2013 GMC SIERRA ECU

Black plate (20,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
9-20 Driving and Operating
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.
Add-On Equipment
When you carry removable
items, you may need to put a
limit on how many people youcarry 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) * Equipment
Maximum
Weight
* 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

Black plate (22,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
9-22 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 9‑15. 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 (28,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
9-28 Driving and Operating
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.
An internal thermostat in the
plug-end of the cord may exist
which will prevent engine coolant
heater operation at temperatures
above−18°C (0°F).
If the vehicle has a diesel engine,
see the Duramax Diesel supplement
for more information.
To Use the Engine Coolant
Heater
1. Turn off the engine.
2. Open the hood and unwrap the electrical cord. The cord is
secured to the Engine
Compartment Fuse Block with a
clip. Carefully remove the wire tie which bundles the electrical
plug. Do not cut the
electrical cord.
3. Plug the cord into a normal, grounded 110-volt AC outlet.
{WARNING
Plugging the cord into an
ungrounded outlet could cause an
electrical shock. Also, the wrong
kind of extension cord could
overheat and cause a fire. You
could be seriously injured. Plug
the cord into a properly grounded
three-prong 110-volt AC outlet.
If the cord will not reach, use a
heavy-duty three-prong extension
cord rated for at least 15 amps.
4. Before starting the engine, be sure to unplug and store the
cord as it was before to keep it
away from moving engine parts.
If you do not, it could be
damaged. The length of time the heater should
remain plugged in depends on
several factors. Ask a dealer in the
area where you will be parking the
vehicle for the best advice on this.
Shifting Into Park
{WARNING
It can be dangerous to get out of
the vehicle if the shift lever is not
fully in P (Park) with the parking
brake firmly set. The vehicle can
roll. 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, use the steps
that follow. With four-wheel drive,
if the transfer case is in
N (Neutral), the vehicle will be
free to roll, even if the shift lever
is in P (Park). Be sure the transfer
(Continued)

Black plate (64,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
9-64 Driving and Operating
A. Chassis harness connector
B. Release tab
4. Feed the wiring harness through the pickup box, then plug the
camera connectors together to
prevent contamination.
5. Remove the tailgate. See Tailgate on page 2‑9 for more
information.
6. Reinstall the license plate.
Reverse this procedure to reinstall
the RVC and make sure the
grommet and connection are
secure.
When the System Does Not
Seem To Work Properly
The RVC system might not work
properly or display a clear image if:
.The RVC is turned off. See
“Turning the RVC System On or
Off” earlier in this section.
.It is dark.
.The sun or the beam of
headlamps is shining directly
into the camera lens.
.Ice, snow, mud, or anything else
builds up on the camera lens.
Clean the lens, rinse it with
water, and wipe it with a soft
cloth.
.The back of the vehicle is in an
accident, the position and
mounting angle of the camera
can change or the camera can
be affected. Be sure to have the
camera and its position and
mounting angle checked at your
dealer. The RVC system display in the
rearview mirror may turn off or not
appear as expected due to one of
the following conditions. If this
occurs the left indicator light on the
mirror will flash.
.A slow flash may indicate a loss
of video signal, or no video
signal present during the reverse
cycle.
.A fast flash may indicate that the
display has been on for the
maximum allowable time during
a reverse cycle, or the display
has reached an Over
Temperature limit.
The fast flash conditions are
used to protect the video device
from high temperature
conditions. Once conditions
return to normal the device will
reset and the green indicator will
stop flashing.

Black plate (72,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
9-72 Driving and Operating
combination moving and then apply
the trailer brake controller by hand
to be sure the brakes work.
During the trip, check occasionally
to be sure that the load is secure
and the lamps and any trailer
brakes still work.
Following Distance
Stay at least twice as far behind the
vehicle ahead as you would when
driving the vehicle without a trailer.
This can help to avoid heavy
braking and sudden turns.
Passing
More passing distance is needed
when towing a trailer. The
combination will not accelerate as
quickly and is longer so it is
necessary to go much farther
beyond the passed vehicle before
returning to the lane.
Backing Up
Hold the bottom of the steering
wheel with one hand. To move the
trailer to the left, move that hand tothe left. To move the trailer to the
right, move your hand to the right.
Always back up slowly and,
if possible, have someone
guide you.
Making Turns
Notice:
Making very sharp turns
while trailering could cause the
trailer to come in contact with the
vehicle. The vehicle could be
damaged. Avoid making very
sharp turns while trailering.
When turning with a trailer, make
wider turns than normal. Do this so
the trailer will not strike soft
shoulders, curbs, road signs, trees,
or other objects. Avoid jerky or
sudden maneuvers. Signal well in
advance.
If the trailer turn signal bulbs burn
out, the arrows on the instrument
cluster will still flash for turns. It is
important to 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 get hot and no longer
work well.
Vehicles can tow in D (Drive). Shift
the transmission to a lower gear if
the transmission shifts too often
under heavy loads and/or hilly
conditions.
The Tow/Haul Mode may be used if
the transmission shifts too often.
See Tow/Haul Mode on page 9‑37.
When towing at high altitude on
steep uphill grades, consider the
following: Engine coolant will boil 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 may show signs similar to
engine overheating. To avoid this,
let the engine run while parked,
preferably on level ground, with the
automatic transmission in P (Park)

Black plate (92,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
9-92 Driving and Operating
exceeds the maximum amperage
rating of 40 amperes for the
auxiliary battery provision.
Trailer Wiring Harness
The vehicle is equipped with one of
the following wiring harnesses for
towing a trailer or hauling a slide-in
camper.
Basic Trailer Wiring
All regular, extended cab and crew
cab pickups have a seven-wire
trailer towing harness.
For vehicles not equipped with
heavy duty trailering, the harness is
secured to the vehicle's frame
behind the spare tire mount. The
harness requires the installation of a
trailer connector, which is available
through your dealer.
If towing a light-duty trailer with a
standard four-way round pin
connector, an adapter is available
from your dealer.Heavy-DutyTrailer Wiring Harness
Package
For vehicles equipped with heavy
duty trailering, the harness
connector is mounted in the bumper.
The seven-wire harness contains
the following trailer circuits:
.Yellow: Left Stop/Turn Signal
.Dark Green: Right Stop/Turn
Signal
.Brown: Taillamps
.White: Ground
.Light Green: Back-up Lamps
.Red: Battery Feed*
.Dark Blue: Trailer Brake*
*The fuses for these two circuits are
installed in the underhood electrical
center, but the wires are not
connected. They should be
connected by your dealer or a
qualified service center. The fuse
and wire for the ITBC is factory
installed and connected if the
vehicle is equipped with an ITBC.
The fuse for the battery feed is not
required if the vehicle has an
auxiliary battery. If the vehicle does
not have an auxiliary battery, have
your dealer or authorized service
center install the required fuse.
If charging a remote (non-vehicle)
battery, press the Tow/Haul Mode
button, if equipped, located at the
end of the shift lever. This will boost
the vehicle system voltage and
properly charge the battery. If the
trailer is too light for Tow/Haul
Mode, or the vehicle is not equipped
with Tow/Haul, turn on the

Black plate (102,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
9-102 Driving and Operating
Here are some guidelines for safely
carrying a snow plow on the vehicle:
.Make sure the weight on the
front and rear axles does not
exceed the axle rating for each.
.For the front axle, if more cargo
or passengers must be carried,
appropriate counter ballast must
be installed rear of the rear axle.
Counter ballast must be properly
secured so it will not move
during driving.
.Follow the snow plow
manufacturer's
recommendations regarding rear
ballast. Rear ballast may be
required to ensure a proper front
and rear weight distribution ratio,
even though the actual weight at
the front axle may be less than
the front axle rating.
.The snow plow manufacturer or
installer can assist you in
determining the amount of rear
ballast required, to help make
sure the snowplow/vehicle
combination does not exceed
the GVW rating, the front and
rear axle ratings, and the front
and rear weight distribution ratio.
.The total vehicle must not
exceed the GVW rating.
Front axle reserve capacity is the
difference between the Gross Axle
Weight Rating (GAWR) and the front
axle weight of the vehicle with full
fuel and passengers. Basically, it is
the amount of weight that can be
added to the front axle before
reaching the front GAWR.
The front axle reserve capacity for
the vehicle can be found in the
lower right corner of the
Certification/Tire label, as shown.
United States
Canada

Black plate (20,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
10-20 Vehicle Care
3. Fill the coolant surge tank withthe proper mixture to the FULL
COLD mark.
4. With the coolant surge tank pressure cap off, start the
engine and let it run until the
engine coolant temperature
gauge indicates approximately
90°C (195°F).
By this time, the coolant level
inside the coolant surge tank
may be lower. If the level is
lower, add more of the proper mixture to the coolant surge tank
until the level reaches the FULL
COLD mark.
5. Replace the pressure cap tightly.
6. Verify coolant level after the engine is shut off and the
coolant is cold. If necessary,
repeat coolant fill procedure
Steps 1 through 6.
Notice: If the pressure cap is not
tightly installed, coolant loss and
possible engine damage may
occur. Be sure the cap is properly
and tightly secured.
Engine Overheating
If the vehicle has the Duramax®
Diesel engine, see the Duramax
Diesel Supplement for more
information.
The vehicle has several indicators
to warn of engine overheating.
There is a coolant temperature
gauge on the vehicle's instrument
panel. See Engine Coolant
Temperature Gauge on page 5‑15. In addition, there are ENGINE
OVERHEATED STOP ENGINE,
ENGINE OVERHEATED IDLE
ENGINE, and ENGINE POWER IS
REDUCED messages in the Driver
Information Center (DIC) on the
instrument panel. See
Engine
Cooling System Messages on
page 5‑39 andEngine Power
Messages on page 5‑40.
If the decision is made not to lift the
hood when this warning appears,
get service help right away. See
Roadside Assistance Program
(Mexico) on page 13‑7 orRoadside
Assistance Program (U.S. and
Canada) on page 13‑11.
If the decision is made to lift the
hood, make sure the vehicle is
parked on a level surface.
Then check to see if the engine
cooling fans are running. If the
engine is overheating, both fans
should be running. If they are not,
do not continue to run the engine
and have the vehicle serviced.