2012 CHEVROLET AVALANCHE ECU

Black plate (27,1)Chevrolet Avalanche Owner Manual - 2012
Driving and Operating 9-27
Notice:The engine is designed to
work with the electronics in the
vehicle. If you add electrical parts
or accessories, you could change
the way the engine operates.
Before adding electrical
equipment, check with your
dealer. If you do not, the engine
might not perform properly. Any
resulting damage would not be
covered by the vehicle warranty.
Engine Heater
The engine coolant 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).
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 secures the electrical
cord. 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.
(Continued)
WARNING (Continued)
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.

Black plate (68,1)Chevrolet Avalanche Owner Manual - 2012
9-68 Driving and Operating
Driving with a Trailer
{WARNING
When towing a trailer, exhaust
gases may collect at the rear of
the vehicle and enter if the
liftgate, trunk/hatch, or rear-most
window is open.
Engine exhaust contains Carbon
Monoxide (CO) which cannot be
seen or smelled. It can cause
unconsciousness and even death.
To maximize safety when towing
a trailer:
.Have the exhaust system
inspected for leaks and make
necessary repairs before
starting a trip.
.Never drive with the liftgate,
trunk/hatch, or rear-most
window open.(Continued)
WARNING (Continued)
.Fully open the air outlets on
or under the instrument
panel.
.Adjust the Climate Control
system to a setting that
brings in only outside air and
set the fan speed to the
highest setting. See Climate
Control System in the Index.
For more information about
Carbon Monoxide, see Engine
Exhaust on page 9‑31.
Towing a trailer requires a certain
amount of experience. The
combination you are driving is
longer and not as responsive as the
vehicle itself. Get acquainted with
the handling and braking of the rig
before setting out for the open road. Before starting, check all trailer
hitch parts and attachments, safety
chains, electrical connectors,
lamps, tires and mirrors. If the trailer
has electric brakes, start the
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.

Black plate (22,1)Chevrolet Avalanche Owner Manual - 2012
10-22 Vehicle Care
4. With the coolant surge tankpressure cap off, start the
engine and let it run until the
upper radiator hose can be felt
getting hot. Watch out for the
engine cooling fan.
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. Be
sure the pressure cap is
hand-tight and fully seated.
6. Verify coolant level after 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
The vehicle has several indicators
to warn of engine overheating.
There is a coolant temperature
gauge on your vehicle's instrument
panel. See Engine Coolant
Temperature Gauge on page 5‑14. In addition, ENGINE OVERHEATED
STOP ENGINE, ENGINE
OVERHEATED IDLE ENGINE, and
an ENGINE POWER IS REDUCED
message comes on in the Driver
Information Center (DIC) on the
instrument panel. See
Engine
Cooling System Messages on
page 5‑37 andEngine Power
Messages on page 5‑39.
If the decision is made not to lift the
hood when this warning appears,
but instead get service help right
away. See Roadside Assistance
Program (U.S. and Canada) on
page 13‑7 orRoadside Assistance
Program (Mexico) on page 13‑9.
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.

Black plate (69,1)Chevrolet Avalanche Owner Manual - 2012
Vehicle Care 10-69
Used Replacement Wheels
{WARNING
Replacing a wheel with a used
one is dangerous. How it has
been used or how far it has been
driven may be unknown. It could
fail suddenly and cause a crash.
When replacing wheels, use a
new GM original equipment
wheel.
Tire Chains
{WARNING
If the vehicle has P265/65R18 or
P275/55R20 size tires, do not use
tire chains. There is not enough
clearance. Tire chains used on a
vehicle without the proper amount
of clearance can cause damage
to the brakes, suspension,(Continued)
WARNING (Continued)
or other vehicle parts. The area
damaged by the tire chains could
cause loss of control and a crash.
Use another type of traction
device only if its manufacturer
recommends it for the vehicle's
tire size combination and road
conditions. Follow that
manufacturer's instructions. To
avoid vehicle damage, drive slow
and readjust or remove the
traction device if it is contacting
the vehicle. Do not spin the
wheels.
If traction devices are used, install
them on the rear tires. Notice:
If the vehicle has
P265/70R17 size tires, use tire
chains only where legal and only
when necessary. Use chains that
are the proper size for the tires.
Install them on the rear tires only.
Do not use chains on the front
tires.
Tighten them as tightly as
possible with the ends securely
fastened. Drive slowly and
follow the chain manufacturer's
instructions. If the chains contact
the vehicle, stop and retighten
them. If the contact continues,
slow down until it stops. Driving
too fast or spinning the wheels
with chains on will damage the
vehicle.

Black plate (82,1)Chevrolet Avalanche Owner Manual - 2012
10-82 Vehicle Care
4. Insert the open end of theextension (F) through the hole in
the rear bumper (G) (hoist shaft
access hole). 5. Raise the tire part way upward.
Make sure the retainer is fully
seated across the underside of
the wheel and is centered in the
wheel opening.
6. Raise the tire fully against the underside of the vehicle by
turning the wheel wrench
clockwise until you hear two
clicks or feel it skip twice. The
cable cannot be overtighten.7. Make sure the tire is storedsecurely. Push, pull (A), and then
try to turn (B) the tire. If the tire
moves, use the wheel wrench to
tighten the cable.
8. Reinstall the spare tire lock.
9. Close the hoist shaft access cover.

Black plate (84,1)Chevrolet Avalanche Owner Manual - 2012
10-84 Vehicle Care
3. Loosen the cable by turning thewrench counterclockwise three
or four turns.
4. Repeat this procedure at least two times. If the spare tire
lowers to the ground, continue
with Step 5 under “Removing the
Spare Tire and Tools” underTire
Changing on page 10‑72.
5. If the spare does not lower, turn the wrench counterclockwise
until approximately 15 cm (6 in)
of cable is exposed.
6. Stand the wheel blocks on their shortest ends, with the backs
facing each other.
A. Jack
B. Wheel Blocks
7. Place the bottom edge of the jack (A) on the wheel blocks (B),
separating them so that the jack
is balanced securely.8. Attach the jack handle,extension, and wheel wrench to
the jack and place it (with the
wheel blocks) under the vehicle
toward the front of the rear
bumper.

Black plate (92,1)Chevrolet Avalanche Owner Manual - 2012
10-92 Vehicle Care
Dinghy Towing
Two-Wheel-Drive Vehicles and
Four-Wheel Drive Vehicles with a
Single Speed Automatic
Transfer Case
Notice:If the vehicle is towed
with all four wheels on the
ground, the drivetrain
components could be damaged.
The repairs would not be covered
by the vehicle warranty. Do not
tow the vehicle with all four
wheels on the ground. Two-wheel-drive vehicles and
four-wheel drive vehicles with a
single speed automatic transfer
case should not be towed with all
four wheels on the ground.
Two-wheel-drive transmissions have
no provisions for internal lubrication
while being towed. Four-wheel drive
vehicles with a single speed
automatic transfer case have no
neutral position and will spin the
transmission when the rear
wheels turn.
Four-Wheel Drive Vehicles with a
Two Speed Automatic
Transfer Case
Use the following procedure to
dinghy tow a four-wheel drive
vehicle with a two speed automatic
transfer case:
1. Position the vehicle being towed
behind the tow vehicle and shift
the transmission to P (Park).
2. Turn the engine off and firmly set the parking brake.
3. Securely attach the vehicle being towed to the tow vehicle.

Black plate (94,1)Chevrolet Avalanche Owner Manual - 2012
10-94 Vehicle Care
Four-Wheel Drive Vehicles with a
Two Speed Automatic
Transfer Case
Use the following procedure to dolly
tow a four-wheel drive vehicle from
the front:
1. Attach the dolly to the towvehicle following the dolly
manufacturer's instructions.
2. Drive the front wheels onto the dolly. 3. Shift the transmission to
P (Park).
4. Firmly set the parking brake.
{WARNING
Shifting a four-wheel-drive
vehicle's transfer case into
N (Neutral) can cause the vehicle
to roll even if the transmission is
in P (Park). The driver or others
could be injured. Make sure the
parking brake is firmly set before
the transfer case is shifted to
N (Neutral).
5. Shift the transfer case to N (Neutral). See “Shifting into
N (Neutral)” under“Four-Wheel
Drive.” 6. Secure the vehicle to the dolly
following the manufacturer's
instructions.
7. Release the parking brake only after the vehicle being towed is
firmly attached to the towing
vehicle.
8. Turn the ignition to LOCK/OFF.
After towing, see “Shifting Out of
N (Neutral)” under“Four-Wheel
Drive.”