2020 GMC ACADIA automatic transmission

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13687875) - 2020 - CRC - 10/28/19
Driving and Operating 193
Caution (Continued)
least 15 seconds between each
try, to let the cranking motor
cool down.
2. If the engine does not start after five to 10 seconds,
especially in very cold weather
(below −18 °C or 0 °F), 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 press ENGINE START/
STOP, 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 button and
the 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.
Stop/Start System
The Stop/Start system will shut off
the engine to help conserve fuel.
It has components designed for the
increased number of starts.
{Warning
The automatic engine Stop/Start
feature causes the engine to shut
off while the vehicle is still on. Do
not exit the vehicle before shifting
to P (Park). The vehicle may
restart and move unexpectedly.
Always shift to P (Park), and then
turn the ignition off before exiting
the vehicle.
Auto Engine Stop/Start
When the brakes are applied and
the vehicle is at a complete stop,
the engine may turn off. When
stopped, the tachometer displays
AUTO STOP. See
Tachometer
0 121. When the brake pedal is
released or the accelerator pedal is
pressed, the engine will restart.
To maintain vehicle performance,
other conditions may cause the
engine to automatically restart
before the brake pedal is released.
Auto Stops may not occur and/or
auto restarts may occur because:
. The climate control settings
require the engine to be running
to cool or heat the vehicle
interior.
. The vehicle battery charge
is low.
. The vehicle battery has recently
been disconnected.
. Minimum vehicle speed has not
been reached since the last
Auto Stop

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13687875) - 2020 - CRC - 10/28/19
194 Driving and Operating
.The accelerator pedal is
pressed.
. The engine or transmission is
not at the required operating
temperature.
. The outside temperature is not
in the required operating range.
. The vehicle is in any gear other
than D (Drive).
. Tow/Haul Mode or other driver
modes have been selected.
. The vehicle is on a steep hill or
grade.
. The driver door has been
opened or driver seat belt has
been unbuckled.
. The hood has been opened.
. The Auto Stop has reached the
maximum allowed time. Auto Stop Disable Switch
If equipped, the automatic engine
Stop/Start feature can be disabled
and enabled by pressing the switch
with the
hsymbol. Auto Stop is
enabled each time you start the
vehicle.
When
his illuminated, the system
is enabled.
Engine Heater
The engine heater can provide
easier starting and better fuel
economy during engine warm-up in
cold weather conditions at or below
−18 °C (0 °F). Vehicles with an
engine heater should be plugged in
at least four hours before starting.
An internal thermostat in the
plug-end of the cord may exist,
which will prevent engine heater
operation at temperatures above
−18 °C (0 °F).
{Warning
Do not plug in the engine block
heater while the vehicle is parked
in a garage or under a carport.
Property damage or personal
injury may result. Always park the
vehicle in a clear open area away
from buildings or structures.

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13687875) - 2020 - CRC - 10/28/19
Driving and Operating 197
Shifting Into Park
{Warning
It can be dangerous to get out of
the vehicle if the vehicle is not in
P (Park) with the parking brake
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 Tips0246.
To shift into P (Park): 1. Hold the brake pedal down and set the parking brake. See
Electric Parking Brake 0207.
2. Press P (Park).
3. Turn the ignition off.
Leaving the Vehicle with the
Engine Running
{Warning
It can be dangerous to leave the
vehicle with the engine running.
It could overheat and catch fire.
It is dangerous to get out of the
vehicle if the vehicle is not in
P (Park) with the parking brake
set. The vehicle can roll.
Do not leave the vehicle when the
engine is running. 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
shift the vehicle to P (Park). See
Shifting Into Park 0197. If you
are towing a trailer, see Driving
Characteristics and Towing Tips
0 246. If you have to leave the vehicle with
the engine running, the vehicle must
be in P (Park) with the parking
brake set.
Confirm that the vehicle is 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.
On certain steep grades, the
transmission will automatically set
the parking brake to prevent
torque lock.

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13687875) - 2020 - CRC - 10/28/19
Driving and Operating 201
Warning (Continued)
.There are holes or openings
in the vehicle body from
damage or aftermarket
modifications that are not
completely sealed.
If unusual fumes are detected or
if it is suspected that exhaust is
coming into the vehicle: . Drive it only with the
windows completely down.
. Have the vehicle repaired
immediately.
Never park the vehicle with the
engine running in an enclosed
area such as a garage or a
building that has no fresh air
ventilation.
Running the Vehicle
While Parked
It is better not to park with the
engine running.
If the vehicle is left with the engine
running, follow the proper steps to
be sure the vehicle will not move.
See Shifting Into Park 0197 and
Engine Exhaust 0200.
If parking on a hill and pulling a
trailer, see Driving Characteristics
and Towing Tips 0246.
Automatic
Transmission
The shift switches are on the center
stack. The selected gear position
will illuminate red on the shift switch,
while all others will be displayed in
white. If the shift is not immediate,
as in very cold conditions, the
indicator on the shift switch may
flash until it is fully engaged.
The transmission does not operate
when the vehicle is off.
If the vehicle is in ACC/
ACCESSORY, the transmission can
be shifted into P (Park).

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13687875) - 2020 - CRC - 10/28/19
202 Driving and Operating
If ENGINE START/STOP is pressed
twice while at a relatively high
speed, the engine will turn off and
the transmission will automatically
shift to N (Neutral). Once the vehicle
is stopped, P (Park) can be
selected.
P :This position locks the drive
wheels. Use P (Park) when starting
the vehicle to ensure the vehicle
does not move.
{Warning
It is dangerous to get out of the
vehicle if the transmission is not
in P (Park) with the parking brake
set. The vehicle can roll.
Do not leave the vehicle when the
engine is running. If the engine
has been left running, the vehicle
can move suddenly. You or others
could be injured. To be sure the
vehicle will not move, even when
on fairly level ground, always set
the parking brake and place the
(Continued)
Warning (Continued)
transmission into P (Park). See
Shifting Into Park0197 and
Driving Characteristics and
Towing Tips 0246.
This vehicle is equipped with an
electronically controlled
transmission. The R (Reverse) and
D (Drive) shift switches are
designed to prevent inadvertent
shifting out of P (Park) unless the
ignition is on, and the brake pedal is
applied.
When the vehicle is stopped, press
ENGINE START/STOP to turn off
the vehicle. The transmission will
shift to P (Park) automatically.
The vehicle will not shift into
P (Park) if it is moving too fast. Stop
the vehicle and shift into P (Park).
To shift in and out of P (Park), see
Shifting Into Park 0197 and
Shifting out of Park 0198.
R : Use this gear to back up. If the vehicle is shifted from either
R (Reverse) to D (Drive),
or D (Drive) to R (Reverse) while the
speed is too high, the vehicle will
shift to N (Neutral). Reduce the
vehicle speed and try the shift
again.
To shift into R (Reverse):
1. Bring the vehicle to a complete stop.
2. Pull the R (Reverse) switch on the center stack.
To shift out of R (Reverse): 1. Bring the vehicle to a complete stop.
2. Shift to the desired gear.
At low vehicle speeds, R (Reverse)
can be used 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 0185.
N : 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.

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13687875) - 2020 - CRC - 10/28/19
Driving and Operating 203
{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.
Caution
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.
Caution
The vehicle is not designed to
stay in N (Neutral) for extended
periods of time. It will
automatically shift into P (Park).
To shift into N (Neutral), press the
N (Neutral) switch until the N
indicator displays.
To shift out of N (Neutral): 1. Bring the vehicle to a complete stop.
2. Shift to the desired gear.
Car Wash Mode
This vehicle includes a Car Wash
Mode that allows the vehicle to
remain in N (Neutral) for use in
automatic car washes.
Car Wash Mode is not to be used
for vehicle towing. If the vehicle
needs to be towed, see Towing the
Vehicle 0338
Caution
The vehicle is not designed to
stay in N (Neutral) for extended
periods of time. It will
automatically shift into P (Park) if
left in Car Wash Mode.
Car Wash Mode (Engine Off –
Driver in Vehicle)
To place the vehicle in N (Neutral)
with the engine off and the vehicle
occupied:
1. Drive to the entrance of the car wash.
2. Apply the brake pedal.
3. Shift to N (Neutral).
4. Turn off the engine and release the brake pedal.
5. The indicator should continue to show N. If it does not, start
the engine and repeat
Steps 2–4.
6. The vehicle is now ready for the car wash.

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13687875) - 2020 - CRC - 10/28/19
204 Driving and Operating
Car Wash Mode (Engine Off–
Driver out of Vehicle)
To place the vehicle in N (Neutral)
with the engine off and the vehicle
unoccupied:
1. Drive to the entrance of the car wash.
2. Apply the brake pedal.
3. Open the door.
4. Shift to N (Neutral).
5. Turn off the engine and release the brake pedal.
6. The indicator should continue to show N. If it does not, start
the engine and repeat
Steps 2–5.
7. Exit the vehicle and close the door. The vehicle is now ready
for the car wash.
8. The vehicle may automatically shift to P (Park) upon re-entry. Car Wash Mode (Engine On
–
Driver in Vehicle)
To place the vehicle in N (Neutral)
with the engine on and the vehicle
occupied:
1. Drive to the entrance of the car wash.
2. Apply the brake pedal.
3. Shift to N (Neutral).
4. Release the brake pedal. The vehicle is now ready for the
car wash.
Car Wash Mode (Engine On –
Driver out of Vehicle)
To place the vehicle in N (Neutral)
with the engine on and the vehicle
unoccupied:
1. Drive to the entrance of the car wash.
2. Apply the brake pedal.
3. Open the door.
4. Shift to N (Neutral), then release the brake pedal. 5. The indicator should continue
to show N. If it does not, repeat
Steps 2–4.
6. Exit the vehicle and close the door. The vehicle is now ready
for the car wash.
7. The vehicle may automatically shift to P (Park) upon re-entry.
Caution
A transmission hot message may
display if the automatic
transmission fluid is too hot.
Driving under this condition can
damage the vehicle. Stop and idle
the engine to cool the automatic
transmission fluid. This message
clears when the transmission fluid
has cooled sufficiently.
D : This position is for normal
driving. If more power is needed for
passing, press the accelerator
pedal down.

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13687875) - 2020 - CRC - 10/28/19
Driving and Operating 213
4AWD (AWD Only) :AWD Mode
provides drive torque to all four
wheels. Select AWD to improve
traction and control on slippery road
surfaces, such as gravel, sand, wet
pavement, snow, and ice. When in
AWD Mode, the AWD Mode
indicator will be on. The AWD Mode
will stay selected until the mode is
changed.
AWD is active in AWD, Sport, Tow/
Haul, and Off-Road Modes.
Sport, Tow/Haul, and Off-Road
Modes are cancelled with each
ignition cycle and will return to Tour
(FWD) Mode.
When using a compact spare tire on
an AWD vehicle, the system
automatically detects the compact
spare and reduces AWD
performance to protect the system.
To restore full AWD operation and
prevent excessive wear on the
system, replace the compact spare
with a full-size tire as soon as
possible. See Compact Spare Tire
0 334.6Snow/Ice (FWD Only) : Snow/
Ice Mode improves vehicle
acceleration on snow and ice
covered roads.
_Tow/Haul : This feature can
assist when towing or hauling a
heavy load. Use this mode to assist
in maintaining desired vehicle
speeds when driving on downhill
grades by using the engine and
transmission. For AWD vehicles,
choosing Tow/Haul Mode also
engages AWD mode. See Driving
Characteristics and Towing Tips
0 246.
Automatic Engine Grade Braking
Automatic Engine Grade Braking
assists when driving downhill.
It maintains vehicle speed by
automatically implementing a shift
pattern that uses the engine and the
transmission to slow the vehicle.
The system will automatically
command downshifts to reduce
vehicle speed. The normal shift
pattern will return once the vehicle
is on a low grade or when the
accelerator pedal is pressed. While in the Electronic Range
Select (ERS) mode, grade braking
is deactivated, allowing the driver to
select a range and limiting the
highest gear available. Grade
braking is available for normal
driving and in Tow/Haul Mode.
See
Automatic Transmission 0201.
7Off-Road (AWD Only) : Use this
mode for off-road recreational
driving. Choosing Off-Road Mode
also engages AWD Mode. For more
information on Off-Road Mode, see
Off-Road Driving 0178.