Cadillac 2007 STS, Owner'S Manual

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This light should come on briefly, as a check to
show you it is working, as you start the engine. 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 misfire condition has
been detected. A misfire 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.
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 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 engine 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.
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 the Tank on page 368 .
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.
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