Cadillac 2011 CTS Coupe Owner's Manual page 162

5-20 Instruments and Controls
Malfunctions often are indicated by
the system before any problem is
apparent. Being aware of the light
can prevent more serious damage
to the vehicle. This system assists
the service technician in correctly
diagnosing any malfunction.
If the vehicle is
continually driven with this light
on, after a while, the emission
controls might not work as well,
the vehicle fuel economy might
not be as good, and the engine
might not run as smoothly. This
could lead to costly repairs that
might not be covered by the
vehicle warranty.
Modifications made to the
engine, transmission, exhaust,
intake, or fuel system of the
vehicle or the replacement
of the original tires with other
than those of the same Tire
Performance Criteria (TPC) can
affect the vehicle's emission
controls and can cause this light
to come on. Modifications to
these systems could lead to
costly repairs not covered by
the vehicle warranty. This
could also result in a failure
to pass a required Emission
Inspection/Maintenance test. See
.
This light comes on during a
malfunction in one of two ways:
Light Flashing: A misfire condition
has been detected. A misfire
increases vehicle emissions and
could damage the emission control
system on the vehicle. Diagnosis
and service might be required.
To prevent more serious damage to
the vehicle:
Reduce vehicle speed.
Avoid hard accelerations.
Avoid steep uphill grades.
If towing a trailer, reduce the
amount of cargo being hauled
as soon as it is possible.
If the light continues to flash,
when it is safe to do so, stop the
vehicle. Find a safe place to park
the vehicle. Turn the vehicle off,
wait at least 10 seconds, and
restart the engine. If the light is still
flashing, follow the previous steps
and see your dealer for service as
soon as possible.
Light On Steady: An emission
control system malfunction has
been detected on the vehicle.
Diagnosis and service might be
required.
The following may correct an
emissions system malfunction:
Make sure the fuel cap is
fully installed. See
. The
diagnostic system can determine
if the fuel cap has been left off or
improperly installed. A loose or
missing fuel cap allows fuel to
evaporate into the atmosphere.
A few driving trips with the cap
properly installed should turn the
light off.