
Black plate (26,1)GMC Sierra Owner Manual (GMNA Localizing-U.S/Canada/Mexico-
7299746) - 2015 - crc - 11/11/13
9-26 Driving and Operating
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. 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 9-97.
{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.

Black plate (27,1)GMC Sierra Owner Manual (GMNA Localizing-U.S/Canada/Mexico-
7299746) - 2015 - crc - 11/11/13
Driving and Operating 9-27
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)
Caution (Continued)
the cranking motor, and drain the
battery. Wait at 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 while holding the
key in START for up to
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 key and 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.
Fast Idle System
If equipped, this feature is available
only with cruise control. The manual
fast idle switch is operated using the
cruise control buttons on the left
side of the steering wheel.
This system can be used to
increase engine idle speed
whenever the following conditions
are met:
.The parking brake is set.
.The brake pedal is not pressed.
.The vehicle must not be moving
and the accelerator must not be
pressed.
To control the fast idle:
.To enable the Fast Idle System,
press and release the cruise
control on/off button and ensure
that the switch indicator light
is lit.

Black plate (28,1)GMC Sierra Owner Manual (GMNA Localizing-U.S/Canada/Mexico-
7299746) - 2015 - crc - 11/11/13
9-28 Driving and Operating
.Press and release the cruise
control SET- button. Engine
speed will be held at
approximately 1200 rpm.
One of the following actions will turn
off the fast idle:
.Pressing the brake.
.Selecting the cruise control
cancel button.
.Releasing the parking brake.
.Moving the transmission shift
lever out of P (Park) or
N (Neutral).
.Selecting the cruise control on/
off button when it was
previously on.
.Pressing the cruise control SET-
button a second time.
.Pressing the accelerator more
than one-quarter of the
way down.
.Turning the ignition switch to the
LOCK/OFF position.
Retained Accessory
Power (RAP)
The following vehicle accessories
can be used for up to 10 minutes
after the engine is turned off:
.Audio System
.Power Windows
.OnStar System (if equipped)
.Sunroof (if equipped)
These features work when the key
is in ON/RUN or ACC/
ACCESSORY. Once the key is
turned from ON/RUN to LOCK/OFF,
the windows and sunroof continue
to work up to 10 minutes or until any
door is opened. The radio continues
to work for up to 10 minutes or until
the driver door is opened.
Accessory Power Outlets (APOs)
The vehicle may have APOs in
several locations. See Power
Outlets on page 5-6. The APOs in the console or center
seat position are powered by RAP.
They will continue to work for up to
10 minutes after the key is turned
from ON/RUN to LOCK/OFF, or until
the driver door is opened.
The APOs on the center stack come
from the factory powered directly
from the vehicle battery, and supply
accessory power at all times,
regardless of ignition key position.
If electronic items are left plugged
into these APOs for long periods of
time with the vehicle off, the vehicle
battery could be drained. The
vehicle may not start if the battery is
allowed to drain for an extended
period of time.
Engine Coolant 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.

Black plate (31,1)GMC Sierra Owner Manual (GMNA Localizing-U.S/Canada/Mexico-
7299746) - 2015 - crc - 11/11/13
Driving and Operating 9-31
When you are ready to drive, move
the shift lever out of P (Park) before
you release the parking brake.
If torque lock does occur, you may
need to have another vehicle push
yours a little uphill to take some of
the pressure from the parking pawl
in the transmission. You will then be
able to pull the shift lever out of
P (Park).
Shifting out of Park
This 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).
.Prevent movement of the shift
lever out of P (Park), unless the
ignition is in ON/RUN 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 10-88.
To shift out of P (Park):
1. Apply the brake pedal.
2. Move the shift lever to the desired position.
If you still are unable to shift out of
P (Park):
1. Ease the pressure on the shift lever.
2. While holding down the brake pedal, press the shift lever all
the way into P (Park).
3. Move the shift lever to the desired position.
If you are still having a problem
shifting, then have the vehicle
serviced soon.
Parking over Things
That Burn
{Warning
Things that can burn could touch
hot exhaust parts under the
vehicle and ignite. Do not park
over papers, leaves, dry grass,
or other things that can burn.
Active Fuel Management®
Vehicles with a V8 or V6 gasoline
engine may have Active Fuel
Management. This system allows
the engine to operate on either all of
its cylinders, or in V4 mode,
depending on the driving conditions.
When less power is required, such
as cruising at a constant vehicle
speed, the system will operate in
the V4 mode, allowing the vehicle to
achieve better fuel economy. When
greater power demands are
required, such as accelerating from

Black plate (95,1)GMC Sierra Owner Manual (GMNA Localizing-U.S/Canada/Mexico-
7299746) - 2015 - crc - 11/11/13
Vehicle Care 10-95
6. Disconnect the negative batterycable at the battery and secure
the nut and bolt. Cover the
negative battery post with a
non-conductive material to
prevent any contact with the
negative battery terminal.
7. Shift the transmission to P (Park).
{Caution
If the steering column is locked,
vehicle damage may occur.
9. Move the steering wheel to make sure the steering column
is unlocked.
10. Release the parking brake.
11. Keep the ignition key in the towed vehicle in ACC/
ACCESSORY to prevent the
steering column from locking. Disconnecting the Towed Vehicle
Before disconnecting the towed
vehicle:
1. Park on a level surface.
2. Set the parking brake, shift the
transmission to P (Park), and
move the ignition key to OFF.
3. Connect the battery.
4. Apply the brake pedal.
5. Start the engine, then shift the transfer case out of N (Neutral)
to Two-Wheel Drive High. See
Four-Wheel Drive for directions
on shifting out of N (Neutral).
6. Check that the vehicle is in Two-Wheel Drive High by
shifting the transmission to
R (Reverse) and then to D
(Drive). There should be
movement of the vehicle while
shifting.
7. Shift the transmission to P (Park) and turn off the ignition.
8. Disconnect the vehicle from the tow vehicle. 9. Release the parking brake.
10. Reset any lost presets.
The outside temperature
display will default to 32°F but
will reset with normal usage.
Dolly Towing
Front Towing (Front Wheels Off
the Ground) –Two-Wheel-Drive
Vehicles

Black plate (8,1)GMC Sierra Owner Manual (GMNA Localizing-U.S/Canada/Mexico-
7299746) - 2015 - crc - 11/11/13
i-8 INDEX
M
MaintenanceRecords . . . . . . . . . . . . . . . . . . . . .11-16
Maintenance and Care Additional . . . . . . . . . . . . . . . . . . . . . 11-9
Maintenance Schedule . . . . . . . . 11-3 Recommended Fluids
and Lubricants . . . . . . . . . . . . .11-12
Transfer Case . . . . . . . . . . . . . . . . 9-38
Malfunction Indicator Lamp . . . . 5-22
Manual Mirrors . . . . . . . . . . . . . . . . 2-13
Manual Mode . . . . . . . . . . . . . . . . . . 9-36
Manual Windows . . . . . . . . . . . . . . 2-18
Memory Features . . . . . . . . . . . . . . 1-10
Memory Seats . . . . . . . . . . . . . . . . . . 3-6
Messages Airbag System . . . . . . . . . . . . . . . . 5-41
Battery Voltage andCharging . . . . . . . . . . . . . . . . . . . . 5-35
Brake System . . . . . . . . . . . . . . . . 5-36
Compass . . . . . . . . . . . . . . . . . . . . . 5-36
Door Ajar . . . . . . . . . . . . . . . . . . . . . 5-36
Engine Cooling System . . . . . . . 5-37
Engine Oil . . . . . . . . . . . . . . . . . . . . 5-37
Engine Power . . . . . . . . . . . . . . . . 5-38
Fuel System . . . . . . . . . . . . . . . . . . 5-38 Messages (cont'd)
Key and Lock . . . . . . . . . . . . . . . . . 5-39
Lamp . . . . . . . . . . . . . . . . . . . . . . . . . 5-39
Object Detection System . . . . . 5-39
Ride Control System . . . . . . . . . . 5-40
Security . . . . . . . . . . . . . . . . . . . . . . 5-41
Steering System . . . . . . . . . . . . . . 5-41
Tire . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-42
Transmission . . . . . . . . . . . . . . . . . 5-42
Vehicle . . . . . . . . . . . . . . . . . . . . . . . 5-35
Vehicle Reminder . . . . . . . . . . . . . 5-44
Vehicle Speed . . . . . . . . . . . . . . . . 5-45
Washer Fluid . . . . . . . . . . . . . . . . . 5-45
Mirrors
Automatic Dimming . . . . . . . . . . . 2-16
Automatic DimmingRearview . . . . . . . . . . . . . . . . . . . . 2-18
Blind Spot . . . . . . . . . . . . . . . . . . . . 2-16
Convex . . . . . . . . . . . . . . . . . . . . . . . 2-13
Folding . . . . . . . . . . . . . . . . . . . . . . . 2-15
Heated . . . . . . . . . . . . . . . . . . . . . . . 2-16
Manual . . . . . . . . . . . . . . . . . . . . . . . 2-13
Manual Rearview . . . . . . . . . . . . . 2-17
Power . . . . . . . . . . . . . . . . . . . . . . . . 2-14
Tilt in Reverse . . . . . . . . . . . . . . . . 2-17
Trailer Tow . . . . . . . . . . . . . . . . . . . . 2-13
Mirrors, Interior Rearview . . . . . . 2-17 Monitor System, Tire
Pressure . . . . . . . . . . . . . . . . . . . . 10-61
Multi-band Antenna . . . . . . . . . . . . 7-11
N
Navigation OnStar®. . . . . . . . . . . . . . . . . . . . . . 14-3
New Vehicle Break-In . . . . . . . . . . 9-23
Noise Control System . . . . . . . . 10-34
O
Object Detection System Messages . . . . . . . . . . . . . . . . . . . . 5-39
Odometer . . . . . . . . . . . . . . . . . . . . . . 5-13 Trip . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-13
Off-Road . . . . . . . . . . . . . . . . . . . . . . . 9-6
Driving . . . . . . . . . . . . . . . . . . . . . . . . . 9-6
Recovery . . . . . . . . . . . . . . . . . . . . . . 9-5
Oil Engine . . . . . . . . . . . . . . . . . . . . . . 10-10
Engine Oil Life System . . . . . 10-13
Engine Oil Pressure
Gauge . . . . . . . . . . . . . . . . . . . . . . 5-15
Messages . . . . . . . . . . . . . . . . . . . . 5-37
Older Children, Restraints . . . . . 3-37
Online Owner Center . . . . . . . . . . 13-4