Battery indicator came on followed by the giant battery on the display. Lasted about 30 seconds than disappeared. Drove home 50 miles no issue. Next day it came back and my voltage was 11v. Tried to pull out if my driveway and car felt sluggish steering felt hard to use.

Changed the battery and nothing changed.

I checked fuse 45 after some researching and my car doesnt have a fuse 45.

I seen a guide with how to test a few things but I can't reach the terminal at the top of the alternator without removing it. Is there a next step or anything I can do to confirm it's my alternator or something else? Otherwise tomorrow I'll have to pull the alternator and replace it.

2012 f150 5.0 Lariat

P0625 code
u0422 afterp driving home and the voltage dropping to 11v before turning the car off

 

https://www.f150forum.com/f4/p0625-g...575723/index4/

 

That thread is exactly the same circumstances as what happened to me. However I have changed both battery and alternator and the problem persist.

Battery indicator is on.
When pressing the gas as soon as you let go the car stutters. The voltage drops from 14.5 to 13~ then returns to normal.

 

You reference code P0625. The code doesn't automatically mean the alternator is at fault. It could be a wiring issue and there are case examples of the communication lines breaking near the right front frame/wheel well area.

P0625: Generator Field/F TerminalCircuit Low
The PCM sets this DTC if the GENMON circuit is shorted to ground, the "A" sense circuit is open or the B+ circuit is open. This DTC also sets by a faulted PCM or generator.

BTW, alternator voltage will vary. It's part of the "smart charging" system that Ford has been using for years to add that fraction increase of MPG.

 

have you done a thorough inspection, cleaning, tightening of cables, terminals and grounds?

if you have what brand alt did you get? in my experience (personally and hearing:reading of others) the main failure on typical alts / reman alts, is failure of the voltage regulator (part of, comes on the alternator). if you feel you’ve done everything thing else, i’d be tempted to try another alt (especially if you got a big box reman) before going too far down other rabbit holes (or spending diag money at a shop).

please update thread as you go and ultimately share the solution. good luck.

 

I had the oem alternator repaired at Napa.
When I first checked the car tbe positive terminal had a good amount of blue corrosion.

Ive wiggled everything made sure nothing was loose or obviously damaged.

after a little trial and error I notice the truck is sitting at 14.7 when running. When I tap the gas, a moment after its released the voltage drops about a point and tne car stutters. If I do this with the fan running the voltage drops all the way to 13 and the fan gets noticeably weaker and the car stutters. All for half a second. This never used to happen.

I have a multi meter. But the directions ive come across for what to test are confusing and I dont have any experience using it

 

id take it back. OR try buying/trying a different one. think it’s a real possibility that the VR passed their bench test and they just reused it (note in my thread, that my old alt passed multiple alt tests, including on napas equipment… but the alt was in fact the problem ).

 

Gonna bring it back and get a new one tomorrow instead. However after more searching I found videos showing how to test continuity between the alternator plug(3 pin) and the connector on the pcm. Assuming the video isnt mistaken my yellow wire isnt making a connection to the pcm. So im going to try routing a new wire for it.

In case anyone anyone knows, I connected the yellow wire to the left most pcm in the second row (from the top) in the 4th pin. I also tried all nearby pins. So hopefully thats the right one.

Also doesnt anyone know which color wire in that pcm connector is the one connected to the yellow on the alternator





Edit.: i can probably figure it out but I can't figure out which circut number corresponds to the left most connector

 

Bump in case anyone has any input.
so far:
cleaned the terminals
Checked every single fuse
Checked the 125/250a fuses
replaced the battery twice
Replace the alternator twice(second time oem)
checked continuity in all 3 wires coming from the alternator (all good)
Replaced all those wires anyway

The car is now at 13.8v at idle. Everytime I let off the gas the car stutters or even stalls. Usually the voltage drops when this happens by about 1v.
please help

 

Here are a few prints from a 2013 manual, maybe they will help.