Probably a dumb question, but I gotta ask it anyway...

[drksd4848]

I have a T2, an unlocked PCM, as well as my factory PCM that is still in the car.

Say I pop in the unlocked PCM, flash the tune, and disaster strikes: the unit freezes, I can't recover the factory tune and the car is bricked. Even better! It happens on a Friday night and I can't reach out to you guys until Monday morning. The car is parked directly behind my wife's car, and she threatens to shoot me in the face with a bazooka because of this.

If I have the original PCM, would I be able to simply put the factory PCM back in the vehicle, start it back up and pretend like nothing happened? Or is the BCM messed up too and I'll still be out of luck until Monday morning.

Again, I'm sure the chances of this happening are small, but like I said, I justr gotta ask....

[mikel]

Before I commit to you not getting shot in the face with a Bazooka, please confirm the specific vehicle we are discussing.

I have to assume 15+ Dodge, which means ZF8 most likely, which means a TCM that cant be accessed. (part of the valve body in the trans) They are incredibly robust controllers, and there's probably 1/10th the chance of having a TCM issue vs a PCM issue.
You'll know the tcm is mad if the shifter is blinking.
If not, swapping the pcm will get you going for sure.

[drksd4848]

Sorry, I should have clarified. 2022 Chrysler 300S hemi. All I’ve done so far is just hooked the T2 to the factory PCM to copy the factory settings. However, some funky things started to happen when I did that: It lost communication with the factory PCM and threw U0100. (I use the T2 to clear it, no problem. but it keeps doing it every time I connect.) Also, traction control, stability control, and some other stuff started flashing and all that had me a little concerned. I was actually planning to call tech-support this morning to talk through this, but I wasn’t able to get around to it.

The other thing that had me concerned: after I copied the factory settings on the T2, I hooked it up to the software on my laptop to verify I had the settings saved in the tunes folder, and there was no file. Also, when I do hook the T2 up to the software, my VIN isn’t displayed. Hence why I was going to call you guys this morning.

To be clear, the factory PCM is still in the car and I have yet to install the unlocked PCM.

The big thing is that scares me is if it throws the U0100 code while flashing the unlocked PCM… that could be pretty bad…

[mikel]

ok, lets walk through this.

the initial read with the stock pcm in place is just copying the security data, there wont be anything in the tunes folder for this process.

the dash will always cycle through messages and warning lights while reading/writing, its 100% normal behavior.

The U0100 is not uncommon in some cases, but I wouldn't expect it every time you use the device. Be sure to follow any key cycle prompts at the end of a read or write which is there to clear any codes left by the process. The U0100 is just telling you the PCM was offline at some point, which is simply part of the flash process, so its not anything to be concerned with.

When you swap in the unlocked pcm, and go to the tune menu on the T2, it will prompt you to load the SKIM data it read from the factory pcm to the unlocked pcm, which will allow the pcm to function in the car and let it start/run.
Once thats done, you can go through the tune menu and load any tune to the pcm and tcm and there will be copies of the backup files and last tune written files in the tunes folder. At that point, it will also be married, and will display your VIN in the update software.


Thanks

[drksd4848]

Thanks for sticking with this for me Mike. I appreciate it.

The U0100 is not uncommon in some cases, but I wouldn't expect it every time you use the device. Be sure to follow any key cycle prompts at the end of a read or write which is there to clear any codes left by the process. The U0100 is just telling you the PCM was offline at some point, which is simply part of the flash process, so its not anything to be concerned with.

Yep, every time I've connected the T2 to the PCM I've gotten the U0100. I've followed all the promps right until the bitter end of the process, but then have had to go back to the diagnostic menu to clear it. For giggles yesterday, I ran the diagnostic as soon as I plugged the T2 it into the PCM and there was no code initially, so it looks like it happens during the reading process. Unfortunately it remains there after I am prompted to unplug the unit, every time.

Since it has happened every time I've plugged it in, do you think it could be something to do with the gateway bypass cable?

BTW, related, but separate issue: I was under the cowl doing a "dress rehearsal" with the PCM: I pulled it out to see how easy it is to disconnect it, and sure enough, I snapped one of the locking levers on the PCM connector. Not a huge deal; I can just take a small flathead screwdriver and push the locking tabs back, but it does annoy me that it broke.

Heard of this happening to anyone else? Is it fixable? Or is it something that's just busted and that;s that. The terminal on the harness itself is fine.

[mikel]

Unfortunately people do seem to break them now and then, especially as they get older and the plastic becomes brittle. You'll notice the connector fits super tight, and it will be fine without the tabs.

Im curious about the U0100, and what exactly you are doing when it comes up. How many times have you read the vehicle with the device?

[drksd4848]

Im curious about the U0100, and what exactly you are doing when it comes up. How many times have you read the vehicle with the device?

I've done this a handful of times. I follow all the screen prompts, turn to run when it says so, unplug it when it say unplug. Throws the code every time. Again, not a show stopper. I just clear it with the T2 or an ODB 2 app.

If you want, I can record a video of what I do, then forward it to you guys.

A little background (for what it's worth):
I've had the unit and the unlocked PCM since summer of 2024, but have held off doing the full swap and tune for a while because I've been waiting to get to a point in the warranty where I'd feel comfortable making the swap. All I've got on it now is the limited power-train warranty.

But during that time, I will occasionally update the T2, then plug it in to the vehicle to copy the factory tune to the unit to make sure everything still works. And I get the code every time.

[mikel]

ahh, its just reading, and not writing. We don't do a code clear at the end of the read, but we do at the end of the write, so if you loaded a tune, you would ideally never see the code.