GMC 2012 Terrain Owner's Manual page 131

The following may correct an
emission system malfunction:
Check that the fuel cap is fully
installed. See Filling the Tank on
page 9 58. The diagnostic
system can determine if the
fuel cap has been left off or
improperly installed. A loose or
missing fuel cap allows fuel to
evaporate into the atmosphere.
A few driving trips with the cap
properly installed should turn
the light off.
Check that good quality fuel
is used. Poor fuel quality
causes the engine not to run
as efficiently as designed and
may cause stalling after start-up,
stalling when the vehicle is
changed into gear, misfiring,
hesitation on acceleration,
or stumbling on acceleration.
These conditions might go away
once the engine is warmed up.
If one or more of these conditions
occurs, change the fuel brand used.
It will require at least one full tank of
the proper fuel to turn the light off.
See Recommended Fuel on
page 9 54.
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
Some local governments may
have programs to inspect the
on-vehicle emission control
equipment. For the inspection, the
emission system test equipment
is connected to the vehicle s Data
Link Connector (DLC).
Instruments and Controls
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.
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