
Ignition Positions
Use the key to turn the ignition switch to
four different positions.
A (LOCK):This position locks the ignition and
transmission. It is a theft-deterrent feature. You will
only be able to remove the key when the ignition
is turned to LOCK.
Notice:Using a tool to force the key from the
ignition switch could cause damage or break
the key. Use the correct key and turn the key
only with your hand. Make sure the key is all the
way in. If it is, turn the steering wheel left and
right while you turn the key hard. If none of this
works, then your vehicle needs service.B (ACCESSORY):This position lets you use
things like the radio and the windshield wipers
when the engine is off.
Lengthy operation of features such as the radio in
the ACCESSORY ignition position and the
RUN position may drain the battery and prevent
your vehicle from starting. Do not operate
your vehicle in the ACCESSORY ignition position
for a long period of time.
C (RUN):This is the position for driving. It is the
position the switch returns to after the engine
starts, and you release the key.
The battery could be drained if you leave the key
in the ACCESSORY or RUN position with the
engine off. You may not be able to start your
vehicle if the battery is allowed to drain for
an extended period of time.
D (START):This position starts the engine.
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Key In the Ignition
Never leave your vehicle with the keys inside, as it
is an easy target for joy riders or thieves. If you
leave the key in the ignition and park your vehicle,
a chime will sound, when you open the driver’s
door. Always remember to remove your key from
the ignition and take it with you. This will lock
your ignition and transmission. Also, always
remember to lock the doors.
The battery could be drained if you leave the key
in the ignition while your vehicle is parked.
You may not be able to start your vehicle after it
has been parked for an extended period of time.
Retained Accessory Power (RAP)
Your vehicle has a Retained Accessory Power
(RAP) feature which will allow certain features on
your vehicle to continue to work up to 10 minutes
after the ignition key is turned to LOCK.
The radio, power windows, and if the vehicle has a
sunroof and the OnStar
®System, will work when
the ignition key is in RUN or ACCESSORY. Once
the key is turned from RUN to LOCK, the windows
and sunroof will continue to work until a door is
opened. The radio will continue to work for up to
10 minutes or until the driver’s door is opened.
Starting the Engine
If your vehicle has the DURAMAX®Diesel engine,
see the DURAMAX®Diesel manual for more
information.
To place the transmission in the proper gear:
Move your shift lever to PARK (P) or NEUTRAL (N).
Your engine will not start in any other position -- this
is a safety feature. To restart when you are already
moving, use NEUTRAL (N) only.
Starting Procedure
1. With your foot off the accelerator pedal, turn
the ignition 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.
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Your 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
ACCESSORY or LOCK 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 allow
the cranking motor to 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 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 brie y 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:Your engine is designed to work with
the electronics in your 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, your engine might not
perform properly. Any resulting damage would
not be covered by your vehicle’s warranty.
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Active Fuel Management™
Your 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 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 your 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.
Your vehicle has an Active Fuel Management™
indicator. For more information on using this
display seeDIC Operation and Displays (With DIC
Buttons) on page 268orDIC Operation and
Displays (Without DIC Buttons) on page 275.
Automatic Transmission Operation
If your vehicle is has an automatic transmission,
it has an electronic shift position indicator
within the instrument panel cluster. This display
comes on when the ignition key is turned to
the RUN position.There are several different positions for the
shift lever.
See “Range Selection Mode” later in this section.
PARK (P):This position locks your rear wheels. It
is the best position to use when you start the engine
because your vehicle cannot move easily.
Hydra-Matic®4-Speed Automatic Transmission
Allison Transmission®or Hydra-Matic®6-Speed
Automatic Transmission
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When parked on a hill, especially when the vehicle
has a heavy load, you might notice an increase in
the effort to shift out of Park. See Torque Lock
(Automatic Transmission) underShifting Into
Park (P) on page 163for more information.
{CAUTION:
It is dangerous to get out of your vehicle
if the shift lever is not fully in PARK (P)
with the parking brake rmly set. Your
vehicle can roll.
Do not leave your 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 your vehicle will not
move, even when you are on fairly level
ground, always set your parking brake
and move the shift lever to PARK (P). See
Shifting Into Park (P) on page 163.Ifyou
are pulling a trailer, seeTowing a Trailer
on page 445.
{CAUTION:
If you have Four-Wheel Drive, your vehicle
will be free to roll — even if your shift lever
is in PARK (P) — if your transfer case is in
NEUTRAL. So, be sure the transfer case is
in a drive gear, Two-Wheel Drive High or
Four-Wheel Drive High or Four-Wheel Drive
Low — not in NEUTRAL. SeeShifting Into
Park (P) on page 163.
REVERSE (R):Use this gear to back up.
Notice:Shifting to REVERSE (R) while your
vehicle is moving forward could damage the
transmission. The repairs would not be covered
by your warranty. Shift to REVERSE (R) only
after your vehicle is stopped.
To rock your vehicle back and forth to get out of
snow, ice, or sand without damaging your
transmission, seeIf Your Vehicle is Stuck in Sand,
Mud, Ice, or Snow on page 422.
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Four-Wheel Drive
If your vehicle has Four-Wheel Drive, you can
send the engine’s driving power to all four wheels
for extra traction. To get the most satisfaction
out of Four-Wheel Drive, you must be familiar with
its operation. Read the part that follows before
using Four-Wheel Drive. See the appropriate text
for the transfer case in your vehicle.
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.
While driving on clean dry pavement and during
tight turns, you may experience vibration in
the steering system.
Front Axle Locking Feature
The front axle locks and unlocks automatically
when you shift the transfer case. Some delay for
the axle to lock or unlock is normal.
Manual Transfer Case
The transfer case shift lever is on the oor to the
right of the driver. Use this lever to shift into
and out of Four-Wheel Drive.
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If the knob is turned to the Four-Wheel-Drive High,
or Two-Wheel-Drive High switch position when
your vehicle is in gear and/or moving, the
Four-Wheel-Drive High, or Two-Wheel-Drive High
indicator light will ash 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 NEUTRAL (N).
Shifting into NEUTRAL
To shift the transfer case to 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. SeeParking Brake on
page 162for more information.
3. Start the vehicle or turn the ignition to RUN.
4. Shift the transmission to NEUTRAL (N).5. Shift the transfer case to
Two-Wheel-Drive High.
6. Turn the transfer case dial clockwise to
NEUTRAL till it stops and hold it for
10 seconds. Then slowly release the dial to
the four low position. The NEUTRAL light will
come on when the transfer case shift to
NEUTRAL is complete.
7. If the engine is running, verify that the
transmission is in NEUTRAL (N) by shifting
the transmission to REVERSE (R) for
one second, then shift the transmission to
DRIVE (D) for one second.
8. Turn the ignition to ACCESSORY, which will
turn the engine off.
9. Place the transmission shift lever in PARK (P).
10. Release the parking brake prior to moving
the vehicle.
11. Turn the ignition to LOCK.
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3. Start the vehicle or turn the ignition to RUN.
4. Put the transmission in NEUTRAL (N).
5. Shift the transfer case to Two-Wheel
Drive High.
6. Turn the transfer case dial clockwise to
NEUTRAL till it stops and hold it for
10 seconds. Then slowly release the dial to
the four low position. The NEUTRAL light will
come on when the transfer case shift to
NEUTRAL is complete.
7. If the engine is running, make sure that the
transmission is in NEUTRAL (N) by shifting
the transmission to REVERSE (R) for
one second, then shift the transmission to
DRIVE (D) for one second.
8. Turn the ignition to ACCESSORY, which will
turn the engine off.
9. Place the transmission shift lever in PARK (P).
10. Release the parking brake prior to moving
the vehicle.
11. Turn the ignition to LOCK.Shifting Out of NEUTRAL
To shift out of NEUTRAL do the following:
1. Set the parking brake and apply the regular
brake pedal.
2. Shift the transmission to NEUTRAL (N) and
turn the ignition to RUN with the engine off.
3. Turn the transfer case dial to Two-Wheel-Drive
High, Four-Wheel-Drive High, AUTO.
After the transfer case has shifted out of
NEUTRAL the 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 ashing could damage the transfer
case. To help avoid damaging your vehicle,
always wait for the mode indicator lights
to stop ashing before shifting the
transmission into gear.
5. Start the engine and shift the transmission to
the desired position.
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