The subject vehicle is a 98 Pontiac Grand Prix.
Serpentine belt failed, possibly due to a tensioner that was getting 'gritty' on the swing bearing.
The car is at the 'bus' mechanic shop, and after a new belt was installed (not sure about the tensioner yet), the engine won't start.

Any advice or experience on the 3800 Series II if a failed (or flailed) serpentine belt could take out the crank sensor? I'm supposed to see this vehicle with my own eyes early tomorrow, so I'll let you know what I find then.

The owner tells me the shop is calling for a new crankshaft.
Couldn't possibly be that, could it?

PS: The owner bought the car on my advice 2 days before it broke down!
PPS: I noticed the suspect tensioner and did not say anything about it during the pre-purchase inspection. It was a private sale.

Its possible the belt nipped the CPS sensor. Or the harmonic balance got out of whack and that is what he'* suggesting be replaced. Not the crank itself.

or the wires/connector to the crank sensor, or icm

After a look and a short discussion with the mechanic, here'* the scoop.
1. Serpentine belt broke and was wrapped around the crank pulley
2. There is no visible trauma to the CPS or electrical wiring
3. I tried moving the wiring connector to the CPS and everything seemed firm and tight; the CPS did not seem to be physically broken
4. There is no signal coming from the CPS as reported by the PCM

The mechanic is going to replace the CPS and see if that fixes it.

This could be an expensive ordeal, even though the mechanic is only charging a budget rate of $60/hour and 20% premium on the parts...

I'll let you know how it all goes, and how it turns out.

He only needs to remove the harmonic balancer to replace the CPS. Not really a big deal especially if he has the proper puller to do it with.