I’m just having a hard time believing this issue is being caused by outdated software.

It is.

 

It is a software issue, but not simply because it's outdated. It's just bad programming/shift logic altogether. A STAR online case (internal service document) that acknowledges the problem was released a few years ago. It said that engineering was working on a solution, but nothing has ever come of it AFAIK.

 

This is the first time you've noticed bang shifting? When did you buy this van?

 

We bought it in 2019 - we’ve not ever had an issue until about two months ago. It doesn’t happen all the time - just occasionally it sort of stalls, then jumps. No lights/warnings have come on - took it in today and had them run a diagnostic - checked out clean - but mechanic said it probably needs a software update.

 

More likely it's dirty fluid causing the issue.
A software issue won't cause issues 73k miles into ownership, but degraded fluid from 73k miles of use WILL.

 

A software issue won't cause issues 73k miles into ownership,

It will.

The adaptive learning is screwed up. It can be reset manually and is easy to do, but why keep doing that when the software can be updated to resolve the issue?

 

I’m just having a hard time believing this issue is being caused by outdated software. Anybody have something similar? We’re at roughly 73,000 miles.

Your software is not necessarily "outdated". Like any software, the software controlling the transmission can become corrupted or damaged through use. A timing issue occurs, a line of code gets garbled, or the learn mapping gets messed up. Reloading a fresh copy of the software can resolve the problem. The software will be the latest version, not the version that was originally installed when the van was manufactured, so that maybe why the "updated" term is used.

 

I found some info about "clearing the transmission feedback loop causing rough shifting."
It's worth a shot!

This video describes the problem:

And this one shows how to reset it (at 1:55 into the video):

They basically say to do this to reset it:
1) Without touching the brake pedal, push start button twice to the ON position.
2) Floor the gas pedal for 10 seconds.
3) Keeping the gas pedal floored, push the start button once to OFF position.
4) Let go of gas pedal, and touch nothing for 2 minutes.

Hopefully that helps!

 

Just had my 2017 TCM updated and it seems to be better. I was occasionally getting P0000D when it occurred. I changed VVT parts on bank 2; phasers, oil control valve, and cam position sensor, and did a drain and fill on the transmission. A few months later, it happened again, throwing a P0000B (bank 1). I had software updated, and waiting to see if I need to now change VVT parts on bank 1. As many have stated, use correct oil, keep the oil full, and changed on time.

 

I have a 2017 with that issue. I was told it was just the 9 speeds and they did reset my system but instead of it hard shifting at 18 mph, it's now 14 mph and my 50k mileage Pacifica is back with the dealer! There's something more to this with so many 2017s having the same problem!

 

The instructions in the reply by DenverDave (above) did help in my case, but only temporarily.

I had occasional rough shifting (both upshift and downshift) around town. But my worst issue was when climbing hills, at low speed on my neighborhood hill, and at high speeds on interstate when climbing a long grade. The transmission would downshift to increase power under load, but would STICK in low gear. The engine would rev way too high for my liking, and would not want to upshift, even after I released the accelerator. Each time I'd have this "bad shifting incident", the engine light would come on. But after a few drive cycles, it would go out. I found that a Diagnostic Trouble Code was STORED each time (P000D and P000B) and it had to do with the engine's VVT (Variable Valve Timing) system which is controlled by the ECM (Engine Control Module).

Yes, strangely enough, the engine performance is causing the transmission to act up (get confused) and shift erratically. I'm hopeful the TCM software update I got contains changes in the algorithms that ALLOW the transmission to better handle the engine's occasional VVT anomalies. I was told that I already had the latest software in my ECM.

So, I definitely suggest updating ALL software that's out-of-date. I'd also strongly suggest asking the mechanic if there are any trouble codes stored in the computer(s). I've found several YouTube videos and forum posts stating the same thing, "UPDATE ALL SOFTWARE, and then attempt to resolve all reported trouble codes, ACTIVE and/or STORED that pertain to the transmission and/or engine performance."

"MotorCity Mechanic" and "Online Mechanic Tips", both on YouTube, have some good videos on performing work on the VVT system and on replacing the transmission valve-body and shift-solenoids, if you're a DIYer like me.

Oh, and something I did that also helped a lot with rough shifting; when I drained and refilled the transmission I added a can of Valvoline Conditioner (not a sponsor)...

 

This is a simple fix, have the fluid changed.
It falls out of "learning" because the fluid breaks down past the point it can adjust for, then shifting starts getting clunky.
This is the joy of manufacturers claiming "lifetime" fluid. (Hint: There's no such thing, it means "life of the warranty")
Change your fluid, then do a relearn on it. It will be fine for another 50-60k miles, at which, another fluid change will be due.

 

This issue has been reported many times with low miles. I remember a few complaints at 1,500 miles. Software updates resolved the issue.

 

Bought a used 2020 Pacifica gas only, a little over a year ago. 62k mi. Was a rental. Selling CJDR dealer couldn't tell me which rental company or any other info regarding maintenance. Logged the VIN with my local dealer and was informed it used to be with Enterprise and was used in southern states. Look really clean underneath compared to what they would be here in NE Ohio. Also found out the transmission control valve body had been replaced at 52k mi. Shifts really well except for a rare small firmer shift into 9th when not completely warmed up. Seems to me the computer is trying to figure out which way you are going to move the throttle pedal. Maybe computer is over analyzing?? Van is very nice to drive. Average 21 to 23 mpg but I live in the country. Have averaged 28mpg on longer trips. See on here that one's are having issues with 2017's. First year and read they might be a little problematic. Oil change and updated control module might be the answer? Don't know. Neighbor drove the van around 100 mi after I picked up an rv. Said the van almost drives itself and doesn't feel like it's a van. So far approx 14k mi since purchasing and it's been perfect. Let's hope it stays that way. Mopar man here having a 2021 1500 Longhorn and 2020 Challenger 392 Shaker. Have owned mostly Mopar vehicles the last 45 years.

 

It is highly likely a transmission software update will help. My 2017 required 4 software dealer updates, and multiple home adaptive learning resets. It is the nature of the transmission, its controller, and the software that is apparently continuously evolving to (try to) meet the balanced objectives. Trans life, smoothness, hardware set, durability, and fuel economy. I have never owned a vehicle with such a quirky transmission but I also never had a minivan that likes to spin its tires (when allowed) and still gets 30 mpg hauling a full crew.