GMC 2003 Envoy - Manual (Page 167)

Thi 5 iigiii shouU come on, as a check to show you it is
working, wheni the ignition ¡0 on and (he engine ia
not running. If the light cEoesn't come on, have it
repaiied. This lighi will also come on during a
malfunction in one of two ways:
■ Light Fiashing — A misfire condition has been
delecled. A misfire increases vehicle emissions
and may damage ihe emission control system on
your vehicle. Dealer or qualified service cenler
diagnosis and service may be required.
* Light On Steady — An emission control syslem
malfunction has been detected on your vehicle
Dealer or qualitied service center diagnosis
and service rnay be required.
Ff the Light Is Flashing
The foltowtng may prevent more serious damage to
your vehiefa;
^ Reducing vehicle speed.
* Avoiding hard acceleratiorts.
% Avoiding steep uphill grades.
* If you are towing a trailer, reduce the amount oi
cargo being hauled as soon as it is possible,
It the light stops flashing and remains on steady,
see "It (he Light Is On Steady" tdllowing.
tt the light continues to flash, when it Is safe to dg so.
stop №e vehich. Find a safe place to park your vehicle.
Turn the key off, wan at least 10 seconds and restart
the engine. И Ihe light remains on sleady, see
"If the Light is On Steady" foUowing, If (he light is still
flashing, follow Ihe pievious steps, and drive (he vehicle
to your dealer or qualrried service center for sarvrea.
If the Light Is On Steady
Vou may be able to correct the emission system
malfunction by considering the following:
Did you recently pul tuel kntu your vehiclo?
If sOf reinstall ihe fuel cap, making sure to fully install
Ihe cap. See Fiiling Your Tank on page5'7. The
diagnostic syslem can determine if the fuel cap has
Ьвеп left off or improperly inslalled. A looso or missing
fuel cap will alJow luel to evaporate irtto The atnicsphere.
A lew driving irips with the cap properly installed
should lum Ihe kg hi oH.
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