Please give me some advice here.

Im trying to get a combination of PCM and wiring harness to work in my truck. Ive done a few different things so far.

QUESTION: Does the body computer communicate with the PCM to determine whether itll start or not, or throw a "no bus"?

I am putting the 5.2 into my 2000 4x4 Dakota. Now, Beginning in 2000 Dodge stopped offering the 5.2 in the Dakota in place of the 4.7. I am just hoping that it will even be possible to make it run correctly because the 5.2 was not an option for this year.

They say you are supposed to get a PCM from the SAME YEAR truck as yours, but obviously I cant do that.

The Harness Im using is from a 99 durango.

-The PCM from the same 99 durango as the motor and wiring will NOT start the truck. I even bought a reman PCM with the Durango VIN thinking it was just a bad PCM. But no go. Neither PCM will fire.

-I picked up a PCM from a 98 Dakota, and that will fire right up and run beautifully. The part that confuses me about this is after about 20 seconds or so the "no bus" comes on. Which I thought ment a bad pcm but obviously it isnt.

I wanna say with no real certainty, that the problem lies somewhere within the connection of the Engine wiring harness, into the Fuse Box portion of the Body harness. I compared the clips from the 5.2 and 3.9 harness, and the 5.2 harness has more wires, some of which are in different spots on the plug.

The one 8-wire plug that goes into the tranny is also different. They both have the same wires, but again the place ment of them in the plug is different. I think this is because one harness has the 42re tranny(3.9) and the other had the 44re(5.2). This throws a CEL saying im getting no signal from my tranny whatsoever. Perhaps this is why at operating temp, my overdrive will lock off, and the TRANS TEMP light comes on?

Im trying to figure out my next move. Do I..

1. Look for a 5.2 harness from a 98 Dakota and swap that out?
2. Get another 3.9 harness and try wiring in injectors 7&8?
3. Try getting a PCM and harness from a 5.9 2000 Dakota? (I dont believe any of these had 4wd tho, how would that work if I needed to do it?

Im leaning toward gettin a 98 Dakota harness, so all the pinups from the harness to the PCM would match. I just hope the fuse box plug will be the same as my 3.9 harness.

I need to get this figured out. I hope I didnt ruin my truck! (I already sold the 3.9 motor too)

 

Find a harness from a 99dak or 00rango and use either pcm, they should work as long as you have the correct harness to that specific PCM.

 

Is their really that much of a difference between a 99 Dakota, and a 99 Durango wiring harness?

After some thought, Im really leaning towards picking up another wiring harness out of a 2000 Dakota(Sold the old one already) and wiring in the 2 injectors. That should work shouldnt it? Im still confused as all hell about the "no bus" though. Because, when I hook up the 3.9 PCM, the truck runs, not great obviously, but the nobus doesnt display with that PCM. That would mean that the truck knows which pcm is in it, am i wrong?

Edit:
What if i tried a PCM out of a 99 Dakota? Since it fires with Dakota PCM's but not Durango PCMS.

 

Im thinking about giving up on this, and selling the truck as is. I cant figure out whats wrong. Im using a PCM and wiring harness out of a 99 Dakota, and im still getting nobus.

How does the truck know what pcm is in it? And how can i make it so it accepts the new one?

Anyone with an idea please... *begs*