You back up and running?
Yessir, I am indeed!
I got it back unchanged last
Thursday after the service techs at the dealership spent that previous 4 days trying to recreate the issue and couldn't. I knew it would be just a matter of time until it occurred again, but I wasn't sure how long it would take.
Well, it faulted on me this last Tuesday morning while heading into work. I pulled over and killed it and restarted to see if it was going to stay in fault, and at first the battery light wasn't coming on immediately after the restart so I figured I would just continue on my way. But then it did light up after a mile or so of driving, so I knew this could be The Time
(to take it back, that is)
I pulled over 2 more times and stopped/started it, and the same behavior persisted (not in fault at first but faulted after a short distance of travel/engine run-time) So I figured surely they would be able to recreate it themselves this time, and I drove it straight to the dealership to drop it off for them to take another shot at it
They were able to recreate it this time, but not after some trouble at first it sounds like. Actually to hear the tech tell it, this latest attempt at diagnosing was off to a rocky start again when they couldn't get it to fault until leaving it running for 25 minutes straight. Then it faulted and he started his diagnosis.
That lasted into today, and he was on the verge of declaring the PCM to be the problem (internal VR) when he decided to do an up-close inspection of the wiring harness plug which connects to the alternator itself. Turns out that plug had corroded some, and while it wasn't bad enough to make the P0620 fault happen every time the car was started, it was bad enough to make it happen intermittently.
So the final fix was for him to cut the plug off that plugs into the back of the alternator and solder in a new one. And that did the trick...at least it has so far, which is what they also said about the new Mopar alternator, so anything's possible I suppose, but I actually believe this will fix it for good myself too...so we'll see.
Now if I could just get my ass-groove reset...