Volvo vnl Multiple ecm's problems out of nowhere

Hello again, hope I'm not to late. This is where it gets tough and "interpretation" gets tricky. Let me just state a few "ground rules" here and glancing at your pics, I have a few questions since I'm not really familiar with nor an expert on your vehicle. When you say the words "don't have continuity 0.00", depending on the scale, my meter would say "open" or wouldn't register anything. 0.00 is perfect continuity, setting it to the diode setting on the meter, you should also have a "tone" as long as you do have continuity. The 120 ohm measurement your getting is a "terminating resistor" reading present in all CAN systems and is a "good thing". A part of troubleshooting CAN databus is "isolating the system" that is producing these faults which you vary well may have done, T-CAN. This is where a diagnostic computer is invaluable and in my opinion a must and this is why; when isolating systems you first need to know what items are involved with each "trunk", in the process (powering up/powering down) of isolating these items you will generate codes which need to be cleared. Explanation!!!- The system generating the fault will be active (which is you problem to begin with), when you isolate that system (disconnect), your code will go "inactive" but in that process you've now generated more codes that you need to clear before you continue on with your troubleshooting, I can't help but think something in your mind made you go straight to the transmission/shifter (good intuition). You hook the component back up and your codes go "active" again. Now your at the game.... is it components or wiring or both within that system. I have a question about your seat? does it have an "operators presence" switch underneath it somewhere? Again I can't reiterate the importance of a computer for these type issues. You really don't know what the "lead" code is to begin with, hope this helps because I'm just getting started with the abc's.

 

Have you considered that there has been some rodent that may have eaten some of the wiring. At 100k and being 14 years old, it sat more than it was used, so it could be a problem with a bad harness or two.