GMC 2003 Sierra - Manual (Page 201)

You may be able to correci the emission sysiem
malfunctian by ijonsidenng Bie lollowldg:
Did you recenfly put I ue I Into ydur vehicle?
If so. reinstall the fuel cap, making sure lo fully Inslall
the cap. See Fitting Vp^r Tank on page 5'7. The
diagnoslic system can determine if the Eael cap has
been left off or improperly in stalled. A loose or missing
fuel cap wilt allow fuel lo evaporare into (he aijinosphera.
A fei* driving Irips with the csp property Installed
should turn the light off.
Did you just drive through a deap puddle of water?
II so, your elocincal systam may be wet. The condition
will usually be corrected wh&n the electrical syssem
dries out. A few driving trips should turn the light off,
Have yOu recently Changed brands of fuel?
If SC, be sure to fuel your vehicle with quality fuef. See
OaSQUne Ocfane on P^ige 5-5. Poor fuel quality will
cause your engine not to run as efficientiy as designed.
You may notics this as stailing after start-up^ stalling
when you pol ihe vehicle into gear, misliring, liesitation
□ n acceleration or stumbling on aocaleratmn. (These
condilions rmay go away once the engine is wannecf up.)
This will be datoctod by the system and cause the
light lo turn on.
If you experience one or more oi ihese conditions,
change the fuel brand you use. It will require at least
one full tank of the proper fuel lo tum the fighi oil,
II the Light Is On Steady If none of the above steps have made the light turn oH,
have yout dealer or qualified service center check
the vehicle. Your dealer has the proper test equipment
and diagnostic tools to fi:< any mechanical or electncaJ
problems that may have developed.
Emission^ Inspection ând Maintenance
Programs
Some state/provindal and local govemmenfs have or
may begin programs to inspect the emission control
equipment on your vehicle. Failure to pass this inspecUcin
could prevent you from gefling g vehicls registration.
Here are some ihings you need to know lo help your
vehicJe pass an inspection:
Your veiiicle will not pass this inspection ¡I the Chock
Engine light is on or not working property.
Vour vehicFe will not pass this inspection if the OBÛ
[on-board diagnosfic) system detennines that crilical
emission control systems have not boen completely
diagnosed by ihe syslem. The vehicle would be
considérée) nor ready for inspeciion. This can happen if
you have recently replaced your baltery or if your
ЬзЬету has run down. The diagnostic system Is
designed to evalúale critical emission control systems
during normal driving, This may take several days
of rouüne driving. If you have done Ihis and your vehicle
still does not pass the tnspaction for Гаек of OBD
system readiness, see your dealer or qual'ilied service
center 10 prepare the vehicle for inspection.
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