Pontiac 2001 Sunfire Owner's Manual page 129

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 the CHECK ENGINE
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.
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 doesn't come on, have it repaired.
This light will also come on during a malfunction in one
of two ways:
D
--
Light Flashing A misfire condition has been
detected. A misfire increases vehicle emissions and
may damage the emission control system on your
vehicle. Dealer or qualified service center diagnosis
and service may be required.
D
--
Light On Steady An emission control
system malfunction has been detected on your
vehicle. Dealer or qualified service center diagnosis
and service may be required.
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