When you throw a CEL code it automatically turns the VSC off, I'd go to a local auto parts store and get the code read, then go from there.
I have a 2003 LX470 with the exact same issue (VSC TRAC, VSC OFF and Check Engine lights on). Can the Lexus dealership help with the CEL code? I also see a posting below suggesting that a gas cap problem could be causing this issue. Rooney - please let me know if you are successful in resolving this issue. Thanks!