Vida CEM swapping

oscilloscope · Post by **oscilloscope** » 22 Jan 2023, 14:50

brobert wrote: ↑22 Jan 2023, 13:58 ECU, ECM, CEM - what a soup of acronyms
I think that I've seen Volvo refer to *any* module in the car as "ECU".
Egg on face for sure but glad that we got this cleared up.

@rkam
Yes, T5Luke wrote a CEM dumper but you need a DICE and I only have a Mongoose cable (DICE clones are stupid expensive).
Now that I think of it, I might be able to edit the embedded DICE string and make it use my Mongoose cable.

In the past I customer would call them brains , so engine brain , body brain , rear body brain. , it did get even more confusing when they would use the correct acronym and use completely different words to fit it.

bobbik · Post by **bobbik** » 22 Jan 2023, 14:53

Yes, T5Luke wrote a CEM dumper but you need a DICE and I only have a Mongoose cable (DICE clones are stupid expensive).
Now that I think of it, I might be able to edit the embedded DICE string and make it use my Mongoose cable.

Is that dumper works also for P1 CEM with two Motorola MCU's? Where can I find it?

dikidera · Post by **dikidera** » 22 Jan 2023, 17:10

brobert wrote: ↑22 Jan 2023, 13:58 ECU, ECM, CEM - what a soup of acronyms
I think that I've seen Volvo refer to *any* module in the car as "ECU".
Egg on face for sure but glad that we got this cleared up.

@rkam
Yes, T5Luke wrote a CEM dumper but you need a DICE and I only have a Mongoose cable (DICE clones are stupid expensive).
Now that I think of it, I might be able to edit the embedded DICE string and make it use my Mongoose cable.

Why would you need DICE? What is so special about DICE? It uses the very same principle as literally anything else. An MCU, a CAN controller and CAN transceiver.

rkam · Post by **rkam** » 22 Jan 2023, 23:47

dikidera wrote: ↑22 Jan 2023, 17:10
Why would you need DICE? What is so special about DICE? It uses the very same principle as literally anything else. An MCU, a CAN controller and CAN transceiver.

DiCE is made to be used as a J2534 interface. It is J2534-2 compliant. Not all J2534 interfaces are.

The reader mentioned looks for DiCE in the registry, and find the path to the .dll file that handles the J2534 communication.
Therefore a DiCE is needed to use this software, unless you change the software or registry entries.

Many software tools, also commercial ones, are based on Marks J2534 implementation starting out as a lua script early 2012.

NFedor · Post by **NFedor** » 23 Jan 2023, 00:08

Hello. Did you manage to find the algorithm for calculating the checksum in eeprom CEM? Example C5EB8216-CRC 71B1, C5EB5B84-CRC C98E.

dikidera · Post by **dikidera** » 23 Jan 2023, 07:25

rkam wrote: ↑22 Jan 2023, 23:47
dikidera wrote: ↑22 Jan 2023, 17:10
Why would you need DICE? What is so special about DICE? It uses the very same principle as literally anything else. An MCU, a CAN controller and CAN transceiver.
DiCE is made to be used as a J2534 interface. It is J2534-2 compliant. Not all J2534 interfaces are.

The reader mentioned looks for DiCE in the registry, and find the path to the .dll file that handles the J2534 communication.
Therefore a DiCE is needed to use this software, unless you change the software or registry entries.

Many software tools, also commercial ones, are based on Marks J2534 implementation starting out as a lua script early 2012.

It is a bummer that all J2534 revisions/specs are paid. But it's actually fairly surprising that no one has leaked a single copy.

Post by **vtl** » 23 Jan 2023, 08:08

dikidera wrote: ↑23 Jan 2023, 07:25 It is a bummer that all J2534 revisions/specs are paid. But it's actually fairly surprising that no one has leaked a single copy.

https://github.com/hackingvolvo

dikidera · Post by **dikidera** » 23 Jan 2023, 08:34

Haha, vtl I know about it and have been using it. I had to modify the code a bit to allow it to work with RPI and my next changes are to allow it to work with high and low speed CAN simultaneously, as it currently only supports low speed CAN. Additionally a very thin wrapper had to be written to allow communication between the Windows driver and the RPI, as it was originally written for Arduino. One little problem is that VIDA sets a 60ms timeout for messages, so this means I have to pass the VIDA message via my chosen communication protocol, to my wrapper which transmits it via can and waits for a reply to send back via the wrapper to VIDA on windows all of which should happen below 60ms.
Additionally it is missing a lot of functionality, like filters and so forth. Olaf never got around to doing it, as he seemingly disappeared after early 2013 and as such the project was abandoned.

But regardless, my comment was about the other revisions of CAN, I can find a PDF for the very first j2534 spec, but nothing about j2534-2.

rkam · Post by **rkam** » 23 Jan 2023, 09:57

I believe J2534-2 is an extension to allow communication with more modules.
Here are some sections marked with J2524-2
https://github.com/diamondman/J2534-Pas ... 34_v0404.h

DiCE J2534 help file can also be useful.

J2534.zip: (116.44 KiB) Downloaded 123 times

Some history and revisions:
https://www.kvaser.com/developer-blog/s ... on-part-1/

Constantinos · Post by **Constantinos** » 23 Jan 2023, 10:23

Good evening.
I have been for a cheap but effective way to unlock my cem pin through the obd2 port
I found the teensy 4.0 method but I'm having a hard time finding parts.
I found a pcb file which has all the wiring for the pcb as well.
However, I cannot find the bosch cf160 transceivers needed for the job.
Also, in the schematic on github, I can see that some resistors that need installing, but I'm not sure where to install them on the pcb.
The pcb link:
https://www.pcbway.com/project/sharepro ... 037d5.html

The github link: https://github.com/vtl/volvo-cem-cracker

Vida CEM swapping

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