2006 CHEVROLET TAHOE 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. See
Fuses and Circuit Breakers on page 5-109. 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. SeeTowing
a Trailer on page 4-62for the trailer towing
capabilities of your vehicle and more
information.
Following break-in, engine speed and load can be
gradually increased.
2-18

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.
3-34

If, after several seconds, all 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 for service.
{CAUTION:
If the off indicator and the airbag readiness
light ever come on together, 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
seat may not have the protection of the
frontal airbag. SeeAirbag Readiness Light
on page 3-37.
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.
3-39

The following situations can cause the transmission to
operate at higher temperatures:
Towing a trailer
Hot outside air temperatures
Hauling a large or heavy load
Vehicle overloading
Low transmission uid level
High transmission uid level
Restricted air ow to the radiator and the auxiliary
transmission oil cooler (if equipped).
A temporary solution to hotter transmission operating
temperatures may be to let the transmission cool down.
If the transmission is operated at higher temperatures
on a frequent basis, seeScheduled Maintenance
on page 6-4for the proper transmission maintenance
intervals.
Tire Pressure Light
If your vehicle is equipped
with the Tire Pressure
Monitor system, this
light will come on if the
system detects low
tire pressure.
A CHECK TIRE PRESSURE DIC message will
accompany the light.
This light will also come on briey as you start the
engine.
SeeTire Pressure Monitor System on page 5-66for
more information.
For more information on your tires, seeTires on
page 5-59.
3-44

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 5-3.
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.
3-45

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.
3-47

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.
BUCKLE SEATBELT
If your vehicle has the passenger sensing system, this
message reminds you to buckle the driver’s seat
belt. SeePassenger Sensing System on page 1-82.
This message will display and a chime will sound when
the ignition is on, the driver’s seat belt is unbuckled,
and the vehicle is in motion. You should buckle
your seat belt.
If the driver remains unbuckled when the ignition is
on and the vehicle is in motion, the reminder will
be repeated. If the driver’s seat belt is already buckled,
this message and chime will not come on.
This message is an additional reminder to the Safety
Belt Reminder Light in the instrument panel cluster.
SeeSafety Belt Reminder Light on page 3-36.
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.
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. See
Engine Oil Life System on page 5-18for information on
how to reset the message. This message will clear
itself after 10 seconds until the next ignition cycle or until
the message is reset. SeeEngine Oil on page 5-15
andScheduled Maintenance 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 3-39
andVoltmeter Gage on page 3-40for more information.
3-56

SERVICE CHARGING SYSTEM
On some vehicles, if there is a problem with the battery
charging system, this message will appear on the
DIC. Under certain conditions, the battery warning light
may also turn on in the instrument panel cluster.
SeeBattery Warning Light on page 3-39. The battery
will not be charging at an optimal rate and the vehicle
will lose the ability to enter the fuel economy mode. The
vehicle is safe to drive, however you should have the
electrical system checked by your GM dealer. 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.
SERVICE RIDE CONTROL
If a problem occurs with the suspension system, this
message will appear on the DIC. See your GM dealer.
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.
SERVICE STABILITY
If you ever see the SERVICE STABILITY message, it
means there may be a problem with your StabiliTrak®
system. If you see this message, try to reset the system.
Stop; turn off the engine; then start the engine again.
If the SERVICE STABILITY message still comes
on, it means there is a problem. You should see your
GM dealer for service. The vehicle is safe to drive,
however, you do not have the benet of StabiliTrak
®,so
reduce your speed and drive accordingly. 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.
SERVICE TIRE MONITOR
If your vehicle has the tire pressure monitor system,
this message will be displayed if one or more of the
tire monitor sensors have malfunctioned or if all of the
tire monitor sensors have not been programmed
successfully. See your GM dealer. 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. The message will
reappear at each ignition cycle until the system has
been serviced. See your GM dealer.
3-62