Read your manual. There is a long list of conditions that must be met before StartStop will engage. There is also a list of things that will cause an automatic restart.

Significant steering wheel angles is one item that will cause Start Stop to disable.

 

Thanks for the reply. Yeah, that's the problem significant steering wheel angles doesn't disable Start-Stop as shown in the video. Turning the wheel 90* would require excessive force as UncleG suggested and in the video I'm already pulling the wheel pretty good.

 

You're not turning the wheel nearly far enough in the video for it to disable auto Start Stop. Most often I notice mine disabling in drivethrus as I round a corner. Think about how much you turn as you round the back of the restaurant.

I don't know for a fact, but steering wheel at 90* doesn't seem like nearly enough to disable it from my memory. The actual tires need to be turned a pretty significant amount, and 90* of steering wheel movement isn't really that much deflection.

When I get into my truck later I'll turn on the off-road gauges that show steering angle and I'll see where it disables Auto Start Stop for you.

 

You shouldn't be able to turn the wheel much, if at all, while the engine is stopped.
Turning the wheel 90+ degrees before A/S/S shuts it down should prevent shutdown. Turning the wheel after shutdown (if that's even possible) does not cause the engine to restart.

This is all explained quite well in the manual.

 

This ^^^

 

I find the auto stop almost dangerous because of this. I was in a drive thru the other day and it shut the engine off right at the window. Once leaving this drive thru you have to make a very sharp turn so you don't hit the side of the building. I let my foot off the brake and the truck started going forward but the power steering wasn't enabled yet so I almost hit the building. I find it takes longer than it should to enable the power steering with this feature.

2018 xtr

 

Ease up on brake (not release, just less pressure), engine will start, turn wheel, let off brake. Whole thing takes less than a second. easy

 

Follow-up... I have to apologise, there is much less steering wheel travel required to disable the Auto StartStop than I remembered.

 

It's not locked. It's just very hard to turn.

 

I like to push the button when I start it up for the first time and avoid all the aggravation later. The worst idea Ford has put into the truck in 40 years and most dangerous.