2009 HUMMER H2 service

Driving in Water
{CAUTION:
Driving through rushing water can be dangerous.
Deep water can sweep your vehicle downstream
and you and your passengers could drown. If it is
only shallow water, it can still wash away the
ground from under your tires, and you could lose
traction and roll the vehicle over. Do not drive
through rushing water.
Heavy rain can mean ash ooding, and ood waters
demand extreme caution.
Find out how deep the water is before driving through
it. Do not try it if it is deep enough to cover the wheel
hubs, axles, or exhaust pipe — you probably will not
get through. Deep water can damage the axle and
other vehicle parts. The vehicle is capable of depths up to
20 inches (50 cm). Know how to judge whether the water
is deeper than this before proceeding into it.If the water is not too deep, drive slowly through it. At
faster speeds, water splashes on the ignition system and
the vehicle can stall. Stalling can also occur if you get
the tailpipe under water. If the tailpipe is under
water, you will never be able to start the engine. When
going through water, remember that when the brakes
get wet, it might take longer to stop. SeeDriving in Rain
and on Wet Roads on page 4-34.
After Off-Road Driving
Remove any brush or debris that has collected on the
underbody, chassis, or under the hood. These
accumulations can be a re hazard.
After operation in mud or sand, have the brake linings
cleaned and checked. These substances can cause
glazing and uneven braking. Check the engine and oil
coolers for mud accumulation. Thoroughly and carefully
clean these devices to allow proper cooling. Check
the body structure, steering, suspension, wheels, tires,
and exhaust system for damage and check the fuel
lines and cooling system for any leakage.
The vehicle requires more frequent service due to
off-road use. Refer to the Maintenance Schedule for
additional information.
4-32

Before Leaving on a Long Trip
To prepare your vehicle for a long trip, consider having
it serviced by your dealer/retailer before departing.
Things to check on your own include:
Windshield Washer Fluid:Reservoir full? Windows
clean — inside and outside?
Wiper Blades:In good shape?
Fuel, Engine Oil, Other Fluids:All levels checked?
Lamps:Do they all work and are lenses clean?
Tires:Are treads good? Are tires inated to
recommended pressure?
Weather and Maps:Safe to travel? Have
up-to-date maps?
Highway Hypnosis
Always be alert and pay attention to your surroundings
while driving. If you become tired or sleepy, nd a
safe place to park your vehicle and rest.
Other driving tips include:
Keep the vehicle well ventilated.
Keep interior temperature cool.
Keep your eyes moving — scan the road ahead
and to the sides.
Check the rearview mirror and vehicle instruments
often.
4-35

Hill and Mountain Roads
Driving on steep hills or through mountains is different
than driving on at or rolling terrain. Tips for driving
in these conditions include:
Keep the vehicle serviced and in good shape.
Check all uid levels and brakes, tires, cooling
system, and transmission.
Going down steep or long hills, shift to a
lower gear.
{CAUTION:
If you do not shift down, the brakes could get so
hot that they would not work well. You would then
have poor braking or even none going down a hill.
You could crash. Shift down to let the engine
assist the brakes on a steep downhill slope.
{CAUTION:
Coasting downhill in N (Neutral) or with the ignition
off is dangerous. The brakes will have to do all the
work of slowing down and they could get so hot
that they would not work well. You would then
have poor braking or even none going down a hill.
You could crash. Always have the engine running
and the vehicle in gear when going downhill.
Stay in your own lane. Do not swing wide or cut
across the center of the road. Drive at speeds
that let you stay in your own lane.
Top of hills: Be alert — something could be in your
lane (stalled car, accident).
Pay attention to special road signs (falling rocks
area, winding roads, long grades, passing or
no-passing zones) and take appropriate action.
SeeOff-Road Driving on page 4-15for information
about driving off-road.
4-36

Blizzard Conditions
Being stuck in snow can be in a serious situation. Stay
with the vehicle unless there is help nearby. If possible,
use theRoadside Service on page 7-7. To get help and
keep everyone in the vehicle safe:
Turn on theHazard Warning Flashers on page 3-6.
Tie a red cloth to an outside mirror.
{CAUTION:
Snow can trap engine exhaust under the vehicle.
This may cause exhaust gases to get inside.
Engine exhaust contains carbon monoxide (CO)
which cannot be seen or smelled. It can cause
unconsciousness and even death.
If the vehicle is stuck in the snow:
Clear away snow from around the base of
your vehicle, especially any that is blocking
the exhaust pipe.
Check again from time to time to be sure
snow does not collect there.
CAUTION: (Continued)
CAUTION: (Continued)

Open a window about two inches (5 cm) on
the side of the vehicle that is away from the
wind to bring in fresh air.
Fully open the air outlets on or under the
instrument panel.
Adjust the Climate Control system to a setting
that circulates the air inside the vehicle and
set the fan speed to the highest setting.
See Climate Control System in the Index.
For more information about carbon monoxide, see
Engine Exhaust on page 2-45.
Snow can trap exhaust gases under your vehicle.
This can cause deadly CO (carbon monoxide) gas
to get inside. CO could overcome you and kill you.
You cannot see it or smell it, so you might not
know it is in your vehicle. Clear away snow from
around the base of your vehicle, especially any
that is blocking the exhaust.
Run the engine for short periods only as needed to
keep warm, but be careful.
To save fuel, run the engine for only short periods as
needed to warm the vehicle and then shut the engine off
and close the window most of the way to save heat.
4-38

Towing
Towing Your Vehicle
To avoid damage, the disabled vehicle should be towed
with all four wheels off the ground. Consult your dealer/
retailer or a professional towing service if the disabled
vehicle must be towed. SeeRoadside Service on
page 7-7.
To tow the vehicle behind another vehicle for
recreational purposes — such as behind a motorhome,
see “Recreational Vehicle Towing” following.
Recreational Vehicle Towing
Recreational vehicle towing means towing the vehicle
behind another vehicle – such as behind a motorhome.
The two most common types of recreational vehicle
towing are known as dinghy towing and dolly towing.
Dinghy towing is towing the vehicle with all four wheels on
the ground. Dolly towing is towing the vehicle with two
wheels on the ground and two wheels up on a device
known as a dolly.Here are some important things to consider before
recreational vehicle towing:
What is the towing capacity of the towing vehicle?
Be sure to read the tow vehicle manufacturer’s
recommendations.
What is the distance that will be travelled? Some
vehicles have restrictions on how far and how
long they can tow.
Is the proper towing equipment going to be used?
See your dealer/retailer or trailering professional
for additional advice and equipment
recommendations.
Is the vehicle ready to be towed? Just as preparing
the vehicle for a long trip, make sure the vehicle is
prepared to be towed. SeeBefore Leaving on a
Long Trip on page 4-35.
4-50

The system includes a compressor, two height sensors
and two air springs supporting the vehicle.
The system is activated when the engine is started
and deactivated when the ignition is returned to OFF.
The engine must be running for the rear of the vehicle to
be raised and the doors must be closed to enable a
transition between Normal Ride Height and Extended
Ride Height.
The compressor may be heard while the system is
active and the release of air similar to a hissing sound
may also be heard. This is normal.
Load leveling will not function normally with the inater
hose attached to the inator outlet. Remove the
hose from the outlet when it is not in use. See
Accessory Inflator on page 5-78.Overload and Overheat Protection
Overload protection is designed to protect the air
suspension system and is an indication to the driver that
the vehicle is overloaded.
If the rear suspension remains at a low height, the rear
axle load has exceeded GAWR (Gross Axle Weight
Rating). When the overload protection mode is activated,
the compressor operates for about 30 seconds to one
minute without raising the vehicle depending on the
amount of overload. This will continue each time the
ignition is turned on until the rear axle load is reduced
below GAWR. The system may reactivate without cycling
the ignition if some of the excess load is removed.
If the total rear GAWR (Gross Axle Weight Rating) is
reached, the suspension may be slightly less than level.
This is normal and does not mean there is a problem
with the air suspension.
In some instances the compressor may stop working
due to being overheated. This is normal. In the instance
of an abnormal overheat condition though the
compressor will stop working and the SERVICE
SUSPENSION SYSTEM will be displayed on the DIC.
SeeDIC Warnings and Messages on page 3-56for
more information.
4-54

Maintenance When Trailer Towing
The vehicle needs service more often when pulling a
trailer. See this manual’s Maintenance Schedule or Index
for more information. Things that are especially important
in trailer operation are automatic transmission uid,
engine oil, axle lubricant, belts, cooling system and brake
system. It is a good idea to inspect these before and
during the trip.
Check periodically to see that all hitch nuts and bolts
are tight.
Trailer Wiring Harness
Heavy-Duty Trailer Wiring Harness
Package
The vehicle is equipped with the seven-wire trailer towing
harness. This harness with a seven-pin universal trailer
connector is attached to a bracket on the hitch platform.The seven-wire harness contains the following trailer
circuits:
Yellow: Left Stop/Turn Signal
Dark Green: Right Stop/Turn Signal
Brown: Taillamps
White: Ground
Light Green: Back-up Lamps
Red/Black: Battery Feed*
Dark Blue: Trailer Brake*
*There is a location in the Underhood Fuse Block for
these circuits, but they are not connected. They should
be connected, and proper fuses installed, by your
dealer/retailer or a qualied service center.
If charging a remote (non-vehicle) battery, press the
Tow/Haul mode button located at the end of the
shift lever. This will boost the vehicle system voltage
and properly charge the battery.
4-67

Electric Brake Control Wiring
Provisions
These wiring provisions are included with the vehicle
as part of the trailer wiring package. These provisions
are for an electric brake controller. The instrument panel
contains blunt cut wires near the data link connector
for the trailer brake controller. The harness contains
the following wires:
Dark Blue: Brake Signal to Trailer Connector
Red/Black: Battery
Light Blue/White: Brake Switch
White: Ground
It should be installed by your dealer/retailer or a
qualied service center.
Trailer Recommendations
Subtract the hitch loads from the Cargo Weight Rating
(CWR). CWR is the maximum weight of the load
the vehicle can carry. It does not include the weight of
the people inside, but you can gure about 150 lbs.
(68 kg) for each passenger. The total cargo load must
not be more than the vehicles CWR.
Weigh the vehicle with the trailer attached, so the GVWR
or GAWR are not exceeded. If using a weight-distributing
hitch, weigh the vehicle without the spring bars in place.
The best performance is obtained by correctly spreading
out the weight of the load and choosing the correct
hitch and trailer brakes.
For more information seeTowing a Trailer on page 4-55.
4-68