I just recently installed an Alpine IVA-W505 and am having a strange issue.  When attempting to adjust the volume on the head unit (not using external amps, but rather the internal one) when it's at volume level 1 it's basically up full blast (not sure if it's really the highest sound level, since the speakers don't distort, but it's definitely not low) and any other volume level keeps the sound coming out the same.

The installation is on a 2008 Toyota FJ Cruiser which has a powered sub, and the complete package includes a Bluetooth module, an IMPRINT sound processor (when I found this problem I actually disconnected both of these to make sure they weren't the issue) and a PAC-7 module (this is the only one I haven't attempted disconnecting).

Could this maybe be a power issue with the head unit, a faulty ground wire or insufficient power leading to it trying to max out the sound level?  

i saw the same problem with the 205.  my only thought is that the terminal on the remote wire (for steering wheel controls) might have touch ground.  i replaced with the 505 and taped up those terminals and so far so good.