ECM troubleshooting

[vilant]

Thought I'd ask for the collective's help on this.
So, I'll start from the beginning, provide the symptoms, what I've done to correct, and where I'm at.
So it started over a year ago, I would get an intermittent Code 31 on the ECM (cam sensor missing or too many pulses). So I ordered a new cam sensor and replaced the old one.
Problem persists but doesn't occur as often. So, I clean up all ground connections to frame and bell housing. Problem still persists.
It was mentioned that the ECM may be bad and when rebuilt it will go away. But first it is recommended to replace the battery, as the battery absorbs a lot of electrical noise, and if it's on it's way out, it may be the culprit (plus it's cheaper than a new ECM). Replace battery, problem still persists but happens even a little less often.
So, I finally bit the bullet and sent my ECM for repair. My ECM tested bad and was previously reconditioned. The future is looking dark. Jerry lent me his personal, spare ECM. I hook it up and when I turn key to "run" the radiator fan immediately comes on (which is weird because it never did that before) when I "start" the car, it turns over, is idling really high, the "service engine soon" light comes on, and I see "SYS" flashing on LCD. So, I turn the car off and go into diagnostic mode. I now have a Code 41 on the CCM (loss of ECM serial data communications). WTF!!
So I go to the diagnostic tree of Code 41 and start following the procedure



I do as directed. Tear apart the interior to access the CCM (really f***ing fun let me tell you) to test connection between WC13 and B15. I get an open.
Now," how the hell did that happen" I'm thinking. My ECM worked except for the Code 31 issue. How did I lose it?
P.S. side note. Follow the diagnostic tree above, notice "If problem is not located, see Diagostics Aids on facing page. Here's a pic



Pretty funny...TBD???
Anyway, that's where I'm at. I did a little digging on Solutions and I found Tccrab's issue where the ECM pins where bad and that was causing his gremlins. So now I'm thinking maybe bad pin connectors. I keep on looking on Solutions and I see the '90 pin diagram. here's the link
http://www.zr1.net/forum/showpost.ph...8&postcount=10

Notice how B15 and B20 are listed as not used, yet the diagnostic tree I have, has me testing those very same pins for continuity. I checked, there's no wires connected there. Again WTF!!! No wonder I have no continuity. The diagnostic tree and facing diagram show B15 & B20 as the serial data connection, yet there's no wires connected (please don't say it works wirelessly, lol).
Can someone look at their FSM and tell me if the Code 41 CCM procedure is the same? Or snap a picture for me. I want to A) make sure my FSM is correct, and B) to check continuity on the serial data line to make sure I have a good connection. If I do, then my CCM is probably bad too
Any thoughts or ideas are greatly welcomed and appreciated.
Thanks, Joe