Page 320 of 410

10-54 Vehicle Care
If the warning light comes on,
stop as soon as possible and
inflate the tires to the recommended
pressure shown on the tire loading
information label. SeeVehicle Load
Limits on page 9‑27.
At the same time, a Driver
Information Center (DIC) message
is displayed on the DIC display
screen. The low tire pressure
warning light and the DIC warning
message come on at each ignition
cycle until the tires are inflated to
the correct inflation pressure. For
additional information and details
about the DIC operation and
displays see Tire Messages
on
page 5‑25.
The low tire pressure warning light
may come on in cool weather when
the vehicle is first started, and then
turn off as you start to drive. This
could be an early indicator that the
air pressure in the tire(s) are getting
low and need to be inflated to the
proper pressure. A Tire and Loading Information
label, attached to the vehicle, shows
the size of the vehicle's original
equipment tires and the correct
inflation pressure for the vehicle's
tires when they are cold. See
Vehicle Load Limits
on page 9‑27,
for an example of the Tire and
Loading Information label and its
location on the vehicle. Also see
Tire Pressure on page 10‑51.
The vehicle's TPMS can warn you
about a low tire pressure condition
but it does not replace normal tire
maintenance. See Tire Inspection
on page 10‑57,Tire Rotationon
page 10‑57and Tires on
page 10‑44.
Notice: Liquid tire sealants could
damage the Tire Pressure Monitor
System (TPMS) sensors. Sensor
damage caused by using a tire
sealant is not covered by your
warranty. Do not use liquid tire
sealants.
TPMS Malfunction Light and
Message
The TPMS will not function properly
if one or more of the TPMS sensors
are missing or inoperable. When the
system detects a malfunction, the
low tire warning light flashes for
about one minute and then stays on
for the remainder of the ignition
cycle. A DIC warning message is
also displayed. The low tire warning
light and DIC warning message
come on at each ignition cycle until
the problem is corrected. Some of
the conditions that can cause the
malfunction light and DIC message
to come on are:
.One of the road tires has been
replaced with the spare tire.
The spare tire does not have
a TPMS sensor. The TPMS
malfunction light and DIC
message should go off once you
re‐install the road tire containing
the TPMS sensor.
Page 323 of 410

Vehicle Care 10-57
10. Set all four tires to therecommended air pressure
level as indicated on the Tire
and Loading Information label.
11. Put the valve caps back on the valve stems.
Tire Inspection
We recommend that you
regularly inspect your vehicle's
tires, including the spare tire,
if the vehicle has one, for
signs of wear or damage. See
When It Is Time for New Tires
on
page 10‑58
for more information.
Tire Rotation
Tires should be rotated every
5,000 to 8,000 miles (8 000 to
13 000 km). See Scheduled
Maintenance
on page 11‑2. The purpose of a regular tire
rotation is to achieve a uniform
wear for all tires on the vehicle.
This will ensure that the vehicle
continues to perform most like it
did when the tires were new.
The first rotation is the most
important. See
Scheduled
Maintenance
on page 11‑2.
Any time you notice unusual
wear, rotate the tires as soon
as possible and check wheel
alignment. Also check for
damaged tires or wheels.
See When It Is Time for New
Tires
on page 10‑58and Wheel
Replacement
on page 10‑63.
Make sure the spare tire is
stored securely. Push, pull and
then try to rotate or turn the tire.
If it moves, use the wheel
wrench/hoist shaft to tighten the
cable. See If a Tire Goes Flat
on
page 10‑64
.
When rotating the vehicle's tires,
always use the correct rotation
pattern shown here. Do not
include the spare tire in the tire
rotation.
After the tires have been
rotated, adjust the front and rear
inflation pressures as shown on
the Tire and Loading Information
label. See Tire Pressure
on
page 10‑51
and Vehicle Load
Limits
on page 9‑27.
Page 325 of 410

Vehicle Care 10-59
The rubber in tires degrades over
time. This is also true for the spare
tire, if the vehicle has one, even
if it is not being used. Multiple
conditions affect how fast this
aging takes place, including
temperatures, loading conditions,
and inflation pressure maintenance.
With proper care and maintenance
tires typically wear out before they
degrade due to age. If you are
unsure about the need to replace
the tires as they get older, consult
the tire manufacturer for more
information.
Buying New Tires
GM has developed and matched
specific tires for your vehicle.
The original equipment tires
installed on your vehicle, when
it was new, were designed tomeet General Motors Tire
Performance Criteria
Specification (TPC spec)
system rating. If you need
replacement tires, GM strongly
recommends that you get tires
with the same TPC Spec rating.
This way, your vehicle will
continue to have tires that are
designed to give the same
performance and vehicle safety,
during normal use, as the
original tires.
GM's exclusive TPC Spec
system considers over a
dozen critical specifications that
impact the overall performance
of your vehicle, including brake
system performance, ride and
handling, traction control, and
tire pressure monitoring
performance. GM's TPC Spec
number is molded onto the tire's
sidewall near the tire size. If the
tires have an all‐season tread
design, the TPC spec number
will be followed by a MS, for
mud and snow. See
Tire
Sidewall Labeling
on page 10‑44
for additional information.
GM recommends replacing tires
in sets of four. This is because
uniform tread depth on all tires
will help keep your vehicle
performing most like it did when
the tires were new. Replacing
less than a full set of tires can
affect the braking and handling
performance of your vehicle.
Page 327 of 410

Vehicle Care 10-61
Additionally, if your vehicle has
electronic systems such as anti‐lock
brakes, rollover airbags, traction
control, and electronic stability
control, the performance of these
systems can be affected.
{WARNING
If you add different sized
wheels, your vehicle may not
provide an acceptable level of
performance and safety if tires not
recommended for those wheels
are selected. You may increase
the chance that you will crash and
suffer serious injury. Only use
Hummer specific wheel and tire
systems developed for your
vehicle, and have them properly
installed by a GM certified
technician.
See Buying New Tires
on
page 10‑59and Accessories and
Modificationson page 10‑3for
additional information.
Uniform Tire Quality
Grading
Quality grades can be found
where applicable on the tire
sidewall between tread shoulder
and maximum section width. For
example:
Treadwear 200 Traction AA
Temperature A
The following information relates
to the system developed by the
United States National Highway
Traffic Safety Administration
(NHTSA), which grades tires
by treadwear, traction, and
temperature performance. This
applies only to vehicles sold in
the United States. The grades
are molded on the sidewalls
of most passenger car tires.
The Uniform Tire Quality
Grading (UTQG) system
does not apply to deep
tread, winter-type snow tires, space-saver, or temporary use
spare tires, tires with nominal
rim diameters of 10 to 12 inches
(25 to 30 cm), or to some
limited-production tires.
While the tires available on
Hummer light trucks may vary
with respect to these grades,
they must also conform to
federal safety requirements and
additional General Motors Tire
Performance Criteria (TPC)
standards.
All Passenger Car Tires Must
Conform to Federal Safety
Requirements In Addition To
These Grades.
Treadwear
The treadwear grade is a
comparative rating based
on the wear rate of the tire
when tested under controlled
conditions on a specified
government test course.
Page 332 of 410
10-66 Vehicle Care
SeeTire Changing (H3T)on
page 10‑66or Tire Changing (H3)on page 10‑75for more information.
To use the wheel blocks, lift the
wheel block and lock it into place.
Use the following example as a
guide to assist in the placement of
the wheel blocks (A) when the
vehicle has a flat tire (B).
A. Wheel Block
B. Flat Tire
The following information explains
how to use the jack and change
a tire.
Tire Changing (H3T)
Removing the Spare Tire and
Tools
To access the jack and tools located
under the rear seat:
1. Turn the wing nut (A)
counterclockwise to release the
jack and tools.
2. Remove the jack and tool kit from the bracket.
3. Release the straps (B) that secure the tool bag to the jack.
Page 333 of 410
Vehicle Care 10-67
The following tools are used to
remove the spare tire and flat tire.
A. Wheel Wrench
B. Jack Handle Extensions
C. Jack Handle
D. Jack
E. Wheel BlocksTo access the spare tire:A. Spare Tire/Flat Tire (Valve Stem
Pointed Down)
B. Tire/Wheel Retainer
C. Hoist Cable
D. Hoist Assembly
E. Hoist Shaft
F. Jack Handle Extension(s)
G. Wheel Wrench
H. Hoist Shaft Access Ramp
I. Hoist End of the Extension Tool
1. Assemble the two jack handle extensions (F) and wheel
wrench (G).
Page 334 of 410
10-68 Vehicle Care
2. Insert the hoist end of theextension tool (I) through the
hoist shaft access ramp (H). 3. The hoist end of the extension
tool (I) must connect to the hoist
shaft (E). The hoist end of the
extension tool is used to lower
the spare tire.
Do not use the chiseled end of
the wheel wrench.
4. Turn the wheel wrench (G) counterclockwise to lower the
spare tire (A) to the ground.
Continue to turn the wheel
wrench (G) until the spare tire (A)
can be pulled from under the
vehicle.
If the spare tire does not lower to
the ground, the secondary latch
is engaged. See Secondary
Latch System on page 10‑84.
5. Pull the spare tire towards you.6. Tilt the tire, with slack in the cable, to access the tire/wheel
retainer (B).
Page 335 of 410
Vehicle Care 10-69
7. Separate the retainer from theguide pin by sliding the retainer
up the pin while pressing down
on the latch. When the retainer
is separated from the guide pin,
tilt the retainer and pull it through
the center of the wheel along
with the cable and guide pin.
8. Put the spare tire near the flat tire.
Removing the Flat Tire and
Installing the Spare Tire
1. Do a safety check before
proceeding. See If a Tire Goes
Flat
on page 10‑64for more
information.
2. Remove the center cap by placing the flat end of the wheel
wrench in the slot on the wheel
and gently pry the center
cap out.
3. Turn the wheel wrench
counterclockwise to loosen the
wheel nuts. Do not remove
them yet.
If the vehicle has locking lug
nuts, the key is supplied in the
tool bag. Use the key along with
the wheel wrench to remove the
wheel nuts from the tire.
Now jack up the vehicle.