WIP, I just pasted some notes here. Poorly formatted for the moment, I'll work on this later
I'll assume most of you already know what J2534 is or are smart enough to look it up. In any case, this sums it up:
(from
http://www.drewtech.com/customers/diagaftmkt.html )
****
SAE J2534 is a standard for communications between a computer and a vehicle. Government regulations require all automakers provide a J2534 service to everyone in the U.S. for re-flashing emissions related controllers. If you own a SAE J2534 Pass-Thru device, you can re-flash and, in some cases, diagnose vehicles with factory functionality.
****
The standard itself is available from SAE ($$), or as a copy hosted on archive.org (copy of the adopted US law; same contents as the SAE doc)
**** what, and why ****
So, a typical setup will look like this
- PC runs proprietary / closed / mfg-provided software which does something interesting and undocumented (reflash, advanced parameter monitoring, work support, etc)
- PC connects to car through a J2534 device (probably over OBD connector, K line / CAN etc)
- the J2534 device comes with J2534 drivers, which provide a standardized, documented API that PC software can use
- the PC software should work with any J2534 device, or at least let the user choose which one to use.
What we want to do, is intercept and log the calls made to the J2534 dll by inserting a "shim" between the application and the normal J2534 dll.
"ptshim" is a J2534-compliant dll that looks just like a regular, physical device. So the PC software doesn't see the difference.
When loaded, the ptshim driver will ask which real, physical J2534 device to use.
Basically this is a "man in the middle" type of deal; all in software.
**** how ****
1) setup ptshim dll
ptshim project page on old google code:
https://code.google.com/archive/p/j2534-logger/They have a prebuilt installer, and misc binairies
https://code.google.com/archive/p/j2534 ... /downloadshttp://j2534-logger.googlecode.com/file ... logger.msiI think I manually extracted the dll from one of those, and added the required registry entry myself. The msi probably takes care of that, I forget. The reg keys needed are described in the J2534 docs, and end up in
HKEY_LOCAL_MACHINE\SOFTWARE\PassThruSupport.04.04\
2) load PC software
easy, proceed as normal but select the ptshim device
3) ptshim should probably show a window like this:
http://j2534-logger.googlecode.com/file ... dialog.jpgand that's where you select your j2534 device (openport, cardaq, whatever)
4) config : set some options in there, and you should be all set.
5) run PC software as usual
6) harvest sweet logs !
