Try this from page 62 of the PDF Infotainment Manual.

Radio Settings
Press the Config button on the Home Page or the CONFIG button on the faceplate to enter the menu options. Turn the TUNE/MENU knob or touch-tap the scroll bar to scroll through the available options. Press the TUNE/MENU knob or press Radio Settings to display the radio settings menu. Press this feature to make changes for radio information displayed, preset pages, Auto Volume Control, and XM Categories Restore.

Startup Volume: Press to set the maximum volume level for startup that will be used even if a higher volume had been set when the radio was turned off.

 

The startup volume is where I'm at, but when I try to increase it I get a message saying Limit Reached. It's only at about 20%. I can't figure out how to get it any higher.

 

That's it. The idea is to prevent you from getting blasted by high volume when you turn on the radio, not to allow you to blast yourself with high volume when you turn on the radio.

I'm not sure if the 2013 is the same as my 2012 ... I don't believe there is a preset option in the config menu for the radio audio volume.

It's not the same, and there IS a configuration to limit the volume at which the radio turns on.

Config/Radio Settings/Auto Volume
You have a choice of Low, Medium, or High on MY 2012

Not at all what he's talking about. You're referring to speed-sensitive volume, not the max-volume limit.

 

I'm not sure if the 2013 is the same as my 2012, but are we talking about the radio audio volume or the futuristic sound that is played when starting up or shutting down the car? The radio auto volume should remember the volume you last left it at. I don't believe there is a preset option in the config menu for the radio audio volume. This maybe different in the newer models.

If it is the startup/shutdown sound we are talking about, that can be adjusted in the config menu (which is where I think you are at in the config menu) and also while that sound is being played at startup and shutdown by adjusting the same volume knob as the radio while is making the sound. The volume knob is context-aware.

 

Config/Radio Settings/Auto Volume
You have a choice of Low, Medium, or High on MY 2012

 

Sightly off-topic, but has anyone noticed that the speed-sensitive volume ramps up faster than the interior noise of the Volt as you go faster? I sometimes find myself backing off the volume at highway speeds. Maybe there is an adjustment for that as well.

---- I see now that JetPIC seems to have answered that as I was asking it.