Chevrolet 2011 Volt Owner's Manual page 142

If the malfunction indicator lamp
comes on and stays on, while the
vehicle is in ON/RUN, this indicates
that there is an OBD II problem and
service is required.
Malfunctions often are indicated by
the system before any problem is
apparent. Being aware of the light
can prevent more serious damage
to the vehicle. This system assists
the service technician in correctly
diagnosing any malfunction.
This light comes on during a
malfunction in one of two ways:
A misfire condition
has been detected. A misfire
increases vehicle emissions and
could damage the emission control
system on the vehicle. Diagnosis
and service might be required.
The following can prevent more
serious damage to the vehicle:
Reduce vehicle speed.
Avoid hard accelerations.
Avoid steep uphill grades.
If the light continues to flash, when
it is safe to do so, stop the vehicle.
Find a safe place to park the
vehicle. Turn the vehicle off, wait at
least 10 seconds, and restart the
vehicle. If the light is still flashing,
follow the previous steps and see
your dealer for service as soon as
possible.