Hill Assist and ABS Lights ON

2017 Freightliner Cascadia DD15 and DT12 Automatic Transmission
For quite sometime I have been having this problem, when I start my truck I have no warning lights of any kind on my dash, after few minues, sometimes hours or when ever I hit a bump or pothole on the road both lights, the Hill Assist and ABS light for the Truck not the Trailer come ON. Both at the same time like in sync.
I have all new Brakes all around my truck, drums and shoes, we did check the ABS sensors for looseness and clean them all around the area, all seems normal, if I shut the truck off and restart both lights go OFF until I hit the next pothole or bump on the road, sometimes they come ON randomly.
I do have an Active Code: SPN 807 FMI 5 don't know.
Took it to the dealer and they can't find anything wrong, in all fairness the truck runs fine but I hate to look at those two lights ON. I am hoping that someone here have seen this problem or may have a hint at what could be the cause.
Thank you all for reading my post. I also have a short video on Youtube but for months no one even looked at it. Here is a picture of them lights.

 

Hopefully someone on here has experience with this..I do not. But a word of advice if and when you get in a puco or dot check I would turn the truck off asap. Then at least when instructed to restart it the lights will behave especially the abs one. If the light don't cycle with the on and off turning of the ignition it will be a citation and csa points. You probably already know but don't talk to them about how its been acting up. They are not your friend IMO.

 

Abs sensor is used for hill assist and traction control... problem is definitely in the wiring or connection to a abs sensor somewhere .. I had abs traction control issues that were random finally it went full time on . Thats when they pulled the abs sensor on a front wheel and it was green with corrosion .. after they fixed it zero problems .why a front sensor affects traction control is beyond me lol

 

I just had this problem on a 2021 Cascadia it turned out to be the tone ring on the drivers side

 

I had corrosion in the connector for the abs sensor. In my case there was an extension cable from the abs controller to the abs sensor. Where the two joined together, water got in.

 

They work in unison

 

If that code is active that is your culprit for the lights being on.
You have a wiring issue to the ABV valve for your steer axle or the valve itself is bad.


And now after posting I realize this thread was brought back from 2020 for no reason at all by the poster before me, lol

 

and he never came back and said what the problem was..

 

Not the same vehicle but I had an abs and traction control lights on
They traced it to the harness
$5000 fix
They did drop the bill down some and I think most of that was labor

 

With most newer Internationals, this combination of warning lights is unusually due to a bad brake switch.