Frickin' Computer Cars, Plymouth Voyager

Flagship One
I used to use them all the time when I was still in the automobile business.
I would get a PCM/TCM/BCM from them at least once a month there for awhile.
They're not expensive, and with a little info on your end, their stuff is plug and play.
For a 98 Voyager, should be no problem.
The nice thing is they come with the latest updates and software. So if your PCM P/N ends with an AD and the most recent update is AM, don't panic, it's ok.
If you're unsure of application, or your application isn't listed, give them a call. They've repaired a couple of PCM's for us over the years.