Grasping at straws here but in my new 2020, the auto start stop doesn’t work if I am just slightly pressing on the brake pedal. I press on it enough to stop the vehicle but not until I put a little more pressure on the brake pedal will it actually engage.

 

https://static.oemdtc.com/GSB/G0000115.pdf

 

That is interesting. Most of the time I forget to disable mine via the switch. I don't like the system, but have not developed the habit of turning it off because it hardly ever actually engages. Sometimes when I am in a drive-thru of whatever and think it would be nice if it would actually work. About the only time it consistently shuts the motor off is when I pull up to my garage. About the time I go to put the transmission in park, it shuts off, then restarts just in time for me to shut it off and climb out. I find that extremely annoying, but I bet it is due to my driveway being on a hill and I am applying more brake pressure than normal.

 

Yeah, sorry, it's probably my fault considering it's a used 2018. A few years ago I explained to the internet how to permanently disable Auto Stop Start with a Windows laptop and a USB cable on these F150's. I'd check these settings with ForScan since 50% of F150 owners hate Auto S/S as much as I do and disable it on day one.

ForScan is free software and I recommend you buy an OBD Link EX to use it. It will pay for itself many times over in the long run.

If these settings check out okay, someone probably physically opened the FCIM circuit which causes the the same result and PID's effectively blocking the system from engaging every time.

Grab ForScan (free utility) or find someone with it or IDS and check this:

BCM 726-48-02: x1xx xxxx xxxx
FCIM 7A7-01-01: xxxx x1xx xxxx
IPC: 720-02-02: xxxx Fxxx

Also, with ForScan you can monitor switches in real time to make sure the circuits are okay and you can monitor all the PID's for Auto S/S in real time to narrow down a particular fault if one exists. Its very powerful open software all of us should have.

If you have no idea what any of this means, print this out, take it to a Ford service centre and they can easily check it for you 1 flat rate hour or less.

 

It should show nothing in the cluster if it was completely disabled with ForScan.

If the previous owner did not edit the IPC then it should indicate Auto Stop Start did not engage at the bottom of the display with a little greyed out icon when it attempts to work. I'm curious if your instrument cluster shows the engine and transmission temperature values above the gauges, because if it does that is an immediate telltale that someone has used software (probably ForScan) to edit your instrument cluster in the past.

 

I did notice that I could "modulate" the system with different brake pedal pressure. It wouldn't operate but I could turn the unavailable icon on with moderate pressure and turn it off with light pressure. I'm not upset it doesn't work but I'd eventually like to figure it out, thank for all the help.

 

That is exactly why I installed an Auto Start/Stop Eliminator. My driveway is on a slope and my engine would turn off while I was parking with the brake firmly depressed. Not just annoying, but unnecessary wear on both the battery and starter. Now it's turned off all the time.

 

wait, people actually want this feature to work?

 

yes my wife does. And she's up too 22.3 mpg with a 6" lift and 35" tires along with the 3.0 diesel

 

My wife's 2017 escape auto start/stop quit working a couple of years ago, I put the battery on a Battery Tender and it started working for awhile. The Auto S/S on my 2019 F-150 doesn't work unless I charge the battery, so I would assume that's your issue.