2005 GMC ENVOY Owner's Manual

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 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 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 Your Tank on page 5-7. 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.
Did you just drive through a deep puddle of water?
If so, your electrical system may be wet. The condition
will usually be corrected when the electrical system
dries out. A few driving trips should turn the light off.
3-43

Have you recently changed brands of fuel?
If so, be sure to fuel your vehicle with quality fuel. See
Gasoline Octane on page 5-5. Poor fuel quality will
cause your engine not to run as efficiently as designed.
You may 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 may 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 can check the vehicle. Your dealer has the
proper test equipment and diagnostic tools to x any
mechanical or electrical problems that may
have developed.Emissions Inspection and
Maintenance Programs
Some state/provincial and local governments have or
may begin programs to inspect the emission control
equipment on your vehicle. Failure to pass this inspection
could prevent you from getting a vehicle registration.
Here are some things you need to know to help your
vehicle pass an inspection:
Your vehicle will not pass this inspection if the check
engine light is on or not working properly.
Your vehicle will not pass this inspection if the OBD
(on-board diagnostic) system determines that critical
emission control systems have not been completely
diagnosed by the system. The vehicle would be
considered not ready for inspection. This can happen if
you have recently replaced your battery or if your battery
has run down. The diagnostic system is designed to
evaluate critical emission control systems during normal
driving. This may take several days of routine driving. If
you have done this and your vehicle still does not pass
the inspection for lack of OBD system readiness, your
GM dealer can prepare the vehicle for inspection.
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).
{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. United States
Canada
3-45

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 be displayed when the engine is on.
Security Light
This light will come on
briey when you turn the
key toward START.
The light will stay on until the engine starts. If the light
ashes, the Passlock
®system has entered a tamper
mode. If the vehicle fails to start, seePasslock®
on page 2-18.
If the light comes on continuously while driving and
stays on, there may be a problem with the Passlock
®
system. Your vehicle will not be protected by Passlock®,
and you should see your dealer.
Also, seeContent Theft-Deterrent on page 2-16for
additional information regarding the security light.
3-46

Cruise Control Light
The cruise light appears
whenever you set your
cruise control.
Reduced Engine Power Light
This light is displayed
when a noticeable
reduction in the vehicle’s
performance may occur.
The vehicle may be driven at a reduced speed when the
reduced engine power light is on but acceleration and
speed may be reduced. The performance may be
reduced until the next time you drive your vehicle. If this
light stays on, see your dealer as soon as possible for
diagnosis and repair.
This light may also come on if there is a problem with the
Electronic Throttle Control (ETC) system. If this happens,
take the vehicle in for service as soon as possible.
3-47

Highbeam On Light
This light will come on
when the high-beam
headlamps are in use.
SeeHeadlamp High/Low-Beam Changer on page 3-8.
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 GM dealer in
correctly diagnosing a malfunction.
3-48

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, your
liftgate or liftglass is not
completely shut.
Close the liftgate or liftglass. Never drive with the liftgate
or liftglass even partially open.
3-49

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. United StatesCanada
3-50