving
1 or 2 mph (1.6 to 3.2 km/h). Turn the knob to
Four-Wheel High, Auto Four-Wheel Drive, or Two-Wheel
High. You must wait for the Four-Wheel High, Auto
Four-Wheel Drive, or Two-Wheel High indicator light to
stop ashing and stay off before shifting your
transmission into gear.
If the knob is turned to Four Wheel-High, Auto
Four-Wheel Drive, or Two-Wheel High when the vehicle
is in gear and/or moving, the Four-Wheel High, Auto
Four-Wheel Drive, or Two-Wheel High indicator light will
ash for 30 seconds. It will not complete the shift
unless the vehicle is moving less than 2 mph (3.2 km/h)
with the transmission in N (Neutral).
2-31

Shifting into Neutral
Before shifting the transfer case to Neutral, rst make
sure the vehicle is parked so that it will not roll.
1. Set the parking brake.
2. Start the vehicle.
3. Put the transmission in N (Neutral).
4. Shift the transfer case to Two-Wheel High.
5. Turn the transfer case knob all of the way past
Four-Wheel Low and hold it there for a minimum
of 10 seconds. The Neutral indicator light will
come on.
6. With the engine running, shift the transmission to
R (Reverse) for one second, then shift the
transmission to D (Drive) for one second, to ensure
that the transfer case is in Neutral.
7. Turn the engine off, by turning the key to
ACC/ACCESSORY.
8. Place the transmission shift lever in P (Park).
9. Turn the ignition to LOCK/OFF.
Shifting Out of Neutral
To shift the transfer case out of Neutral, do the following:
1. Set the parking brake and apply the regular brake
pedal.
2. Turn the ignition to ON/RUN with the engine off.
3. Put the transmission in N (Neutral).
4. Turn the transfer case knob to the desired position
(Two-Wheel High, Four-Wheel High, or Auto
Four-Wheel Drive).
5. After the transfer case has shifted out of Neutral,
the indicator light will go out.
6. Release the parking brake.
7. Start the engine and shift the transmission to the
desired position.
2-32

Shifting Into Park
{CAUTION:
It can be dangerous to get out of the vehicle if the
shift lever is not fully in P (Park) with the parking
brake rmly set. The vehicle can roll. If you have
left the engine running, the vehicle can move
suddenly. You or others could be injured. To be
sure the vehicle will not move, even when you are
on fairly level ground, use the steps that follow.
With four-wheel drive, the vehicle will be free to
roll — even if the shift lever is in P (Park) — if your
transfer case is in Neutral. So, be sure the transfer
case is in a drive gear — not in Neutral. See
Four-Wheel Drive on page 2-28. Always put the
shift lever fully in P (Park) with the parking brake
rmly set. If you are pulling a trailer, seeTowing a
Trailer on page 4-46.To shift into P (Park):
1. Hold the brake pedal down with your foot and set
the parking brake.
2. Move the shift lever into P (Park) by pressing the
button on the side of the shift lever and pushing
the lever all the way toward the front of the vehicle.
3. Turn the ignition key to OFF/LOCK.
4. Remove the key and take it with you. You know the
vehicle is in P (Park) if the key can be removed
from the ignition.
2-34

Leaving the Vehicle With the Engine
Running
{CAUTION:
It can be dangerous to leave the vehicle with the
engine running. The vehicle could move suddenly
if the shift lever is not fully in P (Park) with the
parking brake rmly set.
If you have four-wheel drive, the vehicle will be
free to roll – even if your lever is in P (Park) – if
the transfer case is in Neutral. So be sure the
transfer case is in a drive gear – not Neutral. See
Four-Wheel Drive on page 2-28.
And, if you leave the vehicle with the engine
running, it could overheat and even catch re.
You or others could be injured. Do not leave the
vehicle with the engine running unless you
have to.If you have to leave the vehicle with the engine running,
be sure the vehicle is in P (Park) and the parking
brake is rmly set before you leave it. After you have
moved the shift lever into P (Park), hold the regular
brake pedal down. Then, see if you can move the shift
lever away from P (Park) without rst pressing the
button on the console shift lever. If you can, it means
that the shift lever was not fully locked into P (Park).
Torque Lock
If you are parking on a hill and you do not shift your
transmission into P (Park) properly, the weight of
the vehicle may put too much force on the parking pawl
in the transmission. You may nd it difficult to pull the
shift lever out of P (Park). This is called “torque lock.” To
prevent torque lock, set the parking brake and then
shift into P (Park) properly before you leave the driver
seat. To nd out how, seeShifting Into Park on
page 2-34.
When you are ready to drive, move the shift lever out of
P (Park) before you release the parking brake.
If torque lock does occur, you may need to have another
vehicle push yours a little uphill to take some of the
pressure from the parking pawl in the transmission, so
you can pull the shift lever out of P (Park).
2-35