Hauling 4X8 plywood causes failure of lane keep 2024 F-150 Lightning Flash

[Literider150]

Why is it that when I put a couple of pieces of plywood (or anything else) that hangs out of the bed of the truck; it defeats the lane-keeping function. I'm not using blue cruise but just the basic cruise. There is only about 2.5 ft. sticking out the back of the truck with the tailgate up. I get the same effect when with the tailgate down. I would think that the lane-keep function would not be affected with the cameras, radar, whatever it uses, when going forward.

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[Heliian]

I don't see how this could cause an issue. There is something else you're missing.

 

[MillieChliette]

Just a theory:
There are sensors in the taillights for blind spot monitoring. Maybe the plywood interferes with those, and when that system fails to function correctly lane keeping is also defeated. Alternatively, those sensors may be used for lane keeping, but I'm not sure how or why they would be.

 

[bmwhitetx]

In BC 1.2+ they added a feature to lane-centering that moves you over from center when next to a large truck. I would assume it uses the BLIS sensors. And if those are blocked then maybe lane centering doesn't function?

 

[Henry Ford]

Theory: when the truck senses something hanging beyond the dimensions of the vehicle it disables driver assist features because those features are untested in those conditions.

 

[Runaway Tractor]

Blind spot sensors are a good theory. Also possible it's using the "cargo" camera and doesn't like seeing that blocked.

 

[chriserx]

Blind spot sensors are a good theory. Also possible it's using the "cargo" camera and doesn't like seeing that blocked.

This, if accurate, would be the most likely cause IMO. BLIS last I checked used ultrasonic sensors, pretty useless on lane lines, depending on programming the lane keep would use the front camera for drive angle and rear camera for verification. That being said, I hauled some plywood a couple weeks ago, tailgate up and it was fine, but I also have a Comma so it doesn't really help, sorry...

 

[MaintGrl]

I'm also thinking that it might have to do with BLIS system, it is picking "something" up back there, but it is not moving separate of the vehicle, so it might be disabling the lane centering ability . . . possibly

 

[djryan13]

I put a truck camper on mine on Saturday. Tailgate down. No overhang. But I did hook up trailer wire for lights.

Because it thinks there is a trailer, blind spots don’t work and thus lane keeping didn’t work.

 

[tubby]

Just a theory:
There are sensors in the taillights for blind spot monitoring. Maybe the plywood interferes with those, and when that system fails to function correctly lane keeping is also defeated. Alternatively, those sensors may be used for lane keeping, but I'm not sure how or why they would be.

I would put my bets on MillieChliette's theory is correct.

 

[Aminorjourney]

This is weird.

My wife is a woodworker as a hobby, and we're always carrying large dimensional lumber, as well as lots of slabs.

I've never had the lane-keep assist fail. Out of interest, how are you tying it down? I wonder if there's something creating a false positive?

 

[chl]

My understanding is the lane keeping function uses the forward facing cameras in the rear view mirror(s).

But I can see how the blind spot system might need to interact with it.

So if there is something obstructing the blind spot radar like others have suggested that makes sense.

Did you try using the BLIS with trailer coverage?

The BLIS system might think the hanging out wood is a "fifth wheel or gooseneck trailer" and shut off.
Or maybe you need to input trailer dimensions, if I understand how that works - never used it so not sure about that.

From what I read under some circumstances the system will turn off:

https://www.ford.com/support/how-to...ith-trailer-coverage-and-cross-traffic-alert/

Trailer Coverage supports conventional trailers only and automatically turns off if you select a fifth-wheel or gooseneck trailer.

 

[Literider150]

Blind spot sensors are a good theory. Also possible it's using the "cargo" camera and doesn't like seeing that blocked.

A few weeks ago I had two 10ft. pieces of PVC which I let hang over the edge with the tailgate up. The cameras in the rear-view mirrors would have been able to see it as they stuck out maybe a foot on one side. But that also caused a warning on the dash that disabled the lane keeping function of the cruise; Just some 3/4" plastic PVC.

Thank you for all the brain-storming you all. Maybe I'll have to call Ford and ask about this. I'm heading out on road trip over the weekend and wanted to find out if there is anything I can do about this. I'm not going to have anything extending beyond the tailgate though on this trip.

 

[Aminorjourney]

A few weeks ago I had two 10ft. pieces of PVC which I let hang over the edge with the tailgate up. The cameras in the rear-view mirrors would have been able to see it as they stuck out maybe a foot on one side. But that also caused a warning on the dash that disabled the lane keeping function of the cruise; Just some 3/4" plastic PVC.

Thank you for all the brain-storming you all. Maybe I'll have to call Ford and ask about this. I'm heading out on road trip over the weekend and wanted to find out if there is anything I can do about this. I'm not going to have anything extending beyond the tailgate though on this trip.

Weird.

What I don't get is that the blind spot system isn't in the tailgate - it's in the lights, which are on a fixed body component. I know BLIS doesn't work if you're towing, so maybe the sensor is going into that space a little...

 

[chriserx]

I had forgot I hauled a bunch of 2" 10' EMT for my solar shipping container project before I installed the comma, tailgate was up and no issues encountered. Weird.
¯\_(ツ)_/¯

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