Malfunction Indicator Lamp (Check Engine Light) - GMC C series 2002 Owner's Manual

Malfunction Indicator Lamp
(Check Engine Light)
If your vehicle is equipped with either a gasoline engine
or an electronically controlled diesel engine, you will
have this light.
First, you won't notice any difference in engine
performance, but your tail pipe emissions may increase.
Second, your engine may not run properly or may stall
without warning. If either of these things happen, drive
or tow your vehicle to your dealer for service.
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If this light comes on
or flashes while you
are driving, two things
may happen.
This light should come on when the ignition is on, but
the engine is not running, as a check to show you it is
working. If it does not come on at all, have it repaired.
NOTICE:
If you keep driving your vehicle with this light
on, after a while, 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.