engine HUMMER H2 2006 Service Manual

ENGINE COOLANT HOT
If the cooling system temperature gets hot, this message
will appear in the DIC. Turn off the air conditioning. If
the message is still on, or if the engine coolant
temperature gage continues to rise, pull the vehicle over
when it is safe to do so. SeeEngine Coolant
Temperature Gage on page 3-37for more information.
Stop the vehicle and let the engine idle in PARK (P)
for a few minutes to allow the coolant to reach a
safe temperature. This message will clear when the
coolant temperature drops to a safe operating
temperature. Pressing any of the four DIC buttons or
the trip odometer reset stem will clear the message from
the DIC display.
ENGINE OVERHEATED
If the engine cooling system reaches unsafe
temperatures for operation, this message will appear in
the DIC and you will hear a chime. Stop and turn off
the vehicle as soon as it is safe to do so to avoid severe
damage. This message will clear when the engine
has cooled to a safe operating temperature.
FUEL LEVEL LOW
If the fuel level is low, this message will appear on the
DIC and you will hear a chime. Refuel as soon as
possible. Pressing any of the four DIC buttons or the
trip odometer reset stem will clear the message from the
DIC display. It will also clear itself after 10 seconds.
The low fuel light near the fuel gage will still remain on
in either case. SeeLow Fuel Warning Light on
page 3-44,Fuel Gage on page 3-44, andFuel on
page 5-5for more information.
KEYFOB X BATTERY LOW
If a remote keyless entry transmitter battery is low, this
message will appear on the DIC. The battery needs
to be replaced in the transmitter. See “Battery
Replacement” underRemote Keyless Entry System
Operation on page 2-5. Pressing any of the
four DIC buttons or the trip odometer reset stem
will clear the message from the DIC display.
LEFT REAR DOOR AJAR
If the driver’s side rear door is not fully closed and the
vehicle is in a drive gear, this message will appear
on the display and you will hear a chime. Stop and turn
off the vehicle, check the door for obstacles, and
close the door again. Check to see if the message still
appears on the DIC. Pressing any of the four DIC
buttons or the trip odometer reset stem will clear the
message from the DIC display.
3-50

OIL LIFE RESET
This message will appear on the display for about
10 seconds after resetting the change engine oil
message. SeeEngine Oil on page 5-14and “Engine Oil
Life System” underDIC Operation and Displays on
page 3-45for more information.
OIL PRESSURE LOW
If low oil pressure levels occur, this message will be
displayed on the DIC and a chime will sound. Stop the
vehicle as soon as safely possible and do not operate
it until the cause of the low oil pressure has been
corrected. Check your oil as soon as possible and have
your vehicle serviced by your dealer.
PASSENGER DOOR AJAR
If the passenger’s door is not fully closed and the
vehicle is in a drive gear, this message will appear on
the display and you will hear a chime. Stop and turn off
the vehicle, check the door for obstacles, and close
the door again. Check to see if the message still
appears on the DIC. Pressing any of the four DIC
buttons or the trip odometer reset stem will clear the
message from the DIC display.
REAR ACCESS OPEN
On the SUV, if the liftgate is open while the ignition is in
RUN, this message will appear on the DIC and you
will hear a chime. Turn off the vehicle and check
the liftgate. Restart the vehicle and check for the
message on the DIC display. Pressing any of the
four DIC buttons or the trip odometer reset stem will
clear the message from the DIC display.
On the SUT, if the midgate is open or one or both of the
midgate latches are not fully closed, this message will
appear on the DIC. Turn off the vehicle and check that
the midgate and the latches are closed. Restart the
vehicle and check for the message on the DIC display.
Pressing any of the four DIC buttons or the trip odometer
reset stem will clear the message from the DIC display.
REDUCED ENGINE POWER
This message is displayed when the cooling system
temperature gets too hot and the engine further enters
the engine coolant protection mode.
SeeEngine Overheating on page 5-27for further
information.
You may also see this message when the vehicle
determines a problem with the electronic throttle control.
See your dealer for service.
3-51

SERVICE AIR SUSPENSION
If a problem occurs with the suspension system, this
message will appear on the DIC. If this message
appears, stop as soon as possible and turn off the
vehicle. Restart the vehicle and check for the message
on the DIC display. If the message is still displayed,
or appears again when you begin driving, there is
a problem with the air suspension system. See your
dealer for service.
SERVICE BRAKE SYSTEM
If a problem occurs with the brake system, this message
will appear on the DIC. If this message appears, stop
as soon as possible and turn off the vehicle. Restart the
vehicle and check for the message on the DIC display.
If the message is still displayed, or appears again when
you begin driving, there is a problem with the brake
system. See your dealer for service. Pressing any of the
four DIC buttons or the trip odometer reset stem will
clear the message from the DIC display.
TIGHTEN FUEL CAP
If the vehicle’s fuel cap is not tightened properly, this
message may appear along with the check engine light
on the instrument panel cluster. SeeMalfunction Indicator
Lamp on page 3-39. Reinstall the fuel cap, making sure
to fully install the cap. SeeFilling the Tank on page 5-8.
The diagnostic system can determine if the fuel cap has
been left off or improperly installed. A loose or missing
fuel cap will allow fuel to evaporate into the atmosphere.
A few driving trips with the cap properly installed should
turn the light and message off.
TRACTION ACTIVE
When the traction control system has detected that any
of the vehicle’s wheels are slipping, the traction
control system will activate and this message will appear
on the DIC. SeeTraction Control System (TCS) on
page 4-9for more information.
3-53

TRANS (Transmission) HOT
IDLE ENGINE
Notice:If you drive your vehicle while the
transmission uid is overheating and the
transmission temperature warning is displayed on
the instrument panel cluster and/or DIC, you
can damage the transmission. This could lead to
costly repairs that would not be covered by
your warranty. Do not drive your vehicle with
overheated transmission uid or while the
transmission temperature warning is displayed.
If the transmission uid in the vehicle gets hot,
this message will appear on the DIC along with a
continuous chime. Driving with the transmission uid
temperature high can cause damage to the vehicle. Stop
the vehicle and let it idle to allow the transmission to
cool. This message will clear and the chime will
stop when the uid temperature reaches a safe level.
SeeTransmission Temperature Gage on page 3-37.
TRANSMISSION HOT
Notice:If you drive your vehicle while the
transmission uid is overheating and the
transmission temperature warning is displayed on
the instrument panel cluster and/or DIC, you
can damage the transmission. This could lead to
costly repairs that would not be covered by
your warranty. Do not drive your vehicle with
overheated transmission uid or while the
transmission temperature warning is displayed.
If the transmission uid temperature becomes high, this
message will appear on the DIC.
When the transmission enters the protection mode, you
may notice a change in the transmission shifting
patterns. When the transmission uid temperature
returns to normal, the display will turn off and the
transmission shifting patterns will return to normal.
3-54

While your vehicle is parked:
Familiarize yourself with all of its controls.
Familiarize yourself with its operation.
Set up your audio system by presetting your
favorite radio stations, setting the tone, and
adjusting the speakers. Then, when driving
conditions permit, you can tune to your favorite
radio stations using the presets and steering wheel
controls (if equipped).
Notice:Before adding any sound equipment to
your vehicle, such as an audio system, CD player,
CB radio, mobile telephone, or two-way radio, make
sure that it can be added by checking with your
dealer. Also, check federal rules covering mobile
radio and telephone units. If sound equipment can
be added, it is very important to do it properly.
Added sound equipment may interfere with
the operation of your vehicle’s engine, radio, or
other systems, and even damage them. Your
vehicle’s systems may interfere with the operation
of sound equipment that has been added.
Notice:The chime signals related to safety belts,
parking brake, and other functions of your vehicle
operate through the GM radio/entertainment system.
If that equipment is replaced or additional equipment
is added to your vehicle, the chimes may not work.Make sure that replacement or additional equipment
is compatible with your vehicle before installing it.
SeeAccessories and Modifications on page 5-3.
Your vehicle has a feature called Retained Accessory
Power (RAP). With RAP, the audio system can be played
even after the ignition is turned off. SeeRetained
Accessory Power (RAP) on page 2-25for more
information.
Setting the Time
The radio may have a button marked with an H or HR to
represent hours and an M or MN to represent minutes.
Press and hold the hour button until the correct hour
appears on the display. Press and hold the minute
button until the correct minute appears on the display.
The time can be set with the ignition on or off.
To synchronize the time with an FM station broadcasting
Radio Data System (RDS) information, press and hold
the hour and minute buttons at the same time until RDS
TIME appears on the display. To accept this time, press
and hold the hour and minute buttons, at the same time,
for another two seconds. If the time is not available from
the station, NO UPDAT will appear on the display.
RDS time is broadcast once a minute. After tuning to an
RDS broadcast station, it may take a few minutes for
the time to update.
3-62

Braking
SeeBrake System Warning Light on page 3-35.
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 your 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. This is
a mistake. Your brakes may not have time to cool
between hard stops. Your 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 engine ever stops while you are driving, brake
normally but do not pump your brakes. If you do,
the pedal may get harder to push down. If your engine
stops, you will still have some power brake assist.
But you will use it when you brake. Once the power
assist is used up, it may take longer to stop and
the brake pedal will be harder to push.
Adding non-GM accessories can affect your vehicle’s
performance. SeeAccessories and Modications
on page 5-3.
4-6

Anti-Lock Brake System (ABS)
Your vehicle has anti-lock brakes. ABS is an advanced
electronic braking system that will help prevent a
braking skid.
When you start your engine and begin to drive away,
your anti-lock brake system will check itself. You
may hear a momentary motor or clicking noise while
this test is going on. This is normal.
If there is a problem with
the anti-lock brake system,
this warning light will
stay on. SeeAnti-Lock
Brake System Warning
Light on page 3-36.
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 front wheel
and at both rear wheels.
4-7

If you restart your engine, the system reverts to the
standard TCS mode.
The traction off light will
come on when a Traction
Control System or
Anti-Lock Brake System
problem has been detected
and the vehicle needs
service.
SeeTraction Off Light on page 3-36.
When the traction off light is on, adjust your driving
accordingly.
The traction control system, as delivered from the
factory, will automatically come on whenever you start
your vehicle.
Adding non-GM accessories can affect your vehicle’s
performance. SeeAccessories and Modications
on page 5-3for more information.Locking Rear Axle
The locking rear axle can give your vehicle additional
traction from the rear wheels when traveling in off-road
situations such as mud, snow, sand, steep hills and
uneven terrain.
The button used to turn
this feature on or off is
located above the transfer
case buttons to the
right of the steering wheel.
To lock the rear axle, do the following:
1. Place the transfer case in the Four-Wheel-Low Lock
mode. This is the only mode which will allow the rear
axle to lock. SeeFull-Time Four-Wheel Drive on
page 2-30for more information regarding the transfer
case and Four-Wheel-Low-Lock mode.
2. Press the button with the vehicle stopped or moving
less than 2 mph (3 km/h).
4-10

You must wait for the light in the button to stop ashing
and remain illuminated before the rear axle is locked.
Notice:If you try to lock the rear axle while
your vehicle is stuck and the tires are spinning, you
could damage your vehicle’s drivetrain. The
repairs would not be covered by your warranty.
Always lock the rear axle before attempting
situations and/or navigating terrain which could
possibly cause the vehicle to become stuck.
The locking rear axle will be disengaged when the
vehicle’s speed is greater than 20 mph (32 km/h), if the
vehicle’s battery is low and/or the transfer case is
shifted out of Four-Wheel-Low-Lock mode.
Notice:If you lock the rear axle while driving on
pavement, you could damage your vehicle’s
drivetrain. The repairs would not be covered by
your warranty. Do not use the locking rear axle on
pavement. If you need four-wheel drive when
traveling on pavement, use only 4HI.
Steering
Power Steering
If you lose power steering assist because the engine
stops or the system is not functioning, you can steer but
it will take much more effort.
Steering Tips
It is important to take curves at a reasonable speed.
A lot of the “driver lost control” accidents mentioned on
the news happen on curves. Here is why:
Experienced driver or beginner, each of us is subject to
the same laws of physics when driving on curves.
The traction of the tires against the road surface makes
it possible for the vehicle to change its path when
you turn the front wheels. If there is no traction, inertia
will keep the vehicle going in the same direction. If
you have ever tried to steer a vehicle on wet ice, you
will understand this.
The traction you can get in a curve depends on the
condition of your tires and the road surface, the angle at
which the curve is banked, and your speed. While
you are in a curve, speed is the one factor you
can control.
Suppose you are steering through a sharp curve.
Then you suddenly accelerate. Both control
systems — steering and acceleration — have to do
their work where the tires meet the road. Adding
the sudden acceleration can demand too much of
those places. You can lose control. SeeTraction
Control System (TCS) on page 4-9.
What should you do if this ever happens? Ease up on
the accelerator pedal, steer the vehicle the way you
want it to go, and slow down.
4-11

Loss of Control
Let us review what driving experts say about what
happens when the three control systems — brakes,
steering, and acceleration — do not have enough
friction where the tires meet the road to do what the
driver has asked.
In any emergency, do not give up. Keep trying to
steer and constantly seek an escape route or area
of less danger.
Skidding
In a skid, a driver can lose control of the vehicle.
Defensive drivers avoid most skids by taking reasonable
care suited to existing conditions, and by not overdriving
those conditions. But skids are always possible.
The three types of skids correspond to your vehicle’s
three control systems. In the braking skid, your wheels
are not rolling. In the steering or cornering skid, too much
speed or steering in a curve causes tires to slip and lose
cornering force. And in the acceleration skid, too much
throttle causes the driving wheels to spin.
A cornering skid is best handled by easing your foot off
the accelerator pedal.If your vehicle starts to slide, ease your foot off the
accelerator pedal and quickly steer the way you want
the vehicle to go. If you start steering quickly enough,
your vehicle may straighten out. Always be ready
for a second skid if it occurs.
Of course, traction is reduced when water, snow, ice,
gravel, or other material is on the road. For safety, you
will want to slow down and adjust your driving to
these conditions. It is important to slow down on slippery
surfaces because stopping distance will be longer and
vehicle control more limited.
While driving on a surface with reduced traction, try
your best to avoid sudden steering, acceleration,
or braking, including engine braking by shifting to a
lower gear. Any sudden changes could cause the tires
to slide. You may not realize the surface is slippery
until your vehicle is skidding. Learn to recognize warning
clues — such as enough water, ice, or packed snow
on the road to make a mirrored surface — and
slow down when you have any doubt.
Remember: Any Anti-Lock Brake System (ABS) helps
avoid only the braking skid.
4-15