Random speed changes with cruise control

[Lawduck]

Greetings!

My cruise control has started to randomly change speeds (downward) while on the highway. This is a new problem (2021 F150) that started this summer during our road trip down to CA. We're moving along at 75 or 80 or whatever it was, and suddenly it just drops to 65 or 55, and it uses the brakes to do it so the speed drop is rapid.

Since then, it's happened a number of times in Oregon on parts of I-5 on which it previously worked flawlessly. When it happens, there are no speed signs either on the interstate or on a parallel road, and it doesn't always happen in the same places.

I've been fortunate so far that it hasn't happened while anyone was close-ish behind me, but it's to the point where I won't use it at all if there's anyone within 100 yards behind me.

Is this a known bug to some update, or ... ?

Sponsored

 

[Larrymoe]

Did someone get into the lane I front of you and do you have your adaptive cruise control on?

 

[TxAgs2012]

Try turning off the speed recognition, and see if that changes anything. I wonder if it also does it based on database information? Worth a shot.

 

[nkyhunter]

It seems that your truck doesn't want to move to California due to the high gas prices, that's why it keeps slowing down

 

[HammaMan]

It could be errors in the navigation DB. The speed sign recognition feature relies both on signs it can see, but also an absolutely retarded database full of errors. It's from here.com - I've found data more than 10 years old in it and the way you can suggest edits is just terrible. A block of road can be broke up into sections as small as 200' long and it just takes an error in one of those little blocks to screw things up. I have one area I pass where there's a 70% chance my speed will drop to 30 in a 65 (no visual data present for it to 'see').

Both visual sign data and the DB are both used to set speed. They need to incorporate logic in it that's got just an ounce of intelligence. In my state at least, the speed limit cannot drop more than 10mph at a time -- it must be dropped in 10 mph increments -- such logic would make it impossible for the system to go from 65 to 30mph for instance.

 

[Steve Feldkamp]

It could be errors in the navigation DB. The speed sign recognition feature relies both on signs it can see, but also an absolutely retarded database full of errors. It's from here.com - I've found data more than 10 years old in it and the way you can suggest edits is just terrible. A block of road can be broke up into sections as small as 200' long and it just takes an error in one of those little blocks to screw things up. I have one area I pass where there's a 70% chance my speed will drop to 30 in a 65 (no visual data present for it to 'see').

Both visual sign data and the DB are both used to set speed. They need to incorporate logic in it that's got just an ounce of intelligence. In my state at least, the speed limit cannot drop more than 10mph at a time -- it must be dropped in 10 mph increments -- such logic would make it impossible for the system to go from 65 to 30mph for instance.

Mine drops from 65 to 55 in a zone where they raised the limit and signs two years ago at a stop light intersection.

 

[rjinaz]

Does that for me on 101 Loop in west Phoenix.
There's a 1 mile stretch that suddenly drops from 65 down to 50.
No speed limit sign changes, but it's consistent every time I hit that section of freeway.
As HammaMan stated, their map must be outdated.

 

[whizkidder]

You can use Forscan to turn off the database source for the speed limit recognition, and use the camera only (but then it won't change if anything is blocking the camera's view of the signs -- trucks, tree branches, etc.).

 

[Baz]

This just recently began happening around late September or early October. My truck was @ dealer for warranty work and they completed all available module updates that were available. I picked my truck up on 9/27. I had also received the 10.1.0 on 9/20 via OTA.

I have speed sign recognition off and predictive speed assist is off. This had not happened before with my truck. When pressing resume or setting cruise control speed it will slow down 2-5 MPH quickly and then speed back up to set speed. No warning on IPC and one road it happens on quite frequently is paved, 2 lane highway and when it happens there are no vehicles on the highway besides me.

It happens when setting speed for cruise control and stays at speed for a second or two and then slows down 2-5 MPH then goes back to set speed.

When resuming set cruise control speed, it will speed back to set speed for a second or two and then slows down 2-5 MPH then goes back to set speed.

 

[TremorAdik]

I thought i had the answer for you until I read your last thread now I am just watching. I was only gonna chime in and say my 2024 did not do this but 2023 currently does it all the time to me but I don't use cruise bec well Houston drivers suck

 

[Chappy133]

There's no joy like driving down the interstate and randomly the truck applies the brakes to slow from 65 to 50 MPH for construction zone from two years ago.

 

[DcnPat]

Definitely does this due to bad data in the last database update. It's going to cause an accident or 10 and kill someone. I know it's a recent update that changed things because I've driven the same route from DC to Ohio many times since I picked up.my truck in Jan 2023 and it used to work well (except for picking up the hov speed limit sign from the regular lanes) but this last trip it went from 70 to 30 on I-76 (PA turnpike) several times.

 

[HammaMan]

Definitely does this due to bad data in the last database update. It's going to cause an accident or 10 and kill someone. I know it's a recent update that changed things because I've driven the same route from DC to Ohio many times since I picked up.my truck in Jan 2023 and it used to work well (except for picking up the hov speed limit sign from the regular lanes) but this last trip it went from 70 to 30 on I-76 (PA turnpike) several times.

Honestly I think our only recourse for this to go the NHTSA reporting route. Might be time to start a reporting campaign to get this rectified. It's technically unintended braking.

 

[okmurdog]

It could be errors in the navigation DB. The speed sign recognition feature relies both on signs it can see, but also an absolutely retarded database full of errors. It's from here.com - I've found data more than 10 years old in it and the way you can suggest edits is just terrible. A block of road can be broke up into sections as small as 200' long and it just takes an error in one of those little blocks to screw things up. I have one area I pass where there's a 70% chance my speed will drop to 30 in a 65 (no visual data present for it to 'see').

Both visual sign data and the DB are both used to set speed. They need to incorporate logic in it that's got just an ounce of intelligence. In my state at least, the speed limit cannot drop more than 10mph at a time -- it must be dropped in 10 mph increments -- such logic would make it impossible for the system to go from 65 to 30mph for instance.

Yep, I experience the same issues on a nearby turnpike where the speed limit is 80 MPH. The turnpike was completed a couple of years ago, and when it was under construction, there were areas where the speed limit was reduced to 45 duirng construction. Apparently, there is some bad data in the speed limit database for a very small section (few hundred feet), since the truck speed limit sign display will flip to 45, coupled with sudden braking to reduce speed down to 45 (from 80), and a few seconds later it will flip back up to 80 on the display, and thereafter ramp back up in speed. It is for this reason I no longer use the cruise on this particular section of the turnpike...PITA.

 

[Baz]

Honestly I think our only recourse for this to go the NHTSA reporting route. Might be time to start a reporting campaign to get this rectified. It's technically unintended braking.

Out of curiosity, which module(s) is this data stored or updated to? APIM? Was it 10.1.0?

I have heard of some local people experiencing the same thing and I want to understand this a little more....

Bigger question is that ... is it really the data, even though I have a speed limit sign recognition and predictive speed assist options turned off?

This has never happened with my truck until the last month to month and half... so I am just how this can be occurring if those options are turned off.

I am always trying to learn how these trucks work!

Sponsored