HUMMER H3 2008 Owners Manual

If the engine still does not start with the other key, your
vehicle needs service. If your vehicle does start, the
rst key may be faulty. See your dealer/retailer who can
service the theft-deterrent system and have a new
key made.
It is possible for the theft-deterrent system decoder to
learn the transponder value of a new or replacement
key. Up to 10 keys can be programmed for the vehicle.
The following procedure is for programming additional
keys only.
Canadian Owners:If you lose or damage your keys,
only a dealer/retailer can service the theft-deterrent
system to have new keys made. To program additional
keys you will require two current driver’s keys.
To program a new key do the following:
1. Verify that the new key has PK3+ stamped on it.
2. Insert the current driver’s key in the ignition
and start the engine. If the engine will not start
see your dealer/retailer for service.
3. After the engine has started, turn the key to
LOCK/OFF, and remove the key.4. Insert the second current driver’s key in the ignition
and start the engine within ten seconds of removing
the previous key. If the engine will not start see
your dealer/retailer for service.
5. After the engine has started, turn the key to
LOCK/OFF, and remove the key. Insert the key to
be programmed and turn it to ON/RUN within
ten seconds of removing the previous key.
The security light will turn off once the key has
been programmed.
6. Repeat the Steps 1 through 5 if additional keys are
to be programmed.
If the security light comes on and stays on while driving,
you will be able to restart the engine if you turn it off.
The theft-deterrent system, however, is not working
properly and must be serviced by your dealer/retailer.
Your vehicle is not protected by the theft-deterrent
system at this time.
In an emergency, contact Roadside Assistance.
SeeRoadside Assistance Program on page 7-6.
Do not leave the key or device that disarms or
deactivates the theft deterrent system in the vehicle.
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Starting and Operating
Your Vehicle
New Vehicle Break-In
Notice:Your vehicle does not need an elaborate
break-in. But it will perform better in the long run if
you follow these guidelines:
Keep your speed at 55 mph (88 km/h) or less for
the rst 500 miles (805 km).
Do not drive at any one constant speed, fast or
slow, for the rst 500 miles (805 km). Do not
make full-throttle starts. Avoid downshifting to
brake or slow the vehicle.
Avoid making hard stops for the rst 200 miles
(322 km) or so. During this time the new brake
linings are not yet broken in. Hard stops
with new linings can mean premature wear and
earlier replacement. Follow this breaking-in
guideline every time you get new brake linings.
Do not tow a trailer during break-in. SeeTowing
a Trailer on page 4-50for the trailer towing
capabilities of your vehicle and more
information.
Following break-in, engine speed and load can be
gradually increased.
Ignition Positions
With the key in the ignition
switch, you can turn to
four different positions.
To shift out of PARK (P), the ignition must be in
ON/RUN and the regular brake pedal must be applied.
Notice:Using a tool to force the key from the
ignition switch could cause damage or break the key.
Use the correct key and turn the key only with your
hand. Make sure the key is all the way in. If none of
this works, then your vehicle needs service.
(A) LOCK/OFF:This position locks the ignition. It also
locks the transmission on automatic transmission
vehicles. It locks the steering wheel on manual
transmission vehicles when the key is removed. It is a
theft-deterrent feature. You will only be able to remove
your key when the ignition is turned to LOCK/OFF.
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If you have an automatic transmission, the ignition
switch cannot be turned to LOCK/OFF unless the shift
lever is in PARK (P).
If the steering wheel is locked, move it from right to
left and turn the key to ACC/ACCESSORY. If none of
this works, then your vehicle needs service.
(B) ACC/ACCESSORY:This is the position in which
you can operate your electrical accessories or items
plugged into the accessory power outlets. On automatic
transmission vehicles, this position unlocks the
ignition. On manual transmission vehicles, it unlocks the
ignition and steering wheel. Use this position if your
vehicle must be pushed or towed.
(C) ON/RUN:This is the position that the switch returns
to after you start your engine and release the switch.
The switch stays in ON when the engine is running.
But even when the engine is not running, you can use
ON/RUN to operate the electrical accessories and
to display some instrument panel cluster warning and
indicator lights. The transmission is also unlocked in
this position on automatic transmission vehicles.
The battery could be drained if you leave the key in
the ACC/ACCESSORY or ON/RUN position with
the engine off. You may not be able to start your
vehicle if the battery is allowed to drain for an
extended period of time.START (D):This is the position that starts the engine.
When the engine starts, release the key. The ignition
switch returns to ON/RUN for driving.
When the engine is not running, ACC/ACCESSORY
and ON/RUN allows you to operate the electrical
accessories, such as the radio or items plugged into
the accessory power outlets.
A warning tone will sound if you open the driver’s
door when the ignition is in ACC/ACCESSORY or
LOCK/OFF and the key is in the ignition.
Key In the Ignition
Never leave your vehicle with the keys inside, as it is an
easy target for joy riders or thieves. If you leave the
key in the ignition and park your vehicle, a chime
will sound, when you open the driver’s door. Always
remember to remove your key from the ignition and take
it with you. This will lock your ignition and transmission.
Also, always remember to lock the doors.
The battery could be drained if you leave the key in the
ignition while your vehicle is parked. You may not be
able to start your vehicle after it has been parked for an
extended period of time.
2-19

Retained Accessory Power (RAP)
These vehicle accessories can be used for up to
20 minutes after the engine is turned off:
Audio System
Front Wipers
Power Windows
Sunroof (if equipped)
These features will work when the key is in ON/RUN or
ACC/ACCESSORY. Once the key is turned from
ON/RUN to LOCK/OFF, these features continue working
for up to 20 minutes or until a door is opened.
Starting the Engine
Place the transmission in the proper gear.
Automatic Transmission
Move the shift lever to PARK (P) or NEUTRAL (N).
The engine will not start in any other position -- this
is a safety feature. To restart when you are already
moving, use NEUTRAL (N) only.
Notice:Do not try to shift to PARK (P) if your
vehicle is moving. If you do, you could damage the
transmission. Shift to PARK (P) only when your
vehicle is stopped.
Manual Transmission
The shift lever should be in neutral position and the
parking brake engaged. Hold the clutch pedal down to
the oor and start the engine. Your vehicle will not
start if the clutch pedal is not all the way down.
That is a safety feature.
2-20

Starting Procedure
1. With your foot off the accelerator pedal, turn the
ignition key to START. When the engine starts,
let go of the key. The idle speed will go down as
your engine gets warm. Do not race the engine
immediately after starting it. Operate the engine and
transmission gently to allow the oil to warm up
and lubricate all moving parts.
Your vehicle has a Computer-Controlled Cranking
System. This feature assists in starting the
engine and protects components. If the ignition
key is turned to the START position, and then
released when the engine begins cranking, the
engine will continue cranking for a few seconds or
until the vehicle starts. If the engine does not
start and the key is held in START for many
seconds, cranking will be stopped after 15 seconds
to prevent cranking motor damage. To prevent
gear damage, this system also prevents cranking if
the engine is already running. Engine cranking
can be stopped by turning the ignition switch
to ACC/ACCESSORY or LOCK/OFF.
Notice:Cranking the engine for long periods of
time, by returning the key to the START position
immediately after cranking has ended, can overheat
and damage the cranking motor, and drain the
battery. Wait at least 15 seconds between each try,
to let the cranking motor cool down.2. If the engine does not start after 5-10 seconds,
especially in very cold weather (below 0°F or−18°C),
it could be ooded with too much gasoline. Try
pushing the accelerator pedal all the way to the oor
and holding it there as you hold the key in START for
up to a maximum of 15 seconds. Wait at least
15 seconds between each try, to allow the cranking
motor to cool down. When the engine starts, let go of
the key and accelerator. If the vehicle starts briey
but then stops again, do the same thing. This clears
the extra gasoline from the engine. Do not race the
engine immediately after starting it. Operate the
engine and transmission gently until the oil warms
up and lubricates all moving parts.
Notice:The engine is designed to work with the
electronics in your vehicle. If you add electrical
parts or accessories, you could change the way the
engine operates. Before adding electrical equipment,
check with your dealer/retailer. If you do not, your
engine might not perform properly. Any resulting
damage would not be covered by your vehicle’s
warranty.
2-21

Engine Coolant Heater
The engine coolant heater, if available, can help in cold
weather conditions at or below 0°F (−18°C) for easier
starting and better fuel economy during engine warm-up.
Plug in the coolant heater at least four hours before
starting your vehicle. An internal thermostat in the
plug-end of the cord may exist which will prevent
engine coolant heater operation at temperatures
above 0° F (−18°C).
To Use the Engine Coolant Heater
1. Turn off the engine.
2. Open the hood and unwrap the electrical cord.
The cord is located in the engine compartment
behind the underhood fuse block on the driver’s
side of the vehicle.
3. Plug it into a normal, grounded 110-volt AC outlet.
{CAUTION:
Plugging the cord into an ungrounded outlet
could cause an electrical shock. Also, the
wrong kind of extension cord could overheat
and cause a re. 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.
How long should you keep the coolant heater plugged
in? The answer depends on the outside temperature, the
kind of oil you have, and some other things. Instead
of trying to list everything here, we ask that you contact
your dealer/retailer in the area where you will be
parking your vehicle. The dealer/retailer can give you
the best advice for that particular area.
2-22

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

If you cannot shift out of PARK (P), ease pressure on
the shift lever and push the shift lever all the way
into PARK (P) as you maintain brake application. Then
press the shift lever button and move the shift lever
into another gear. SeeShifting Out of PARK (P)
(Automatic Transmission) on page 2-35
REVERSE (R):Use this gear to back up.
Notice:Shifting to REVERSE (R) while your vehicle
is moving forward could damage the transmission.
The repairs would not be covered by your warranty.
Shift to REVERSE (R) only after your vehicle is
stopped.
To rock your vehicle back and forth to get out of snow,
ice, or sand without damaging your transmission,
seeIf Your Vehicle is Stuck in Sand, Mud, Ice, or Snow
on page 4-39
NEUTRAL (N):In this position, your engine does not
connect with the wheels. To restart when you are
already moving, use NEUTRAL (N) only.
{CAUTION:
Shifting into a drive gear while the engine is
running at high speed is dangerous. Unless
your foot is rmly on the brake pedal, your
vehicle could move very rapidly. You could
lose control and hit people or objects. Do not
shift into a drive gear while your engine is
running at high speed.
Notice:Shifting out of PARK (P) or NEUTRAL (N)
with the engine running at high speed may damage
the transmission. The repairs would not be covered
by your warranty. Be sure the engine is not running
at high speed when shifting your vehicle.
2-24

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

Manual Transmission Operation
This is your shift pattern.
Here is how to operate your manual transmission:
FIRST (1):Press the clutch pedal and shift into
FIRST (1). Then, slowly let up on the clutch pedal as
you slowly press down on the accelerator pedal.
You can shift into FIRST (1) when you are going less
than 20 mph (30 km/h). If you have come to a complete
stop and it is hard to shift into FIRST (1), put the shift
lever in NEUTRAL and let up on the clutch. Then press
the clutch pedal back down and shift into FIRST (1).
SECOND (2):Press the clutch pedal as you let up
on the accelerator pedal and shift into SECOND (2).
Then, slowly let up on the clutch pedal as you press
the accelerator pedal.THIRD, FOURTH AND FIFTH (3, 4 and 5):Shift into
THIRD (3), FOURTH (4) and FIFTH (5) the same
way you do for SECOND (2). 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
your engine.
REVERSE (R):To back up, press the clutch pedal.
After the vehicle stops, shift into REVERSE (R).
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 REVERSE (R).
Do not attempt to shift into the fth gear position prior
to shifting into REVERSE (R). Your transmission has a
lock out feature which prevents a fth gear to reverse
gear shift.
Notice:Shifting to REVERSE (R) while your vehicle
is moving forward could damage the transmission.
The repairs would not be covered by your warranty.
Shift to REVERSE (R) only after your vehicle is
stopped.
Use REVERSE (R), along with the parking brake,
for parking your vehicle.
2-26