Chrysler SKIM Reset

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julespatch
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Re: Chrysler SKIM Reset

Post by julespatch »

If you want a good piece of software buy AlfaOBD.
This gets into quite a lot of FCA vehicles where other scanners don't.
Also, if you just want to change engine ECUs just call up the dealer and get the security code for the vehicle and do the replace pcm in RFA or WCM. It will transfer the secret key to the PCM.
There is no need to reset it or anything like that in my experience. I do these with my Autel IM608 a bit.
Job done
Last edited by julespatch on Sun Oct 24, 2021 4:19 pm, edited 1 time in total.
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Tazzi
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Re: Chrysler SKIM Reset

Post by Tazzi »

julespatch wrote:If you want a good piece of software buy AlfaOBD.
This gets into quite a lot of FCA vehicles where other scanners don't.
Also, if you just want to change engine ECUs just call up the dealer and get the security code for the vehicle and do the replace pcm in RFA or WCM. It will transfer the secret key to the PCM.
There is no need to reset it or anything like that in my experience. I do these with my Autel IM608 a bit.
Job done
Interesting, I am going to have to log those processes and see what they do. From what I have ready, people full stop cannot get the ECMs to security link again after they have been, thus require the reset.

The secret keys stuff is what is basically wiped so its ready to go. I am yet to see what the security code after does, or which module it gets sent to so that will be interesting to see.
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Tazzi
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Re: Chrysler SKIM Reset

Post by Tazzi »

OK after learning some more!
The secret keys in the ECM need to match that of the WCM (I think I got that name right). These keys are normally transferred from the WCM to the ECM when doing an ECM replacement. And vice versa if replacing the WCM. The secret keys are not what indicates SKIM being locked/unlocked/reset, thats completely separate. Secret keys are what are compared to check if valid to start and used for replacement procedures. Whereas the SKIM section is the ECM itself being told whether it has previously detected the SKIM and to use the SKIM security. Once reset, the ECM does not look for the SKIM anymore so long as the SKIM is disconnected and not connected up again.

I am currently working with the GPEC2, I am hoping some if not all will apply to the other modules, but currently solved:
• Seed/key unlock
• Read/Write VIN
• Read/Write SRI (Odometer)
• Read/Reset SKIM

These are the 4 main things I've been tasked with, but Id like to extend this to properly link this in car by matching the secret keys from the WCM to ECM and even flash a base file in. Basically an all in one FCA ECM replacement tool.
Next will be the GPEC1 and GPEC2A, just cleaning up the app currently for some pictures of its current progress.

I am still SO AMAZED none of this is documented anywhere or even spoken about. Well.. I do get why since the one or two individuals on the planet which have gone to this extent don't want others to figure it out, but technicians need to understand the concept first so they are able to understand what needs to be done and why. Hopefully this will enlighten some poor sole reading about all this SKIM/SRI/Reset stuff and can have a better grip of it. :thumbup:
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The1
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Re: Chrysler SKIM Reset

Post by The1 »

smaller companies i guess have less leaked information not as highly sort after and depends on failure rate to i guess as to how important it is for someone to find a workaround.

Nice work though mate. :thumbup:
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Tazzi
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Re: Chrysler SKIM Reset

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The1 wrote:smaller companies i guess have less leaked information not as highly sort after and depends on failure rate to i guess as to how important it is for someone to find a workaround.

Nice work though mate. :thumbup:
That is true!
I was just more amused that not even basic things like common FCA commands like reading tables ect are even mentioned online, FCA vehicles seem to be a very secretive business.
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In-Tech
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Re: Chrysler SKIM Reset

Post by In-Tech »

Tazzi, you impress me every day :)
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Tazzi
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Re: Chrysler SKIM Reset

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In-Tech wrote:Tazzi, you impress me every day :)
I surprise myself sometimes. :lol:
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julespatch
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Re: Chrysler SKIM Reset

Post by julespatch »

Tazzi wrote: Interesting, I am going to have to log those processes and see what they do. From what I have ready, people full stop cannot get the ECMs to security link again after they have been, thus require the reset.

The secret keys stuff is what is basically wiped so its ready to go. I am yet to see what the security code after does, or which module it gets sent to so that will be interesting to see.
If you want to try it on a car one day send me the vin and I'll get the code for you. I've done a few and haven't had an issue. It's when you need to replace the WCM etc that things get tricky, with second hand bits anyway
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Tazzi
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Re: Chrysler SKIM Reset

Post by Tazzi »

julespatch wrote:If you want to try it on a car one day send me the vin and I'll get the code for you. I've done a few and haven't had an issue. It's when you need to replace the WCM etc that things get tricky, with second hand bits anyway
Seems many have massive issues with second hand. Maybe its an issue with VIN/secret keys mismatches or something along those lines, but when you have direct access to making modifications to this, that issue is eliminated.

With the WCM, I believe the same should be possible whereby the secret keys can be copied from the ECU into the WCM, and then programmed to the key FOBS (if I got that right.. something along those lines).
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Re: Chrysler SKIM Reset

Post by Tazzi »

A bit more work with the WCM.

So when it comes to key programming, at least on the variants I am dealing with, the WCM has a unique PIN which must be entered to then be allowed to erase or code keys. (Finally understanding this stupid pin implementation).
This pin can be read from the device (How stupid) and then entered back in to enable key programming/erase mode which seems to only be a couple commands which is very basic.

There are a few commands which I am a bit unsure about what they mean, they appear to be preparation commands or sorts, like "Dont log faults" or something along those lines.. going to have to dig through some more factory software to understand it better I believe. I could not find any SAE documents for FCA vehicle relating to common commands.. the best I found is this: https://www.sae.org/standards/content/j2610_202101/

Its snippet does state this which is kinda lame:

Code: Select all

This document does not specify the content or meaning of the application messages or diagnostic protocol to be transmitted on the SCI communication link
It does make references to alot of documents, but nothing that specifically says FCA with canbus.
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