2007 PONTIAC GRAND PRIX check engine light

Warning Lights, Gages, and
Indicators
This part describes the warning lights and gages
that may be on the vehicle. The pictures help
to 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 the 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 the vehicle’s functions. As
the details show on the next few pages, some
warning lights come on briey when the engine is
started just to indicate 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 the vehicle’s functions. Often
gages and warning lights work together to
indicate when there is a problem with the vehicle.
When one of the warning lights comes on and
stays on while the vehicle is being driven, or when
one of the gages shows there may be a problem,
check the section that tells you what to do
about it. Follow this manual’s advice. Waiting to
do repairs can be costly – and even dangerous.
So please get to know the vehicle’s warning lights
and gages. They can be a big help.
The vehicle also has a Driver Information
Center (DIC) that works along with the warning
lights and gages. SeeDriver Information
Center (DIC) on page 186for more information.
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Low Tire Pressure Warning Light
This light should come
on briey as you start
the engine.
This light will also come on when one or more of
your tires is signicantly under-inated. Stop and
check your tires as soon as it is safe to do so.
If underinated, inate them to the proper pressure.
SeeTires on page 400for more information. This
light will ash for 60 seconds and then turn on solid
if a problem is detected with the Tire Pressure
Monitor System. SeeTire Pressure Monitor System
on page 409for more information.
Traction Control System (TCS)
Warning Light
If the vehicle has the
Traction Control
System (TCS), this light
may come on for the
following reasons:
The traction control button, located on the
center console, is pressed, turning the
system off. The light will stay on. To turn the
system back on, press the button again
and the warning light should go out. See
Traction Control System (TCS) on page 292
for more information.
If there is a brake system problem that is
specically related to traction control, the TCS
will turn off and the warning light will come on.
If the brakes begin to overheat, the TCS will
turn off and the warning light will come on until
the brakes cool down.
If the TCS warning light comes on and stays on
for an extended period of time when the system is
turned on, the vehicle needs service.
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Engine Coolant Temperature Gage
The vehicle has a gage
that shows the engine
coolant temperature.
If the gage pointer moves into the shaded area,
the engine is too hot. That reading means
the engine coolant has overheated. If you have
been operating the vehicle under normal
driving conditions, you should pull off the road,
stop the vehicle, and turn off the engine as soon
as possible.
SeeCooling System on page 366for more
information.
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.
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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,
transaxle, 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 336.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.
181

Have you recently changed brands of fuel?
If so, be sure to fuel your vehicle with quality fuel.
SeeGasoline Octane on page 338. 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 dealer
can prepare the vehicle for inspection.
183

Oil Pressure Light
If there is a problem
with the vehicle’s oil
pressure, this light may
stay on when the
engine is started.
It may also come on while the vehicle is being
driven. This indicates that the engine could be low
on oil or could have some other oil problem.
Have it xed right away.
The oil light could also come on in two other
situations:
When the ignition is on but the engine is not
running, the light will come on as a test to
indicate it is working. The light will go out when
the ignition is turned to RUN. If it does not come
on while the ignition is in the on position, there
may be a problem with the fuse or bulb. See
Fuses and Circuit Breakers on page 460.
If the brakes are applied quickly and the vehicle
makes a hard stop, the light may come on for a
moment. This is normal.
{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.
184

CHECK TIRE PRESSURE
This message displays when the tire pressure in
one of the tires needs to be checked. This
message also displays LEFT FRONT, RIGHT
FRONT, LEFT REAR, or RIGHT REAR to indicate
which tire needs to be checked. You can receive
more than one tire pressure message at a time.
To read the other messages that may have
been sent at the same time, press the set/reset
button. If a tire pressure message appears on the
DIC, stop as soon as you can. Have the tire
pressures checked and set to those shown on the
Tire Loading Information label. SeeTires on
page 400,Loading Your Vehicle on page 317, and
Ination - Tire Pressure on page 408. The DIC
display also shows the tire pressure values for the
front and rear tires by pressing the options
button. SeeDIC Controls and Displays (Base
Level DIC) on page 186orDIC Controls and
Displays (Uplevel DIC with Trip Computer)
on page 190. If the tire pressure is low, the low
tire pressure warning light comes on. SeeLow Tire
Pressure Warning Light on page 178for more
information.This message displays while the ignition is in
RUN. Press the set/reset button to acknowledge
this message and to clear it from the screen.
This message continues to display for
three seconds if it has not been acknowledged
when the engine is turned off. It also re-displays for
three seconds if the message has been
acknowledged, but the condition still exists when
the engine is turned off.
If the condition still exists, the message re-appears
when the engine is turned on.
CRUISE SET
This symbol comes on
with this message.
204

Avoid needless heavy braking. Some people drive
in spurts — heavy acceleration followed by
heavy braking — rather than keeping pace with
traffic. This is a mistake. The brakes may not have
time to cool between hard stops. The brakes
will wear out much faster if you do a lot of heavy
braking. If you keep pace with the traffic and
allow realistic following distances, you will
eliminate a lot of unnecessary braking. That means
better braking and longer brake life.
If your vehicle’s engine ever stops while you are
driving, brake normally but do not pump the
brakes. If you do, the pedal may get harder to
push down. If the engine stops, you will still have
some power brake assist. But you will use it
when you brake. Once the power assist is used
up, it may take longer to stop and the brake pedal
will be harder to push.
Adding non-GM accessories can affect your
vehicle’s performance. SeeAccessories and
Modications on page 336.Anti-Lock Brake System (ABS)
Your vehicle may have the Anti-Lock Brake
System (ABS), an advanced electronic braking
system that will help prevent a braking skid.
If your vehicle has ABS,
this warning light on the
instrument panel will
come on briey when
you start your vehicle.
When you start your engine, or when you begin to
drive away, your ABS will check itself. You may
hear a momentary motor or clicking noise while this
test is going on, and you may even notice that your
brake pedal moves or pulses a little. This is normal.
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