CAUTION! (Continued)• When replacing a flat, the spare tire may have to be
remounted on the rim or installed at a different
location to maintain the correct placement of the tire
on the wheel relative to the tire/wheel position on
the vehicle. For example, if the spare is used to
replace an outer rear tire it will have to be remounted
on the rim so that the wheel is dished inward. That
way the tread design of asymmetrical tires will
maintain proper position.
DEPARTMENT OF TRANSPORTATION UNIFORM
TIRE QUALITY GRADES
The following tire grading categories were established by
the National Highway Traffic Safety Administration. The
specific grade rating assigned by the tire’s manufacturer in
each category is shown on the sidewall of the tires on your
vehicle.
All passenger vehicle 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 condi-
tions on a specified government test course. For example, a
tire graded 150 would wear one and one-half times as well
on the government course as a tire graded 100. The relative
performance of tires depends upon the actual conditions of
their use, however, and may depart significantly from the
norm due to variations in driving habits, service practices,
and differences in road characteristics and climate.
Traction Grades
The Traction grades, from highest to lowest, are AA, A, B,
and C. These grades represent the tire’s ability to stop on
wet pavement, as measured under controlled conditions on
specified government test surfaces of asphalt and concrete.
A tire marked C may have poor traction performance.
WARNING!The traction grade assigned to this tire is based on
straight-ahead braking traction tests, and does not
include acceleration, cornering, hydroplaning, or peak
traction characteristics. 5STARTING AND OPERATING 389
Temperature Grades
The temperature grades are A (the highest), B, and C,
representing the tire’s resistance to the generation of heat
and its ability to dissipate heat, when tested under con-
trolled conditions on a specified indoor laboratory test
wheel. Sustained high temperature can cause the material
of the tire to degenerate and reduce tire life, and excessive
temperature can lead to sudden tire failure. The grade C
corresponds to a level of performance, which all passenger
vehicle tires must meet under the Federal Motor Vehicle
Safety Standard No. 109. Grades B and A represent higher
levels of performance on the laboratory test wheel, than the
minimum required by law.
WARNING!The temperature grade for this tire is established for a
tire that is properly inflated and not overloaded. Ex-
cessive speed, under-inflation, or excessive loading,
either separately or in combination, can cause heat
buildup and possible tire failure. TIRE PRESSURE MONITOR SYSTEM (TPMS)
The Tire Pressure Monitor System (TPMS) will warn the
driver of a low tire pressure based on the vehicle recom-
mended cold placard pressure.
The tire pressure will vary with temperature by about 1 psi
(7 kPa) for every 12°F (6.5°C). This means that when the
outside temperature decreases, the tire pressure will de-
crease. Tire pressure should always be set based on cold
inflation tire pressure. This is defined as the tire pressure
after the vehicle has not been driven for at least three
hours, or driven less than 1 mile (1.6 km) after a three hour
period. The cold tire inflation pressure must not exceed the
maximum inflation pressure molded into the tire sidewall.
Refer to “Tires – General Information” in “Starting And
Operating” for information on how to properly inflate the
vehicle’s tires. The tire pressure will also increase as the
vehicle is driven - this is normal and there should be no
adjustment for this increased pressure.
The TPMS will warn the driver of a low tire pressure if the
tire pressure falls below the low-pressure warning limit for
any reason, including low temperature effects and natural
pressure loss through the tire.390 STARTING AND OPERATING
The TPMS will continue to warn the driver of low tire
pressure as long as the condition exists, and will not turn
off until the tire pressure is at or above the recommended
cold placard pressure. Once the low tire pressure warning
(Tire Pressure Monitoring [TPM] Telltale Light) illumi-
nates, you must increase the tire pressure to the recom-
mended cold placard pressure in order for the “Tire
Pressure Monitoring Telltale Light” to turn off. The system
will automatically update and the “Tire Pressure Monitor-
ing Telltale Light” will turn off once the system receives the
updated tire pressures. The vehicle may need to be driven
for up to 20 minutes above 15 mph (24 km/h) in order for
the TPMS to receive this information.
For example, your vehicle may have a recommended cold
(parked for more than three hours) placard pressure of 30
psi (207 kPa). If the ambient temperature is 68°F (20°C) and
the measured tire pressure is 27 psi (186 kPa), a tempera-
ture drop to 20°F (-7°C) will decrease the tire pressure to
approximately 23 psi (158 kPa). This tire pressure is suffi-
ciently low enough to turn ON the “Tire Pressure Moni-
toring Telltale Light.” Driving the vehicle may cause the
tire pressure to rise to approximately 27 psi (186 kPa), but
the “Tire Pressure Monitoring Telltale Light” will still be
ON. In this situation, the “Tire Pressure Monitoring Telltale Light” will turn OFF only after the tires are inflated to the
vehicle’s recommended cold placard pressure value.
CAUTION!• The TPMS has been optimized for the original
equipment tires and wheels. TPMS pressures and
warning have been established for the tire size
equipped on your vehicle. Undesirable system op-
eration or sensor damage may result when using
replacement equipment that is not of the same size,
type, and/or style. Aftermarket wheels can cause
sensor damage.
• Using aftermarket tire sealants may cause the Tire
Pressure Monitoring System (TPMS) sensor to be-
come inoperable. After using an aftermarket tire
sealant it is recommended that you take your vehicle
to an authorized dealership to have your sensor
function checked.
• After inspecting or adjusting the tire pressure always
reinstall the valve stem cap. This will prevent mois-
ture and dirt from entering the valve stem, which
could damage the TPMS sensor. 5STARTING AND OPERATING 391
NOTE:
• The TPMS is not intended to replace normal tire care and
maintenance or to provide warning of a tire failure or
condition.
• The TPMS should not be used as a tire pressure gauge
while adjusting your tire pressure.
• Driving on a significantly under-inflated tire causes the
tire to overheat and can lead to tire failure. Under-
inflation also reduces fuel efficiency and tire tread life,
and may affect the vehicle’s handling and stopping
ability.
• The TPMS is not a substitute for proper tire mainte-
nance, and it is the driver ’s responsibility to maintain
correct tire pressure using an accurate tire pressure
gauge, even if under-inflation has not reached the level
to trigger illumination of the “Tire Pressure Monitoring
Telltale Light.”
• Seasonal temperature changes will affect tire pressure,
and the TPMS will monitor the actual tire pressure in the
tire. Base System — If Equipped
The Tire Pressure Monitor System (TPMS) uses wireless
technology with wheel rim mounted electronic sensors to
monitor tire pressure levels. Sensors mounted to each
wheel as part of the valve stem transmit tire pressure
readings to the receiver module.
NOTE: It is particularly important for you to check the tire
pressure in all of the tires on your vehicle monthly and to
maintain the proper pressure.
The TPMS consists of the following components:
• Receiver module
• Four TPM sensors
• TPM Telltale Light
The matching full size spare wheel and tire assembly (if
equipped) has a TPM sensor. The matching full size spare
can be used in place of any of the four road tires. The TPMS
will only monitor the pressure in the full size spare when
it is used in place of a road tire. Otherwise, a spare with a
pressure below the low-pressure limit will not cause the
“Tire Pressure Monitoring Telltale Light” to illuminate or
the chime to sound.392 STARTING AND OPERATING
Premium System
The Tire Pressure Monitor System (TPMS) uses wireless
technology with wheel rim mounted electronic sensors to
monitor tire pressure levels. Sensors mounted to each
wheel as part of the valve stem transmit tire pressure
readings to the receiver module.
NOTE: It is particularly important for you to check the tire
pressure in all of the tires on your vehicle monthly and to
maintain the proper pressure.
The TPMS consists of the following components:
• Receiver module
• Four TPM sensors
• Various TPMS messages, which display in the instru-
ment cluster
• TPM Telltale Light
Tire Pressure Monitoring Low Pressure Warnings
The “Tire Pressure Monitoring Telltale Light” will
illuminate in the instrument cluster and a chime
will sound when tire pressure is low in one or more
of the four active road tires. In addition, the instrument
cluster will display a “LOW TIRE” message and a graphic showing the pressure values of each tire with the low tire
pressure values in a different color. An Inflate to XX
message will also be displayed.
Should this occur, you should stop as soon as possible and
inflate the tires with a low pressure condition (those in a
different color in the instrument cluster graphic) to the
vehicle’s recommended cold placard pressure inflation
value as shown in the Inflate to XX message. Once the
system receives the updated tire pressures, the system will
automatically update, the graphic display in the instru-
ment cluster will return to it’s original color, and the “Tire
Pressure Monitoring Telltale Light” will turn off. The “LOW TIRE PRESSURE” Message 5STARTING AND OPERATING 393
Gross Vehicle Weight Rating (GVWR)
The GVWR is the total permissible weight of your vehicle
including driver, passengers, vehicle, options and cargo.
The label also specifies maximum capacities of front and
rear axle systems (GAWR). Total load must be limited so
GVWR and front and rear GAWR are not exceeded.
Payload
The payload of a vehicle is defined as the allowable load
weight a truck can carry, including the weight of the driver,
all passengers, options and cargo.
Gross Axle Weight Rating (GAWR)
The GAWR is the maximum permissible load on the front
and rear axles. The load must be distributed in the cargo
area so that the GAWR of each axle is not exceeded.
Each axle GAWR is determined by the components in the
system with the lowest load carrying capacity (axle,
springs, tires or wheels). Heavier axles or suspension
components sometimes specified by purchasers for in-
creased durability does not necessarily increase the vehi-
cle’s GVWR. Tire Size
The tire size on the Vehicle Certification Label represents
the actual tire size on your vehicle. Replacement tires must
be equal to the load capacity of this tire size.
Rim Size
This is the rim size that is appropriate for the tire size
listed.
Inflation Pressure
This is the cold tire inflation pressure for your vehicle for
all loading conditions up to full GAWR.
Curb Weight
The curb weight of a vehicle is defined as the total weight
of the vehicle with all fluids, including vehicle fuel, at full
capacity conditions, and with no occupants or cargo loaded
into the vehicle. The front and rear curb weight values are
determined by weighing your vehicle on a commercial
scale before any occupants or cargo are added.402 STARTING AND OPERATING
WARNING! (Continued)PARK. For four-wheel drive vehicles, make sure the
transfer case is not in NEUTRAL (N). Always block
or chock the trailer wheels.
• GCWR must not be exceeded.
• Total weight must be distributed between the tow
vehicle and the trailer such that the following four
ratings are not exceeded:
1. GVWR
2. GTW
3. GAWR
4. Tongue weight rating for the trailer hitch utilized.
Towing Requirements — Tires
• Do not attempt to tow a trailer while using a compact
spare tire.
• Proper tire inflation pressures are essential to the safe
and satisfactory operation of your vehicle. Refer to
“Tires – General Information” in “Starting And Operat-
ing” for proper tire inflation procedures.
• Check the trailer tires for proper tire inflation pressures
before trailer usage. • Check for signs of tire wear or visible tire damage before
towing a trailer. Refer to “Tires – General Information”
in “Starting And Operating” for the proper inspection
procedure.
• When replacing tires, refer to “Tires – General Informa-
tion” in “Starting And Operating” for proper tire re-
placement procedures. Replacing tires with a higher
load carrying capacity will not increase the vehicle’s
GVWR and GAWR limits.
Towing Requirements — Trailer Brakes
WARNING!• Do not connect trailer brakes to your vehicle’s hy-
draulic brake lines. It can overload your brake sys-
tem and cause it to fail. You might not have brakes
when you need them and could have an accident.
• Towing any trailer will increase your stopping dis-
tance. When towing you should allow for additional
space between your vehicle and the vehicle in front
of you. Failure to do so could result in an accident.410 STARTING AND OPERATING
NOTE: Dual wheels are flat mounted, center piloted. The
lug nuts are a two-piece assembly. When the tires are being
rotated or replaced, clean these lug nuts and add two drops
of oil at the interface between the hex and the washer.
Do not oil wheel studs. For chrome wheels, do not substi-
tute with chrome plated wheel nuts. Retighten the wheel nuts in the same sequence to the
torques listed in the table. Go through the sequence a
second time to verify that specific torque has been
achieved. Retighten to specifications after 25 miles (40 km)
and check the lug nut/bolt torque to be sure that all the lug
nuts/bolts are properly seated against the wheel.Two-Piece Lug Nut Wheel Mounting Surface428 WHAT TO DO IN EMERGENCIES