QUOTE(01 Ultra @ May 29 2008, 01:35 PM)

I'm not positive, but all of the electrical items (clock included) should run off of your main car battery. I've not heard of the clock having a seperate battery just for itself.
You can get your battery checked at any parts store to see if it is still good. If it's not, the clock may run a bit slow. I would think that you would also be experiencing other electrical problems if this was the case (hard to start, dim lights, stalling, etc..)
my lexus repair manual says to change battery?? but does not give location....maybe somewhere behind the clock