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Discussion Starter · #1 ·
Hey all, I just got my 4xe Sahara last month and I've started to notice some issues when I have max regen on at low (5-10 mph) speeds. It's a little tough to describe. I sometimes feel like my jeep lurches forward a little when I brake. Today when I used the brake it actually felt like the car jumped forward a bit. I understand that the max regen sort of turns off when you are rolling at really low speeds, but it seems the transition to/from this is rough on the transmission or something. This only happens at low speeds (in parking lots, etc) Anyone else experiencing these issues or have suggestions? Thanks in advance!
 

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I wouldn't say mine has an issue but with max regen if your movement of the pedal is not very smooth I have felt a rough engage/disengage. If it doesn't clear up with a little more time getting used to it you might take it in for a check up
 

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My braking was rough for a while when new, I think the 4xE has some "learning computer" things going on with the brake blend and trans shifting. When you brake at low speeds in a PHEV, the car will shift from regen to friction brakes which is a really tricky thing to do and I think that's what you are feeling. Fortunately, the Jeep seems to get better about managing that transition over time, or at least mine felt like it did after a while.
 

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Yep, mine does it too. Seems to have gotten better. I hit the pedal a little harder when it’s almost stopped, that’s where the hiccup is. Seems to help. It is strange and annoying.
 

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Hey all, I just got my 4xe Sahara last month and I've started to notice some issues when I have max regen on at low (5-10 mph) speeds. It's a little tough to describe. I sometimes feel like my jeep lurches forward a little when I brake. Today when I used the brake it actually felt like the car jumped forward a bit. I understand that the max regen sort of turns off when you are rolling at really low speeds, but it seems the transition to/from this is rough on the transmission or something. This only happens at low speeds (in parking lots, etc) Anyone else experiencing these issues or have suggestions? Thanks in advance!
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Kate
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Yep, mine does it too. Seems to have gotten better. I hit the pedal a little harder when it’s almost stopped, that’s where the hiccup is. Seems to help. It is strange and annoying.
Did you get any of the firmware updates? I believe one of them was designed to smooth out the transmission in lower gears. I experience this as well but have not updated the software.
 

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Did you get any of the firmware updates? I believe one of them was designed to smooth out the transmission in lower gears. I experience this as well but have not updated the software.
I did get all the available ones as of 3 weeks ago. Maybe that’s why it feels better. I can’t remember when I thought it got better. Sorry, I wasn’t really paying attention to it closely enough.
 

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Only had my Rubicon for a week. Does this occasionally. I've decided max regen is best for coasting down hill and on the interstate with esave, but is sort of a wash in electric mode cause it uses more than you capture to get you back to speed when accelerating.
 

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Ask, and you SHALL receive !!!

If you want to “visualize” why/when this happens, go into the setting on the instrument closer and turn on the option to show your current gear. This will place a number (1, 2, 3 etc) as a sub-script next to the “D” (drive indicator) at the bottom right corner of your cluster. This shows you what gear you are in.

Now, first the SHORT ANSWER of what you’re feeling:

Every time the car DOWNSHIFTS, the REGEN being on causes a JERKY reaction

Now the LONGER ANSWER from what I’ve been able to determine:
Our cars are drive-by-wire … and so the car is smart enough to be calling for the same amount of input from the stop/go (on the right pedal) — but even though the motor is TRYING to draw the same kW of regen, the gear shift DOWNWARD actually changes gearing such that the same pedal input in that gear ratio is different. Lower gears multiply (add) power — most cars have a 3rd or 4th gear nearest to 1:1 (I’ve not googled our gear ratios). So as the car downshifts but you are using regen, you’re actually increasing the stoping power — this is not much unlike engine braking in a manual transmisison car, except at least in that case, you can let out the clutch as you downshift at your own rate. Here the drive-by-wire system is guessing best it can to make things “smooth” but it fails.

What I’ve noticed, being someone who has had many EVs and driven over 150k BEV miles is that this gear ratio also inhibits my ability to “get to the stop bar” — as I lift off the accelerator, and anticipate what would normally be a LINEAR (no gear changes) experience, becomes amplified with each down shift such that by the time the car has shifted down the final gear cog or two, i actually end up stopping SHORT of the stop bar if I do not modulate the pedal. Best way to resolve this: you have to lift slightly off the accelerator with each gear shift. And sadly, since you cant really perfectly anticipate the downshift, you’re just left with that slight jerkyness described above.

I could be wrong with those presumptions but, at least in my experience, i have noted the jerks correspond to the D2 -> D1 of D3->D2 down shifts displayed on the cluster. Hopefully someone else can experiment and confirm my findings. Cheers!
 

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I noticed the same thing transitioning from slow braking, then rolling gently back onto throttle. Sometimes when coming to a complete stop, it feels like someone ‘bumped’ me from the rear. The most recent firmware updates to the drivetrain control modules have improved this and I’m hoping future ones will refine this even better.
 

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This was actually mentioned in this article by motortrend posted in the FB group.

"Not that the Wrangler 4xe's powertrain is fully sorted, either. As we noted in our 4xe First Drive and First Test reviews, the 4xe plug-in hybrid system has a lot going on and doesn't always manage all the moving parts well. It, too, is touchy at throttle tip-in, gear changes are stiff in pure EV mode, and some odd shuddering occurs nearly every time you come to a stop."
 

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This is interesting because it would imply better regen at higher speeds under manual shifting where you force the gearing to stay higher and allow less of the engine braking effect to slow you down.

There is about 300 ft of elevation gain (or loss) going up my street before you hit a stop sign so I’ll test it out tomorrow with the hybrid screen pulled up to see what numbers I get.

Ask, and you SHALL receive !!!

If you want to “visualize” why/when this happens, go into the setting on the instrument closer and turn on the option to show your current gear. This will place a number (1, 2, 3 etc) as a sub-script next to the “D” (drive indicator) at the bottom right corner of your cluster. This shows you what gear you are in.

Now, first the SHORT ANSWER of what you’re feeling:
Every time the car DOWNSHIFTS, the REGEN being on causes a JERKY reaction

Now the LONGER ANSWER from what I’ve been able to determine:
Our cars are drive-by-wire … and so the car is smart enough to be calling for the same amount of input from the stop/go (on the right pedal) — but even though the motor is TRYING to draw the same kW of regen, the gear shift DOWNWARD actually changes gearing such that the same pedal input in that gear ratio is different. Lower gears multiply (add) power — most cars have a 3rd or 4th gear nearest to 1:1 (I’ve not googled our gear ratios). So as the car downshifts but you are using regen, you’re actually increasing the stoping power — this is not much unlike engine braking in a manual transmisison car, except at least in that case, you can let out the clutch as you downshift at your own rate. Here the drive-by-wire system is guessing best it can to make things “smooth” but it fails.

What I’ve noticed, being someone who has had many EVs and driven over 150k BEV miles is that this gear ratio also inhibits my ability to “get to the stop bar” — as I lift off the accelerator, and anticipate what would normally be a LINEAR (no gear changes) experience, becomes amplified with each down shift such that by the time the car has shifted down the final gear cog or two, i actually end up stopping SHORT of the stop bar if I do not modulate the pedal. Best way to resolve this: you have to lift slightly off the accelerator with each gear shift. And sadly, since you cant really perfectly anticipate the downshift, you’re just left with that slight jerkyness described above.

I could be wrong with those presumptions but, at least in my experience, i have noted the jerks correspond to the D2 -> D1 of D3->D2 down shifts displayed on the cluster. Hopefully someone else can experiment and confirm my findings. Cheers!
 

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This is interesting because it would imply better regen at higher speeds under manual shifting where you force the gearing to stay higher and allow less of the engine braking effect to slow you down.

There is about 300 ft of elevation gain (or loss) going up my street before you hit a stop sign so I’ll test it out tomorrow with the hybrid screen pulled up to see what numbers I get.
I’m not savvy enough in engineering to know how the choice of gear will impact the kW of energy you’ll get during regen braking. But look forward to your findings.

PS: I’ve never been able to initiate manual gear changes w/o gas motor coming on. I saw somewhere that 4L may allow this but that’s it. Bummer. Good luck!
 

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Discussion Starter · #14 ·
Thanks to everyone for making me feel like I'm not alone in the issue! I'll figure out how to check if there is a firmware update and update that if possible to see if there is a change. If there isn't on, it seems like this isn't worth bringing in right now? Or at least they'll just say 'this is how it works' ha? Also thanks to @Shaka for that lengthy writeup!
 
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