Thanks Paul. I'll talk to the folks at my Lexus dealership. I took the RX in last month with a couple of stuck CDs and the infamous Error 4 and, just as predicted in this forum, they said I needed to replce the entire unit. Since I'm not THAT much of an audiophile, I'm not doing it. I took the advice i found on this forum and got the stuck CDs out and haven't had an Error 4 since. This may be a related problem but, like I said, it's not life threatening and it's really amusing to try to predict whether the radio will be on or off.