Junkyard Engine Computer Issues

I think the PCM (powertrain control module) in my 1998 Grand Voyager,
3.3L w/anti-theft is bad, and I'd like to swap in one from a junk yard.


In reading what I can find on the net, it seems like this should work.
It sounds like there are problems with the BCM (body control module) if
it does NOT have the anti-theft option and the replacement PCM DOES.
But I do have anti-theft, so it sounds like if I get a non-anti-theft
PCM it will not damage anything.

However, I'm wondering about my VIN number and odometer readings. Will
those come from the junkyard PCM? If so, how can that be corrected?

It would be worthwhile to me to verify that the problem is the PCM by
swapping in a used one, even if I have to buy another one from the
dealer or pay to have the junk one reprogrammed.

The junkyard PCM's can be had for ~$100, sounds like one from the
dealer will cost many times that.

I think my PCM is bad because it behaves erratically even when I just
turn the key on, with the ASD, fuel pump, and purge valve relays
clicking wildly.

Battery is good, cranks well and measures 13.4V after charging. Cleaned
battery cables, checked fuses, reseated power distribution and PCM
connectors.
-Paul