Hello everyone.....I've done the search on this forum for posts relating to PCM replacements. But I still have a question....how do I know what part number to get? The number on my old PCM said "3W4A-JJ replaces 3W6A-BJ." But I can find both part numbers online. And I'm finding many of the same part number but different letters after the last dash i.e. 3W6A-12A650-AA vs 3W6A-12A650-BJ. How do I know which one I need? Thanks!