Got an intermittent charging issue I'm trying to isolate, wondering if anyone has any thoughts on.
2015 AWD w/ 110k miles, only 50k miles on the engine (dealer replaced)
Started on a cold morning a couple weeks ago when camped out in the middle of nowhere far from cell svc. Got a charging system dash message throwing DTC P0625. The message warning light went away after a few seconds. I grabbed my meter to check voltage and current going into the battery both were reasonable.
I couldn't reproduce the error and it didn't happen again, everything I checked over the next day or two seemed fine. Fast forward to the next camping trip and it happened again. This time, it was below freezing and the error would not go away. I only did a couple basic checks as we were hooking up to leave in the middle of a snow storm and wanted to get out before getting stuck there for a few days. I ended up pulling the 3 pin connector to test the alternator in dumb mode and it engaged at the fixed voltage. Left it that way and towed our trailer 4 hours home with no issues -- electrical system was rock solid at roughly 13.6 volts the entire time.
Back at home, the only way I can reproduce the error is by letting the explorer sit overnight and it'll *sometimes* happen in the morning. Seems to be more consistent if it's < 50 degrees.
I replaced the battery, didn't have a ton of confidence in it, and it was due. Other than that, I've done the voltage and resistance tests on the alt and wiring listed in the manual. I haven't reproduced the issue when hooked up to forscan, but I did this morning see that it took a while for the alternator to react to the ramp up. The image on the left is from a start yesterday morning and seemed normal. The image on the right is from this morning, it didn't throw a DTC but you can see the alternator didn't respond to GENCMD and it was 10-15 seconds or so after engine start before it started charging.
When I do reproduce it, it'll either clear on it's on after 15-20 seconds or just turning the engine off and back on again will fix it.
I'm thinking wiring rather than alternator based on what I've seen, but I can't find a fault... I'm perfectly happy to take it to a dealer to get it fixed, but I'd like to have confidence it's actually fixed rather than just throwing parts at it.
Any thoughts / suggestions?
