engine GMC ACADIA 2015 Repair Manual

Black plate (24,1)GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-7576030) - 2015 - CRC - 8/18/14
9-24 Driving and Operating
{Caution
If the vehicle accelerates slowly,
or does not shift gears, the
transmission could be damaged.
Have the vehicle serviced
right away.
If the vehicle is stopped on a hill,
with your foot off the brake pedal,
the vehicle may roll. This is normal
and is due to the torque converter
designed to improve fuel economy
and performance. Use the brake to
hold the vehicle on a hill. Do not use
the accelerator pedal.
L (Low): 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 Mode on page 9-24.
Manual Mode
Electronic Range Select
(ERS) Mode
ERS mode allows you to choose the
top-gear limit of the transmission
and the vehicle's speed while
driving downhill or towing a trailer.
The vehicle has an electronic shift
position indicator within the
instrument cluster. When using the
ERS mode a number will display
next to the L, indicating the current
gear that has been selected.
To use this feature:
1. Move the shift lever to L (Low).
2. Press the plus/minus button on
the shift lever, to increase or
decrease the gear range
available.
When you shift from D (Drive) to
L (Low), the transmission will shift to
a pre-determined lower gear range.
The highest gear available for this
pre-determined range is displayed
next to the L in the DIC. See Driver
Information Center (DIC) on
page 5-23. The number displayed in
the DIC is the highest gear that the
transmission will be allowed to
operate in. This means that all
gears below that number are
available. For example, when
4 (Fourth) is shown next to the L,
1 (First) through 4 (Fourth) gears are
automatically shifted by the vehicle.
The transmission will not shift into
5 (Fifth) until the + (Plus) button is
used or you shift back into D (Drive).

Black plate (25,1)GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-7576030) - 2015 - CRC - 8/18/14
Driving and Operating 9-25
While in L (Low), the transmission
will prevent shifting to a lower gear
range if the engine speed is too
high. You have a brief period of time
to slow the vehicle. If vehicle speed
is not reduced within the time
allowed, the lower gear range shift
will not be completed. You must
further slow the vehicle, then press
the−(Minus) button to the desired
lower gear range.
Automatic Engine Grade Braking is
not available when the ERS is
active. It is available in D (Drive) for
both normal and Tow/Haul mode.
While using the ERS, cruise control
and the Tow/Haul mode can be
used. See “Tow/Haul Mode”
following.Tow/Haul Mode
_
(Tow/Haul): If equipped with
Tow/Haul mode, the button is on the
center stack under the climate
controls.
Press the button to activate the
system. Press it again to deactivate
the system. This feature can assist
when towing or hauling a
heavy load.
When Tow/Haul is activated, the
Tow/Haul symbol will come on in the
instrument cluster. See Driving
Characteristics and Towing Tips on
page 9-46.
Automatic Engine Grade
Braking
Automatic Engine Grade Braking
assists when driving on a downhill
grade. It maintains vehicle speed by
automatically implementing a shift
schedule that uses the engine and
the transmission to slow the vehicle.
The system will automatically
command downshifts to reduce
vehicle speed, until the brake pedal
is no longer being 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 on
page 9-22.

Black plate (26,1)GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-7576030) - 2015 - CRC - 8/18/14
9-26 Driving and Operating
Drive Systems
All-Wheel Drive
Vehicles with this feature transfer
engine power, as required, to all
four wheels. It is fully automatic, and
adjusts itself as needed for road
conditions.
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. SeeCompact Spare Tire
on page 10-68.
Brakes
Antilock Brake
System (ABS)
This vehicle has ABS, an advanced
electronic braking system that helps
prevent a braking skid.
When the vehicle begins to drive
away, ABS checks itself.
A momentary motor or clicking noise
might be heard while this test is
going on, and it might even be
noticed that the brake pedal moves
a little. This is normal.
If there is a problem with ABS, this
warning light stays on. See Antilock
Brake System (ABS) Warning Light
on page 5-19. If driving safely on a wet road and it
becomes necessary to slam on the
brakes and continue braking to
avoid a sudden obstacle, a
computer senses the wheels are
slowing down. If one of the wheels
is about to stop rolling, the computer
will separately work the brakes at
each wheel.
ABS can change the brake pressure
to each wheel, as required, faster
than any driver could. This can help
you steer around the obstacle while
braking hard.
As the brakes are applied, the
computer keeps receiving updates
on wheel speed and controls
braking pressure accordingly.
Remember: ABS does not change
the time needed to get a foot up to
the brake pedal or always decrease
stopping distance. If you get too
close to the vehicle in front of you,
there will not be enough time to
apply the brakes if that vehicle

Black plate (28,1)GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-7576030) - 2015 - CRC - 8/18/14
9-28 Driving and Operating
Brake Assist
The Brake Assist feature is
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.
Hill Start Assist (HSA)
This vehicle has an HSA feature,
which may be useful when the
vehicle is stopped on a grade
sufficient enough to activate HSA.
This feature is designed to prevent
the vehicle from rolling, either
forward or rearward, during vehicle
drive off. After the driver completely
stops and holds the vehicle in a
complete standstill on a grade, HSA
will be automatically activated.
During the transition period between
when the driver releases the brake
pedal and starts to accelerate to
drive off on a grade, HSA holds the
braking pressure for a maximum of
two seconds to ensure that there is
no rolling. The brakes will
automatically release when the
accelerator pedal is applied within
the two-second window. It will not
activate if the vehicle is in a drive
gear and facing downhill, or if the
vehicle is facing uphill and in
R (Reverse).
Ride Control Systems
Traction Control/
Electronic Stability
Control
System Operation
The vehicle has a Traction Control
System (TCS) and StabiliTrak®, an
electronic stability control system.
These systems help limit wheel slip
and assist the driver in maintaining
control, especially on slippery road
conditions.
TCS activates if it senses that any
of the drive wheels are spinning or
beginning to lose traction. When this
happens, TCS applies the brakes to
the spinning wheels and reduces
engine power to limit wheel spin.
StabiliTrak activates when the
vehicle senses a difference between
the intended path and the direction
the vehicle is actually traveling.
StabiliTrak selectively applies
braking pressure to any one of the

Black plate (29,1)GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-7576030) - 2015 - CRC - 8/18/14
Driving and Operating 9-29
vehicle wheel brakes to assist the
driver in keeping the vehicle on the
intended path.
If cruise control is being used and
traction control or StabiliTrak begins
to limit wheel spin, cruise control will
disengage. Cruise control may be
turned back on when road
conditions allow.
Both systems come on
automatically when the vehicle is
started and begins to move. The
systems may be heard or felt while
they are operating or while
performing diagnostic checks. This
is normal and does not mean there
is a problem with the vehicle.
It is recommended to leave both
systems on for normal driving
conditions, but it may be necessary
to turn TCS off if the vehicle gets
stuck in sand, mud, ice, or snow.
SeeIf the Vehicle Is Stuck on
page 9-9 and“Turning the Systems
Off and On” later in this section.
The indicator light for both systems
is in the instrument cluster. This
light will:
.Flash when TCS is limiting
wheel spin.
.Flash when StabiliTrak is
activated.
.Turn on and stay on when either
system is not working.
If either system fails to turn on or to
activate, a message displays in the
Driver Information Center (DIC), and
dcomes on and stays on to
indicate that the system is inactive
and is not assisting the driver in
maintaining control. The vehicle is
safe to drive, but driving should be
adjusted accordingly. If
dcomes on and stays on:
1. Stop the vehicle.
2. Turn the engine off and wait 15 seconds.
3. Start the engine.
Drive the vehicle. If
dcomes on
and stays on, the vehicle may need
more time to diagnose the problem.
If the condition persists, see your
dealer.
Turning the Systems Off
and On
The button for TCS and StabiliTrak
is on the center stack.

Black plate (42,1)GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-7576030) - 2015 - CRC - 8/18/14
9-42 Driving and Operating
Fuel
Use of the recommended fuel is an
important part of the proper
maintenance of this vehicle. When
driving in the U.S. and Canada, to
help keep the engine clean and
maintain optimum vehicle
performance, we recommend using
TOP TIER Detergent Gasolines.
See www.toptiergas.com for a list of
TOP TIER Detergent Gasolines.
Use regular unleaded gasoline
meeting ASTM specification D4814
with a posted octane rating of 87 orhigher. Do not use gasoline with an
octane rating below 87, as it may
cause engine damage and will lower
fuel economy.
Use of Seasonal Fuels
Use summer and winter fuels in the
appropriate season. The fuels
industry automatically modifies the
fuel for the appropriate season.
If fuel is left in the vehicle tank for
long periods of time, driving or
starting could be affected. Drive the
vehicle until the fuel is at one-half
tank or less, then refuel with the
current seasonal fuel.
Prohibited Fuels
Gasolines containing oxygenates
such as ethers and ethanol, as well
as reformulated gasolines, are
available in some cities. If these
gasolines comply with the
previously described specification,
then they are acceptable to use.
However, E85 (85% ethanol) and
other fuels containing more than
15% ethanol must be used only in
FlexFuel vehicles.
{Caution
Do not use fuel containing
methanol. It can corrode metal
parts in the fuel system and also
damage plastic and rubber parts.
That damage would not be
covered under the vehicle
warranty.
Some gasolines, mainly high octane
racing gasolines, can contain an
octane-enhancing additive called
methylcyclopentadienyl manganese
tricarbonyl (MMT). Do not use
gasolines and/or fuel additives with
MMT as they can reduce spark plug
life and affect emission control
system performance. The
malfunction indicator lamp may turn
on. If this occurs, see your dealer
for service.

Black plate (43,1)GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-7576030) - 2015 - CRC - 8/18/14
Driving and Operating 9-43
California Fuel
Requirements
If the vehicle is certified to meet
California Emissions Standards, it is
designed to operate on fuels that
meet California specifications. See
the underhood emission control
label. If this fuel is not available in
states adopting California Emissions
Standards, the vehicle will operate
satisfactorily on fuels meeting
federal specifications, but emission
control system performance might
be affected. The malfunction
indicator lamp could turn on and the
vehicle may not pass a smog-check
test. SeeMalfunction Indicator
Lamp on page 5-15. If this occurs,
return to your authorized dealer for
diagnosis. If it is determined that the
condition is caused by the type of
fuel used, repairs may not be
covered by the vehicle warranty.
Fuels in Foreign
Countries
If planning to drive in countries
outside the U.S. or Canada, the
proper fuel might be hard to find.
Check regional auto club or fuel
retail brand websites for availability
in the country where driving. Never
use leaded gasoline, fuel containing
methanol, manganese, or any other
fuel not recommended. Costly
repairs caused by use of improper
fuel would not be covered by the
vehicle warranty.
Fuel Additives
To keep fuel systems clean, TOP
TIER Detergent Gasoline is
recommended. See Fuel on
page 9-42.
If TOP TIER Detergent Gasoline is
not available, one bottle of Fuel
System Treatment PLUS added to
the fuel tank at every engine oil
change, can help. Fuel System
Treatment PLUS is the only gasoline additive recommended by
General Motors. It is available at
your dealer.
Filling the Tank
{Warning
Fuel vapors and fuel fires burn
violently and can cause injury or
death.
.To help avoid injuries to you
and others, read and follow
all the instructions on the fuel
pump island.
.Turn off the engine when
refueling.
.Keep sparks, flames, and
smoking materials away
from fuel.
.Do not leave the fuel pump
unattended.
.Do not reenter the vehicle
while pumping fuel.
(Continued)

Black plate (46,1)GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-7576030) - 2015 - CRC - 8/18/14
9-46 Driving and Operating
Trailer Towing
General Towing
Information
Only use towing equipment that has
been designed for the vehicle.
Contact your dealer or trailering
dealer for assistance with preparing
the vehicle for towing a trailer. Read
the entire section before towing a
trailer.
For towing a disabled vehicle, see
Towing the Vehicle on page 10-72.
For towing the vehicle behind
another vehicle such as a motor
home, seeRecreational Vehicle
Towing on page 10-72.
Driving Characteristics
and Towing Tips
Driving with a Trailer
When towing a trailer:
.Become familiar with the state
and local laws that apply
specifically to trailer towing.
.Do not tow a trailer during the
first 800 km (500 mi), to prevent
damage to the engine, axle or
other parts.
.Then, during the first 800 km
(500 mi) trailer towing, do not
drive over 80 km/h (50 mph) and
do not make starts at full throttle.
.The vehicle can tow in D (Drive)
but M (Manual Mode) is
recommended. See Manual
Mode on page 9-24. Use a lower
gear if the transmission shifts
too often.
.Turn off Park Assist when
towing.
{Warning
When towing a trailer, exhaust
gases may collect at the rear of
the vehicle and enter if the
liftgate, trunk/hatch, or rear-most
window is open.
When towing a trailer:
.Do not drive with the liftgate,
trunk/hatch, or rear-most
window open.
.Fully open the air outlets on
or under the instrument
panel.
.Also adjust the Climate
Control system to a setting
that brings in only outside air.
See “Climate Control
Systems” in the Index.
For more information about
Carbon Monoxide, see Engine
Exhaust on page 9-21.

Black plate (48,1)GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-7576030) - 2015 - CRC - 8/18/14
9-48 Driving and Operating
Properly hooked up, the trailer
lamps also flash, telling other
drivers the vehicle is turning,
changing lanes or stopping.
When towing a trailer, the arrows on
the instrument cluster flash for turns
even if the bulbs on the trailer are
burned out. Check occasionally to
be sure the trailer bulbs are still
working.
Driving on Grades
Reduce speed and shift to a lower
gear before starting down a long or
steep downgrade. If the
transmission is not shifted down, the
brakes might have to be used so
much that they would get hot and no
longer work well.
The vehicle can tow in D (Drive).
Use a lower gear if the transmission
shifts too often.
The Tow/Haul Mode may be used if
the transmission shifts too often.
SeeTow/Haul Mode on page 9-25. When towing at high altitude on
steep uphill grades, engine coolant
boils at a lower temperature than at
normal altitudes. If the engine is
turned off immediately after towing
at high altitude on steep uphill
grades, the vehicle could show
signs similar to engine overheating.
To avoid this, let the engine run
while parked, preferably on level
ground, with the transmission in
P (Park) for a few minutes before
turning the engine off. If the
overheat warning comes on, see
Engine Overheating on page 10-16.
Parking on Hills
{Warning
Parking the vehicle on a hill with
the trailer attached can be
dangerous. If something goes
wrong, the rig could start to move.
People can be injured, and both
the vehicle and the trailer can be
damaged. When possible, always
park the rig on a flat surface. If parking the rig on a hill:
1. Press the brake pedal, but do
not shift into P (Park) yet. Turn
the wheels into the curb if facing
downhill or into traffic if facing
uphill.
2. Have someone place chocks under the trailer wheels.
3. When the wheel chocks are in place, release the brake pedal
until the chocks absorb the load.
4. Reapply the brake pedal. Then apply the parking brake and shift
into P (Park).
5. Release the brake pedal.
Leaving After Parking on a Hill
1. Apply and hold the brake pedal while you:
.Start the engine.
.Shift into a gear.
.Release the parking brake.
2. Let up on the brake pedal.

Black plate (49,1)GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-7576030) - 2015 - CRC - 8/18/14
Driving and Operating 9-49
3. Drive slowly until the trailer isclear of the chocks.
4. Stop and have someone pick up and store the chocks.
Maintenance When Trailer
Towing
The vehicle needs service more
often when pulling a trailer. See the
Maintenance Schedule on
page 11-2. Things that are
especially important in trailer
operation are automatic
transmission fluid, engine oil, axle
lubricant, belts, cooling system and
brake system. Inspect these before
and during the trip.
Check periodically to see that all
hitch nuts and bolts are tight.
Engine Cooling When Trailer
Towing
The cooling system may temporarily
overheat during severe operating
conditions. See Engine Overheating
on page 10-16.
Trailer Towing
Three important considerations
have to do with weight:
.The weight of the trailer.
.The weight of the trailer tongue.
.The total weight on the vehicle's
tires.
Weight of the Trailer
How heavy can a trailer safely be?
Speed, altitude, road grades,
outside temperature, special
equipment, and the amount of
tongue weight the vehicle can carry
must be considered. See “Weight of
the Trailer Tongue” later in this
section for more information.
Maximum trailer weight is calculated
assuming only the driver is in the
tow vehicle and it has all the
required trailering equipment. The
weight of additional optional
equipment, passengers and cargo in
the tow vehicle must be subtracted
from the maximum trailer weight.