
Black plate (18,1)GMC Acadia/Acadia Denali Owner Manual - 2011
9-18 Driving and Operating
Ignition Positions
The ignition switch has four different
positions.
In order to shift out of P (Park),
the ignition must be in ON/RUN or
ACC/ACCESSORY and the brake
pedal must be applied.Notice:
Using a tool to force the
key to turn in the ignition could
cause damage to the switch or
break the key. Use the correct
key, make sure it is all the way in,
and turn it only with your hand.
If the key cannot be turned by
hand, see your dealer.
((STOPPING THE ENGINE/
LOCK/OFF): When the vehicle is
stopped, turn the ignition switch to
LOCK/OFF to turn the engine off.
Retained Accessory Power (RAP)
will remain active. See Retained
Accessory Power (RAP) on
page 9‑21.
This position locks the ignition
and transmission. The key can
be removed in LOCK/OFF.
Do not turn the engine off when the
vehicle is moving. This will cause
a loss of power assist in the brake
and steering systems and disable
the airbags. In an emergency:
1. Brake using a firm and steady
pressure. Do not pump the
brakes repeatedly. This may
deplete power assist, requiring
increased brake pedal force.
2. Shift the vehicle to N (Neutral). This can be done while the
vehicle is moving. After shifting
to N (Neutral), firmly apply the
brakes and steer the vehicle to
a safe location.
3. Come to a complete stop, shift to P (Park), and turn the ignition
to LOCK/OFF. On vehicles with
an automatic transmission, the
shift lever must be in P (Park) to
turn the ignition switch to the
LOCK/OFF position.
4. Set the parking brake. See Parking Brake on
page 9‑30.

Black plate (19,1)GMC Acadia/Acadia Denali Owner Manual - 2011
Driving and Operating 9-19
The steering can bind with the
wheels turned off center. If this
happens, move the steering wheel
from right to left while turning the
key to ACC/ACCESSORY. If this
doesn't work, then the vehicle
needs service.
ACC (ACC/ACCESSORY):This
is the position in which you can
operate the electrical accessories
or items plugged into the accessory
power outlets. This position unlocks
the ignition and steering wheel. Use
this position if the vehicle must be
pushed or towed.
R(ON/RUN): This position can
be used to operate the electrical
accessories and to display some
instrument panel warning and
indicator lights. The switch stays
in this position when the engine
is running. The transmission is
also unlocked in this position. If you leave the key in the
ACC/ACCESSORY or ON/RUN
position with the engine off, the
battery could be drained. You may
not be able to start the vehicle if
the battery is allowed to drain for
an extended period of time.
/(START):
This is the position
that starts the engine. When the
engine starts, release the key.
The ignition switch will return to
ON/RUN for driving.
Starting the Engine
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.
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. Starting Procedure
1. With your foot off the accelerator
pedal, turn the ignition to START.
When the engine starts, let go
of the key. The idle speed
will slow down as the engine
warms. 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, cranking will be stopped
after 15 seconds to prevent
cranking motor damage.

Black plate (20,1)GMC Acadia/Acadia Denali Owner Manual - 2011
9-20 Driving and Operating
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 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
briefly 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. If you do not, the engine
might not perform properly. Any
resulting damage would not be
covered by the vehicle warranty.Engine 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.
Some models may have an internal
thermostat in the cord 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. It is routed
around the windshield washer
fluid reservoir.
3. Plug the cord into a normal, grounded 110-volt AC outlet.

Black plate (21,1)GMC Acadia/Acadia Denali Owner Manual - 2011
Driving and Operating 9-21
{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.
Retained Accessory
Power (RAP)
These vehicle accessories can be
used for up to 10 minutes after the
ignition key is turned off:
.Audio System
.Power Windows
.Sunroof (if equipped)
Power to the windows and sunroof
will work up to 10 minutes or until a
door is opened.
The radio continues to work for
10 minutes or until the driver's door
is opened.
For an additional 10 minutes of
operation, close all the doors and
turn the key to ON/RUN and then
back to LOCK/OFF.
All these features will work when
the key is in the ON/RUN or
ACC/ACCESSORY positions.
Shifting Into Park
{WARNING
It can be dangerous to get out of
the vehicle if the shift lever is not
fully in P (Park) with the parking
brake firmly 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. If you are pulling a
trailer, see Driving Characteristics
and Towing Tips on page 9‑47.
1. Hold the brake pedal down and set the parking brake.
See Parking Brake on page 9‑30
for more information.

Black plate (22,1)GMC Acadia/Acadia Denali Owner Manual - 2011
9-22 Driving and Operating
2. Move the shift lever into P (Park)by holding in the button on the
shift lever and pushing the shift
lever all the way toward the front
of the vehicle.
3. Turn the ignition key to LOCK/OFF.
4. Remove the key and take it with you. If you can leave the vehicle
with the ignition key in your
hand, the vehicle is in P (Park).
Leaving the Vehicle with the
Engine Running
{WARNING
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
firmly set. And, if you leave the
(Continued)
WARNING (Continued)
vehicle with the engine running,
it could overheat and even catch
fire. You or others could be
injured. Do not leave the vehicle
with the engine running.
If you have to leave the vehicle
with the engine running, be sure
the vehicle is in P (Park) and the
parking brake is firmly 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 first pushing the button.
If you can, it means that the shift
lever was not fully locked in
P (Park).
Torque Lock
Torque lock is when the weight
of the vehicle puts too much
force on the parking pawl in the
transmission. This happens when
parking on a hill and shifting the
transmission into P (Park) is not
done properly and then it is difficult
to shift out of P (Park). To prevent
torque lock, set the parking brake
and then shift into P (Park). To find
out how, see “Shifting Into Park”
listed previously.
If torque lock does occur, your
vehicle may need to be pushed
uphill by another vehicle to relieve
the parking pawl pressure, so you
can shift out of P (Park).

Black plate (23,1)GMC Acadia/Acadia Denali Owner Manual - 2011
Driving and Operating 9-23
Shifting Out of Park
The vehicle is equipped with
an electronic shift lock release
system. The shift lock release is
designed to:
.Prevent ignition key removal
unless the shift lever is in
P (Park) with the shift lever
button fully released, and
.Prevent movement of the shift
lever out of P (Park), unless
the ignition is in ON/RUN or
ACC/ACCESSORY and the
regular brake pedal is applied.
The shift lock release is always
functional except in the case of an
uncharged or low voltage (less than
9 volt) battery. If the vehicle has an uncharged
battery or a battery with low voltage,
try charging or jump starting the
battery. See
Jump Starting on
page 10‑83 for more information.
To shift out of P (Park):
1. Apply the brake pedal.
2. Press the shift lever button.
3. Move the shift lever to the desired position.
If you still are unable to shift out of
P (Park):
1. Fully release the shift lever button.
2. While holding down the brake pedal, press the shift lever
button again.
3. Move the shift lever to the desired position.
If you still cannot move the shift
lever from P (Park), see your dealer.
Parking Over Things
That Burn
{WARNING
Things that can burn could touch
hot exhaust parts under the
vehicle and ignite. Do not park
over papers, leaves, dry grass,
or other things that can burn.

Black plate (26,1)GMC Acadia/Acadia Denali Owner Manual - 2011
9-26 Driving and Operating
You must fully apply the regular
brake first and then press the shift
lever button before shifting 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, then 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 9‑23.
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, see If
the Vehicle is Stuck on page 9‑11. 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. Also, use
N (Neutral) when the vehicle is
being towed.
{WARNING
Shifting into a drive gear while the
engine is running at high speed is
dangerous. Unless your foot is
firmly 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 56 km/h
(35 mph), push the accelerator
pedal about halfway down.
.Going about 56 km/h (35 mph) or
more, push the accelerator all
the way down.
Notice: If the vehicle seems to
accelerate slowly or not shift
gears when you go faster, and
you continue to drive the vehicle
that way, you could damage the
transmission. Have the vehicle
serviced right away. You can
drive in L (Low) when you are
driving less than 56 km/h (35 mph)
and D (Drive) for higher speeds
until then.
If the vehicle is stopped on
a hill, with your foot off the brake
pedal, the vehicle may roll.

Black plate (30,1)GMC Acadia/Acadia Denali Owner Manual - 2011
9-30 Driving and Operating
Parking Brake
To set the parking brake, hold the
regular brake pedal down, then
push the parking brake pedal down.
If the ignition is on, the brake
system warning light will come on.
SeeBrake System Warning Light on
page 5‑20. Notice:
Driving with the parking
brake on can overheat the brake
system and cause premature
wear or damage to brake system
parts. Make sure that the parking
brake is fully released and the
brake warning light is off before
driving.
To release the parking brake, hold
the regular brake pedal down, then
push down momentarily on the
parking brake pedal until you feel
the pedal release. Slowly pull your
foot up off the park brake pedal.
If the parking brake is not released
when you begin to drive, the brake
system warning light will be on and
a chime will sound warning you that
the parking brake is still on.
If you are towing a trailer and
are parking on a hill, see Driving
Characteristics and Towing Tips on
page 9‑47.
Brake Assist
This vehicle has a brake assist
feature designed to assist the
driver in stopping or decreasing
vehicle speed in emergency
driving conditions. This feature
uses the stability system hydraulic
brake control module to supplement
the power brake system under
conditions where the driver has
quickly and forcefully applied the
brake pedal in an attempt to quickly
stop or slow down the vehicle.
The stability system hydraulic brake
control module increases brake
pressure at each corner of the
vehicle until the ABS activates.
Minor brake pedal pulsation or
pedal movement during this time
is normal and the driver should
continue to apply the brake pedal
as the driving situation dictates.
The brake assist feature will
automatically disengage when
the brake pedal is released or
brake pedal pressure is quickly
decreased.