Active Fuel
Management™
Vehicles with V8 engines and an
automatic transmission have Active
Fuel Management™. This system
allows the engine to operate on
either all or half of its cylinders,
depending on the driving conditions.
When less power is required, such
as cruising at a constant vehicle
speed, the system will operate in
the half cylinder mode, allowing
the vehicle to achieve better fuel
economy. When greater power
demands are required, such as
accelerating from a stop, passing, or
merging onto a freeway, the system
will maintain full-cylinder operation.
Engine Exhaust
{WARNING
Engine exhaust contains Carbon
Monoxide (CO) which cannot be
seen or smelled. Exposure to CO
can cause unconsciousness and
even death.
Exhaust may enter the vehicle if:
•The vehicle idles in areas
with poor ventilation (parking
garages, tunnels, deep snow
that may block underbody
airflow or tail pipes).
•The exhaust smells or
sounds strange or different.
•The exhaust system leaks
due to corrosion or damage.
(Continued)
WARNING (Continued)
•The vehicle’s exhaust system
has been modified, damaged
or improperly repaired.
•There are holes or openings
in the vehicle body from
damage or after-market
modifications that are not
completely sealed.
If unusual fumes are detected or
if it is suspected that exhaust is
coming into the vehicle:
•Drive it only with the windows
completely down.
•Have the vehicle repaired
immediately.
Never park the vehicle with the
engine running in an enclosed
area such as a garage or a
building that has no fresh air
ventilation.
Driving and Operating 8-25
When the System Does Not
Seem to Work Properly
If the URPA system does not
activate due to a temporary
condition, the message PARK
ASSIST OFF displays on the DIC
and a red light comes on the rear
URPA display when the shift lever is
moved into R (Reverse). This can
occur under the following conditions:
•The ultrasonic sensors are not
clean. Keep the vehicle’s rear
bumper free of mud, dirt, snow,
ice and slush. For cleaning
instructions, seeExterior Care
on page 9-88.
•A trailer was attached to the
vehicle, or an object was hanging
out of the trunk during the last
drive cycle, making the red light
come on in the rear display.
Once the attached object is
removed, URPA will return
to normal operation.
•A tow bar is attached to the
vehicle.
•The vehicle’s bumper is
damaged. Take the vehicle to
your dealer/retailer to repair the
system.
•Other conditions may affect
system performance, such as
vibrations from a jackhammer or
the compression of air brakes on
a very large truck that is near the
vehicle.
If the system is still disabled, after
driving forward at least 25 km/h
(15 mph), take the vehicle to your
dealer/retailer.
Fuel
Use of the recommended fuel
is an important part of the proper
maintenance of this vehicle. To help
keep the engine clean and maintain
optimum vehicle performance, we
recommend the use of gasoline
advertised as TOP TIER Detergent
Gasoline.
Look for the TOP TIER label on the
fuel pump to ensure gasoline meets
enhanced detergency standards
developed by auto companies. A list
of marketers providing TOP TIER
Detergent Gasoline can be found
at www.toptiergas.com.
Driving and Operating 8-43
California Fuel
Requirements
If the vehicle is certified to meet
California Emissions Standards, it is
designed to operate on fuels that
meet California specifications.
See the underhood emission control
label. If this fuel is not available in
states adopting California emissions
standards, the vehicle will operate
satisfactorily on fuels meeting federal
specifications, but emission control
system performance might be
affected. The malfunction indicator
lamp could turn on and the vehicle
might fail a smog-check test.
SeeMalfunction Indicator Lamp
on page 4-19. If this occurs, return
to your authorized dealer/retailer for
diagnosis. If it is determined that the
condition is caused by the type of
fuel used, repairs might not be
covered by the vehicle warranty.
Fuels in Foreign
Countries
If you plan on driving in another
country outside the United States
or Canada, the proper fuel might
be hard to find. Never use leaded
gasoline or any other fuel not
recommended in the previous text
on fuel. Costly repairs caused by
use of improper fuel would not be
covered by the vehicle warranty.
To check the fuel availability, ask
an auto club, or contact a major oil
company that does business in the
country where you will be driving.
Fuel Additives
To provide cleaner air, all gasolines
in the United States are now required
to contain additives that help prevent
engine and fuel system deposits
from forming, allowing the emission
control system to work properly.
In most cases, you should not have
to add anything to the fuel. However,
some gasolines contain only theminimum amount of additive
required to meet U.S. Environmental
Protection Agency regulations.
To help keep fuel injectors and
intake valves clean, or if the vehicle
experiences problems due to dirty
injectors or valves, look for gasoline
that is advertised as TOP TIER
Detergent Gasoline. Look for the
TOP TIER label on the fuel pump to
ensure gasoline meets enhanced
detergency standards developed
by the auto companies. A list of
marketers providing TOP TIER
Detergent Gasoline can be found
at www.toptiergas.com.
For customers who do not use
TOP TIER Detergent Gasoline
regularly, one bottle of GM Fuel
System Treatment PLUS, added
to the fuel tank at every engine oil
change, can help clean deposits
from fuel injectors and intake valves.
GM Fuel System Treatment PLUS
is the only gasoline additive
recommended by General Motors.
It is available at your dealer/retailer.
Driving and Operating 8-45
Engine Air Cleaner/Filter
SeeEngine Compartment
Overview on page 9-6for the
location of the engine air
cleaner/filter.
When to Inspect the Engine
Air Cleaner/Filter
Inspect the air cleaner/filter at the
MaintenanceIIintervals and replace
it at the first oil change after each
50,000 mile (80 000 km) interval.
See “Schedule Maintenance” in
Service and Maintenance for more
information. If driving in dusty/dirty
conditions, inspect the filter at each
engine oil change.
How to Inspect the Engine Air
Cleaner/Filter
To inspect the air cleaner/filter,
remove the filter from the vehicle
and lightly shake the filter to release
loose dust and dirt. If the filter
remains caked with dirt, a new
filter is required.
To inspect or replace the engine air
cleaner/filter:
1. Open the hood. SeeHood on
page 9-5.
2. Locate the air filter housing
on the front of the driver
side of the engine compartment.
SeeEngine Compartment
Overview on page 9-6.
3.6 L V6 Engine Air Cleaner/
Filter Housing shown
(6.2 L V8 Engines similar)
9-16 Vehicle Care