If The Light Is On Steady; If The Light Is Flashing - Chevrolet 2003 Impala Owner's Manual

•
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 possible.
If the light stops flashing and remains on steady, see "If
the Light Is On Steady" following.
If the light continues to flash, 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 flashing, follow the
previous steps, and see your dealer for service as soon
as possible.
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If the Light Is on Steady

You also 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. See Filling 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.
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, misfiring, 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.