ECU HUMMER H2 2004 Service Manual

Loading Your Vehicle for Off-Road
Driving
There are some important things to remember about
how to load your vehicle.
The heaviest things should be on the load oor and
forward of your rear axle. Put heavier items in the
rear area, as far forward as you can.
Be sure the load is secured properly, so driving on
the off-road terrain does not toss things around.
{CAUTION:
Cargo on the load oor piled higher than
the seatbacks can be thrown forward
during a sudden stop. You or your
passengers could be injured. Keep cargo
below the top of the seatbacks.
CAUTION: (Continued)
CAUTION: (Continued)

Unsecured cargo on the load oor can be
tossed about when driving over rough
terrain. You or your passengers can be
struck by ying objects. Secure the cargo
properly.
Heavy loads on the roof raise the vehicle’s
center of gravity, making it more likely to
roll over. You can be seriously or fatally
injured if the vehicle rolls over. Put heavy
loads inside the cargo area, not on the
roof. Keep cargo in the cargo area as far
forward and low as possible.
You will nd other important information in this manual.
SeeLoading Your Vehicle on page 4-67andTires
on page 5-60.
4-22

Winter Driving
Here are some tips for winter driving:
Have your vehicle in good shape for winter.
You may want to put winter emergency supplies in
your vehicle.
Also seeTires on page 5-60.Include an ice scraper, a small brush or broom, a
supply of windshield washer uid, a rag, some winter
outer clothing, a small shovel, a ashlight, a red
cloth and a couple of reective warning triangles. And, if
you will be driving under severe conditions, include a
small bag of sand, a piece of old carpet or a couple of
burlap bags to help provide traction. Be sure you
properly secure these items in your vehicle.
Driving on Snow or Ice
Most of the time, those places where your tires meet
the road probably have good traction.
However, if there is snow or ice between your tires and
the road, you can have a very slippery situation. You
will have a lot less traction or “grip” and will need to be
very careful.
4-52

Power Winch Platform (If Equipped)
You can use the power winch platform with an
aftermarket winch. Connect the winch to the platform
and wiring to the vehicle following the winch
manufacturer’s guidelines.
1. Slide the winch platform into the front receiver of
your vehicle. To secure it, follow the next step.
You will be using the locking pin (if equipped) stored
with the jack/tool kit. SeeChanging a Flat Tire on
page 5-79for more information on location.
2. Slide the pin down through the hole in the front
bumper and into the receiver.If you look under the
receiver, you will see the
locking portion (clip) of the
pin coming through the
bottom hole in the receiver.
3. Turn the clip so that it is
perpendicular to the
pin. Pin is shown off the
vehicle for clarity.
4-62

4. Push the clip so it
locks in place. Pin is
shown off the
vehicle for clarity.
5. With the clip locked
and the pin secure,
your setup should look
like this if you look
under the receiver. The
pin is now secure
and you will be able to
use the winch.To remove the winch platform, you must rst unlock the
clip so you can pull out the pin. To unlock the clip,
squeeze the clip and turn it so it is in line with the rest
of the pin. Remove the pin and slide the winch platform
out from the receiver.
Notice:Do not use the winch platform to winch at
a tension of more than 9,000 lbs. (4 082 kg). This
would damage your vehicle’s frame. This damage
would not be covered by your vehicle’s warranty.
4-63

Dinghy Towing
Use the following procedure to tow your vehicle:
1. Shift the transmission to PARK (P).
2. Turn the engine off, but leave the ignition on.
3. Firmly set the parking brake.
4. Securely attach the vehicle being towed to the
tow vehicle.
5. Shift the transfer case to NEUTRAL (N). See
All-Wheel Drive on page 2-25for the proper
procedure to select the NEUTRAL position for
your vehicle.
6. Release the parking brake only after the vehicle
being towed is rmly attached to the towing
vehicle. You can use your vehicle’s front mounted
receiver with the proper accessories to tow it.
See “Front Mounted Receiver” underIf You Are
Stuck: In Sand, Mud, Ice or Snow on page 4-56.
7. Turn the engine off and leave the steering column
unlocked.{CAUTION:
Shifting an all-wheel-drive vehicle’s transfer
case into NEUTRAL can cause your vehicle to
roll even if the transmission is in Park (P). You
or others could be injured. Make sure the
parking brake is rmly set before you shift the
transfer case to NEUTRAL.
Dolly Towing
Your vehicle can not be dolly towed. If you must tow
your vehicle behind another, use the dinghy towing
procedure listed previously.
Notice:Dolly towing your vehicle will damage
drivetrain components. Do not dolly tow your
vehicle.
4-66

Using heavier suspension components to get added
durability might not change your weight ratings. Ask your
dealer to help you load your vehicle the right way.
If you put things inside your vehicle – like suitcases,
tools, packages, or anything else – they go as fast
as the vehicle goes. If you have to stop or turn quickly,
or if there is a crash, they’ll keep going.
{CAUTION:
Things you put inside your vehicle can strike
and injure people in a sudden stop or turn, or
in a crash.
Put things in the cargo area of your
vehicle. Try to spread the weight evenly.
Never stack heavier things, like suitcases,
inside the vehicle so that some of them
are above the tops of the seats.
Do not leave an unsecured child restraint
in your vehicle.
When you carry something inside the
vehicle, secure it whenever you can.
Do not leave a seat folded down unless
you need to.There’s also important loading information for off-road
driving in this manual. See “Loading Your Vehicle
for Off-Road Driving” underOff-Road Driving on
page 4-17.
Add-On Equipment
When you carry removable items, you may need to put
a limit on how many people you can carry inside
your vehicle. Be sure to weigh your vehicle before you
buy and install the new equipment.
Notice:Overloading your vehicle may cause
damage. Repairs would not be covered by your
warranty. Do not overload your vehicle.
Remember not to exceed the Gross Axle Weight
Rating (GAWR) of the front or rear axle. SeeLoading
Your Vehicle on page 4-67.
The Cargo Weight Rating (CWR) is the maximum
weight of the load your vehicle can carry. It doesn’t
include the weight of the people inside. But you
can gure about 150 lbs. (68 kg) for each seat.
The total cargo load must not be more than your
vehicle’s CWR.
4-72

Trailer Brakes
If your trailer weighs more than 2,000 lbs. (900 kg)
loaded, then it needs its own brakes – and they must be
adequate. Be sure to read and follow the instructions
for the trailer brakes so you’ll be able to install,
adjust and maintain them properly.
Your trailer brake system can tap into the vehicle’s
hydraulic brake system only if:
The trailer parts can withstand 3,000 psi
(20 650 kPa) of pressure.
The trailer’s brake system will use less than
0.02 cubic inch (0.3 cc) of uid from your vehicle’s
master cylinder. Otherwise, both braking systems
won’t work well. You could even lose your brakes.
If everything checks out this far, make the brake tap at
the port on the master cylinder that sends the uid
to the rear brakes. But don’t use copper tubing for this.
If you do, it will bend and nally break off. Use steel
brake tubing.
Driving with a Trailer
Towing a trailer requires a certain amount of experience.
Before setting out for the open road, you’ll want to get
to know your rig. Acquaint yourself with the feel of
handling and braking with the added weight of the trailer.
And always keep in mind that the vehicle you are
driving is now a good deal longer and not nearly as
responsive as your vehicle is by itself.
Before you start, check all trailer hitch parts and
attachments, safety chains, electrical connector, lamps,
tires and mirror adjustment. If the trailer has electric
brakes, start your vehicle and trailer moving and then
apply the trailer brake controller by hand to be sure
the brakes are working. This lets you check your
electrical connection at the same time.
During your trip, check occasionally to be sure that the
load is secure, and that the lamps and any trailer
brakes are still working.
4-81

Adding Coolant
If you need more coolant, add the proper DEX-COOL®
coolant mixtureat the surge tank, but only when the
engine is cool.
{CAUTION:
You can be burned if you spill coolant on hot
engine parts. Coolant contains ethylene glycol,
and it will burn if the engine parts are hot
enough. Do not spill coolant on a hot engine.
When replacing the pressure cap, make sure it is
hand-tight.
Coolant Surge Tank Pressure Cap
The coolant surge tank pressure cap must be fully
installed on the coolant surge tank. SeeEngine
Compartment Overview on page 5-12for more
information on location.
Notice:If the pressure cap is not tightly installed,
coolant loss and possible engine damage may
occur. Be sure the cap is properly and tightly
secured.
Engine Overheating
You will nd a coolant temperature gage on your
vehicle’s instrument panel. SeeEngine Coolant
Temperature Gage on page 3-35. In addition, you will
nd an ENGINE COOLANT HOT, ENGINE
OVERHEATED and a REDUCED ENGINE POWER
message in the DIC on the instrument panel. SeeDIC
Warnings and Messages on page 3-56.
5-27

Used Replacement Wheels
{CAUTION:
Putting a used wheel on your vehicle is
dangerous. You can’t know how it’s been used
or how far it’s been driven. It could fail
suddenly and cause a crash. If you have to
replace a wheel, use a new GM original
equipment wheel.
Tire Chains
Notice:Use tire chains only where legal and only
when you must. Use only SAE Class″S″type chains
that are the proper size for your tires. Install them
on the rear axle tires and tighten them as tightly as
possible with the ends securely fastened. Drive
slowly and follow the chain manufacturer’s
instructions. If you can hear the chains contacting
your vehicle, stop and retighten them. If the contact
continues, slow down until it stops. Driving too
fast or spinning the wheels with chains on will
damage your vehicle.
5-75

Rear Flat Tire:Place the
jack under the curved rear
axle pad. Make sure
the jack head is positioned
so that the rear axle
pad is resting securely on
the jack head.
{CAUTION:
Getting under a vehicle when it is jacked up is
dangerous. If the vehicle slips off the jack you
could be badly injured or killed. Never get under
a vehicle when it is supported only by a jack. X= 28.5 inches (72.0 cm)
Rear Position
5-85