2006 GMC SIERRA check engine light

Passlock®
Your vehicle is equipped with the Passlock®
theft-deterrent system.
Passlock
®is a passive theft-deterrent system.
Passlock®enables fuel if the ignition lock cylinder is
turned with a valid key. If a correct key is not used or the
ignition lock cylinder is tampered with, fuel is disabled.
If the engine stalls and the security light ashes, wait until
the light stops ashing before trying to restart the engine.
Remember to release the key from START as soon as
the engine starts.
If the engine is running and the security light comes on,
you will be able to restart the engine if you turn the engine
off. However, your Passlock
®system is not working
properly and must be serviced by your dealer. Your
vehicle is not protected by Passlock
®at this time. You
may also want to check the fuse. SeeFuses and Circuit
Breakers on page 5-123. See your dealer for service.
In an emergency, call the GM Roadside Assistance
Center. SeeRoadside Assistance Program on page 7-6.
Starting and Operating Your
Vehicle
New Vehicle Break-In
Notice:Your vehicle does not need an elaborate
break-in. But it will perform better in the long run if
you follow these guidelines:
Keep your speed at 55 mph (88 km/h) or less for
the rst 500 miles (805 km).
Do not drive at any one constant speed, fast or
slow, for the rst 500 miles (805 km). Do not
make full-throttle starts. Avoid downshifting to
brake, or slow, the vehicle.
Avoid making hard stops for the rst 200 miles
(322 km) or so. During this time your new brake
linings are not yet broken in. Hard stops with
new linings can mean premature wear and earlier
replacement. Follow this breaking-in guideline
every time you get new brake linings.
Do not tow a trailer during break-in. See
Towing a Trailer on page 4-67for the trailer
towing capabilities of your vehicle and more
information.
Following break-in, engine speed and load can be
gradually increased.
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Warning Lights, Gages, and
Indicators
This part describes the warning lights and gages on
your vehicle. The pictures will help you locate them.
Warning lights and gages can signal that something is
wrong before it becomes serious enough to cause an
expensive repair or replacement. Paying attention to your
warning lights and gages could also save you or others
from injury.
Warning lights come on when there may be or is a
problem with one of your vehicle’s functions. As you will
see in the details on the next few pages, some warning
lights come on briey when you start the engine just to
let you know they are working. If you are familiar with this
section, you should not be alarmed when this happens.Gages can indicate when there may be or is a problem
with one of your vehicle’s functions. Often gages and
warning lights work together to let you know when there
is a problem with your vehicle.
When one of the warning lights comes on and stays on
when you are driving, or when one of the gages shows
there may be a problem, check the section that tells you
what to do about it. Please follow this manual’s advice.
Waiting to do repairs can be costly – and even
dangerous. So please get to know your warning lights
and gages. They are a big help.
Your vehicle also has a Driver Information Center (DIC)
that works along with warning lights and gages. See
DIC Warnings and Messages on page 3-55.
3-31

Battery Warning Light
If this light is displayed
when the engine is running,
you may have a problem
with your charging system.
The battery display will also stay on while the key is in
RUN until the engine is started.
If the light stays on after starting the engine it could
indicate a problem with the generator drive belt, or some
other charging system problem. Have it checked right
away. Driving with this light displayed could drain your
battery.
If you must drive a short distance with this light
displayed, it helps to turn off all your accessories,
such as the radio and the air conditioner.
Voltmeter Gage
When your engine is not
running, but the ignition is
in RUN, this gage shows
your battery’s state of
charge 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.
3-40

Malfunction Indicator Lamp
Check Engine Light
Your vehicle is equipped
with 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 5-4.
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.
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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 the Tank on page 5-10. 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.
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 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.
3-47

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.
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.
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.
See “OIL PRESSURE LOW” underDIC Warnings and
Messages on page 3-55andEngine Oil (Gasoline
Engine) on page 5-20. United States
Canada
3-48

{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.
Security Light
This light ashes when the
vehicle security system is
activated.
Cruise Control Light
This light comes on
whenever you set
your cruise control.
The light will go out when the cruise control is turned off.
SeeCruise Control on page 3-10for more information.
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.
3-49

CHANGE ENGINE OIL
This message is displayed when the engine oil needs to
be changed.
When you change the engine oil, be sure to reset the
CHANGE ENGINE OIL message. SeeEngine Oil Life
System (Gasoline Engine) on page 5-23,Engine Oil
(Gasoline Engine) on page 5-20, andScheduled
Maintenance (Gasoline Engine) on page 6-4for more
information.
CHARGING SYSTEM FAILURE
On some vehicles, if there is a problem with the generator
and battery charging system, this message will appear on
the DIC, a chime will sound, and the battery warning light
on the instrument panel cluster will come on. Driving
with this problem could drain your battery. Turn off all
unnecessary accessories. Stop and turn off the vehicle
as soon as it is safe to do so. Have the electrical system
checked by your GM dealer immediately. SeeBattery
Warning Light on page 3-40andVoltmeter Gage on
page 3-40for more information.
CHECK OIL LEVEL
If your vehicle has an oil level sensor, and the oil level in
the vehicle is low, this message will appear on the DIC.
Check the oil level and correct it as necessary. You may
need to let the vehicle cool or warm up and cycle the
ignition to be sure this message will clear. Once the
problem is corrected, pressing any of the four DIC
buttons will acknowledge the message and clear it from
the DIC display. If your vehicle does not have the four
DIC buttons, pressing the trip odometer reset stem will
acknowledge the message and clear it from the DIC
display. SeeEngine Oil (Gasoline Engine) on page 5-20
for additional information.
CHECK WASHER FLUID
If the washer uid level is low, this message will appear
on the DIC. SeeWindshield Washer Fluid on page 5-46.
Adding washer uid to the windshield washer reservoir
will clear the message. Pressing any of the four DIC
buttons will acknowledge the message and clear it from
the DIC display. If your vehicle does not have the four
DIC buttons, pressing the trip odometer reset stem will
acknowledge the message and clear it from the DIC
display.
3-57