engine HUMMER H3 2010 Workshop Manual

9-40 Driving and Operating
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.
Engine Exhaust
{WARNING
Engine exhaust contains Carbon
Monoxide (CO) which cannot be
seen or smelled. Exposure to CO
can cause unconsciousness and
even death.
Exhaust may enter the vehicle if:
.The vehicle idles in areas
with poor ventilation (parking
garages, tunnels, deep snow
that may block underbody
airflow or tail pipes).
.The exhaust smells or
sounds strange or different.
.The exhaust system leaks
due to corrosion or damage.(Continued)
WARNING (Continued)
.The vehicle’s exhaust system
has been modified, damaged
or improperly repaired.
.There are holes or openings
in the vehicle body from
damage or after-market
modifications that are not
completely sealed.
If unusual fumes are detected or
if it is suspected that exhaust is
coming into the vehicle:
.Drive it only with the windows
completely down.
.Have the vehicle repaired
immediately.
Never park the vehicle with the
engine running in an enclosed
area such as a garage or a
building that has no fresh air
ventilation.

Driving and Operating 9-41
Running the Vehicle
While Parked
It is better not to park with the
engine running. But if you ever have
to, here are some things to know.
{WARNING
Idling a vehicle in an enclosed
area with poor ventilation is
dangerous. Engine exhaust may
enter the vehicle. Engine exhaust
contains Carbon Monoxide (CO)
which cannot be seen or smelled.
It can cause unconsciousness
and even death. Never run the
engine in an enclosed area that
has no fresh air ventilation. For
more information, seeEngine
Exhaust on page 9‑40.
{WARNING
It can be dangerous to get out
of the vehicle if the automatic
transmission shift lever is not fully
in P (Park) with the parking brake
firmly set. The vehicle can roll.
Do not leave the vehicle when
the engine is running unless you
have to. 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
it is on fairly level ground, always
set the parking brake and move
the automatic transmission shift
lever to P (Park), or the manual
transmission shift lever to Neutral.
Follow the proper steps to be sure
the vehicle will not move. See
Shifting Into Park
on page 9‑37and Parking on page 9‑39.
If pulling a trailer, see Driving
Characteristics and Towing Tips
on
page 9‑70.
Automatic
Transmission
The automatic transmission has a
shift lever on the console.

9-42 Driving and Operating
It features an electronic shift
position indicator within the
instrument cluster.
There are several different positions
for the shift lever.
P (Park):This position locks the
rear wheels. It is the best position
to use when you start the engine
because the vehicle cannot move
easily.
{WARNING
It is 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.
Do not leave the vehicle when
the engine is running unless you
have to. 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,
always set the parking brake and
move the shift lever to P (Park).
See Shifting Into Park
on
page 9‑37
. If you are pulling a
trailer, see Driving Characteristics
and Towing Tips on page 9‑70. Make sure the shift lever is fully in
P (Park) before starting the engine.
The vehicle has an automatic
transmission shift lock control
system. You must fully apply the
regular brakes first and then press
the shift lever button before you can
shift from P (Park) when the ignition
key is in ON/RUN. If you cannot
shift out of P (Park), ease pressure
on the shift lever and push the shift
lever all the way into P (Park) as
you maintain brake application.
Then press the shift lever button
and move the shift lever into
another gear. See
Shifting Out of
Park on page 9‑38.
R (Reverse): Use this gear to
back up.
Notice: Shifting to R (Reverse)
while the vehicle is moving
forward could damage the
transmission. The repairs would
not be covered by the vehicle
warranty. Shift to R (Reverse) only
after the vehicle is stopped.

Driving and Operating 9-43
To rock the vehicle back and forth to
get out of snow, ice, or sand without
damaging the transmission, see
If the Vehicle is Stuck on page 9‑26.
N (Neutral):In this position, the
engine does not connect with the
wheels. To restart the engine when
the vehicle is already moving, use
N (Neutral) only.
{WARNING
Shifting into a drive gear while the
engine is running at high speed is
dangerous. Unless your foot is
firmly on the brake pedal, the
vehicle could move very rapidly.
You could lose control and hit
people or objects. Do not shift
into a drive gear while the engine
is running at high speed. Notice:
Shifting out of P (Park)
or N (Neutral) with the engine
running at high speed may
damage the transmission. The
repairs would not be covered by
the vehicle warranty. Be sure the
engine is not running at high
speed when shifting the vehicle.
D (Drive): This position is for
normal driving. It provides the best
fuel economy. If you need more
power for passing, and you are:.Going less than about 55 km/h
(35 mph), push the accelerator
pedal about halfway down.
.Going about 55 km/h (35 mph) or
more, push the accelerator all
the way down. Downshifting the transmission in
slippery road conditions could result
in skidding, see
“Skidding”under
Loss of Control on page 9‑6.
D (Drive) can be used when towing
a trailer. You may want to shift
the transmission to 3 (Third) or,
if necessary, a lower gear if the
transmission shifts too often under
heavy loads or in hilly conditions.
3 (Third): This position is also
used for normal driving. However it
reduces vehicle speed more than
D (Drive) without using the brakes.
You might choose 3 (Third) instead
of D (Drive) when driving on hilly or
winding roads, or when towing a
trailer, so there is less shifting
between gears, or when going down
a steep hill.

Driving and Operating 9-45
You can shift into 1 (First) when
you are going less than 30 km/h
(20 mph). If you have come to a
complete stop and it is hard to shift
into 1 (First), put the shift lever in
Neutral and let up on the clutch.
Then press the clutch pedal back
down and shift into 1 (First).
2 (Second):Press the clutch pedal
as you let up on the accelerator
pedal and shift into 2 (Second).
Then, slowly let up on the clutch
pedal as you press the accelerator
pedal.
3 (Third), 4 (Fourth) and 5 (Fifth):
Shift into 3 (Third), 4 (Fourth) and
5 (Fifth) the same way you do for
2 (Second). Slowly let up on the
clutch pedal as you press the
accelerator pedal.
To stop, let up on the accelerator
pedal and press the brake pedal.
Just before the vehicle stops, press
the clutch pedal and the brake
pedal, and shift to Neutral.
Neutral: Use this position when
you start or idle the engine. R (Reverse):
To back up, stop the
vehicle. Press the clutch pedal and
shift into R (Reverse). Slowly let up
on the clutch pedal as you press
the accelerator pedal. If it is hard
to shift, let the shift lever return to
Neutral and release the clutch
pedal. Then press the clutch again
and shift into R (Reverse). Do not
attempt to shift into the fifth gear
position prior to shifting into
R (Reverse). The transmission has
a lock out feature which prevents a
5 (Fifth) gear to R (Reverse) gear
shift.
Notice: Shifting to R (Reverse)
while the vehicle is moving
forward could damage the
transmission. The repairs would
not be covered by the vehicle
warranty. Shift to R (Reverse) only
after the vehicle is stopped.
Use R (Reverse), along with the
parking brake, for parking the
vehicle.Up-Shift Light
This light will show you when to shift
to the next higher gear for best fuel
economy.
When this light comes on, you
can shift to the next higher gear if
weather, road and traffic conditions
permit. For the best fuel economy,
accelerate slowly and shift when the
light comes on.
While you accelerate, it is normal
for the light to go on and off if you
quickly change the position of the
accelerator. Ignore the shift light
when you downshift.
Disregard the shift light when the
transfer case is in four-wheel low.
For more information, see Up-Shift
Light on page 5‑15.

9-46 Driving and Operating
Shift Speeds
{WARNING
If you skip a gear when you
downshift, you could lose control
of the vehicle. You could injure
yourself or others. Do not shift
down more than one gear at a
time when you downshift.
Hill Start Assist
H3 and H3T vehicles have a Hill
Start Assist feature, which may be
useful when stopped on a grade.
SeeBraking
on page 9‑3for more
information.
Drive Systems
Four-Wheel Drive
Full-Time Four-Wheel Drive sends
engine power to all four wheels for
extra traction. To get the most out of
Full-Time Four-Wheel Drive, you
must be familiar with its operation.
Transfer Case Buttons
The transfer case buttons are
located to the right of the instrument
panel cluster. Use these switches
to shift into and out of the different
Full-Time Four-Wheel Drive modes. 4
m(Four-Wheel High):
This
setting is used for driving in most
street and highway situations. You
can also use this setting for light or
variable off-road conditions.
N (Neutral): Shift the transfer case
to Neutral only when towing the
vehicle. See Driving Characteristics
and Towing Tips
on page 9‑70for
more information.
Notice: Driving on pavement
in Four-Wheel High Lock or
Four Wheel Low Lock for
extended periods may cause
premature wear on the vehicle
powertrain and tires. Do not
drive in Four-Wheel High Lock
or Four-Wheel Low Lock on
pavement for extended periods.
4
m Q(Four-Wheel-High Lock):
Use this setting when you need
extra traction in most off-road
situations such as sand, mud,
snow or level, rocky trails.

Driving and Operating 9-49
5. Simultaneously press andhold the Four-Wheel High and
Four-Wheel-Low Lock buttons
for 10 seconds. The Neutral light
will come on when the transfer
case shift to Neutral is complete.
6. Press and hold the regular brake pedal and shift the transmission
to R (Reverse), then shift the
transmission to D (Drive) for
an automatic transmission,
or 1 (First) for vehicles have a
manual transmission and then
let out the clutch. This is to
ensure the transfer case is in
Neutral. If not, repeat this
procedure starting at Step 3.
7. Turn the engine off. 8. Place the transmission shift
lever in P (Park) for an automatic
transmission, or 1 (First) for
vehicles that have a manual
transmission.
9. Turn the ignition to LOCK/OFF.
Shifting Out of Neutral
To shift out of Neutral:
1. Set the parking brake and apply the regular brake pedal.
2. Shift the transmission to N (Neutral) for an automatic
transmission, or press the clutch
pedal for vehicles that have a
manual transmission. Then turn
the ignition to ON/RUN but do
not start the engine. 3. Press the button for the
desired transfer case shift
position (Four-Wheel High,
Four-Wheel-High Lock or
Four-Wheel-Low Lock).
After the transfer case has
shifted out of Neutral the light
will go out.
4. Release the parking brake.
Notice: Shifting the transmission
into gear before the indicator
light stops flashing could cause
damage to the transfer case.
Always wait until the indicator
light stops flashing before putting
the transmission back in gear.
5. You may start the engine and shift the transmission to the
desired position.

9-50 Driving and Operating
Brakes
Antilock Brake
System (ABS)
This vehicle has the Antilock Brake
System (ABS), an advanced
electronic braking system that helps
prevent a braking skid.
When the engine is started and the
vehicle begins to drive away, ABS
checks itself. A momentary motor or
clicking noise might be heard while
this test is going on, and it might
even be noticed that the brake
pedal moves a little. This is normal.
If there is a problem with ABS, this
warning light stays on. SeeAntilock
Brake System (ABS) Warning Light
on page 5‑15. If driving safely on a wet road and
it becomes necessary to slam on
the brakes and continue braking
to avoid a sudden obstacle, a
computer senses that the wheels
are slowing down. If one of the
wheels is about to stop rolling, the
computer will separately work the
brakes at each wheel.
ABS can change the brake pressure
to each wheel, as required, faster
than any driver could. This can help
the driver steer around the obstacle
while braking hard.
As the brakes are applied, the
computer keeps receiving updates
on wheel speed and controls
braking pressure accordingly.
Remember: ABS does not change
the time needed to get a foot up to
the brake pedal or always decrease
stopping distance. If you get too
close to the vehicle in front of you,
there will not be enough time to
apply the brakes if that vehicle
suddenly slows or stops. Always
leave enough room up ahead to
stop, even with ABS.
Using ABS
Do not pump the brakes. Just hold
the brake pedal down firmly and let
ABS work. The ABS pump or motor
might be heard operating, and the
brake pedal might be felt to pulsate,
but this is normal.
Braking in Emergencies
ABS allows the driver to steer and
brake at the same time. In many
emergencies, steering can help
more than even the very best
braking.

9-52 Driving and Operating
The stability system hydraulic brake
control module increases brake
pressure at each corner of the
vehicle until the ABS activates.
Minor brake pedal pulsations or
pedal movement during this time
is normal and the driver should
continue to apply the brake pedal
as the driving situation dictates.
The brake assist feature will
automatically disengage when
the brake pedal is released or
brake pedal pressure is quickly
decreased.
Hill Start Assist (HSA)
This vehicle has a Hill Start Assist
(HSA) feature, which may be useful
when the vehicle is stopped on a
grade. This feature is designed to
prevent the vehicle from rolling,
either forward or rearward, during
vehicle drive off. After the vehicle
is stopped on an incline, quickly
push the brake pedal to the floor
to activate Hill Start Assist.When the system activates, a
chime will sound and the HSA ON
message will be displayed. The
brakes will automatically be held
for a maximum of two seconds
while the driver switches from
applying the brakes to pushing
the accelerator pedal. When Hill
Start Assist is active, the driver
might experience a
“hard brake
pedal.” This is normal and does
not affect safe brake operation.
After activation, the system will
automatically disengage when the
accelerator pedal is pressed. Do
not turn off the ignition while this
feature is active. The Hill Start
Assist feature may not disengage
fully if the ignition is turned off.
The system will not activate with
the transmission in P (Park), when
traveling down a steep grade in a
drive gear, or if the vehicle is facing
uphill with the transmission in
R (Reverse).
Ride Control Systems
Traction Control
System (TCS)
The vehicle has a Traction Control
System (TCS) that limits wheel
spin. This is especially useful in
slippery road conditions. The
system operates only if it senses
that any of the wheels are spinning
or beginning to lose traction. When
this happens, TCS reduces engine
power. The system may be heard
or felt while it is working. This is
normal and does not mean there is
a problem with the vehicle.
TCS can operate on dry roads
under some conditions. When
this happens, the system may be
heard working or a reduction in
acceleration may be noticed. This
is normal and does not mean there
is a problem with the vehicle.

9-64 Driving and Operating
Fuel
Use of the recommended fuel is
an important part of the proper
maintenance of this vehicle. To help
keep the engine clean and maintain
optimum vehicle performance, we
recommend the use of gasoline
advertised as TOP TIER Detergent
Gasoline.
Look for the TOP TIER label on the
fuel pump to ensure gasoline meets
enhanced detergency standards
developed by auto companies. A list
of marketers providing TOP TIER
Detergent Gasoline can be found at
www.toptiergas.com.
The 8th digit of the Vehicle
Identification Number (VIN) shows
the code letter or number that
identifies the vehicle's engine.The VIN is at the top left of the
instrument panel. See
Vehicle
Identification Number (VIN)
on
page 12‑1.
If the vehicle has the 5.3L V8 engine
(VIN Code P), you can use either
unleaded gasoline or ethanol fuel
containing up to 85% ethanol (E85).
See Fuel E85 (85% Ethanol)
on
page 9‑66. In all other engines, use
only regular unleaded gasoline.
Recommended Fuel
Use regular unleaded gasoline with
a posted octane rating of 87 or
higher. If the octane rating is less
than 87, an audible knocking noise,
commonly referred to as spark
knock, might be heard when driving.
If this occurs, use a gasoline rated
at 87 octane or higher as soon as
possible. If heavy knocking is heard
when using gasoline rated at
87 octane or higher, the engine
needs service.