Chevrolet 2007 HH7 Owner's Manual page 189

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: Modifications 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. Modifications 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. See Accessories
and Modifications on page 289.
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 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.
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