In theory a battery test at AAP or AZ will catch bad diodes or diode packs. Even a moderately sophisticated battery tester, like the $60 hand held one I have, will test diodes in the alternator.
What battery load test will not test, however, is a rectifier that has failed in a specific way: DC ripple smoothing. The output of the diode packs is ripple DC voltage - essentially the bottom part of the sine wave is flipped up so it looks like a bunch of McDonalds' logos lined up next to each other. The rectifier smooths this via a tuned inductor/capacitor (LC) circuit, then regulates the output voltage via a number of different means. Usually the voltage regulator part on them fails since it contains active circuitry, but it's possible that the rectifier portion failed and is outputting, in essence, dirty-ass power.
It's kind of a long shot, tbh, and I'd look at a dozen other things before I put an oscilloscope on the B+ terminal, but it seems you've done most of them already and nothing's fixed it. A load test comes up positive and you've double-checked all your grounds; there isn't much else to check, other than to start shotgunning modules and hoping you replace the right one--which would be hideously expensive and super time-consuming, by the way--or setting fire to the ****er.
Does the PCM have a dedicated ground? I don't know if it does or not, but if it does, have you checked that?
Thanks, some that is over my head lol. Biggest issue for me is I am at ~56,250 miles on it, so close to the end of warranty
I have double checked the grounds under the air box. I am not sure about the PCM but I will assume Ford checked it when they replaced it Friday. I will look at it today. I have my reservations about the dealer, auto up/down on windows still functions post PCM swap. Didn't disconnect the battery to replace the PCM? They have never reset the windows before...
The battery was tested at the auto parts store, hand held, while running and off. All was good.
I put a volt meter on the car running was my only test for the alternator, putting out 14.5 running. I don't have access to an oscilloscope
Ford initially re flashed PCM, then replaced it.
It is a weird problem:
1. Doesn't do it everyday
2. When it occurs it is within the first 5 minutes/2 miles of driving
3. When it occurs the computer cannot be scanned, say needs to be running even though the car is driving going down the road. Cannot run vehicle heath report either
4. After a few minutes of the gauges going up and down it will settle out and the airbag and traction control lights stay on. Vehicle health report can be run, tell you to go to dealer immediately. Can scan codes. Always different codes, sometimes multiple some times single: P1934, P2610, U0121, U0284, PP26DE (all codes seen since early August)
5. Turn it off and back on all is cleared. Runs fine and does not do it again even after sitting at work for 6-10 hours
Might be time to put it back to stock and hello carmax