I have a 2017 chevy camaro as well. My issue occurs when I've unplugged my phone at JUST THE WRONG TIME. Like maybe right before shutting the car off. It's most definitely a software glitch. It also occurs, because my phone sometimes has a bad connection to the USB cable. So it cuts in and out and causes the software to act retarded.
Usually, mine will reset on it's own. If I shut the car off for a good time, the software will reset. BUT, when it occurred most recently, I noticed the volume still would not increase, and still was actually getting quieter the further I turned it up. So, this time, I did everything I possibly could. I reset all factory settings in my car. I reset all radio settings too. It should erase any software you've installed onto the vehicle's infotainment system (e.g. android auto or apple auto). Then I went into my apps on my phone and uninstalled all updates for my android auto. Android auto is an app built into my phone. It will only allow me to uninstall the updates. I can't delete the entire app. If you can delete and install the app, I would do that. Once you've done all that, the next time you get in your car and plug it in, the infotainment system will ask you a series of questions. "Link all contacts? Allow device to share information?" Etc. Etc. This is what worked for me. The volume immediately went back to normal. My phone also won't allow me to project my android auto onto the infotainment screen unless it's plugged in. It's dumb. My galaxy s5 would project android auto without a usb connection. I always keep my settings in my car to "launch USB automatic" and android auto is turned on while apple auto is turned off.
I haven't tried Rush's method, so his might work as well. I know damn well thus will happen again. Hope this helps, bud.
