service CHEVROLET AVALANCHE 2008 2.G Owner's Manual

Electric Power Management
The vehicle has Electric Power Management (EPM) that
estimates the battery’s temperature and state of charge.
It then adjusts the voltage for best performance and
extended life of the battery.
When the battery’s state of charge is low, the voltage is
raised slightly to quickly put the charge back in. When
the state of charge is high, the voltage is lowered slightly
to prevent overcharging. If the vehicle has a voltmeter
gage or a voltage display on the Driver Information
Center (DIC), you may see the voltage move up
or down. This is normal. If there is a problem,
an alert will be displayed.
The battery can be discharged at idle if the electrical
loads are very high. This is true for all vehicles. This is
because the generator (alternator) may not be spinning
fast enough at idle to produce all the power that is
needed for very high electrical loads.
A high electrical load occurs when several of the
following loads are on: headlamps, high beams, fog
lamps, rear window defogger, climate control fan at
high speed, heated seats, engine cooling fans, trailer
loads, and loads plugged into accessory power outlets.EPM works to prevent excessive discharge of the
battery. It does this by balancing the generator’s output
and the vehicle’s electrical needs. It can increase
engine idle speed to generate more power, whenever
needed. It can temporarily reduce the power demands of
some accessories.
Normally, these actions occur in steps or levels, without
being noticeable. In rare cases at the highest levels of
corrective action, this action may be noticeable to the
driver. If so, a Driver Information Center (DIC) message
might be displayed, such as Battery Saver Active or
Service Battery Charging System. If this message is
displayed, it is recommended that the driver reduce the
electrical loads as much as possible. SeeDIC Warnings
and Messages on page 3-59.
Battery Run-Down Protection
This feature shuts off the dome lamps if they are left on
for more than 10 minutes when the ignition is in LOCK.
This will help prevent the battery from running down.
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If the airbag readiness light stays on after you start
the vehicle or comes on when you are driving,
your airbag system may not work properly.
Have your vehicle serviced right away.
{CAUTION:
If the airbag readiness light stays on after you
start your vehicle, it means the airbag system
may not be working properly. The airbags in
your vehicle may not inate in a crash, or they
could even inate without a crash. To help
avoid injury to yourself or others, have your
vehicle serviced right away.
The airbag readiness light should ash for a
few seconds when you start the engine. If the light
does not come on then, have it xed immediately.
If there is a problem with the airbag system, an airbag
Driver Information Center (DIC) message may also come
on. SeeDIC Warnings and Messages on page 3-59for
more information.
Passenger Airbag Status Indicator
Your vehicle has the passenger sensing system.
Your overhead console has a passenger airbag status
indicator.
When you start the vehicle, the passenger airbag status
indicator will light ON and OFF, or the symbol for on
and off, for several seconds as a system check.
Then, after several more seconds, the status indicator
will light either ON or OFF, or either the on or off symbol
to let you know the status of the right front passenger’s
frontal airbag.
If the word ON or the on symbol is lit on the passenger
airbag status indicator, it means that the right front
passenger’s frontal airbag is enabled (may inate).United States
Canada
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If, after several seconds, both status indicator lights
remain on, or if there are no lights at all, there may be
a problem with the lights or the passenger sensing
system. See your dealer/retailer for service.
{CAUTION:
If the airbag readiness light in the instrument
panel cluster ever comes on and stays on,
it means that something may be wrong with
the airbag system. If this ever happens, have
the vehicle serviced promptly, because an
adult-size person sitting in the right front
passenger’s seat may not have the protection
of the airbag(s). SeeAirbag Readiness Light
on page 3-35for more on this, including
important safety information.
Charging System Light
This light will come on
briey when you turn
on the ignition key, but
the engine is not running,
as a check to show
you it is working.
It should go out once the engine is running. If it stays
on, or comes on while driving, there could be a problem
with the charging system. A charging system Driver
Information Center (DIC) message may also appear.
SeeDIC Warnings and Messages on page 3-59for more
information. This light could indicate that there are
problems with a generator drive belt, or that there is an
electrical problem. Have it checked right away. If you
must drive a short distance with the light on, be certain
to turn off all the accessories, such as the radio and air
conditioner.
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Voltmeter Gage
When your engine is not
running, but the ignition is
on, this gage shows
the battery’s state of
charge in DC volts.
When the engine is running, the gage shows the
condition of the charging system. The charging system
regulates voltage based on the state of the battery for
improved fuel economy and battery life. The gage may
transition from a higher to lower or a lower to higher
reading, this is normal. Readings between the low and
high warning zones indicate the normal operating range.
The gage may also read low during the fuel economy
mode, this is normal.Readings in the low warning zone may occur when a
large number of electrical accessories are operating in
the vehicle and the engine is left at an idle for an
extended period. This condition is normal since the
charging system is not able to provide full power at
engine idle. As engine speeds are increased, this
condition should correct itself as higher engine speeds
allow the charging system to create full power. If there
is a problem with the battery charging system, this light
will come on or the SERVICE BATTERY CHARGING
SYSTEM DIC message will display. SeeDIC Warnings
and Messages on page 3-59andCharging System Light
on page 3-38for more information.
Brake System Warning Light
With the ignition on, the brake system warning light
will come on when you set the parking brake. If you
try to drive with the parking brake engaged, a chime
will sound when the vehicle speed is greater than
5 mph (8 km/h).
Your vehicle’s hydraulic brake system is divided into
two parts. If one part is not working, the other part can
still work and stop you. For good braking, though,
you need both parts working well.
If the warning light comes on and a chime sounds there
could be a brake problem. Have your brake system
inspected right away.
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This light may also come on due to low brake uid.
SeeBrakes on page 5-38for more information.
This light should come on briey when you turn the
ignition key to RUN. If it does not come on then,
have it xed so it will be ready to warn you if there
is a problem.
{CAUTION:
Your brake system may not be working
properly if the brake system warning light is on.
Driving with the brake system warning light on
can lead to an accident. If the light is still on
after you have pulled off the road and stopped
carefully, have the vehicle towed for service.
If the light comes on while you are driving, pull off the
road and stop carefully. You may notice that the pedal
is harder to push or may go closer to the oor. It
may take longer to stop. If the light is still on, have the
vehicle towed for service. SeeTowing Your Vehicle
on page 4-42. United States
Canada
3-40

Anti-lock Brake System (ABS)
Warning Light
For vehicles with
the Antilock Brake
System (ABS), this light
comes on briey when
the engine is started.
That is normal. If the light does not come on then, have
it xed so it will be ready to warn you if there is a problem.
If the ABS light stays on, turn the ignition off. If the light
comes on when you are driving, stop as soon as it is
safely possible and turn the ignition off. Then start the
engine again to reset the system. If the ABS light still
stays on, or comes on again while you are driving, your
vehicle needs service. If the regular brake system
warning light is not on, your vehicle still has brakes, but
not antilock brakes. If the regular brake system warning
light is also on, your vehicle does not have antilock
brakes and there is a problem with the regular brakes.
SeeBrake System Warning Light on page 3-39.
For vehicles with a Driver Information Center (DIC),
seeDIC Warnings and Messages on page 3-59for all
brake related DIC messages.
StabiliTrak®Indicator Light
This warning light should
come on briey when the
engine is started.
If the warning light does not come on then, have it xed
so it will be ready to warn you if there is a problem. If it
stays on, or comes on when you are driving, there may
be a problem with your StabiliTrak
®system and your
vehicle may need service. When this warning light is on,
the system is off and will not limit wheel spin. Adjust your
driving accordingly.
This light will also ash when the StabiliTrak
®system is
active.
If the StabiliTrak
®system warning light comes on
and stays on for an extended period of time when
the system is turned on, your vehicle needs service.
SeeStabiliTrak
®System on page 4-6for more
information.
3-41

Malfunction Indicator Lamp
Check Engine Light
A computer system called OBD II (On-Board
Diagnostics-Second Generation) monitors operation
of the fuel, ignition, and emission control systems.
It makes sure that emissions are at acceptable levels
for the life of the vehicle, helping to produce a cleaner
environment.
The check engine light
comes on to indicate
that there is an OBD II
problem and service
is required.
Malfunctions often are indicated by the system before
any problem is apparent. This can prevent more serious
damage to your vehicle. This system is also designed
to assist your service technician in correctly diagnosing
any malfunction.
Notice:If you keep driving your vehicle with
this light on, after a while, the emission controls
might not work as well, your vehicle’s fuel economy
might not be as good, and the engine might not
run as smoothly. This could lead to costly repairs
that might not be covered by your warranty.Notice:Modications made to the engine,
transmission, exhaust, intake, or fuel system of
your vehicle or the replacement of the original tires
with other than those of the same Tire Performance
Criteria (TPC) can affect your vehicle’s emission
controls and can cause this light to come on.
Modications to these systems could lead to costly
repairs not covered by your warranty. This could
also result in a failure to pass a required Emission
Inspection/Maintenance test. SeeAccessories
and Modifications on page 5-3.
This light comes on, as a check to show it is working,
when the ignition is turned ON/RUN but the engine is not
running. If the light does not come on, have it repaired.
This light also comes on during a malfunction in
one of two ways:
Light Flashing— A misre condition has been
detected. A misre increases vehicle emissions
and could damage the emission control system
on your vehicle. Diagnosis and service might
be required.
Light On Steady— An emission control system
malfunction has been detected on your vehicle.
Diagnosis and service might be required.
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If the Light is Flashing
The following can prevent more serious damage to your
vehicle:
Reduce vehicle speed.
Avoid hard accelerations.
Avoid steep uphill grades.
If you are towing a trailer, reduce the amount of
cargo being hauled as soon as it is possible.
If the light stops ashing and remains on steady,
see “If the Light Is On Steady” following.
If the light continues to ash, when it is safe to do so,
stop the vehicle. Find a safe place to park the vehicle.
Turn the ignition off, wait at least 10 seconds, and restart
the engine. If the light remains on steady, see “If the
Light Is On Steady” following. If the light is still ashing,
follow the previous steps and see your dealer/retailer
for service as soon as possible.
If the Light Is On Steady
You might be able to correct the emission system
malfunction by considering the following:
Did you recently put fuel into your vehicle?
If so, reinstall the fuel cap, making sure to fully install
the cap. SeeFilling the Tank on page 5-9. The
diagnostic system can determine if the fuel cap has
been left off or improperly installed. A loose or missing
fuel cap allows fuel to evaporate into the atmosphere.
A few driving trips with the cap properly installed should
turn the light off.
Did you just drive through a deep puddle of water?
If so, your vehicle’s electrical system might be wet.
The condition is usually corrected when the electrical
system dries out. A few driving trips should turn the
light off.
3-44

Oil Pressure Gage
The oil pressure gage shows the engine oil pressure
in psi (pounds per square inch) when the engine
is running. Canadian vehicles indicate pressure in
kPa (kilopascals).
Oil pressure may vary with engine speed, outside
temperature and oil viscosity, but readings above the
low pressure zone indicate the normal operating range.
When the oil pressure reaches the low pressure zone,
the OIL PRESSURE LOW STOP ENGINE message
will appear in the Driver Information Center (DIC). See
DIC Warnings and Messages on page 3-59andEngine
Oil on page 5-15for more information.A reading in the low pressure zone may be caused by a
dangerously low oil level or some other problem causing
low oil pressure. Check your oil as soon as possible.
{CAUTION:
Do not keep driving if the oil pressure is low.
If you do, your engine can become so hot that
it catches re. You or others could be burned.
Check your oil as soon as possible and have
your vehicle serviced.
Notice:Lack of proper engine oil maintenance
may damage the engine. The repairs would not
be covered by your warranty. Always follow
the maintenance schedule in this manual for
changing engine oil. United States
Canada
3-46

Oil Pressure Light
{CAUTION:
Do not keep driving if the oil pressure is low.
If you do, your engine can become so hot that
it catches re. You or others could be burned.
Check your oil as soon as possible and have
your vehicle serviced.
Notice:Lack of proper engine oil maintenance
may damage the engine. The repairs would not
be covered by your warranty. Always follow
the maintenance schedule in this manual for
changing engine oil.This light will come on
briey when you start your
engine as a check to be
sure it works. If it does not,
have your vehicle serviced.
If the light comes on and stays on, it means that oil is
not owing through your engine properly. You could
be low on oil and you might have some other system
problem.
Security Light
For information regarding
this light and the vehicle’s
security system, see
Content Theft-Deterrent
on page 2-26.
3-47