JeepJammer

Having a "No Bus" issue on my 1999 Cherokee Sport 4.0 V6.

I'll try to spare you some of the ridiculous details, but I had an overheating problem while trying to get my AC working, because apparently the front electric fan was burnt out. Got home turned it off. A while later I found I had the "classic" turn-over but no start issue that can be caused by a bad crankshaft position sensor. Replaced it with new sensor. Replaced camshaft pickup coil. Tested all relays and fuses in PDC.

I initially didn't have the "no bus" issue until about 3 days into my monkeying around with it. Can't recall if gauges worked before I had the no bus issue, but they definitely don't now.

I tried swapping the PCM with a unit from the junkyard to no avail. Still cranks but doesn't start.

I'm getting 2.4V on the Data Link Connector between pins 3 and 4, and 11 and 16.

With the battery disconnected, I'm only getting 60 Ohms between pins 3 and 11, but I think I'm supposed to be getting 120 Ohms. When I disconnect the instrument panel, I do get 120 Ohms between pins 3 and 11.

That doesn't seem quite right, based on the many postings I've read by CCKen, but I'm not quite sure if that means my instrument panel is bad, my PCM is bad, neither or both!

Anybody have some time to help me through this?

EDIT: I should have added that that I'm not able to read any codes. I don't necessarily know fully how to use it, but I do have a seemingly professional quality code reader at my disposal (genisys spx otc). When I used it to scan the bus, all it seemed to find was the Airbag control module. I don't have SKIM or an overhead control module. When I used it to read live data though I was getting changing numbers for the Camshaft and Crankshaft sensors, if I understood what I was reading correctly. The camshaft sensor was from the junkyard, too. I have an old oscilloscope too, but I've only used it for some electronics tinkering...