brakes HUMMER H3 2008 Owners Manual

Automatic Transmission Operation
The automatic transmission has a shift lever on the
console.
It features an electronic shift position indicator within
the instrument cluster. This display must be powered
anytime the shift lever is capable of being moved out of
PARK (P). This means that if your key is turned off,
but not in LOCK, there will be a small current drain on
your battery which could discharge your battery over
a period of time. If you need to leave your key in
the ignition but not in LOCK for an extended period,
it is recommended that you disconnect the battery cable
from the battery to prevent discharging your battery.
There are several different positions for your shift lever.PARK (P):This position locks your rear wheels. It is
the best position to use when you start the engine
because your vehicle cannot move easily.
{CAUTION:
It is dangerous to get out of your vehicle if
the shift lever is not fully in PARK (P) with the
parking brake rmly set. Your vehicle can roll.
Do not leave your 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 your
vehicle will not move, even when you are on
fairly level ground, always set your parking
brake and move the shift lever to PARK (P).
SeeShifting Into PARK (P) (Automatic
Transmission) on page 2-33. If you are pulling a
trailer, seeTowing a Trailer on page 4-50.
Make sure the shift lever is fully in PARK (P)
before starting the engine. Your vehicle has an
automatic transmission shift lock control system.
You must fully apply your regular brakes rst and
then press the shift lever button before you can
shift from PARK (P) when the ignition key is in ON.
2-23

DRIVE (D):This position is for normal driving.
It provides the best fuel economy for your vehicle.
If you need more power for passing, and you are:
Going less than about 35 mph (55 km/h),
push your accelerator pedal about halfway down.
Going about 35 mph (55 km/h) or more,
push the accelerator all the way down.
Downshifting the transmission in slippery road conditions
could result in skidding, see “Skidding” underLoss of
Control on page 4-10.
DRIVE (D) can be used when towing a trailer. You may
want to shift the transmission to THIRD (3) or, if
necessary, a lower gear if the transmission shifts too
often under heavy loads and/or hilly conditions.
THIRD (3):This position is also used for normal
driving. However it reduces vehicle speed more than
DRIVE (D) without using your brakes. You might
choose THIRD (3) instead of DRIVE (D) when driving
on hilly, winding roads, when towing a trailer, so there
is less shifting between gears and when going down
a steep hill.SECOND (2): This position reduces vehicle speed
even more than THIRD (3) without using your brakes.
You can use SECOND (2) on hills. It can help
control your speed as you go down steep mountain
roads, but then you would also want to use your
brakes off and on.
FIRST (1): This position reduces vehicle speed even
more than SECOND (2) without using your brakes.
You can use it on very steep hills, or in deep snow or
mud. If the shift lever is put in FIRST (1) while the
vehicle is moving forward, the transmission will not shift
into rst gear until the vehicle is going slowly enough.
Notice:Spinning the tires or holding the vehicle
in one place on a hill using only the accelerator
pedal may damage the transmission. The repair will
not be covered by your warranty. If you are stuck,
do not spin the tires. When stopping on a hill,
use the brakes to hold the vehicle in place.
2-25

Shifting Out of PARK (P)
(Automatic Transmission)
Your vehicle has an automatic transaxle shift lock
control system. You have to fully apply your regular
brakes before you can shift from PARK (P) when
the ignition is RUN. SeeAutomatic Transmission
Operation on page 2-23.
The shift lock control system is designed to do the
following:
Prevent the ignition key from being removed
unless the shift lever is in PARK (P).
Prevent movement of the shift lever out of
PARK (P), unless the ignition is in ON/RUN
and the regular brake pedal is applied.
The shift lock control system is always functional
except in the case of a dead battery or low voltage
(less than 9 V) battery.
If your vehicle has an uncharged battery or a battery
with low voltage, try charging or jump starting the
battery. SeeJump Starting on page 5-42for more
information.To shift out of PARK (P) use the following:
1. Apply the brake pedal.
2. Move the shift lever to the desired position.
If you still are unable to shift out of PARK (P):
1. Ease the pressure on the shift lever.
2. While holding down the brake pedal, push the
shift lever all the way into PARK (P)
3. Move the shift lever to the desired position.
If you are still having a problem shifting, then have
your vehicle serviced soon.Parking Your Vehicle
(Manual Transmission)
Your vehicle has a manual transmission. Before you
get out of your vehicle, move the shift lever into
REVERSE (R), and rmly apply the parking brake.
Once the shift lever has been placed into REVERSE (R)
with the clutch pedal pressed in, turn the ignition key
to LOCK, remove the key and release the clutch.
If you are parking on a hill, or if your vehicle is pulling
a trailer, seeTowing a Trailer on page 4-50.
2-35

Cruise control will not work if your parking brake is set,
or if the master cylinder brake uid level is low.
If you apply your brakes, the cruise control shuts off.
{CAUTION:
Cruise control can be dangerous where you
cannot drive safely at a steady speed. So, do
not use your cruise control on winding roads
or in heavy traffic.
Cruise control can be dangerous on slippery
roads. On such roads, fast changes in tire
traction can cause excessive wheel slip, and
you could lose control. Do not use cruise
control on slippery roads.
The cruise control disengages, if the vehicle has the
Traction Control System (TCS) and it begins to
limit wheel spin. SeeTraction Control System (TCS) on
page 4-5. When road conditions allow you to safely
use it again, you can turn cruise control back on.
Setting Cruise Control
{CAUTION:
If you leave your cruise control on when you
are not using cruise, you might hit a button
and go into cruise when you do not want to.
You could be startled and even lose control.
Keep the cruise control switch off until you
want to use cruise control.
1. Move the cruise control switch to on.
2. Get up to the speed desired.
3. Press in the set button at the end of the lever and
release it.
4. Take your foot off the accelerator pedal.
The cruise symbol on the
instrument panel comes on
when the cruise control
is engaged.
3-12

Antilock Brake System Warning
Light
For vehicles with the
Antilock Brake System
(ABS), this light will come
on briey when you
start the engine.
That is normal. If the light does not come on then, have it
xed so it will be ready to warn you if there is a problem.
If the ABS light stays on, turn the ignition off, if the light
comes on when you are driving, stop as soon as it
is safely possible and turn the ignition off. Then start the
engine again to reset the system. If the ABS light still
stays on, or comes on again while you are driving, your
vehicle needs service. If the regular brake system
warning light is not on, you still have brakes, but you do
not have antilock brakes. If the regular brake system
warning light is also on, you do not have antilock brakes
and there is a problem with your regular brakes. See
Brake System Warning Light on page 3-33
For vehicles with a Driver Information Center (DIC), see
DIC Warnings and Messages on page 3-43for all
brake related DIC messages.
Traction Off Light
If you have the Traction
Control System (TCS), this
light will come on when the
TCS has been turned off.
This light will come on briey when the ignition is turned
to ON, if it does not the system may require service.
For more information on the traction off light, see
Traction Control System (TCS) on page 4-5.
StabiliTrak®Not Ready Light
If you have the StabiliTrak®
system, this light will come
on when the StabiliTrak®
system has been
turned off.
This light will come on briey when the ignition is turned
to ON, if it does not the system may require service.
For more information, seeStabiliTrak
®System on
page 4-7.
3-34

AC (Air Conditioning) OFF
This message displays when the engine coolant
temperature is too high and the air conditioning in your
vehicle needs to be turned off. SeeEngine Overheating
on page 5-29andClimate Control System on
page 3-22for more information. This message displays
along with the ENG HOT message.
ABS (Antilock Brake System) FAULT
This message displays if there is a problem with
the Antilock Brake System (ABS). Check the ABS as
soon as possible and have your vehicle serviced by your
dealer/retailer. SeeBrakes on page 5-38andAntilock
Brake System Warning Light on page 3-34for more
information. Press and release the reset stem to
acknowledge the message and clear it from the display.
BRAKES
This message displays if there is a problem with the
brakes. Check the brakes as soon as possible and have
your vehicle serviced by your dealer/retailer. See
Brakes on page 5-38andBrake System Warning Light
on page 3-33for more information. Press and release
the reset stem to acknowledge the message and clear it
from the display.
CHANGE OIL
This message displays when the oil needs to be
changed. Check the oil in your vehicle as soon as
possible and have your vehicle serviced by your
dealer/retailer. SeeEngine Oil on page 5-15and
Scheduled Maintenance on page 6-4for more
information. Press and release the reset stem to
acknowledge the message and clear it from the display.
DOORS
This message displays when one or more of the doors
is ajar. Check all the doors on your vehicle to make
sure they are closed. The message clears from
the display after all of the doors are closed.
ENG (Engine) HOT
This message displays when the engine coolant
temperature is hot. Check the engine coolant
temperature gage. SeeEngine Coolant Temperature
Gage on page 3-35. Have your vehicle serviced by your
dealer/retailer as soon as possible if you suspect the
engine is overheating. SeeEngine Overheating on
page 5-29for more information.
3-44

FLUID
This message displays if the brake uid is low. Check
the brake uid as soon as possible and have your
vehicle serviced by your dealer/retailer. SeeBrakes on
page 5-38for more information. Press and release
the reset stem to acknowledge the message and clear it
from the display.
FUEL CAP
This message displays if the vehicle’s fuel cap is either
off or loose. Pull over as soon as possible and check
to see if the fuel cap is secure. You may also see
the check engine light on the instrument panel cluster.
If the check engine light does come on when the
fuel cap was loose, it may take a few driving trips before
the light turns off. SeeMalfunction Indicator Lamp on
page 3-36for more information if the light still remains
on. Press and release the reset stem to acknowledge
the message and clear it from the display.
LOW FUEL
This message displays if the level of fuel in the vehicle
is low. Also check the fuel gage. SeeFuel Gage on
page 3-40for more information. Rell the fuel tank as
soon as possible.
LOW TIRE
This message displays if a low tire pressure is detected
in any of the vehicle’s tires. Press and release the reset
stem to acknowledge the message and clear it from the
display. The message appears at each ignition cycle until
the tires are inated to the correct ination pressure. See
Tires on page 5-54andInflation - Tire Pressure on
page 5-62for more information on tires and the correct
ination pressures.
OIL
This message displays when the oil pressure is low.
SeeOil Pressure Light on page 3-38andEngine Oil
on page 5-15for more information.
PARK BRK (Brake)
This message displays when the parking brake is set.
SeeParking Brake on page 2-32andBrake System
Warning Light on page 3-33for more information. The
message clears from the display after the parking brake
is released or by pressing and releasing the reset stem.
3-45

For persons under 21, it is against the law in every
U.S. state to drink alcohol. There are good medical,
psychological, and developmental reasons for
these laws.
The obvious way to eliminate the leading highway
safety problem is for people never to drink alcohol
and then drive.
Medical research shows that alcohol in a person’s
system can make crash injuries worse, especially
injuries to the brain, spinal cord, or heart. This means
that when anyone who has been drinking — driver
or passenger — is in a crash, that person’s chance
of being killed or permanently disabled is higher than
if the person had not been drinking.
Control of a Vehicle
The following three systems help to control your vehicle
while driving — brakes, steering, and accelerator.
At times, as when driving on snow or ice, it is easy to
ask more of those control systems than the tires and
road can provide. Meaning, you can lose control of your
vehicle. SeeTraction Control System (TCS) on page 4-5.
Adding non-dealer/non-retailer accessories can affect
your vehicle’s performance. SeeAccessories and
Modifications on page 5-3.
Braking
SeeBrake System Warning Light on page 3-33.
Braking action involves perception time and reaction
time. First, you have to decide to push on the brake
pedal. That is perception time. Then you have to bring
up your foot and do it. That is reaction time.
Average reaction time is about three-fourths of a
second. But that is only an average. It might be less
with one driver and as long as two or three seconds or
more with another. Age, physical condition, alertness,
coordination, and eyesight all play a part. So do alcohol,
drugs, and frustration. But even in three-fourths of a
second, a vehicle moving at 60 mph (100 km/h) travels
66 feet (20 m). That could be a lot of distance in an
emergency, so keeping enough space between
your vehicle and others is important.
And, of course, actual stopping distances vary greatly
with the surface of the road, whether it is pavement or
gravel; the condition of the road, whether it is wet, dry,
or icy; tire tread; the condition of the brakes; the weight
of the vehicle; and the amount of brake force applied.
Avoid needless heavy braking. Some people drive
in spurts — heavy acceleration followed by heavy
braking — rather than keeping pace with traffic.
4-3

This is a mistake. The brakes might not have time to
cool between hard stops. The brakes will wear out
much faster if you do a lot of heavy braking. If you
keep pace with the traffic and allow realistic following
distances, you will eliminate a lot of unnecessary
braking. That means better braking and longer
brake life.
If your vehicle ever loses electrical power while you
are driving, brake normally but do not pump the brakes.
If you do, the pedal could get harder to push down.
If your vehicle loses electrical power, you will still have
some power brake assist. But you will use it when
you brake. Once the power assist is used up, it can take
longer to stop, the brake pedal will be harder to push,
and you might experience longer pedal travel.
Adding non-dealer/non-retailer accessories can affect
your vehicle’s performance. SeeAccessories and
Modifications on page 5-3.Antilock Brake System (ABS)
Your vehicle has the Antilock Brake System (ABS),
an advanced electronic braking system that will
help prevent a braking skid.
When you start the engine and begin to drive away,
ABS will check itself. You might hear a momentary
motor or clicking noise while this test is going on.
This is normal.
If there is a problem with
ABS, this warning light will
stay on. SeeAntilock
Brake System Warning
Light on page 3-34.
Let us say the road is wet and you are driving safely.
Suddenly, an animal jumps out in front of you. You slam
on the brakes and continue braking. Here is what
happens with ABS:
A computer senses that wheels are slowing down.
If one of the wheels is about to stop rolling, the computer
will separately work the brakes at each wheel.
4-4

ABS can change the brake pressure faster than any
driver could. The computer is programmed to make the
most of available tire and road conditions. This can
help you steer around the obstacle while braking hard.
As you brake, the computer keeps receiving updates
on wheel speed and controls braking pressure
accordingly.
Remember: ABS does not change the time you need to
get your foot up to the brake pedal or always decrease
stopping distance. If you get too close to the vehicle
in front of you, you will not have time to apply the brakes
if that vehicle suddenly slows or stops. Always leave
enough room up ahead to stop, even though you
have ABS.
Using ABS
Do not pump the brakes. Just hold the brake pedal down
rmly and let antilock work for you. You might feel the
brakes vibrate or notice some noise, but this is normal.
Braking in Emergencies
With ABS, you can steer and brake at the same time.
In many emergencies, steering can help you more
than even the very best braking.
Traction Control System (TCS)
Your 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, the system applies the brakes to limit
wheel spin and also reduces engine power. You may feel
or hear the system working, but this is normal.
The Traction Control System may operate on dry roads
under some conditions. When this happens, you may
notice a reduction in acceleration or a pumping sound.
This is normal and doesn’t mean there’s a problem with
your vehicle. Examples of these conditions include hard
acceleration in a turn, an abrupt upshift or downshift of
the transmission or driving on rough roads.
If your vehicle is in cruise control when the TCS begins
to limit wheel spin, the cruise control will automatically
disengage. When road conditions allow you to safely
use it again, you may re-engage the cruise control.
SeeCruise Control on page 3-11.
If your vehicle has a Driver information Center (DIC),
a TRACTION FAULT message will appear when a
Traction Control System or Anti-Lock Brake System
problem has been detected and the vehicle needs
service. SeeDIC Warnings and Messages on page 3-43
for more information.
4-5