PCM - powertain control module. Controls the engine and trans and receives inputs from many sensors, like the O2 sensor, RWAL sensor etc. I would have to find my manual to help you further but I would work backward/upward.

Start at the trans external connector (round connector - enters the trans on driver side behind shift linkage). Be careful taking all these connectors apart and putting them together as some of them have very small pins and are easily bent.

Work your way up. PM me if you hit a road block and I can try to send you some screen shots of a schematic.