the front/rear rcas are 2 volt.
the sub RCA reaches 4V at vol 30 or 31 or something with the sub nonfader volume at +3 or something like that. i tested them repeatedly with an o-scope and a 40hz tone.
He's right. We install a ton of these Clarion DVD decks at my shop. They are very good decks. I have the double din version (MAX675VD) and love it. The rest of my system consists of the JL HD 600/4 running Focal K2 Comps in all the doors, and a JL 1000/1 amp running two 13.5" JL W3v3 subs.
The deck you are looking at is a solid deck. I've yet to hear any customers complaining of any issues with them, or see any warantee return issues (except for one when a guy's wife manually forced the screen closed and broke the motor on it, while it was powered off. Hahaha) The 2 volts front and rear also concerned me as I was switching from an 8 volt preout Eclipse deck to this one, but to be honest, I really have not noticed any difference other than having to adjust my amp gains a little higher. Jigga is right about the non-fader voltage, put the non-fader at +3 or more and you'll get 4 volts from it. (I have mine at +5 and also have a Bass amp RCA (line level input contol) volume knob to turn up or down the bass to my taste.
Hope this info helps.