Unintended Acceleration in 4L

[Ocnorb]

My 2023, 2.7 10-speed is definitely doing this. Noticed it several times on a recent cross country trip. Glad to see it wasn't just me.

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[5280Bronco]

Yeah, mine does the same thing. I'm gonna get the Ford tune and see if it helps it at all. If not, I'll have to keep driving it in M in those situations like I've been doing to minimize it.

 

[CR_IN_UT]

It's been a while but wanted to update because I went back out this weekend and worked through it trying to figure it all out.

I noticed that if I just go to 4L and keep it in second gear (where it naturally starts) then I dont have an issue. IF I go to 4LO and then try to manually go into 1st gear BEFORE I move, then it is NOT in gear and then I have an issue if on a downhill and it not only seems to accelerate but I get the dreaded foot all the way to the floor trying to get the thing to stop.

If I start crawling downhill and then manually hit it into 1st while moving then I dont notice an issue and it seems to be in gear. It's almost like once you have pressure on the transfer case then it stays in 4LO. If I then come to full stop and start to go again while in first then it's a 50/50 shot if I am actually in 4LO. If not, I have to go through the whole thing again, go to 4HI or 2HI then go to 4LO and start over.

I also tried to use the fancy one pedal set at 1.0 MPH to hold me from screaming down the hill and it did a good job but at the bottom, it smelled like brake. It's nice as a backup though and never had a lurch with it. it was a good experience but I was paranoid the whole time because of 4LO experiences we have had. Like I said before, once it happens to you, you dont soon forget it!

Anyone else find this to be what they are experiencing?

 

[Built2Wild]

It's been a while but wanted to update because I went back out this weekend and worked through it trying to figure it all out.

I noticed that if I just go to 4L and keep it in second gear (where it naturally starts) then I dont have an issue. IF I go to 4LO and then try to manually go into 1st gear BEFORE I move, then it is NOT in gear and then I have an issue if on a downhill and it not only seems to accelerate but I get the dreaded foot all the way to the floor trying to get the thing to stop.

If I start crawling downhill and then manually hit it into 1st while moving then I dont notice an issue and it seems to be in gear. It's almost like once you have pressure on the transfer case then it stays in 4LO. If I then come to full stop and start to go again while in first then it's a 50/50 shot if I am actually in 4LO. If not, I have to go through the whole thing again, go to 4HI or 2HI then go to 4LO and start over.

I also tried to use the fancy one pedal set at 1.0 MPH to hold me from screaming down the hill and it did a good job but at the bottom, it smelled like brake. It's nice as a backup though and never had a lurch with it. it was a good experience but I was paranoid the whole time because of 4LO experiences we have had. Like I said before, once it happens to you, you dont soon forget it!

Anyone else find this to be what they are experiencing?

I experienced that issue in both my Wildtrak and Badlands, once I installed the Ford Pro Cal Tuner the issue was resolved.

 

[CR_IN_UT]

I experienced that issue in both my Wildtrak and Badlands, once I installed the Ford Pro Cal Tuner the issue was resolved.

excellent news!

 

[swamp2]

Hmmm. I see at least 2 issues here and just wondering if there is a 3rd. Most are talking about unintended acceleration, but the other description with the gears indicator showinng all sorts of (likely) incorrect gears is something entirely different.

I do not believe I have experienced this unintended acceleration and I have crawled, up and down, in M and A in 4L. What I have experienced is the very "lurchy", unsettling 1->2 shift in A in 4L. This is only during normal acceleration. This is not the issue most of ya'll are talking about, correct?

 

[CR_IN_UT]

For me its more that Bronco said it was in LO but it wasn't in LO in any way based on the speed I picked up when I took my foot off brake. It just started heading down the hill fast. It wasn't a shift that I noticed but I was so focused on where I was going to ditch it because my foot was in the floor and it wasn't stopping! This last couple of times I tried different things to try and figure out what the problem is and posted to see if anyone else had figured it out yet. Based on others posts it sounds like the shift could be an issue but if your in LO then you still would be going slow so thats why I am tending to think its not in LO even though it says it is. I could be wrong.

 

[Built2Wild]

Hmmm. I see at least 2 issues here and just wondering if there is a 3rd. Most are talking about unintended acceleration, but the other description with the gears indicator showinng all sorts of (likely) incorrect gears is something entirely different.

I do not believe I have experienced this unintended acceleration and I have crawled, up and down, in M and A in 4L. What I have experienced is the very "lurchy", unsettling 1->2 shift in A in 4L. This is only during normal acceleration. This is not the issue most of ya'll are talking about, correct?

You are correct, this is the best way to describe it. The Bronco lurches in 4Lo prior to the Pro Cal Tune

 

[swamp2]

You are correct, this is the best way to describe it. The Bronco lurches in 4Lo prior to the Pro Cal Tune

I still do not think what I described in the 4L 1->2 shift is the same as what most are talking about here. I could be wrong.

 

[SierraBronco]

I still do not think what I described in the 4L 1->2 shift is the same as what most are talking about here. I could be wrong.

With ours it has always been the downshift from 2 -> 1 while in 4L. With enough 4L driving Mrs. Sierra has developed a sixth sense for when it will happen. And damn sometimes it is aggressive.

 

[Ramble_Offroad]

Agreed. 4Low downshift from 2nd to 1st is improperly mapped.

 

[SoCal Bronco]

I've had this happen several times in my badlands, it is unnerving to say the least. I have only noticed it when I am in 4lo and it happens when you are slowing down, it might be a down shift but the rpm surges to over 3k which causes the truck to accelerate even though you are on the brakes. I've been reading a ton of posts with this both happening and people trying to explain it as driver error. The engine should not surge in rpm to the point it is launching the car forward. This is clearly a mapping problem in the software. Perhaps it is a problem with the transmissions learn function. I am going to have the dealer reset mine and see if it fixes it. I have driven all kinds of 4x4 all my life and never experienced this before. It's definitely a software problem

 

[brkdncr]

Anyone report this to a dealership yet?

 

[CR_IN_UT]

Many people have. I can only speak for myself but with no lights and no codes there is “nothing they can do”. And that was not only the Ford dealer but also Ford because I had a case open with them.

 

[SierraBronco]

Just a heads up to those still receiving notifications on this thread and not involved in the other thread:

Goosetuned and I have been working on getting the downshifting resolved. He made some adjustments to the schedule for 4L, then I write the tune and try to replicate the issue and send him the logs. We used to be able to replicate it pretty easily shifting from 3-2 going downhill, but now with our third tune for the problem and logs going into the teens, it seems to be fixed. 4-3-2 it will still rev up pretty high BUT the transmission is not locked up, so no lurching forward. Now we’re in the process of getting the transmission learn’t up to.

Bronco now defaults to first gear in 4L too! And we made some adjustments to the anti-hop settings to gain more initial torque. Damn thing didn’t work anyway to prevent bouncing. The bronco drives so much better now in both normal driving and 4L. (Not gonna tag goosetuned in the middle of the night. He’s on the forum)

https://www.goosetuned.com/product-page/goosetuned-21-25-bronco-2-7l-custom-tuning-package

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