Main computer replacement? Dodge neon 2001

What is your question?

I am trying to buy a car that the person is not totally accurate with which "computer" in the Dodge neon 2001 needs replacing. He said he took it to a shop and they said it would cost around $350 range to fix the problem. When I asked which code or which computer sensor exactly it was that it was that needs replaced he has no idea! As he is not from around here at all. Does ANYONE know which computer this could be?