I own a 2016 Ford F-150 with about 118,000 miles. When I initially purchased it, I was unaware that it featured an auto start-stop system, which, as it turns out, has never functioned during the four years I've owned the truck. Whenever the system should engage, the dashboard displays the auto start-stop icon with a line through it, indicating it is not working. I've had Ford technicians test various components and even installed a new battery, but they have been unable to diagnose the issue. One suggestion from Ford was to add a trailer brake controller, but other mechanics I've consulted have assured me that this shouldn't be necessary and wouldn't resolve the auto start-stop problem. Given that even Ford's mechanics are stumped, do you have any advice on what I might try or check next to get this feature working?

 

Welcome, I would go to the appropriate 2016 forum and look for the post their related to Forscan and see if folks their can tell you what settings to look for. Quite possible it was turned off by the previous owner, but I would think that if a Ford dealer put it on their IDS system, they could see it was turned off.

 

Mine will tell me why it is off, does yours?

I did notice when it was time for a new battery it would quit working and there is a specific procedure to follow when installing a new battery to reset the battery monitor.

 

You bought it used? It could be anything the previous owner did. If everything else works, I would forget about it. *** is PITA.

 

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Be sure to consult your Owner Manual pages 172/173 to be sure your not doing something to cause A S/S to be inhibited.
The whole system consists of many working parts all of which must be fault free or it inhibits the system from working.
To touch the high points;
Battery voltage must be above a Min state of charge..
Transmission aux electric fluid pump must be fault free.
All parts of the electrical chain in a fault free condition.
Brake Pedal switch adjustment etc.
Since you can't supply any data such as Codes set, we cannot even get close to the cause.
The Dealer should have found some fault code to point to the issue by performing tests on the system to see what is not functioning.
The Body Control Module conducts the auto start operation and has it's own monitor to see faults.
If there is any detected, the auto function is inhibited.
In the Body Control Module is a Voltage Quality section that involves a DC to DC converter that supplies at least 5 other separate Modules that must be employed for auto start. If the voltage is too low for these to function, there will be system failure so the DC to DC Converter is used to boost voltage fed to those Modules at Cranking time.. However, if the overall system voltage is to low as detected by the Quality Module of 1 volt or more , the system will still be inhibited.
As you can see, the system is complex.
Leading me to think your Dealer is a bit down on competence to handle the issue or it has been Hacked out before you purchased the vehicle.
Take a look at the Sensor located on the Battery Negative Terminal or the Ground cable for being disconnected. This will also be a cause for system non-function.
Sorry to be so in-depth, but its not a simple function.
Good luck.

 

4 years not working. My guess, previous owner put a jumper behind the switch on the dash to disable it, or disabled it with Forscan (software program). I have a plug in module to my obdii port, some unplug the bcm wire at the battery (not a good idea), and some unplug a wire down by left foot that disables trailer lighting, and also the AS/S. Long story short, there are several ways to disable, Dealer battery boy likely not well versed on the practices.

 

This^. The service manual assumes the truck hasn't been modified by a previous owner, so it doesn't tell the mechanic to check all these possibilities. You will have to do it yourself. If it's not any of these things, it could be disabled in Forscan, or the battery could be too old to charge sufficiently for A.S.S. to work. Good luck tracking down the problem. You instrument panel should have a screen that tells you why A.S.S. is or is not working, that would be your first clue.

 

2019, I purchased mine new. Had the cable under the dash for the tow lights unplugged (this stops *** from working.) Plugged it back in last year when taking it to the dealer for VCT issue. It hasn't worked since, no codes, it's glorious!
The "disabled" light on the instrument cluster will come on every now and again, that's about it.

 

Welcome to the Forum! There are numerous methods to disable the A.S.S. (Auto Stop Start). Here is a link to the known solutions (back in 2018 when it was posted). Disable auto start/stop for good - Page 43 - Ford F150 Forum - Community of Ford Truck Fans
If it were me, I'd start by looking at the Instrument Cluster Menu. There is an option to see the A.S.S. status. it will indicate why the A.S.S. is not engaging. Watch this screen as you drive/stop and it will give you some ideas to start with... I don't recall exactly where it is in the menu, but look for it. If by chance, you do not have this menu, it might suggest the previous owner removed the A.S.S. with FORScan. With FORScan, A.S.S. can be disabled and removed from the menu so you don't even see it. Of course that is only one possibility. With the FORScan change, they can leave that menu or remove it but if it is missing, that would probably indicate a FORScan change as this would be in the menu when the truck left the factory if it had A.S.S. The only way to really know if FORScan was used or not, is to use FORScan to look at your module values. One would have to use Livnitup's FORScan spreadsheet to compare your current values to the specific values in the spreadsheet. Hopefully you are aware of and know about FORScan (if not, it is pretty easy to use).
Another easy to check option is to remove the center console bezel and look at the back of the A.S.S switch. It could have a paperclip or wire jumped across 2 wires, or there could be an AutoStop Eliminator installed. The AutoStop Eliminator is a shor wire with a small module. It will have a male and female plug as well - it is installed by unplugging the factory plug from the A.S.S. switch and placing the Autostop Eliminator in line (factory wire into the female of the AutoStop Eliminator, and Autostop Eliminator male into the switch) It is only about 6" in total length.
As others have stated, also check: Take a look at the Sensor located on the Battery Negative Terminal or the Ground cable for being disconnected. This will also be a cause for system non-function. This will also prevent the A.S.S. from engaging and was not known when the chart was published.
Net is, you have to start checking one thing at a time. Good luck!