2008 GMC ENVOY DENALI service

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 3-33for 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 3-53for
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 displays the
battery voltage in DC volts.
When the engine is running, the gage shows the
condition of the charging system. 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 voltmeter gage may also read lower when
in 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 idling 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 maximum power.
You can only drive for a short time with the reading
in either warning zone. If you must drive, turn off
all unnecessary accessories.
Readings in either warning zone indicate a possible
problem in the electrical system. Have the vehicle
serviced as soon as possible.
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Brake System Warning Light
When the ignition is on, the brake system warning light
will come on when you set your parking brake. The light
will stay on if your parking brake does not release fully.
If it stays on after your parking brake is fully released, it
means your vehicle has a brake problem. A chime may
also sound when the light comes on.
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, there could be a brake
problem. Have your brake system inspected right away.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.
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 the pedal 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 4-40.
{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.
United States
Canada
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Antilock Brake System
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 3-38.
For vehicles with a Driver Information Center (DIC),
seeDIC Warnings and Messages on page 3-53for
all brake related DIC messages.
StabiliTrak®Service Light
This light will come on
briey when the engine
is started.
This light will come on if a problem is detected in the
StabiliTrak
®system.
For more information seeStabiliTrak
®System on
page 4-6.
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Tire Pressure Light
Your vehicle has a tire
pressure light.
This light comes on briey when the engine is started
and provides information about tire pressures and
the Tire Pressure Monitoring System.
When the Light is Solid
This indicates that one or more of your tires are
signicantly underinated.
A tire pressure message in the Driver Information
Center (DIC), may accompany the light. SeeDIC
Warnings and Messages on page 3-53for more
information. Stop and check your tires as soon as it
is safe to do so. If underinated, inate to the proper
pressure. SeeTires on page 5-57for more information.
When the Light Flashes First and Then is
Solid
This indicates that there may be a problem with the Tire
Pressure Monitor System. The light ashes for about a
minute and stays on solid for the remainder of the ignition
cycle. This sequence will repeat with every ignition cycle.
SeeTire Pressure Monitor System on page 5-67for more
information.
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.
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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 5-8. The diagnostic
system can determine if the fuel cap has been left off orimproperly 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.
Have you recently changed brands of fuel?
If so, be sure to fuel your vehicle with quality fuel. See
Gasoline Octane on page 5-6. Poor fuel quality causes
the engine not to run as efficiently as designed. You
might notice this as stalling after start-up, stalling when
you put the vehicle into gear, misring, hesitation on
acceleration, or stumbling on acceleration — these
conditions might go away once the engine is warmed up.
This will be detected by the system and cause the light to
turn on.
If you experience one or more of these conditions,
change the fuel brand you use. It will require at least
one full tank of the proper fuel to turn the light off.
If none of the above steps have made the light turn
off, your dealer/retailer can check the vehicle. Your
dealer/retailer has the proper test equipment and
diagnostic tools to x any mechanical or electrical
problems that might have developed.
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{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.
Oil pressure may vary with engine speed, outside
temperature and oil viscosity, but readings above the
low pressure zone indicate the normal operating range.
A reading in the low pressure zone may be caused
by a dangerously low oil level or other problems causing
low oil pressure.
Change Engine Oil Light
Your vehicle may have a
change engine oil light.
When this light comes on it means that an oil change
and other maintenance procedures are required for your
vehicle.
SeeScheduled Maintenance on page 6-4andEngine
Oil on page 5-16for more information.
Once the engine oil has been changed, the change
engine oil light must be reset. Until it is reset, the light
will stay on when the engine is on.
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