Page 275 of 468

Black plate (17,1)GMC Acadia/Acadia Denali Owner Manual - 2012
Driving and Operating 9-17
If the vehicle cannot be pulled
over, and must be shut off while
driving, turn the ignition to
ACC/ACCESSORY.
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
does not 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. This position can
also be used for service and
diagnostics, and to verify the
proper operation of the malfunction
indicator lamp as may be required
for emission inspection purposes.
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.
Key Lock Release
Vehicles with an automatic
transmission are equipped with an
electronic key lock release system.
This system is to prevent ignition
key removal unless the shift lever is
in P (Park).
The key lock release will not work
if the battery is charged less than
9‐volts, or uncharged. Try charging
or jump starting the battery. See
Jump Starting on page 10‑78.
Page 279 of 468

Black plate (21,1)GMC Acadia/Acadia Denali Owner Manual - 2012
Driving and Operating 9-21
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).
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 10‑78 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.
Page 393 of 468

Black plate (81,1)GMC Acadia/Acadia Denali Owner Manual - 2012
Vehicle Care 10-81
10. Now start the vehicle with thegood battery and run the
engine for a while.
11. Try to start the vehicle that had the dead battery. If it will not
start after a few tries, it
probably needs service.
Notice: If the jumper cables are
connected or removed in the
wrong order, electrical shorting
may occur and damage the
vehicle. The repairs would not be
covered by the vehicle warranty.
Always connect and remove the
jumper cables in the correct
order, making sure that the
cables do not touch each other
or other metal.
Jumper Cable Removal
A. Heavy, Unpainted Metal Engine Part or Remote Negative (−)
Terminal
B. Good Battery or Remote Positive (+) and Remote
Negative (−) Terminals
C. Dead Battery or Remote Positive (+) Terminal To disconnect the jumper cables
from both vehicles, do the following:
1. Disconnect the black
negative (−) cable from the
vehicle that had the dead
battery.
2. Disconnect the black negative (−) cable from the
vehicle with the good battery.
3. Disconnect the red positive (+) cable from the vehicle with the
good battery.
4. Disconnect the red positive (+) cable from the other vehicle.