2015 GMC SIERRA power steering

Black plate (1,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Lighting 6-1
Lighting
Exterior Lighting
Exterior Lamp Controls . . . . . . . . 6-1
Exterior Lamps OffReminder . . . . . . . . . . . . . . . . . . . . 6-2
Headlamp High/Low-Beam Changer . . . . . . . . . . . . . . . . . . . . . 6-2
Flash-to-Pass . . . . . . . . . . . . . . . . . 6-2
Daytime Running Lamps (DRL) . . . . . . . . . . . . . . . . 6-3
Automatic Headlamp System . . . . . . . . . . . . . . . . . . . . . . 6-3
Hazard Warning Flashers . . . . . 6-4
Turn and Lane-Change Signals . . . . . . . . . . . . . . . . . . . . . . 6-4
Fog Lamps . . . . . . . . . . . . . . . . . . . . 6-5
Auxiliary Roof-Mounted Lamp . . . . . . . . . 6-5
Interior Lighting
Instrument Panel IlluminationControl . . . . . . . . . . . . . . . . . . . . . . 6-6
Cargo Lamp . . . . . . . . . . . . . . . . . . 6-6
Dome Lamps . . . . . . . . . . . . . . . . . 6-7
Reading Lamps . . . . . . . . . . . . . . . 6-7
Lighting Features
Entry Lighting . . . . . . . . . . . . . . . . . 6-8
Exit Lighting . . . . . . . . . . . . . . . . . . . 6-8
Battery Load Management . . . . 6-8
Battery Power Protection . . . . . . 6-9Exterior Lighting
Exterior Lamp Controls
The exterior lamp control is on the
instrument panel to the left of the
steering wheel.
O(Off): Turns off the automatic
headlamps and Daytime Running
Lamps (DRL). Turn the headlamp
control to the off position again to
turn the automatic headlamps or
DRL back on.
For vehicles first sold in Canada, off
will only work when the vehicle is in
P (Park).

Black plate (6,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
6-6 Lighting
When the wiring is connected to an
auxiliary roof-mounted lamp,
pressing the bottom of the button
will activate the lamp and illuminate
an indicator light at the bottom of
this button. Pressing the top of the
button will turn off the roof-mounted
lamp and indicator.
The emergency roof lamp circuit is
fused at 30 amps, so the total
current draw of the attached lamps
should be less than this value. The
attachment points for the roof lamp
circuits are two blunt cut wires
above the overhead console: a dark
green with blue stripe switched
power wire and a black ground wire.
For information on roof-mounted
emergency lamp installation, see
www.gmupfitter.com or contact your
dealer.
If the vehicle has this button, the
vehicle may have the snow plow
prep package. SeeAdd-On
Electrical Equipment on page 9-88.Interior Lighting
Instrument Panel
Illumination Control
This feature controls the brightness
of the steering wheel and instrument
panel lights. The instrument panel
illumination control is next to the
exterior lamp control.
D(Instrument Panel
Illumination): Move the
thumbwheel up or down to brighten
or dim the lights.
Cargo Lamp
The cargo lamp provides more light
in the cargo area or on the sides of
the vehicle, if needed. The lights
inside the pickup box and/or on the
outside rearview mirrors also turn
on, if equipped.
Press the switch down to turn the
cargo lamp on or off. An indicator
light will turn on when the lamp is
turned on, if equipped. The shift
lever must be in the P (Park)
position to operate the cargo lamp.
The lights on the outside rearview

Black plate (1,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-1
Driving and
Operating
Driving Information
Distracted Driving . . . . . . . . . . . . . 9-2
Defensive Driving . . . . . . . . . . . . . 9-3
Drunk Driving . . . . . . . . . . . . . . . . . 9-3
Control of a Vehicle . . . . . . . . . . . 9-3
Braking . . . . . . . . . . . . . . . . . . . . . . . 9-3
Steering . . . . . . . . . . . . . . . . . . . . . . . 9-4
Off-Road Recovery . . . . . . . . . . . . 9-5
Loss of Control . . . . . . . . . . . . . . . . 9-5
Off-Road Driving . . . . . . . . . . . . . . 9-6
Driving on Wet Roads . . . . . . . . 9-11
Hill and Mountain Roads . . . . . 9-11
Winter Driving . . . . . . . . . . . . . . . 9-12
If the Vehicle Is Stuck . . . . . . . . 9-14
Vehicle Load Limits . . . . . . . . . . 9-15
Truck-Camper LoadingInformation . . . . . . . . . . . . . . . . . 9-21
Starting and Operating
New Vehicle Break-In . . . . . . . . 9-23
Adjustable Throttle and BrakePedal . . . . . . . . . . . . . . . . . . . . . . . 9-23
Ignition Positions . . . . . . . . . . . . 9-24
Starting the Engine . . . . . . . . . . 9-26 Fast Idle System . . . . . . . . . . . . . 9-27
Engine Heater . . . . . . . . . . . . . . . 9-28
Retained Accessory
Power (RAP) . . . . . . . . . . . . . . . 9-29
Shifting Into Park . . . . . . . . . . . . 9-30
Shifting out of Park . . . . . . . . . . 9-31
Parking over Things
That Burn . . . . . . . . . . . . . . . . . . 9-32
Active Fuel Management
®. . . 9-32
Engine Exhaust
Engine Exhaust . . . . . . . . . . . . . . 9-32
Running the Vehicle While Parked . . . . . . . . . . . . . . . . . . . . . 9-33
Automatic Transmission
Automatic Transmission . . . . . 9-33
Manual Mode . . . . . . . . . . . . . . . . 9-36
Tow/Haul Mode . . . . . . . . . . . . . . 9-39
Drive Systems
Four-Wheel Drive . . . . . . . . . . . . 9-40
Brakes
Antilock BrakeSystem (ABS) . . . . . . . . . . . . . . 9-46
Parking Brake . . . . . . . . . . . . . . . 9-47
Brake Assist . . . . . . . . . . . . . . . . . 9-48
Hill Start Assist (HSA) . . . . . . . 9-48
Ride Control Systems
Traction Control/Electronic Stability Control . . . . . . . . . . . . 9-49
Hill Descent Control (HDC) . . . . . . . . . . . . . . 9-51
Locking Rear Axle . . . . . . . . . . . 9-52
Cruise Control
Cruise Control . . . . . . . . . . . . . . . 9-52
Driver Assistance Systems
Driver Assistance
Systems . . . . . . . . . . . . . . . . . . . . 9-55
Assistance Systems for Parking or Backing . . . . . . . . . 9-56
Assistance Systems for Driving . . . . . . . . . . . . . . . . . . . . . 9-59
Forward Collision Alert (FCA) System . . . . . . . . . . . . . . . . . . . . . 9-59
Lane Departure Warning (LDW) . . . . . . . . . . . . . 9-61
Fuel
Fuel . . . . . . . . . . . . . . . . . . . . . . . . . 9-63
California FuelRequirements . . . . . . . . . . . . . . 9-64
Fuels in Foreign Countries . . . 9-64
Fuel Additives . . . . . . . . . . . . . . . 9-64

Black plate (4,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
9-4 Driving and Operating
If the engine ever stops while the
vehicle is being driven, brake
normally but do not pump the
brakes. Doing so could make the
pedal harder to push down. If the
engine stops, there will be some
power brake assist but it will be
used when the brake is applied.
Once the power assist is used up, it
can take longer to stop and the
brake pedal will be harder to push.
Steering
Electric Power Steering (1500
Series)
If the vehicle has electric power
steering, it does not have power
steering fluid. Regular maintenance
is not required.
If power steering assist is lost due
to a system malfunction, the vehicle
can be steered, but may require
increased effort. See your dealer if
there is a problem.If the steering wheel is turned until it
reaches the end of its travel, and is
held in that position for an extended
period of time, power steering assist
may be reduced.
If the steering assist is used for an
extended period of time, power
assist may be reduced.
Normal use of the power steering
assist should return when the
system cools down.
See specific vehicle steering
messages under
Steering System
Messages on page 5-38.Hydraulic Power Steering
(2500/3500 Series)
If the vehicle has hydraulic power
steering, it may require
maintenance. See Power Steering
Fluid (1500 Series) on page 10-24
or Power Steering Fluid (2500/3500
Series) on page 10-24. If power steering assist is lost
because the engine stops or a
system malfunctions, the vehicle
can be steered but may require
increased effort.
See your dealer if there is a
problem.
{Caution
If the steering wheel is turned
until it reaches the end of its
travel, and is held in that position
for more than 15 seconds,
damage may occur to the power
steering system and there may be
loss of power steering assist.
Curve Tips
.Take curves at a reasonable
speed.
.Reduce speed before entering a
curve.
.Maintain a reasonable steady
speed through the curve.

Black plate (24,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
9-24 Driving and Operating
No adjustment to the pedals can be
made when the vehicle is in
R (Reverse) or while using cruise
control.
The switch used to adjust the
pedals is on the center stack, below
the climate controls.
Lift the switch up to move the
pedals closer to your body. Press
the switch down to move the
pedals away.Before you start driving, fully press
the brake pedal to confirm the
adjustment is right for you. While
driving, make only small
adjustments.
The vehicle may have a memory
function, which lets pedal settings
be saved and recalled. See
Memory
Seats on page 3-5.
Ignition Positions
Vehicles with Key Access have an
ignition switch with four different
positions. To shift out of P (Park), the ignition
must be in ON/RUN or ACC/
ACCESSORY and the regular brake
pedal must be applied.
1 (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 9-29.
This position locks the ignition and
steering wheel. It also locks the
transmission on automatic
transmission vehicles. The key can
be removed in LOCK/OFF.
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.

Black plate (25,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-25
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.
If the vehicle must be shut off in an
emergency:
1. Brake using a firm and steadypressure. 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 9-47.
{Warning
Turning off the vehicle while
moving may cause loss of power
assist in the brake and steering
systems and disable the airbags.
While driving, only shut the
vehicle off in an emergency.
If the vehicle cannot be pulled over,
and must be shut off while driving,
turn the ignition to ACC/
ACCESSORY.
{Caution
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. 2 (ACC/ACCESSORY):
This
position lets things like the radio
and the windshield wipers operate
while the engine is off. It also
unlocks the steering wheel. Use this
position if the vehicle must be
pushed or towed.
3 (ON/RUN): This position can be
used to operate the electrical
accessories and to display some
instrument cluster 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 on automatic transmission
vehicles.
If the key is left in the ACC/
ACCESSORY or ON/RUN position
with the engine off, the battery could
be drained. The vehicle may not
start if the battery is allowed to drain
for an extended period of time.

Black plate (26,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
9-26 Driving and Operating
4 (START):This is the position that
starts the engine. When the engine
starts, release the key. The ignition
switch returns to ON/RUN for
driving.
A warning tone will sound when the
driver door is opened and the
ignition is in ACC/ACCESSORY or
LOCK/OFF, and the key is in the
ignition.
Starting the Engine
If the vehicle has a diesel engine,
see the Duramax diesel
supplement.
{Caution
If you add electrical parts or
accessories, you could change
the way the engine operates. Any
resulting damage would not be
covered by the vehicle warranty.
See Add-On Electrical Equipment
on page 9-88.
{Caution
If the steering wheel is turned
until it reaches the end of its
travel, and is held in that position
while starting the vehicle, damage
may occur to the hydraulic power
steering system and there may be
loss of power steering assist.
Move the shift lever to P (Park) or
N (Neutral). To restart the engine
when the vehicle is already moving,
use N (Neutral) only.
{Caution
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. Turn the ignition key to START. When the engine starts, let go of
the key. The idle speed will go
down as the engine gets warm.
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.
When the low fuel warning light
is on and the FUEL LEVEL LOW
message is displayed in the
Driver Information Center (DIC),
hold the ignition switch in the
START position to continue
engine cranking.
{Caution
Cranking the engine for long
periods of time, by returning the
ignition to the START position
immediately after cranking has
ended, can overheat and damage
(Continued)

Black plate (84,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
9-84 Driving and Operating
Trailer Brake Control Panel
1. Manual Trailer Brake ApplyLever
2. Trailer Gain Adjustment Buttons
The ITBC system has a control
panel on the instrument panel to the
left of the steering column. See
Instrument Panel on page 1-2. The
control panel allows adjustment to
the amount of output, referred to as
Trailer Gain, available to the trailer
brakes and allows manual
application of the trailer brakes. The Trailer Brake Control Panel is used
along with the Trailer Brake Display
Page on the Driver Information
Center (DIC) to adjust and display
power output to the trailer brakes.
Trailer Brake DIC Display Page
The ITBC system displays
messages in the DIC.
The display page indicates Trailer
Gain setting, power output to the
trailer brakes, trailer connection, and
system operational status.
To display the Trailer Brake Display
Page, do any of the following:
.Scroll through the DIC menu
pages.
.Press a Trailer Gain button.
If the Trailer Brake Display Page
is not currently displayed, press
a Trailer Gain button to recall the
current Trailer Gain setting.
Each press and release of the
gain buttons will then change the
Trailer Gain setting.
.Activate the Manual Trailer
Brake Apply Lever.
TRAILER GAIN: This setting can be
adjusted from 0.0 to 10.0 with either
a trailer connected or disconnected.
To adjust the Trailer Gain, press one
of the Trailer Gain Adjustment
buttons. Press and hold a gain
button to continuously adjust the
Trailer Gain. To turn the output to
the trailer off, adjust the Trailer Gain
setting to 0.0 (zero).
TRAILER OUTPUT: This displays
anytime a trailer with electric brakes
is connected. Output to the trailer
brakes is based on the amount of
vehicle braking present and relative
to the Trailer Gain setting. Output is
displayed from 0 to 100% for each
gain setting.
The Trailer Output will indicate
“- - - - - -” on the Trailer Brake
Display Page whenever the
following occur:
.No trailer is connected.