Chevrolet 2011 Volt Owner's Manual page 143

An emission
control system malfunction has
been detected on the vehicle.
Diagnosis and service might be
required.
The following may correct an
emission system malfunction:
Check that the fuel cap is fully
installed. 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 the electrical system
is not wet. The system could
be wet if the vehicle was
driven through a deep puddle of
water. The condition is usually
corrected when the electrical
system dries out. A few driving
trips 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
or misfiring. 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.
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.
Some state and local governments
have or might begin programs
to inspect the emission control
equipment on the vehicle. Failure to
pass this inspection could prevent
getting a vehicle registration.
Here are some things to know to
help the vehicle pass an inspection:
The vehicle will not pass this
inspection if the malfunction
indicator lamp is on while the
vehicle is in ON/RUN, or if the
vehicle is placed in Service
Only Mode and the malfunction
indicator lamp does not come
on. See your dealer for
assistance in verifying proper
operation of the malfunction
indicator lamp.