Cadillac 2014 CTS Owner's Manual page 134

5-20 Instruments and Controls
on when the vehicle is placed in
Service Only Mode, as a check to
show it is working. If it does not,
have the vehicle serviced by your
dealer. See Ignition Positions on
page 9-16.
If the malfunction indicator lamp
comes on while the engine is
running, this indicates that there is
an OBD II problem and diagnosis
and service might be required.
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 also
assists the service technician in
correctly diagnosing any
malfunction.
Caution
If the vehicle is continually driven
with this light on, 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.
Caution
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
(Continued)
Caution (Continued)
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
Accessories and Modifications on
page 10-2.
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.