Originally Posted by ala_xfire

Yes, the engine will turn over with a bad CPS.
You really cannot heat shield it, it mounts to the engine block just above the flywheel, so any engine heat will be conducted to it regardless of what you do.

The CPS is just a rod magnet with turns of wire wound around it. Think of it as a mini-generator, as the flywheel spins below it, it is excited by either a notch or a high point ( not sure which ) in the flywheel once per revolution. This signal is monitored by the PTCM and is used to set the base timing. The camshaft position sensor is then used to tell the PTCM the EXACT engine position, then it consults it's magical programming and factors in all sorts of other sensors to arrive at when to fire the plugs.

The camshaft position sensor is a "Hall Effect" sensor, means it has a transistor in it that is triggered by a magnet in the passenger side camshaft.
The CPS, or crankshaft position sensor is a "reluctance head pickup" in industry terms, means it has no electronic parts, just a magnet and coil.

We have found that the non-Bosch CPS sensors from China seem to have thinner pins for the harness to connect to, therefore the connection is not as secure.

NOTE: There is a guard shield around the CPS mounted by 2 of the bell housing bolts, it you remove this shield you will have much easier access to replace it.
This is however an extra step that many prefer not to do. ( Put the shield back on when you are done )