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Update: J2534 Bus Analysis Tool (and specs!)

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by MrPete, Aug 24, 2023.

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  1. MrPete

    MrPete Active Member

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    I spent a few round-toit's digging into the details on the J2534 bus, its specs, and the free Bus Analysis Tool. Here's what I learned. (NOTE: I've not yet used any of these tools ;) )

    There are two versions of the tool, for two different versions of the J2534 spec
    Does it matter which version? I think it may make a BIG difference. This could explain many incompatibilities. NOTE: 2004-12 was the first rev since 2002-02 version. And 2015-10 was first since 2004-12!

    While SAE charges over $150 for a copy of the specs, there's no charge for a preview of the Table of Contents. That told me much of what I needed!
    • The 2004-12 version standardized many things, not least the ability to "Pass-Thru" various communications.
      • More importantly, it standardized support for seven communication protocols (ISO 9141, ISO 14230-4 (KWP2000), SAE J1850 41.6 kbps PWM, SAE J1850 10.4 kbps VPW, CAN, ISO 15765-4 CAN, SAE J2610 DaimlerCHrysler SCI)
      • And it standardized Simul-cast on multiple protocols
    • The 2015-10 version made significant improvements
      • Support for ISO 15765 both full and half duplex; individual per-channel timing/control
      • Specs refined to handle ambiguities, error handling and more.
      • Support for combined/same-link CAN + ISO 15765
      • Pass-Thru Device Discovery added (and specific support for wireless/BT devices)
      • Support for larger messages (original:4-4101 bytes; 4128 for J1850VPW; not sure how much more the newer spec supports, but I am pretty sure it's needed for various reprogramming/update tasks.)
    Since the 2015-10 revision, of course there's been an ongoing series of further refinements.

    AFAIK, 2015-10 is now known as J2534-2 while 2004-12 is J2534-1.

    I'm hoping the above bit of research may help our community untangle why some cables and dongles work well, and others don't.
     
  2. ChapmanF

    ChapmanF Senior Member

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    You could probably color me surprised if any of the J2534 devices we typically talk about on here even claim or try to support a spec from the last decade.

    Possibly the pro-level Drew Tech ones (or whatever the name of that outfit is now).
     
    Tombukt2 likes this.
  3. jzchen

    jzchen Newbie!

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    I believe several of the pins on the OBDII interface are manufacturer prerogative. What you really need to handle all the manufacturers combined is what I believe is called in electronics a big MUX, lines are assigned depending on manufacturer. Some are fixed, and some manufacturers are shifting to using the J whatever # standard for diagnostics.

    My VXDiag Multi Diag is one device that handles quite a few manufacturers based on a license I have to pay per manufacture, (unless you buy a package with all of them):

    VXDIAG Multi Diag Serie
     
  4. jzchen

    jzchen Newbie!

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  5. MrPete

    MrPete Active Member

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    What did you attach? It's a bad link :(