
D (START):This is the position that starts the engine.
When the engine starts, release the key. The ignition
switch returns to ON/RUN for driving.
A warning tone will sound when the driver door is
opened, the ignition is in ACC/ACCESSORY or LOCK/
OFF and the key is in the ignition.
Retained Accessory Power (RAP)
The following vehicle accessories can be used for up to
10 minutes after the engine is turned off:
.Audio System
.Power Windows
.OnStar®System (if equipped)
.Sunroof (if equipped)
These features work when the key is in ON/RUN or
ACC/ACCESSORY. Once the key is turned from ON/
RUN to LOCK/OFF, the windows and sunroof continue
to work up to 10 minutes until any door is opened. The
radio continues to work for up to 10 minutes or until the
driver door is opened.
Starting the Engine
If the vehicle has the DURAMAX®Diesel engine, see
the DURAMAX®Diesel manual for more information.
If the vehicle is a Two-mode Hybrid, see the Two-mode
Hybrid manual for more information.
Notice: Do not try to shift to P (Park) if the vehicle is
moving. If you do, you could damage the
transmission. Shift to P (Park) only when the vehicle
is stopped.
Move the shift lever to P (Park) or N (Neutral). The
engine will not start in any other position. To restart the
engine when the vehicle is already moving, use
N (Neutral) only.
3-23

Starting Procedure
1. With your foot off the accelerator pedal, turn theignition key to START. When the engine starts, let
go of the key. The idle speed will go down as your
engine gets warm. Do not race the engine
immediately after starting it. Operate the engine
and transmission gently to allow the oil to warm up
and lubricate all moving parts.
The vehicle has a Computer-Controlled Cranking
System. This feature assists in starting the engine
and protects components. If the ignition key is
turned to the START position, and then released
when the engine begins cranking, the engine will
continue cranking for a few seconds or until the
vehicle starts. If the engine does not start and the
key is held in START for many seconds, cranking
will be stopped after 15 seconds to prevent
cranking motor damage. To prevent gear damage,
this system also prevents cranking if the engine is
already running. Engine cranking can be stopped
by turning the ignition switch to the ACC/
ACCESSORY or LOCK/OFF position.
Notice: Cranking the engine for long periods of
time, by returning the key to the START position
immediately after cranking has ended, can overheat
and damage the cranking motor, and drain the
battery. Wait at least 15 seconds between each try,
to let the cranking motor cool down. 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 flooded with too much gasoline.
Try pushing the accelerator pedal all the way to the
floor and holding it there as you hold the key in
START for up to 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
briefly but then stops again, do the same thing.
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. If you do not,
the engine might not perform properly. Any
resulting damage would not be covered by the
vehicle warranty.
3-24

To Use the Engine Coolant Heater
1. Turn off the engine.
2. Open the hood and unwrap the electrical cord. Thecord is secured to the Engine Compartment Fuse
Block with a clip. Carefully remove the wire tie
which bundles the electrical plug. Do not cut the
electrical cord.
3. Plug the cord into a normal, grounded 110-volt AC outlet.
{WARNING:
Plugging the cord into an ungrounded outlet could
cause an electrical shock. Also, the wrong kind of
extension cord could overheat and cause a fire.
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. If you do not, it could be
damaged. The length of time the heater should remain plugged in
depends on several factors. Ask a dealer in the area
where you will be parking the vehicle for the best advice
on this.
Active Fuel Management™
Vehicles with V8 engines may have Active Fuel
Management™. This system allows the engine to
operate on either all or half of its cylinders, depending
on the 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 demands are
required, such as accelerating from a stop, passing,
or merging onto a freeway, the system will maintain
full-cylinder operation.
If the vehicle has an Active Fuel Management™
indicator, see
DIC Operation and Displays (With DIC
Buttons)
on page 4‑49or DIC Operation and Displays
(Without DIC Buttons)on page 4‑56for more
information on using this display.
3-27

The vehicle has a shift stabilization feature that adjusts
the transmission shifting to the current driving
conditions in order to reduce rapid upshifts and
downshifts. This shift stabilization feature is designed to
determine, before making an upshift, if the engine is
able to maintain vehicle speed by analyzing things such
as vehicle speed, throttle position, and vehicle load.
If the shift stabilization feature determines that a current
vehicle speed cannot be maintained, the transmission
does not upshift and instead holds the current gear. In
some cases, this could appear to be a delayed shift,
however the transmission is operating normally.
The transmission uses adaptive shift controls. Adaptive
shift controls continually compares key shift parameters
to pre-programmed ideal shifts stored in the
transmissions computer. The transmission constantly
makes adjustments to improve vehicle performance
according to how the vehicle is being used, such as
with a heavy load or when temperature changes. During
this adaptive shift control process, shifting might feel
different as the transmission determines the best
settings.
When temperatures are very cold, the Allison
Transmission
®and Hydra-Matic®6-Speed
transmission's gear shifting could be delayed providing
more stable shifts until the engine warms up. Shifts
could be more noticeable with a cold transmission. This
difference in shifting is normal. M (Manual Mode):
This position is available on vehicles
with the Allison Transmission
®or Hydra-Matic®6-Speed
transmission. It lets drivers select the range of gears
appropriate for current driving conditions. If the vehicle
has this feature, see Range Select Mode (Allison
Transmission
®or Hydra-Matic®6-Speed transmission)
later in this section.
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 (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 control vehicle
speed as you go down steep mountain roads, but then
you would also want to use the brakes off and on.
If you manually select 2 (Second) in an automatic
transmission, the transmission will start in second gear.
You can use this feature for reducing the speed of the
rear wheels when you are trying to start the vehicle
from a stop on slippery road surfaces.
3-31

Shifting Out of Four-Wheel-Drive Low
To shift from Four-Wheel-Drive Low to
Four-Wheel-Drive High, or Two-Wheel-Drive High, the
vehicle must be stopped or moving less than 3 mph
(5 km/h) with the transmission in N (Neutral) and the
ignition in ON/RUN. The preferred method for shifting
out of Four-Wheel-Drive Low is to have the vehicle
moving 1 to 2 mph (1.6 to 3.2 km/h). Turn the knob to the
Four-Wheel-Drive High, or Two-Wheel-Drive High
position. You must wait for the Four-Wheel-Drive High,
or Two-Wheel-Drive High indicator light to stop flashing
and remain on before shifting the transmission
into gear.
Notice:Shifting the transmission into gear before
the requested mode indicator light has stopped
flashing could damage the transfer case. To help
avoid damaging the vehicle, always wait for the
mode indicator lights to stop flashing before
shifting the transmission into gear.
It is typical for the vehicle to exhibit significant
engagement noise and bump when shifting between
Four-Wheel-Drive Low and Four-Wheel-Drive High
ranges or from transfer case N (Neutral) with the engine
running. If the knob is turned to the Four-Wheel-Drive High,
or Two-Wheel-Drive High switch position when the
vehicle is in gear and/or moving, the Four-Wheel-Drive
High, or Two-Wheel-Drive High indicator light will flash
for 30 seconds but will not complete the shift unless
your vehicle is moving less than 3 mph (5 km/h) and the
transmission is in N (Neutral).
Shifting into Neutral
To shift the transfer case to N (Neutral) do the following:
1. Make sure the vehicle is parked so that it will not roll.
2. Set the parking brake and press and hold the regular brake pedal. See Parking Brake
on
page 3‑50for more information.
3. Start the vehicle or turn the ignition to ON/RUN.
4. Shift the transmission to N (Neutral).
5. Shift the transfer case to Two-Wheel-Drive High.
6. Turn the transfer case dial clockwise to N (Neutral) until it stops and hold it there until the Neutral light
starts blinking. This will take at least 10 seconds.
Then slowly release the dial to the four low
position. The N (Neutral) light will come on when
the transfer case shift to N (Neutral) is complete.
3-44

7. If the engine is running, verify that the transfercase is in N (Neutral) by shifting the transmission
to R (Reverse) for one second, then shift the
transmission to D (Drive) for one second.
8. Turn the ignition to ACC/ACCESSORY, which will turn the engine off.
9. Place the transmission shift lever in P (Park).
10. Release the parking brake prior to moving the vehicle.
11. Turn the ignition to LOCK/OFF.
Shifting Out of Neutral
To shift the transfer case out of N (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, and shift the transmission to N (Neutral). 3. Turn the transfer case dial to
Two-Wheel-Drive High.
After the transfer case has shifted out of
N (Neutral), the N (Neutral) light will go out.
4. Release the parking brake prior to moving the vehicle.
Notice: Shifting the transmission into gear before
the requested mode indicator light has stopped
flashing could damage the transfer case. To help
avoid damaging the vehicle, always wait for the
mode indicator lights to stop flashing before
shifting the transmission into gear.
5. Start the engine and shift the transmission to the desired position.
Excessively shifting the transfer case into or out of the
different modes may cause the transfer case to enter
the shift protection mode. This will protect the transfer
case from possible damage and will only allow the
transfer case to respond to one shift per 10 seconds.
The transfer case may stay in this mode for up to
three minutes.
3-45

Shifting into Neutral
To shift the transfer case to N (Neutral) do the following:1. Make sure the vehicle is parked so that it will not roll.
2. Set the parking brake and apply the regular brake pedal. See Parking Brake
on page 3‑50for more
information.
3. Shifting the transfer case into N (Neutral) can be done with or without the engine running. Shifting
without the engine running should be done with the
ignition in ON/RUN.
4. Put the transmission in N (Neutral).
5. Shift the transfer case to Two-Wheel Drive High.
6. Turn the transfer case dial clockwise to N (Neutral) until it stops and hold it there until the N (Neutral)
light starts blinking. This will take at least
10 seconds. Then slowly release the dial to the
four low position. The N (Neutral) light will come on
when the transfer case shift to N (Neutral) is
complete.
7. If the engine is running, make sure that the transfer case is in N (Neutral) by shifting the transmission
to R (Reverse) for one second, then shift the
transmission to D (Drive) for one second.
8. Turn the ignition to ACC/ACCESSORY, which will turn the engine off. 9. Place the transmission shift lever in P (Park).
10. Release the parking brake prior to moving the vehicle.
11. Turn the ignition to LOCK/OFF.Shifting Out of Neutral
To shift out of N (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, and shift the transmission to N (Neutral).
3. Turn the transfer case dial to Two-Wheel-Drive High, Four-Wheel-Drive High, AUTO.
After the transfer case has shifted out of
N (Neutral), the N (Neutral) light will go out.
4. Release the parking brake prior to moving the vehicle.
Notice: Shifting the transmission into gear before
the requested mode indicator light has stopped
flashing could damage the transfer case. To help
avoid damaging the vehicle, always wait for the
mode indicator lights to stop flashing before
shifting the transmission into gear.
5. Start the engine and shift the transmission to the desired position.
3-49

Roof Rack System
{WARNING:
If something is carried on top of the vehicle that is
longer or wider than the roof rack—like paneling,
plywood, or a mattress— the wind can catch it
while the vehicle is being driven. The item being
carried could be violently torn off, and this could
cause a collision, and damage the vehicle. Never
carry something longer or wider than the roof rack
on top of the vehicle unless using a GM Certified
accessory carrier. For vehicles with a roof rack, the rack can be used to
load items. For roof racks that do not have crossrails
included, GM Certified crossrails can be purchased as
an accessory. See your dealer for additional
information.
Notice:
Loading cargo on the roof rack that weighs
more than 91 kg (200 lbs) or hangs over the rear or
sides of the vehicle may damage the vehicle. Load
cargo so that it rests evenly between the crossrails,
making sure to fasten cargo securely.
To prevent damage or loss of cargo when driving, check
to make sure crossrails and cargo are securely
fastened. Loading cargo on the roof rack will make the
vehicle’s center of gravity higher. Avoid high speeds,
sudden starts, sharp turns, sudden braking or abrupt
maneuvers, otherwise it may result in loss of control.
If driving for a long distance, on rough roads, or at high
speeds, occasionally stop the vehicle to make sure the
cargo remains in its place.
3-77