Can you train your JLU's shift habits?

[Yellow Cake Kid]

Hi,
I have been experiencing less than smooth operation at low speed.

I have read a few comments that imply that the drive line is influenced by an ECU that attempts to adapt to your driving style.

My Jeep was driven gently on the highway at highway speed for about 600 miles to get to our home.

Now more often than not, it is driven off road at very low speed between 5 and 10 mph. In fact, the only time the Jeep sees pavement use is when we are driving to a trailhead.

Our small town's neighborhoods have 20mph speed limits and I usually keep it below that speed while heading out from home.

When I am climbing the system works great, but when I am driving on level road, or when I would expect to glide smoothly down a very slight incline, the system feel "surgy" as if the shift points are confused. Sometimes I shift into manual override to keep the transmission from searching, but even then the idle will surge ever so slightly.

I just drove down to the post office in my 2003 Honda Element beater car and the drive line is as smooth as silk. Tonight when we take the dog for a ride in the Jeep and a walk in the desert, the brand new Jeep is going to surge-n-hesitate all the way down to main street.

The Jeep acts like it doesn't want to be driven by old people who are not in a rush to get anywhere.

With regard to the comments I have read, I have inferred that you can pull the connections to the battery and force the Jeep to "relearn" your driving habits after the battery is reconnected.

I have two questions;

1) Is this "reboot" concept valid and based on facts published in Jeep service manuals or is it just speculation on the part of end users?

2) My Jeep is 100% stock with no mods or tunes. If I do disconnect the battery and then reconnect it, are there any other "gotchas" I should be aware of?

Thank you.

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[Uhdinator]

I would try the TCM fuse F08. Leave if out for 10 min or longer and see if that helps. if not then try the same on F22 ECU. Or pull both.

https://www.sellaband.com/how-to-reset-car-computer/

 

[Yellow Cake Kid]

Thanks to both of you for the replies.

I have not checked for codes, and guess I need to get one of the security work around harnesses to use my current ODB reader.

I think I will try the better grade of gasoline before doing much else.

I live in the valley at 4,000 feet elevation. We play on the mesas at 6,000, picnic in the mountain meadows at 8,000, and cross the mountain passes on forest roads at 10,000. The passes are only 28 miles from the house so it averages 4% grade, and almost all of the driving is off road.

The ECU must be getting a workout trying to figure out how to balance the system with all the variation in air pressures etc.

Nevertheless, our old beater Honda 4 banger and 2017 3.5L Ecoboost Ford van seem to have it figured out and run smoothly up and down the slopes.

As I mentioned, the Jeep does great when there is work to be done, it just doesn't seem to know how to relax when its time to take it easy.

I have been using mid grade gas, and am only marginally familiar with the Tier 1 terminology. I think I take it for granted as I don't go out of my way to buy gas at off brand stations. I'll give the higher octane a run and see if that introduces a bit more consistency to the experience.

Thank you.

 

[basinite]

Regarding the elevation changes; I live in similar terrain and constantly go from 5,000' - > 10,000' within hours when out messing around. I do not have the issues you are having and my Jeep runs/shifts normal at all elevations.

I do have the following problem; My Jeep hardly ever wants to shift into 8th gear while cruising down the highway on my daily commute to work. I have to manually shift it into 8th gear, dropping my RPM's from 1900 to around 1600, driving at 65 MPH. I've watched my fuel economy and it goes up a bit after doing this. Power is not an issue and the engine doesn't lug down or anything like that. Not really sure why it doesn't want to shift on its own. It's kind of annoying, but I've always driven sticks so I don't mind.

If I was you, I would pull the fuses and/or battery and try to reset everything as others have stated. I bet this fixes the issue.

 

[The Fixer]

Just curious @JeepScares what engine does your Wrangler have?

I've noticed the 3.6/A8 in my wife's Wrangler shifts a bit more firmly and decisively than the 2.0T/A8 in my Wrangler. I catch mine staying in 2nd gear when I do a "Jersey roll" at a Stop sign instead of downshifting all the way to 1st, and it is slower to downshift when climbing a hill.

 

[Yellow Cake Kid]

Thank you to both for the ideas and comments.

I should have specified that my Jeep is a 2020 Rubicon JLU with the 3.6L v6 engine and automatic transmission.

Thank you.

 

[Powerwagon1]

Thank you to both for the ideas and comments.

I should have specified that my Jeep is a 2020 Rubicon JLU with the 3.6L v6 engine and automatic transmission.

Thank you.

Do some research on the forums, There are several threads on Surging. Mine only did it while I was in Houston, TX. for some reason and when I left that area the problem went away and has not happened again. Possible lean run condition at low speeds by a glichy Sensor who knows ? Even my dealer could not explain it ( No Surprise) . There is a update to help fix this issue but mine had the update and the problem ?

 

[Swagger]

The 8 speed trans in our jeeps are used in other vehicles that have a learning algorithm set up. My other vehicle with this same transmission was constantly changing to try to get the best fuel economy. Not sure if the jeep is this way, but i noticed a difference in performance when i did a reset of the tcm.

 

[Yellow Cake Kid]

Thanks for sharing your thoughts.

Is there a specific way to reset the TCM?

Is it the fuse pull method described above, or something different?

Thank you.

 

[roaniecowpony]

I'm at sea level and nearly all my driving is street. I too, have this surge feel at lower rpm, especially notable in lower gears. It's not terrible. Feels more like driving a car with a street/strip cam in the old days. I chalked it up to the engine being tuned up pretty hard to get 285 hp out of 220 cu/in.

My other thought was that these mfrs seem to like to make the throttle non-linear with more response in the first part of peddle movement than latter. It gives the illusion of a powerful engine. But to me, it makes driving nicely a challenge. This non-linear throttle programming is particularly apparent in my wife's Flex. If I get out of my truck and drive her car with the same peddle movement for taking off nicely, the dog ends up cartwheeling, I backpeddle the throttle and we get a jerky takeoff. My JLUR doesn't seem quite as bad, but it seems like a combination of a "cammy" engine and quick throttle.

 

[Toycrusher]

Can you train your Jeep?

Yes, but it requires special treats...

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