ECU GMC SIERRA 2006 Repair Manual

The Certication/Tire label also contains important
information about your Front Axle Reserve Capacity.
See “What is front axle reserve capacity, and how do
I calculate it?” underAdding a Snow Plow or Similar
Equipment on page 4-54.
{CAUTION:
In the case of a sudden stop or collision,
things carried in the bed of your truck could
shift forward and come into the passenger
area, injuring you and others. If you put things
in the bed of your truck, you should make sure
they are properly secured.
{CAUTION:
Do not load your vehicle any heavier than the
Gross Vehicle Weight Rating (GVWR), or either
the maximum front or rear Gross Axle Weight
Rating (GAWR). If you do, parts on your vehicle
can break, and it can change the way your
vehicle handles. These could cause you to
lose control and crash. Also, overloading can
shorten the life of your vehicle.
Notice:Overloading your vehicle may cause
damage. Repairs would not be covered by your
warranty. Do not overload your vehicle.
Using heavier suspension components to get added
durability might not change your weight ratings. Ask your
dealer to help you load your vehicle the right way.
If you put things inside your vehicle — like suitcases,
tools, packages, or anything else — they go as fast
as the vehicle goes. If you have to stop or turn quickly,
or if there is a crash, they will keep going.
4-52

{CAUTION:
Things you put inside your vehicle can strike
and injure people in a sudden stop or turn, or
in a crash.
Put things in the cargo area of your
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 your 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“ underOff-Road Driving on
page 4-16.
Two-Tiered Loading
By positioning four 2 inches (5 cm) by 6 inches (15 cm)
wooden planks across the width of the pickup box,
you can create an upper load platform. The planks
must be inserted in the pickup box depressions.
The length of the planks must allow for at least a
3/4 inch (2 cm) bearing surface on each end of
the plank.
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 areboard.
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.
4-53

Q:How heavy can a snow plow safely be?
A:The plow your vehicle can carry depends on many
things, such as:
The options your vehicle came with, and the weight
of those options.
The weight and number of passengers you intend
to carry.
The weight of items you have added to your
vehicle, like a tool box or truck cap.
The total weight of any additional cargo you intend
to carry.
Say, for example, you have a 700 lb (318 kg) snow plow.
The total weight of all occupants and cargo inside the cab
should not exceed 300 lb (135 kg). This means that you
may only be able to carry one passenger. But, even this
may be too much if you have got other equipment already
adding to the weight of your vehicle.Here are some guidelines for safely carrying a snow
plow on your 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 your 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.
4-55

Secure loose items to prevent weight shifts that could
affect the balance of your vehicle. When the truck-camper
is loaded, drive to a scale and weigh the front and the
rear wheels separately to determine axle loads. Individual
axle loads should not exceed either of the GAWRs. The
total of the front and rear axle loads should not exceed
your vehicle’s GVWR. These ratings are given on the
vehicle certication label attached to the rear edge of
the driver’s door. See “Certication/Tire Label” under
Loading Your Vehicle on page 4-48. If weight ratings are
exceeded, move or remove items to bring all weights
below the ratings.
When you install and load your slide-in camper, check
the manufacturer’s instructions.
If you want more information on curb weights, cargo
weights, Cargo Weight Rating and the correct center of
gravity zone for your vehicle, your dealer can help
you. Just ask for a copy of “Consumer Information,
Truck-Camper Loading.”Pickup Conversion to Chassis Cab
General Motors is aware that some vehicle owners
may consider having the pickup box removed and a
commercial or recreational body installed. Before you do
so, rst contact GM Customer Assistance for information
on such conversions specic to this vehicle. Owners
should be aware that, as manufactured, there are
differences between a chassis cab and a pickup with
the box removed which may affect vehicle safety. The
components necessary to adapt a pickup to permit its
safe use with a specialized body should be installed by a
body builder in accordance with the information available
from GM Customer Assistance. SeeCustomer
Assistance Offices on page 7-4.
4-61

Four-Wheel-Drive Vehicles
Use the following procedure to tow your vehicle:
1. Shift an automatic transmission to PARK (P), or a
manual transmission to FIRST (1).
2. Turn the engine off, but leave the ignition on.
3. Firmly set the parking brake.
4. Securely attach the vehicle being towed to the tow
vehicle.
{CAUTION:
Shifting a four-wheel-drive vehicle’s transfer
case into NEUTRAL can cause your vehicle to
roll even if the transmission is in PARK (P) for
an automatic transmission, or if your vehicle
is in gear, for a manual transmission. You or
others could be injured. Make sure the parking
brake is rmly set before you shift the transfer
case to NEUTRAL.
5. Shift the transfer case to NEUTRAL. See
Four-Wheel Drive on page 2-38for the proper
procedure to select the neutral position for
your vehicle.
6. Release the parking brake only after the vehicle
being towed is rmly attached to the towing vehicle.
7. Turn the ignition off and leave the steering column
unlocked.
4-63

Dolly Towing
Front Towing (Front Wheels
Off the Ground)
Two-Wheel-Drive Vehicles
Notice:If you tow a two-wheel-drive vehicle with the
rear wheels on the ground, the transmission could be
damaged. The repairs would not be covered by your
warranty. Never tow your vehicle with the rear wheels
on the ground.
Two-wheel-drive vehicles should not be towed
with the rear wheels on the ground. Two-wheel-drive
transmissions have no provisions for internal lubrication
while being towed.
To dolly tow a two-wheel-drive vehicle, you must tow
the vehicle with the rear wheels on the dolly. See “Rear
Towing (Rear Wheels Off the Ground)” later in this
section for more information.
Four-Wheel-Drive Vehicles
Use the following procedure to tow your vehicle:
1. Drive the vehicle up onto the tow dolly.
2. Shift an automatic transmission to PARK (P), or a
manual transmission to FIRST (1).
3. Turn the engine off, but leave the ignition on.
4. Firmly set the parking brake.
5. Securely attach the vehicle being towed to the
tow dolly.
4-64

{CAUTION:
Shifting a four-wheel-drive vehicle’s transfer
case into NEUTRAL can cause your vehicle to
roll even if the transmission is in PARK (P) for
an automatic transmission, or if your vehicle
is in gear, for a manual transmission. You or
others could be injured. Make sure the parking
brake is rmly set before you shift the transfer
case to NEUTRAL.
6. Shift the transfer case to NEUTRAL. See
Four-Wheel Drive on page 2-38for the proper
procedure to select the neutral position for
your vehicle.
7. Release the parking brake only after the vehicle
being towed is rmly attached to the towing vehicle.
8. Turn the ignition off and lock the steering column.
Rear Towing (Rear Wheels
Off the Ground)
Two-Wheel-Drive Vehicles
Use the following procedure to tow your vehicle from
the rear:
1. Drive the vehicle onto the dolly.
2. Firmly set the parking brake. SeeParking Brake on
page 2-52
3. Put an automatic transmission in PARK (P) or a
manual transmission in FIRST (1).
4. Follow the dolly manufacturer’s instructions to
attach and secure the vehicle being towed to
the dolly and then the loaded dolly to the tow
vehicle. Make sure the wheels are straight before
towing.
For manual transmission vehicles, make sure the
wheels are straight before proceeding to the next
steps. On automatic transmission vehicles, use an
adequate clamping device to ensure that the front
wheels are locked into the straight position.
5. Release the parking brake only after the vehicle
being towed is rmly attached to the tow vehicle.
6. Turn the ignition to LOCK.
4-65

Four-Wheel-Drive Vehicles
Use the following procedure to tow your vehicle from
the rear:
1. Drive the vehicle onto the dolly.
2. Firmly set the parking brake. SeeParking Brake on
page 2-52
3. Put an automatic transmission in PARK (P) or a
manual transmission in FIRST (1).
4. Follow the dolly manufacturer’s instructions to
attach and secure the vehicle being towed to
the dolly and then the loaded dolly to the tow
vehicle.
For manual transmission vehicles, make sure the
wheels are straight before proceeding to the next
steps. On automatic transmission vehicles, use an
adequate clamping device to ensure that the front
wheels are locked into the straight position.{CAUTION:
Shifting a four-wheel-drive vehicle’s transfer
case into NEUTRAL can cause your vehicle to
roll even if the transmission is in PARK (P) for
an automatic transmission, or if your vehicle
is in gear, for a manual transmission. You or
others could be injured. Make sure the parking
brake is rmly set before you shift the transfer
case to NEUTRAL.
5. Shift the transfer case to NEUTRAL.
SeeFour-Wheel Drive on page 2-38
6. Release the parking brake only after the vehicle
being towed is rmly attached to the tow vehicle.
7. Turn the ignition to LOCK.
4-66

Towing a trailer requires a certain amount of experience.
Before setting out for the open road, you’ll want to get to
know your rig. Acquaint yourself with the feel of handling
and braking with the added weight of the trailer. And
always keep in mind that the vehicle you are driving is
now a good deal longer and not nearly as responsive as
your vehicle is by itself.
Before you start, check all trailer hitch parts and
attachments, safety chains, electrical connector, lamps,
tires and mirror adjustment. If the trailer has electric
brakes, start your vehicle and trailer moving and then
apply the trailer brake controller by hand to be sure the
brakes are working. This lets you check your electrical
connection at the same time.
During your trip, check occasionally to be sure that the
load is secure, and that the lamps and any trailer brakes
are still working.
While towing a trailer or when exposed to long periods
of sunshine, the oor of the truck bed may become very
warm. Avoid putting items in the truck bed that might be
affected by high ambient temperatures.Following Distance
Stay at least twice as far behind the vehicle ahead as you
would when driving your vehicle without a trailer. This can
help you avoid situations that require heavy braking and
sudden turns.
Passing
You’ll need more passing distance up ahead when
you’re towing a trailer. And, because you’re a good
deal longer, you’ll need to go much farther beyond
the passed vehicle before you can return to your lane.
Backing Up
Hold the bottom of the steering wheel with one hand.
Then, to move the trailer to the left, just move that hand
to the 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.
4-89

The vehicle must be on a level surface. When your
engine is cold, the coolant level should be at the
FULL COLD mark.
If your vehicle is equipped with a low coolant sensor
and the LOW COOLANT LEVEL message comes
on and stays on, it means you are low on engine
coolant. See “LOW COOLANT LEVEL” underDIC
Warnings and Messages on page 3-55.
Adding Coolant
If you need more coolant, add the proper DEX-COOL®
coolant mixture at the surge tank, but only when the
engine is cool.
{CAUTION:
You can be burned if you spill coolant on hot
engine parts. Coolant contains ethylene glycol,
and it will burn if the engine parts are hot
enough. Do not spill coolant on a hot engine.
When replacing the pressure cap, make sure it is
hand-tight and fully seated.
Coolant Surge Tank Pressure Cap
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.
The coolant surge tank pressure cap must be fully
installed on the coolant surge tank. SeeEngine
Compartment Overview on page 5-14for more
information on location.
Engine Overheating
You will nd a coolant temperature gage on your
vehicle’s instrument panel. SeeEngine Coolant
Temperature Gage on page 3-43.
In addition, you will nd an ENGINE OVERHEATED and
a REDUCED ENGINE POWER message in the Driver
Information Center (DIC) on the instrument panel.
SeeDIC Warnings and Messages on page 3-55.
5-37