2012 GMC SIERRA 1500 Owners Manual

Black plate (21,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-21
{WARNING
Things you put inside the
vehicle can strike and injure
people in a sudden stop or
turn, or in a crash.
.Put things in the cargo
area of the vehicle. Try to
spread the weight evenly.
.Never stack heavier
things, like suitcases,
inside the vehicle so that
some of them are above
the tops of the seats.
.Do not leave an
unsecured child restraint
in the vehicle.
.When you carry something
inside the vehicle, secure
it whenever you can.
.Do not leave a seat folded
down unless you need to. There is also important loading
information for off-road driving
in this manual. See
“Loading
Your Vehicle for Off-Road
Driving“under Off-Road Driving
on page 9‑6.
Two-Tiered Loading
Depending on the model of your
pick‐up, an upper load platform
can be created by positioning
three or four 5 cm (2 inches) by
15 cm (6 inches) wooden planks
across the width of the pickup
box. The planks must be
inserted in the pickup box
depressions. When using this upper load
platform, be sure the load is
securely tied down to prevent it
from shifting. The load's center
of gravity should be positioned
in a zone over the rear axle.
The zone is located in the area
between the front of each wheel
well and the rear of each wheel
well. The center of gravity height
must not extend above the top
of the pickup box flareboard.
Any load that extends beyond
the vehicle's taillamp area must
be properly marked according to
local laws and regulations.
Remember not to exceed
the Gross Axle Weight
Rating (GAWR) of the front or
rear axle.

Black plate (22,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
9-22 Driving and Operating
Add-On Equipment
When you carry removable
items, you may need to put a
limit on how many people you
carry inside your vehicle. Be
sure to weigh your vehicle
before you buy and install the
new equipment.
Notice:Overloading the
vehicle may cause damage.
Repairs would not be covered
by the vehicle warranty. Do
not overload the vehicle.
Remember not to exceed
the Gross Axle Weight
Rating (GAWR) of the front or
rear axle. * Equipment
Maximum
Weight
Ladder Rack
and Cargo 340 kg
(750 lbs)
Cross Toolbox
and Cargo 181 kg
(400 lbs)
Side Boxes
and Cargo 113 kg per
side (250 lbs
per side)
* The combined weight for all
rail‐mounted equipment should
not exceed 454 kg (1,000 lbs).Loading Points
A. Primary Load Points
B. Secondary Load Areas
C. Cargo Management Option Holes
Structural members (A) and (B) are
included in the pick-up box design.
Additional accessories should use
these load points. Depending on
the accessory design, use a
spacer under the accessory
at the load points to remove gap.

Black plate (23,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-23
The holes for the Cargo
Management System (C) are not
intended for attachment of
aftermarket equipment. See
www.gmupfitter.com for additional
pick-up box load bearing structural
information.
Truck-Camper Loading
Information
A vehicle-specific Truck‐Camper
Loading Information label is
attached to the inside of the
vehicle's glove box. This label
indicates if a slide-in camper
can be carried, how much of a
load the vehicle can carry, and
how to correctly spread out the
load. It will help to match the
right slide in camper to the
vehicle.
Your dealer can help make a
good vehicle-camper match and
help determine the Cargo
Weight Rating (CWR).When installing and loading a
slide-in camper, check the
manufacturer's instructions.
When carrying a slide-in
camper, the total cargo load of
the vehicle is the weight of the
camper, plus the following:
.Everything added to the
camper after it left the factory
.Everything in the camper
.All the people inside
The CWR is the maximum
weight of the load the vehicle
can carry. It does not include the
weight of the people inside. But,
use about 68 kg (150 lbs) for
each seat.
The total cargo load must not be
more than the vehicle's CWR. Refer to the Truck-Camper
Loading Information label in
the glove box for dimensions A
and B as shown in the following
illustration.
Use the rear edge of the load
floor for measurement purposes.
The recommended location for
the cargo center of gravity is at
point C for the CWR. It is the
point where the mass of
a body is concentrated and,
if suspended at that point, would
balance the front and rear.

Black plate (24,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
9-24 Driving and Operating
Here is an example of proper
truck and camper match:
A.Camper Center of Gravity
B.Recommended Center of
Gravity Location Zone
When the truck is used to carry
a slide‐in camper, the total cargo
load of the truck consists of the
manufacturer's camper weight
figure, the weight of installed
additional camper equipment not
included in the manufacturer's
camper weight figure, the weight of camper cargo, and the weight
of passengers in the camper.
The total cargo load should not
exceed the truck's cargo weight
rating, and the camper's center
of gravity (A) should fall within
the truck's recommended
center of gravity zone (B) when
installed.
Any accessories or other
equipment that are added to the
vehicle must be weighed. Then,
subtract this extra weight from
the CWR. This extra weight may
shorten the center of gravity
zone of the vehicle.
If the slide-in camper and its
load weighs less than the CWR,
the center of gravity zone for
your vehicle may be larger.
Secure loose items to prevent
weight shifts that could affect the
balance of the vehicle. When the
truck‐camper is loaded, drive to
a scale and weigh on the frontand on the rear wheels
separately to determine axle
loads. Individual axle loads
should not exceed either of
the gross axle weight ratings
(GAWR). The total axle loads
should not exceed your vehicle's
gross vehicle weight rating
(GVWR). These ratings are
given on the vehicle certification
label attached to the rear
edge of the driver door. See
“Certification/Tire Label”
under
Vehicle Load Limits on
page 9‑16. If weight ratings are
exceeded, move or remove
items to bring all weights below
the ratings.
See your dealer for more
information on curb weights,
cargo weights, Cargo Weight
Rating and the correct center of
gravity zone.

Black plate (25,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-25
Starting and
Operating
New Vehicle Break-In
Notice:The vehicle does not
need an elaborate break-in. But it
will perform better in the long run
if you follow these guidelines:
.Keep the vehicle speed at
88 km/h (55 mph) or less for
the first 805 km (500 miles).
.Do not drive at any one
constant speed, fast or
slow, for the first 805 km
(500 miles). Do not make
full-throttle starts. Avoid
downshifting to brake or
slow the vehicle.
.Avoid making hard stops for
the first 322 km (200 miles) or
so. During this time the new
brake linings are not yet
broken in. Hard stops with
new linings can mean
premature wear and earlier replacement. Follow this
breaking-in guideline every
time you get new brake
linings.
.Do not tow a trailer during
break-in. See
Trailer Towing
on page 9‑78 for the trailer
towing capabilities of the
vehicle and more
information.
Following break‐in, engine
speed and load can be gradually
increased.
Adjustable Throttle and
Brake Pedal
On vehicles with this feature, you
can change the position of the
throttle and brake pedals.
No adjustment to the pedals can
be made when the vehicle is in
R (Reverse) or while using cruise
control.
The control used to adjust the
pedals is located on the instrument
panel below the climate control
system.
Press the bottom of the control to
move the pedals closer. Press the
top of the control 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 3‑7.

Black plate (26,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
9-26 Driving and Operating
Ignition Positions
The ignition switch has 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.
A (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.
It also locks the transmission on
automatic transmission vehicles.
The key can be removed in
LOCK/OFF.
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 steady pressure. 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 9‑54.
{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.

Black plate (27,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-27
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.
Notice: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.
B (ACC/ACCESSORY): This
position lets things like the radio
and the windshield wipers operate
while the engine is off. Use this
position if the vehicle must be
pushed or towed.
C (ON/RUN): This position can
be used to operate the electrical
accessories and to display some
instrument panel 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 you leave the key in the ACC/
ACCESSORY or ON/RUN position
with the engine off, the battery could
be drained. You may not be able to
start the vehicle if the battery is
allowed to drain for an extended
period of time.
D (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 for more information.
If the vehicle is a hybrid, see the
hybrid supplement for more
information.
Notice: 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.
Move the shift lever to P (Park) or
N (Neutral). The engine will not start
in any other position. To restart the
engine when the vehicle is already
moving, use N (Neutral) only.
Notice: 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 9‑105.

Black plate (28,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
9-28 Driving and Operating
Starting Procedure
1. With your foot off the acceleratorpedal, turn the ignition key to
START. When the engine starts,
let go of the key. The idle speed
will go down as your 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.
The vehicle has a
Computer-Controlled Cranking
System. This feature assists in
starting the engine and protects
components. If the ignition key is
turned to the START position,
and then released when the
engine begins cranking, the
engine will continue cranking
for a few seconds or until the
vehicle starts. If the engine does
not start and the key is held in
START for many seconds,
cranking will be stopped after
15 seconds to prevent cranking
motor damage. To prevent gear damage, this system also
prevents cranking if the engine
is already running. Engine
cranking can be stopped by
turning the ignition switch
to the ACC/ACCESSORY or
LOCK/OFF position.
When the Low Fuel warning
lamp is on and the FUEL LEVEL
LOW message is displayed in
the Driver Information Center
(DIC), the Computer-Controlled
Cranking System is disabled
to prevent possible vehicle
component damage. When
this happens, hold the ignition
switch in the START position to
continue engine cranking.
Notice: Cranking the engine for
long periods of time, by returning
the key to the START position
immediately after cranking has
ended, can overheat and damage
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
5-10 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 hold 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.