Car Stereos: failure message, sony xplod, pioneer speakers

Question
hey man im just wondering...when i first hooked up my system-(sony xplod head unit...4 pioneer speakers and 2 mtx 12' subs with an amp already in the box) it sounded great and my subs were louder than ever. Now a year and a half later my subs sound shitty and arn't that loud. My head unit shows an error message whenevr its turned on, but goes away when i hit any button, it did that ever since i hooked it up. I'm just wondering if there's anything i can do to make my subs loud and heavy hitting again.  Thanks -Tyler

Answer
Tyler, the sound issue shouldn't be too hard to repair.  There is probably a loose wire somewhere that needs to be reattached.  Check all of your connections going to your subs (all the way from the radio), and you should find the problem.  Hope this helps, Scott