ignition GMC ENVOY DENALI 2007 Service Manual

Charging System Light
The charging system
light will come on briey
when you turn on the
ignition, 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 you are driving,
you may have a problem with the charging system.
It could indicate that you have problems with a
generator drive belt, or another electrical problem.
Have it checked right away. Driving while this
light is on could drain your battery.
If you must drive a short distance with the light on,
be certain to turn off all your accessories, such
as the radio and air conditioner.
Voltmeter Gage
When your engine is not
running, but the ignition
is in RUN, 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.
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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.
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. See
Towing Your Vehicle on page 354.
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206

{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.
Anti-Lock Brake System
Warning Light
With the Anti-Lock
Brake System (ABS),
this light will come
on when you start your
engine and may
stay on for several
seconds, that is normal.
A chime may also sound when the light comes on.If the light stays on, or comes on when you are
driving, your vehicle needs service. If the regular
brake system warning light is not on, you still have
brakes, but you do not have anti-lock brakes. If the
regular brake system warning light is also on, you
do not have anti-lock brakes and there is a problem
with your regular brakes. SeeBrake System
Warning Light on page 206earlier in this section.
The ABS warning light should come on briey
when you turn the ignition key to RUN. If the light
does not come on then, have it xed so it will
be ready to warn you if there is a problem.
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 309.
207

Tire Pressure Light
This light will come on
briey when you turn
the ignition to RUN.
This light will also come on when one or more of
your tires are signicantly underinated.If your vehicle has a Driver Information
Center (DIC), a CHECK TIRE PRESSURE DIC
message will accompany the light, seeDIC
Warnings and Messages on page 222
Stop and check your tires as soon as it is safe to
do so. If underinated, inate to the proper
pressure. SeeTires on page 439for more
information.
This light will ash for approximately 70 seconds
and then turn on solid if a problem is detected with
the Tire Pressure Monitor system.
SeeTire Pressure Monitor System on page 448
for more information.
209

Malfunction Indicator Lamp
Check Engine Light
Your vehicle has a
computer which
monitors operation of
the fuel, ignition, and
emission control
systems.
This system is called OBD II (On-Board
Diagnostics-Second Generation) and is intended
to assure 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 a problem and
service is required. Malfunctions often will be
indicated by the system before any problem is
apparent. This may 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 awhile, your emission
controls may not work as well, your fuel
economy may not be as good, and your engine
may not run as smoothly. This could lead to
costly repairs that may 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 may
cause this light to come on. Modications to
these systems could lead to costly repairs not
covered by your warranty. This may also
result in a failure to pass a required Emission
Inspection/Maintenance test. SeeAccessories
and Modifications on page 380.
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This light should come on, as a check to show
you it is working, when the ignition is on and the
engine is not running. If the light does not
come on, have it repaired. This light will also
come on during a malfunction in one of two ways:
Light Flashing— A misre condition has
been detected. A misre increases vehicle
emissions and may damage the emission
control system on your vehicle. Diagnosis and
service may be required.
Light On Steady— An emission control
system malfunction has been detected on
your vehicle. Diagnosis and service may
be required.
If the Light is Flashing
The following may prevent more serious damage
to your vehicle:
Reducing vehicle speed
Avoiding hard accelerations
Avoiding steep uphill grades
If you are towing a trailer, reduce the amount of
cargo being hauled as soon as it is possibleIf 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
your vehicle. Turn the key 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 for service as
soon as possible.
If the Light Is On Steady
You may 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 385.
The diagnostic system can determine if the
fuel cap has been left off or improperly installed.
A loose or missing fuel cap will allow fuel to
evaporate into the atmosphere. A few driving trips
with the cap properly installed should turn the
light off.
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Service Four-Wheel Drive
Warning Light
This light should come
on briey when you turn
on the ignition, as a
check to show you
it is working.
The service four-wheel drive light comes on to
indicate that there may be a problem with the drive
system and service is required. Malfunctions
can be indicated by the system before any problem
is apparent, which may prevent serious damage
to the vehicle. This system is also designed
to assist your dealer in correctly diagnosing a
malfunction.
Check Gages Warning Light
The check gages light
will come on briey
when you are starting
the engine.
If the light comes on and stays on while you are
driving, check your coolant temperature and
engine oil pressure gages to see if they are in the
warning zones.
Gate Ajar Light
If this light comes on,
the liftgate or liftglass is
not completely shut.
Close the liftgate or liftglass. Never drive with the
liftgate or liftglass even partially open.
216

Fuel Gage
When the ignition is on, the fuel gage tells you
about how much fuel you have remaining.
Here are four things that some owners ask about.
None of these show a problem with your fuel gage:
At the gas station, the gas pump shuts off
before the gage reads full.
It takes a little more or less fuel to ll up than
the gage indicated. For example, the gage may
have indicated the tank was half full, but it
actually took a little more or less than half the
tank’s capacity to ll the tank.
The gage moves a little when you turn a corner
or speed up.
The gage doesn’t go back to empty when you
turn off the ignition.
Low Fuel Warning Light
The light next to the fuel gage will come on briey
when you are starting the engine.
This light comes on when the fuel tank is low on
fuel. To turn it off, add fuel to the fuel tank.
SeeFuel on page 382.
Check Gas Cap Light
If your vehicle has this
light, it will come on if
your gas cap is not
securely fastened.
SeeMalfunction Indicator Lamp on page 210for
more information.
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217

DIC Operation and Displays
The DIC comes on when the ignition is on. After a
short delay the DIC will display the information
that was last displayed before the engine
was turned off.
If a problem is detected, a warning message will
appear on the display. Pressing the trip stem
will acknowledge any warning or service
messages. Pressing any of the DIC steering wheel
buttons — trip information, fuel information,
customization, or select button — will also
acknowledge any warnings or service messages.
You should take any message that appears on
the display seriously and remember that clearing
the message will only make the message
disappear, not correct the problem.
The DIC has different modes which can be
accessed by pressing the four DIC buttons located
on the steering wheel. These buttons are trip
information, fuel information, customization, and
select. The button functions are detailed in
the following pages.
Trip Information Button
3
(Trip Information):Press the trip
information button to scroll through the
ODOMETER, TRIP A, TRIP B, TIRE
PRESSURES, and TIMER.
Odometer:Press the trip information button until
ODOMETER appears on the display. This
mode shows the total distance the vehicle has
been driven in either miles or kilometers. Pressing
the reset stem located on the instrument cluster
with the vehicle off will also display the odometer.
Trip A:Press the trip information button until
TRIP A appears on the display. This mode shows
the current distance traveled since the last
reset for TRIP A in either miles or kilometers.
Trip B:Press the trip information button
until TRIP B appears on the display. This mode
shows the current distance traveled since the last
reset for TRIP B in either miles or kilometers.
219

To reset TRIP A or TRIP B information, press and
hold the select button for one second while in
one of the trip modes. This will reset the
information for TRIP A or TRIP B.
You can also reset the TRIP A or TRIP B while they
are displayed by pressing the reset stem on the
cluster. If you press and hold the reset stem or the
select button for more than four seconds, the
display will show the distance traveled since the last
ignition cycle for TRIP A or TRIP B.
Tire Pressures:Press the trip information button
until TIRE PRESSURES appears on the display.
This mode shows the tire pressure in pounds
per square inch (psi) or kilopascals (kPa). Press
the select button to scroll through the following
information:
LF TIRE shows the tire pressure for the front
driver’s side tire.
RF TIRE shows the tire pressure for the front
passenger’s side tire.
LR TIRE shows the tire pressure for the rear
driver’s side tire.
RR TIRE shows the tire pressure for the rear
passenger’s side tire.Timer:The DIC can be used as a timer. Press
the select button while TIMER is displayed to start
the timer. The display will show the amount of
time that has passed since the timer was
last reset, not including time the ignition is off.
Time will continue to be counted as long as
the ignition is on, even if another display is being
shown on the DIC. The timer will record up to
99 hours, 59 minutes and 59 seconds (99:59:59)
after which the display will roll back to zero.
To stop the counting of time, press the select
button briey while TIMER is displayed.
To reset the timer to zero, press and hold the
select button while TIMER is displayed.
Fuel Information Button
t
(Fuel Information):Press the fuel information
button to scroll through the range, fuel used,
average fuel economy, and the engine oil
life system.
Fuel Range:Press the fuel information button until
RANGE appears on the display. This mode shows
the remaining distance you can drive without
refueling. It is based on fuel economy and the fuel
remaining in the fuel tank. The display will show
LOW if the fuel level is low.
220