2021 GMC ACADIA automatic transmission

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-14608671) - 2021 - CRC - 10/26/20
Driving and Operating 199
Driving and Operating
Driving Information
Driving for Better Fuel Economy . . . . . . 200
Distracted Driving . . . . . . . . . . . . . . . . . . . . . 200
Defensive Driving . . . . . . . . . . . . . . . . . . . . . . 201
Impaired Driving . . . . . . . . . . . . . . . . . . . . . . . 201
Control of a Vehicle . . . . . . . . . . . . . . . . . . . 201
Braking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
Steering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
Off-Road Recovery . . . . . . . . . . . . . . . . . . . . . 203
Loss of Control . . . . . . . . . . . . . . . . . . . . . . . . 203
Off-Road Driving . . . . . . . . . . . . . . . . . . . . . . . 203
Driving on Wet Roads . . . . . . . . . . . . . . . . . 207
Hill and Mountain Roads . . . . . . . . . . . . . . 207
Winter Driving . . . . . . . . . . . . . . . . . . . . . . . . 208
If the Vehicle Is Stuck . . . . . . . . . . . . . . . . . 209
Vehicle Load Limits . . . . . . . . . . . . . . . . . . . 209
Starting and Operating
New Vehicle Break-In . . . . . . . . . . . . . . . . . . 212
Ignition Positions . . . . . . . . . . . . . . . . . . . . . . 213
Starting the Engine . . . . . . . . . . . . . . . . . . . . 214
Stop/Start System . . . . . . . . . . . . . . . . . . . . . 215
Engine Heater . . . . . . . . . . . . . . . . . . . . . . . . . 216
Retained Accessory Power (RAP) . . . . . . . 217Shifting Into Park . . . . . . . . . . . . . . . . . . . . . . 217
Shifting out of Park . . . . . . . . . . . . . . . . . . . . 218
Parking over Things That Burn . . . . . . . . . 219
Active Fuel Management . . . . . . . . . . . . . . 219
Extended Parking . . . . . . . . . . . . . . . . . . . . . . 219
Engine Exhaust
Engine Exhaust . . . . . . . . . . . . . . . . . . . . . . . . 219
Running the Vehicle While Parked . . . . . 220
Automatic Transmission
Automatic Transmission . . . . . . . . . . . . . . . 220
Manual Mode . . . . . . . . . . . . . . . . . . . . . . . . . 223
Tow/Haul Mode . . . . . . . . . . . . . . . . . . . . . . . 224
Drive Systems
All-Wheel Drive . . . . . . . . . . . . . . . . . . . . . . . . 224
Brakes
Electric Brake Boost . . . . . . . . . . . . . . . . . . . 224
Antilock Brake System (ABS) . . . . . . . . . . 224
Electric Parking Brake . . . . . . . . . . . . . . . . . . 224
Brake Assist . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
Hill Start Assist (HSA) . . . . . . . . . . . . . . . . . 226
Ride Control Systems
Traction Control/Electronic Stability
Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
Hill Descent Control (HDC) . . . . . . . . . . . . . 228
Driver Mode Control . . . . . . . . . . . . . . . . . . . 228
Cruise Control
Cruise Control . . . . . . . . . . . . . . . . . . . . . . . . . 230
Adaptive Cruise Control (Advanced) . . . . 232
Driver Assistance Systems
Driver Assistance Systems . . . . . . . . . . . . . 239
Assistance Systems for Parking or Backing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241
Assistance Systems for Driving . . . . . . . . 245
Forward Collision Alert (FCA) System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245
Automatic Emergency Braking (AEB) . . . 247
Front Pedestrian Braking (FPB) System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248
Side Blind Zone Alert (SBZA) . . . . . . . . . . 250
Lane Change Alert (LCA) . . . . . . . . . . . . . . . 250
Lane Keep Assist (LKA) . . . . . . . . . . . . . . . . . 252

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-14608671) - 2021 - CRC - 10/26/20
Driving and Operating 215
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
Tachometer0102. 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
.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 transmission is shifted out of
D (Drive) to any gear other than P (Park).
.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/Start Disable Switch
The automatic engine Stop/Start feature can
be disabled and enabled by pressing
h.
Auto Stop/Start is enabled each time you
start the vehicle.

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-14608671) - 2021 - CRC - 10/26/20
218 Driving and Operating
able to release the EPB using the EPB
switch. It should automatically release when
the vehicle is shifted out of P (Park).
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). SeeShifting Into
Park 0217. If you are towing a trailer,
see Driving Characteristics and Towing
Tips 0256. 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.
If torque lock does occur, the 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
This vehicle is equipped with an electronic
transmission. If the vehicle has an
uncharged battery or a battery with low
voltage, try charging or jump starting the
battery. See Jump Starting - North America
0 332.
To shift out of P (Park): 1. Ensure the engine is running.
2. Apply the brake pedal.
3. Press or pull the desired shift switch on the center stack.
The P indicator will turn white and the gear
indicator will turn red when the vehicle is
no longer in P (Park).
If the vehicle cannot shift from P (Park), a
Driver Information Center (DIC) message will
be displayed. Check that the ignitionis on,
the engine is running, and the brake pedal
is applied when you are attempting to shift
out of P (Park). If all of these are met but
the vehicle will not shift out of P (Park), see
your dealer for service.

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-14608671) - 2021 - CRC - 10/26/20
220 Driving and Operating
Warning (Continued)
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
0 217 and
Engine Exhaust 0219.
If parking on a hill and pulling a trailer, see
Driving Characteristics and Towing Tips
0 256.
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). 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
transmission into P (Park). See Shifting
Into Park 0217 and
Driving Characteristics and Towing Tips
0 256.

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-14608671) - 2021 - CRC - 10/26/20
Driving and Operating 221
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), seeShifting
Into Park 0217 and
Shifting out of Park 0218.
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 0209.
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.
{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.

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-14608671) - 2021 - CRC - 10/26/20
222 Driving and Operating
Car Wash Mode is not to be used for vehicle
towing. If the vehicle needs to be towed,
seeTowing the Vehicle 0334
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. 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.

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-14608671) - 2021 - CRC - 10/26/20
Driving and Operating 223
D :This position is for normal driving.
If more power is needed for passing, press
the accelerator pedal down.
To shift into D (Drive):
1. Bring the vehicle to a complete stop.
2. Pull the D (Drive) switch on the center stack.
To shift out of D (Drive): 1. Bring the vehicle to a complete stop.
2. Shift to the desired gear.
Downshifting the transmission in slippery
road conditions could result in skidding. See
“Skidding” underLoss of Control 0203.
Caution
Spinning the tires or holding the vehicle
in one place on a hill using only the
accelerator pedal may damage the
transmission. The repair will not be
covered by the vehicle warranty. If the
vehicle is stuck, do not spin the tires.
When stopping on a hill, use the brakes
to hold the vehicle in place. If equipped with the 2.0L L4 engine, engine
speeds may be increased while driving at
highway speeds while the engine is still
warming up.
L :
This position gives you access to gear
ranges. This provides more engine braking
but lower fuel economy than D (Drive). You
can use it on very steep hills, or in deep
snow or mud. See Manual Mode0223.
Manual Mode
Electronic Range Select (ERS) Mode
ERS or manual mode allows for the selection
of the range of gear positions. Use this
mode when driving downhill or towing a
trailer to limit the top gear and vehicle speed. The shift position indicator within the
Driver Information Center (DIC) will display a
number next to the L indicating the highest
available gear under manual mode and the
driving conditions when manual mode was
selected.
To use this feature:
1. With the vehicle in D (Drive), press the L (Low) button.
2. Press the plus or minus button on the center stack to increase or decrease the
gear range available.
When shifting to L (Low), the transmission
will shift to a preset lower gear range. For
this preset range, the highest gear available
is displayed next to the L in the DIC. See
Driver Information Center (DIC) (Base) 0115
or
Driver Information Center (DIC) (Midlevel and
Uplevel) 0117. All gears below that number
are available to use. For example, when
4 (Fourth) is shown next to the L, 1 (First)
through 4 (Fourth) gears are shifted
automatically. To shift to 5 (Fifth) gear, press
the + (Plus) button or shift into D (Drive).
L (Low) will prevent shifting to a lower gear
range if the engine speed is too high.
If vehicle speed is not reduced within the

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-14608671) - 2021 - CRC - 10/26/20
Driving and Operating 229
Driver Mode Control Knob (AWD)
Driver Mode Control Knob (FWD)
5orqTour (FWD) :Vehicle is in Tour
(FWD) Mode. Use this mode during normal
driving conditions. See Driving for Better Fuel
Economy 0200. Tour (FWD) Mode operates
in Front-Wheel Drive to improve fuel
economy.
8Sport : Sport Mode improves vehicle
handling and acceleration on dry pavement.
When active, Sport Mode modifies steering
efforts, transmission shifting, AWD torque,
and suspension tuning (when properly
equipped). For AWD vehicles, choosing Sport
Mode also engages AWD Mode.
The Performance Algorithm Liftfoot (PAL)
feature is enabled in Sport Mode. PAL allows
the transmission to hold the current gear
after a quick release of a heavily applied
accelerator pedal. This provides greater
engine braking and enhanced vehicle control.
When PAL is activated, there may be an
additional green gear symbol which appears
in the instrument cluster display. See Gear
Shifting Light 0110.
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 0331.
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
0 256.