2009 HUMMER H2 Owners Manual

Dinghy Towing
This full-time four-wheel-drive vehicle can be dinghy
towed from the front. These vehicles can also be towed
by placing them on a platform trailer with all four wheels
off the ground. These vehicles cannot be towed using
a dolly.
Use the following procedure to tow the vehicle:
1. Shift the transmission to P (Park).
2. Turn the engine off, but leave the ignition in
ACC/ACCESSORY.
3. Firmly set the parking brake.
4. Securely attach the vehicle being towed to the tow
vehicle.
{CAUTION:
Shifting a full-time four-wheel-drive vehicle’s
transfer case into N (Neutral) can cause the vehicle
to roll even if the transmission is in P (Park). The
driver or others could be injured. Make sure the
parking brake is rmly set before the transfer case
is shifted to N (Neutral).
5. Shift the transfer case to N (Neutral). SeeFull-Time
Four-Wheel Drive on page 2-37for the proper
procedure to select the N (Neutral) position for the
vehicle.
6. Release the parking brake only after the vehicle
being towed is rmly attached to the towing
vehicle.
7. Turn the ignition to ACC/ACCESSORY.
8. Disconnect the battery if the vehicle will be towed
for long distances or long periods of time.
When towing the vehicle for extended periods of time,
start the vehicle as often as possible to prevent
battery drain. This should only be done when the tow
vehicle is parked.
4-51

Dolly Towing
The vehicle cannot be dolly towed. If the vehicle must
be towed behind another vehicle, use the dinghy towing
procedure explained previously.
Notice:Dolly towing the vehicle will damage
drivetrain components. Do not dolly tow the vehicle.
Selectable Extended Rear Ride
Height
If the vehicle has this feature it comes as part of the
electronically controlled air suspension system.
The selectable rear ride height allows the rear of the
vehicle to be raised about 2 inches (5 cm) over the
normal ride height. This can be helpful when driving
off-road where more ground clearance may be needed
to clear an obstacle.
The button that controls
this feature is located on
the instrument panel to the
right of the steering wheel.
4-52

To use this feature, ensure that the following conditions
are met:
The engine must be running.
All doors must be fully closed. The suspension will
not raise or lower if a door is open.
The vehicle speed must be less than 40 mph
(64 km/h). The system will not activate otherwise.
Press the height control button to raise the rear of the
vehicle.
A light in the button will begin to ash as the rear of
the vehicle rises. Once the extended height has been
reached (this may take up to a minute), the warning light
will stop ashing and will stay lit while the vehicle is at the
extended height.
To lower the vehicle to the normal ride height, press the
button again. The light in the button will ash as the
suspension lowers. When the light in the button stops
ashing and goes out, the suspension has reached
the normal ride height.
This feature will lower the vehicle to the normal height if
vehicle speed exceeds 40 mph (64 km/h).
This feature may also be used when ascending,
descending or cresting a steep hill to help prevent the
rear bumper from dragging on the base of the hill
or prevent the vehicle from grounding out (high
centering) on the crest of the hill.
Do not use this feature when towing a trailer.
Electronically Controlled Air
Suspension System
With this feature, the electronically controlled air
suspension keeps the rear of the vehicle level under all
load conditions. The system maintains the vehicle at the
currently selected ride height. There are two ride heights:
Normal Ride Height and Extended Ride Height. The
Extended Ride Height feature is only available if the
vehicle speed is below 40 mph (64 km/h). If the vehicle is
at Extended Ride Height and the speed exceeds 40 mph
(64 km/h), the system will automatically return the vehicle
to Normal Ride Height.
The activation and
deactivation of the
Extended Ride Height
feature is controlled by
this switch on the
instrument panel.
4-53

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

Towing a Trailer
{CAUTION:
The driver can lose control when pulling a trailer if
the correct equipment is not used or the vehicle is
not driven properly. For example, if the trailer is
too heavy, the brakes may not work well — or
even at all. The driver and passengers could be
seriously injured. The vehicle may also be
damaged; the resulting repairs would not be
covered by the vehicle warranty. Pull a trailer only
if all the steps in this section have been followed.
Ask your dealer/retailer for advice and information
about towing a trailer with the vehicle.Notice:Pulling a trailer improperly can damage the
vehicle and result in costly repairs not covered
by the vehicle warranty. To pull a trailer correctly,
follow the advice in this section and see your
dealer/retailer for important information about
towing a trailer with the vehicle.
To identify the trailering capacity of the vehicle, read the
information in “Weight of the Trailer” that appears
later in this section.
Trailering is different than just driving the vehicle by itself.
Trailering means changes in handling, acceleration,
braking, durability and fuel economy. Successful, safe
trailering takes correct equipment, and it has to be used
properly.
The following information has many time-tested,
important trailering tips and safety rules. Many of these
are important for your safety and that of your passengers.
So please read this section carefully before pulling a
trailer.
4-55

Pulling A Trailer
Here are some important points:
There are many different laws, including speed limit
restrictions, having to do with trailering. Make sure
the rig will be legal, not only where you live but
also where you will be driving. A good source for
this information can be state or provincial police.
Consider using a sway control. See “Hitches” later
in this section.
Do not tow a trailer at all during the rst 500 miles
(800 km) the new vehicle is driven. The engine,
axle or other parts could be damaged.
Then, during the rst 500 miles (800 km) that a
trailer is towed, do not drive over 50 mph (80 km/h)
and do not make starts at full throttle. This helps
the engine and other parts of the vehicle wear in at
the heavier loads.
Vehicles can tow in D (Drive). Shift the transmission
to a lower gear if the transmission shifts too often
under heavy loads and/or hilly conditions. See
“Tow/Haul Mode” following.Three important considerations have to do with weight:
The weight of the trailer
The weight of the trailer tongue
The weight on the vehicle’s tires
Weight of the Trailer
How heavy can a trailer safely be?
It depends on how the rig is used. For example, speed,
altitude, road grades, outside temperature and how
much the vehicle is used to pull a trailer are all
important. It can depend on any special equipment on
the vehicle, and the amount of tongue weight the vehicle
can carry. See “Weight of the Trailer Tongue” later in
this section for more information.
Maximum trailer weight is calculated assuming only the
driver is in the tow vehicle and it has all the required
trailering equipment. The weight of additional optional
equipment, passengers and cargo in the tow vehicle
must be subtracted from the maximum trailer weight.
4-56

Use the following chart to determine how much the vehicle can weigh, based upon the vehicle model and options.
Engine Axle Ratio Maximum Trailer Weight **GCWR
6.2L V8 (SUV) 3.73 8,200 lbs (3 720 kg) 15,000 lbs (6 804 kg)
6.2L V8 (SUT)* 3.73 8,200 lbs (3 720 kg) 15,000 lbs (6 804 kg)
*Sport utility truck (SUT) models are neither designed nor intended to tow 5th wheel or gooseneck trailers.
**The Gross Combination Weight Rating (GCWR) in the total allowable weight of the completely loaded vehicle and
trailer including any passengers, cargo, equipment and conversions. The GCWR for the vehicle should not be
exceeded.
Ask your dealer/retailer for our trailering information or advice, or write us at our Customer Assistance Offices. See
Customer Assistance Offices on page 7-6for more information.
4-57

Weight of the Trailer Tongue
The tongue load (A) of any trailer is an important weight
to measure because it affects the total gross weight of the
vehicle. The Gross Vehicle Weight (GVW) includes the
curb weight of the vehicle, any cargo carried in it, and the
people who will be riding in the vehicle. If there are a lot of
options, equipment, passengers or cargo in the vehicle, it
will reduce the tongue weight the vehicle can carry, which
will also reduce the trailer weight the vehicle can tow.
If towing a trailer, the tongue load must be added to the
GVW because the vehicle will be carrying that weight,
too. SeeLoading the Vehicle on page 4-44for more
information about the vehicle’s maximum load capacity.The trailer tongue weight (A) should be 10 percent to
15 percent of the total loaded trailer weight (B), up to a
maximum of 600 lbs (272 kg) with a weight carrying hitch.
The trailer tongue weight (A) should be 10 percent to
15 percent of the total loaded trailer weight (B), up to a
maximum of 1,000 lbs (454 kg) with a weight distributing
hitch.
4-58