crank and cam sensors

My svx wont start. It cranks but will not start.
I replaced the alternator (had it checked and got a free one on warranty) and it started after some hesisitation. It drove fine and started fine that night. The next morning it would not start again.
I checked the codes and got #13 Crank sensor #2, and #29 cam position sensor. Is it likely that both sensors would go bad at the same time?

Is there any thing that they have in common that would cause them to give me these codes?
Thanks for any help.