Chevrolet 2013 Express Owner's Manual page 125

If one or more of these conditions
occurs, change the fuel brand used.
It may require at least one full tank
of the proper fuel to turn the light off.
See Recommended Fuel on
page 9 42.
If none of the above have made the
light turn off, your dealer can check
the vehicle. The dealer has the
proper test equipment and
diagnostic tools to fix any
mechanical or electrical problems
that might have developed.
Emissions Inspection and
Maintenance Programs
Depending on where you live,
your vehicle may be required to
participate in an emission control
system inspection and maintenance
program. For the inspection, the
emission system test equipment will
likely connect to the vehicle's Data
Link Connector (DLC).
The DLC is under the instrument
panel to the left of the steering
wheel. See your dealer if assistance
is needed.
The vehicle may not pass
inspection if:
The malfunction indicator lamp
is on with the engine running,
or if the light does not come on
when the ignition is turned to
ON/RUN while the engine is off.
See your dealer for assistance in
verifying proper operation of the
malfunction indicator lamp.
Instruments and Controls
The OBD II (On-Board
Diagnostics) system determines
that critical emission control
systems have not been
completely diagnosed. The
vehicle would be considered
not ready for inspection.
This can happen if the 12-volt
battery has recently been
replaced or run down. The
diagnostic system is designed to
evaluate critical emission control
systems during normal driving.
This can take several days of
routine driving. If this has been
done and the vehicle still does
not pass the inspection for lack
of OBD II system readiness,
your dealer can prepare the
vehicle for inspection.
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