Chevrolet Volt 2013 Owner's Manual page 236

9-50 Driving and Operating
If the vehicle is plugged in and
vehicle power is on, the CSI will be
on solid green. The same is true
during a remote start if the vehicle is
plugged in.
If the vehicle is plugged in and the
CSI is off, a total utility interruption
using OnStar or a charging fault has
been detected. See Utility
Interruption of Charging or Charge
Cord Status Indicators in the
charge cord user guide.