ignition GMC ENVOY DENALI 2008 Owner's Guide

Headlamps on Reminder
A reminder tone sounds when the headlamps or parking
lamps are manually turned on, if the driver’s door is
open and the ignition is in LOCK or ACC. To turn the
tone off, turn the knob all the way counterclockwise.
In the automatic mode, the headlamps turn off once the
ignition key is in LOCK.
Daytime Running Lamps (DRL)
Daytime Running Lamps (DRL) can make it easier
for others to see the front of your vehicle during the day.
DRL can be helpful in many different driving conditions,
but they can be especially helpful in the short periods
after dawn and before sunset. Fully functional DRL
are required on all vehicles rst sold in Canada.
The DRL system makes the headlamps come on at
reduced brightness when the following conditions
are met:
The ignition is on.
The exterior lamps knob is in automatic
headlamp mode.
The light sensor detects daytime light.
The transmission is not in PARK (P).When the DRL are on, only the headlamps will be on.
The taillamps, sidemarker and other lamps will not
be on. The instrument panel will not be lit up either.
When it begins to get dark, the headlamps automatically
switch from DRL to the regular headlamps.
Automatic Headlamp System
When it is dark enough outside, the Automatic
Headlamp System turns on the headlamps when the
vehicle is started and after the transaxle has been
shifted out of the PARK (P) position. The headlamps,
taillamps, sidemarker, and parking lamps will come
on. The instrument panel lights and radio lights will
also turn on at normal brightness. Once on, the system
remains on during these conditions even if the vehicle
is shifted back into PARK (P).
The vehicle has a light sensor on the top of the
instrument panel. Make sure it is not covered or the
system may come on whenever the ignition is on and
the vehicle is shifted out of the PARK (P) position.
The system could also turn on the lamps when driving
through a parking garage, heavy overcast weather
or a tunnel. This is normal.
3-15

There is a delay in the transition between the daytime and
nighttime operation of the Daytime Running Lamps (DRL)
and the automatic headlamp systems, so that driving
under bridges or bright overhead street lights does not
affect the system. The DRL and automatic headlamp
system are only affected when the light sensor sees a
change in lighting lasting longer than the delay.
If you start your vehicle in a dark garage, the automatic
headlamp system comes on after the transmission is
shifted out of PARK (P). Once you leave the garage,
it will take about one minute for the automatic headlamp
system to change to DRL if it is light outside. During
that delay, the instrument panel cluster might not be
as bright as usual. Make sure the instrument panel
brightness control is in the full bright position.
If the vehicle is running and the automatic headlamp
system is already on, it can be turned off by turning
and releasing the headlamp control at the off position.
The automatic headlamp system stays off until you
turn and release the headlamp control at the off
position again. SeeHeadlamps on page 3-14.Fog Lamps
Use the fog lamps for better vision in foggy or misty
conditions. The ignition must be in RUN for the
fog lamps to work.
The fog lamp button is
located on the instrument
panel to the right of the
exterior lamps knob.
Press the button to turn the fog lamps on. Press the
button again to turn them off. A light glows near the
button while the fog lamps are on. Fog lamps turn off
whenever the high-beam headlamps are on.
Some localities have laws that require the headlamps to
be on along with the fog lamps.
3-16

Entry Lighting
The vehicle has entry lighting.
When any door is opened, the dome lamps come on as
long as the dome override lamp override button is not
pressed in. When all the doors are closed, the lamps
stay on for a short period of time and then turn off
automatically. If you use the Remote Keyless Entry (RKE)
transmitter to unlock the vehicle, the interior lamps come
on for a short time whether or not the dome lamp override
is on.
Exit Lighting
With exit lighting, the interior lamps come on when you
remove the key from the ignition. If the dome override
is off, these lamps stay on for a short period of time
and then go out.
Reading Lamps
The reading lamps are located in the front console.
Press the lens on the lamps to turn the reading lamps
on or off.
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.
3-18

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 3-53.Battery Run-Down Protection
This feature shuts off the dome, courtesy, and vanity
lamps if they are left on for more than 20 minutes
when the ignition is off. This will keep the battery
from running down.
If the battery run-down protection shuts off the interior
lamps, it may be necessary to do one of the following to
return to normal operation:
Shut off all lamps and close all doors.
Turn the ignition key to RUN.
This feature will also turn off the parking lamps and
headlamps under most circumstances, if they are left on.
If you would like to turn them back on, turn the exterior
lamps knob.
3-19

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.
3-36

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.
3-37

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
3-38

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.
3-39

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.
3-41

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.
3-42