So I'm chasing the no start/no bus problem on the newly acquired 2000 Durango. I have bus bias and the bus is not shorted (although the resistance doesn't match the web site I found, but maybe it changed at some point). Anyway, my PCM has both 12v sources and is providing both 5v outputs, BUT the ASR isn't switching. I have continuity between the relay and the PCM, but never get a ground. I am assuming that any time the PCM is powered up, the ASR feed should be grounded. Can anybody confirm this? Does anybody have a spare 2000 PCM for a 5.9?

My mind tells me that the ASD relay should"click" in at the first instant you turn on the key to "run". That primes the fuel system pressure.It only stays engaged for about 1 second. Then when cranking, the PCM needs to see an input from the cam sensor to "re-engage" the relay so it will start and run.
The "cam" sensor is the pick-up plate inside the distributor.

No, the fuel pump relay only comes on for a short time. The ASR should be on all the time, I think. I'm not getting either one.

Sounds like you may be right. More to check.

Ok, the PCM is not supplying the ground for the ASR for any length of time or during cranking, so it must be a bad computer since I have ground everywhere I'm supposed to on the PCM. I looked at the wiring diagrams and it appears likely that the 96 PCM I have would at least fire the engine if the PCM is the problem. Then on Monday I can see if the shop I got the Durango form can warrantee the PCM they just put in a few months ago or I'm looking for a used one.

Have you tried grounding the circuit to energize the relay just to see if it'll fire up? I would..

asd relay does not stay powered up.Did you pull the relay and make sure you have 2 12v power sources?.1 with key on power and 1 with battery constant power.yes, ecu controls ground circuit of relays.make sure you have 2 power sources at the relay.

"moretoys" is right that you should have two 12 volt sources at the shutdown relay. One hot all the time and the other will be hot with the key on as was stated.
The PCM will turn the ASD and the fuel pump relay on for about a second when the key is turned on. It will work both the ASD and Fuel pump relays as they share the same ground provided by the PCM. You can see if look at the wire diagrahm and see that the ASD and fuel pump relay ground wires splice together and go to one pin at the PCM. The PCM must see the Crank sensor and Cam sensor signals to turn the ASD on and keep it on once the eng is cranked.
A scanner really makes this so much easier as you can have the scanner comand the PCM to turn the relays on to test them but without a scanner you have to do it the hard way. You can check for power at the injectors while you crank to see if the relay is working. But if its not then you will need to check the basic componets that cause the ASD relay to turn on like the crank and cam sensors.
I like to moniter the ground circuit for the ASD and fuel pump relays. You can just use a digital voltmeter and tap into the asd ground. When you crank the eng it should go to right about zero volts but if it stays near 12 volts then the PCM is not grounding the relay. You could even have somone ground the asd ground for a second while cranking to see what it does. I have done this before but was using a scanner as it told me more info when I supplied the ground myself to se what it did. Some engines will start without a cam sensor signal if the eng is cranked long enough. The PCM will start trying different fireing orders to work the injectors if it does not see the cam sensor but all else works. But you need to see just what the ASD is doing. Thats why if you tap a voltmeter into the ASD ground that the PCM supplies you can watch the volts.
When you turn the key on the volts should go to 0 for a second and then to 12 as that is the relay turning off. Then when you crank it should go to 0 if the ASD relay turns on. If it stays at 12 while cranking then you have to figure out why the PCM is not grounding it.
Do you have any scanner at all to use while you are working on it. Ron

Yes, I have both 12v sources. The PCM is not providing the ground for any length of time. I am going to substitute a '96 PCM (I've aleady confirmed the important connections are the same - a couple of the 2000 circuits are not in the PCM, but they don't appear to be important for the test) just to see if I get the ASR and fuel pump, maybe start it. I also need to make sure that the ground pins in the connector to the PCM are making contact. That would kill everything, but considering that I also have a "no bus" condition and no communication with the scan tool I figure the PCM is bad.

Yes, I know. I had the meter connected and sitting against the windshield when I turned the ignition on.

Jim, I have seen this problem on several different Dakotas. It's always been a shorted out o2 sensor. PCM sees the short and shuts down the ASD relay. I would start by disconnecting the o2 sensors. And please dont fry my 96 PCM, I will need it back someday.

Yeah, it's not that. IT is the PCM. I've actually got two here and I think yours is the one in the baggie, which is not the one I tried. It runs on the spare 96 which has all the same critical circuits. Now the hunt is on for a spare 2000 PCM. The one I have is "rebuilt". They used a hole saw to remove part of the back side to replace something.

Brad, he lives in the trailer park at the end of Hickey at El Camino. Like I said, I've got two here. I believe yours is the one that has writing on it, but I may just send both with him and you can confirm (or let me know the part number if you've got it).

Jim, heres the part number. 56040766