2004 HUMMER H2 engine overheat

Engine Coolant Heater
Your vehicle may be equipped with an engine coolant
heater.
In very cold weather, 0°F (−18°C) or colder, the engine
coolant heater can help. You’ll get easier starting
and better fuel economy during engine warm-up.
Usually, the coolant heater should be plugged in a
minimum of four hours prior to starting your vehicle. At
temperatures above 32°F (0°C), use of the coolant
heater is not required.
To Use the Engine Coolant Heater
1. Turn off the engine.
2. Locate the electrical
cord near the front
recovery loop 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 don’t, 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 in the area where you’ll be parking your
vehicle. The dealer can give you the best advice for that
particular area.
2-21

3. While still pressing the
button, move the lever
forward as far as it
will go. Let go of
the button and the
lever.
4. Turn the ignition key to LOCK.
5. Remove the key and take it with you. If you can
leave your vehicle with the ignition key in your
hand, your vehicle is in PARK (P).Leaving Your Vehicle With the Engine
Running
{CAUTION:
It can be dangerous to leave your vehicle with
the engine running. Your vehicle could move
suddenly if the shift lever is not fully in
PARK (P) with the parking brake rmly set.
And, if you leave the vehicle with the engine
running, it could overheat and even catch re.
You or others could be injured. Do not leave
your vehicle with the engine running.
If you have to leave your vehicle with the engine
running, be sure your vehicle is in PARK (P) and the
parking brake is rmly set before you leave it. After you
move the shift lever into PARK (P), hold the regular
brake pedal down. Then, see if you can move the shift
lever away from PARK (P) without rst pulling it
toward you. If you can, it means that the shift lever
wasn’t fully locked into PARK (P).
2-31

Traction Off Light
The traction off light will
come on when a traction
control system or anti-lock
brake system problem
has been detected.
The vehicle may need
service.
When this light is on, the system will not limit wheel
spin. Adjust your driving accordingly. SeeTraction
Control System (TCS) on page 4-9.
If the Traction Control System (TCS) detects that the
vehicle’s brake’s are overheating, the TCS will shut off
and the traction off light will come on. When the
brakes cool off, the TCS will turn back on automatically
and the traction off light will go out.
Engine Coolant Temperature Gage
This gage shows the engine coolant temperature.
It also provides an indicator of how hard your vehicle is
working. During a majority of the operation, the gage
will read 210°F (100°C) or less. If you are pulling a load
or going up hills, it is normal for the temperature to
uctuate and approach the 250°F (122°C) mark. If the
gage reaches the 260°F (125°C) mark, it indicates
that the cooling system is working beyond its capacity.
SeeEngine Overheating on page 5-27.
United StatesCanada
3-35

Driver Information Center (DIC)
The DIC display is located on the instrument panel
cluster above the steering column. The DIC can display
information such as the trip odometer, fuel economy
and personalization features.
A (Trip Information):Press this button to scroll
through the odometer, personal trip odometer, business
trip odometer, hourmeter, annual log and the timer.
B (Fuel Information):Press this button to scroll
through the current range, average fuel economy, instant
fuel economy and engine oil life.C (Personalization):Press this button to change
personal settings of various features for your vehicle.
D (Select):Press this button to reset certain functions
and turn off or acknowledge messages on the DIC.
DIC Operation and Displays
The DIC comes on when the ignition is on. After a short
delay the DIC will display the current driver (1 or 2)
and the information that was last displayed before the
engine was turned off.
If a problem is detected, a warning message will appear
on the display. Pressing any of the four buttons will
acknowledge (clear) most current warnings or service
messages. Some warnings that cannot be
acknowledged (cleared) are: ENGINE OVERHEATED,
OIL PRESSURE LOW, REDUCED ENGINE POWER,
TRANS HOT IDLE ENGINE. These warnings must
be dealt with immediately and therefore cannot
be cleared until the problem has been corrected.
The DIC has different modes which can be accessed by
pressing the four buttons on the DIC. These buttons are
trip information, fuel information, personalization and
select. The button functions are detailed in the following.
3-44

ENGINE COOLANT HOT
If the cooling system temperature gets hot, this message
will appear in the DIC. Stop the vehicle and let the
engine idle in PARK (P) to allow the coolant to reach a
safe temperature. This message will clear when the
coolant temperature drops to a safe operating
temperature. Pressing the select button will clear it from
the DIC display.
LOW COOLANT LEVEL
If your vehicle has a low coolant sensor and the engine
coolant level is low, this message will appear on the
DIC. Adding coolant will clear the message. This
message will clear itself after 10 seconds until the next
ignition cycle.
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.
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.
BATTERY NOT CHARGING
If the battery is not charging during operation, this
message will appear on the DIC. Driving with this
problem could drain your battery. Have the electrical
system checked as soon as possible. Pressing the
select button will clear it from the DIC display.
3-57

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. SeeMalfunction Indicator
Lamp on page 3-38. Reinstall the fuel cap, making sure
to fully install the cap. SeeFilling Your Tank on
page 5-7. 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.
CHECK WASHER FLUID
If the washer uid level is low, this message will appear
on the DIC. Adding washer uid will clear the message.
Pressing the select button will clear it from the DIC
display. This message will clear itself after 10 seconds
until the next ignition cycle.
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.
TRANSMISSION HOT
If the transmission uid temperature becomes high, the
message center will display this message.
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.
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 transmission
temperature warning is displayed.
3-59

Q:Suppose, after stalling, I try to back down the
hill and decide I just can not do it. What should
I do?
A:Set the parking brake, put your transmission in
PARK (P) and turn off the engine. Leave the
vehicle and go get some help. Exit on the uphill
side and stay clear of the path the vehicle
would take if it rolled downhill. Do not shift the
transfer case to NEUTRAL when you leave
the vehicle. Leave it in some gear.
{CAUTION:
Shifting the transfer case to NEUTRAL can
cause your vehicle to roll even if the
transmission is in PARK (P). This is because
the NEUTRAL position on the transfer case
overrides the transmission. You or someone
else could be injured. If you are going to leave
your vehicle, set the parking brake and shift
the transmission to PARK (P). But do not shift
the transfer case to NEUTRAL. Leave the
transfer case in the 4 HI, 4 HI Lock or 4 LO
Lock position.
Driving Downhill
When off-roading takes you downhill, you will want to
consider a number of things:
How steep is the downhill? Will I be able to maintain
vehicle control?
What is the surface like? Smooth? Rough?
Slippery? Hard-packed dirt? Gravel?
Are there hidden surface obstacles? Ruts? Logs?
Boulders?
What is at the bottom of the hill? Is there a hidden
creek bank or even a river bottom with large rocks?
If you decide you can go down a hill safely, then try to
keep your vehicle headed straight down, and use a
low gear. This way, engine drag can help your brakes
and they will not have to do all the work. Descend
slowly, keeping your vehicle under control at all times.
{CAUTION:
Heavy braking when going down a hill can
cause your brakes to overheat and fade. This
could cause loss of control and a serious
accident. Apply the brakes lightly when
descending a hill and use a low gear to keep
vehicle speed under control.
4-35

Q:Are there some things I should not do when
driving down a hill?
A:Yes! These are important because if you ignore
them you could lose control and have a serious
accident.
When driving downhill, avoid turns that take you
across the incline of the hill. A hill that is not too
steep to drive down may be too steep to drive
across. You could roll over if you do not drive
straight down.
Never go downhill with the transmission in
NEUTRAL (N). This is called “free-wheeling.”
Your brakes will have to do all the work and could
overheat and fade.
Q:Am I likely to stall when going downhill?
A:It is much more likely to happen going uphill. But if
it happens going downhill, here is what to do.
Stop your vehicle by applying the regular brakes.
Apply the parking brake.
Shift to PARK (P) and, while still braking, restart the
engine.
Shift back to a low gear, release the parking brake,
and drive straight down.
If the engine will not start, get out and get help.
Driving Across an Incline
Sooner or later, an off-road trail will probably go across
the incline of a hill. If this happens, you have to
decide whether to try to drive across the incline. Here
are some things to consider:
A hill that can be driven straight up or down may be
too steep to drive across. When you go straight up
or down a hill, the length of the wheel base (the
distance from the front wheels to the rear wheels)
reduces the likelihood the vehicle will tumble
end over end. But when you drive across an incline,
the much more narrow track width (the distance
between the left and right wheels) may not prevent
the vehicle from tilting and rolling over. Also,
driving across an incline puts more weight on the
downhill wheels. This could cause a downhill
slide or a rollover.
4-36