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Thread: GMLAN canbus messages

  1. #1
    Tuner in Training
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    GMLAN canbus messages

    I have recently been reading and learning about the messages on the high speed (HS) gmlan canbus. My goal is to understand which of the messages are and make them available for everyone

    Searching the internet, there are some messages covered and the 'GMLAN bible' doesn't help a lot when it comes to the HS messages. My understanding is that GMW8762 covers the message ID's and format.

    Does anyone have access to GMW8762? It would help a lot. To start I really want to hunt down the elusive "AC compressor command" so I can manually send it without the BCM.

    Otherwise, does anyone have any captured data from their vehicle they are willing to share or exchange so I can pick it apart for the communities benefit?

    This is an example of the datastream:

    ID DATA
    F9 00004000000000FF
    3C9 0400000000000000
    1ED 0190000000000E54
    C7 03FE0000
    280 0000000000000000
    1AF 0000
    191 06150615056F0000
    1ED 0190000000000E54
    C7 03FE0000
    1F9 000000008000FF00
    19D 00000000000000FF
    C7 03FE0000
    12A 42000000B2661FFF
    134 00001000
    1ED 0190000000000E54
    1EF 00000000
    F9 00004000000000FF
    3C9 0000000000000000
    F1 8D000040
    C7 03FE0000
    F1 B1000040
    19D 40003FFF000000FF
    1F5 0F0F000100000300
    1ED 0190000000000E54
    C7 03FE0000
    199 8FFF0E70F18E00FF
    F1 99000040
    1E1 00FE060040
    C7 03FE0000
    1F9 000000008000FF00
    C9 0000000700400800
    1EF 00000000
    F1 A5000040

    example. message id's with ID 1F5 have the PRNDL shifter status (great to know if you 6l80 tcm sends reverse status over gmlan)

    byte 4 is the status

    1F5 0F0F000100000300 - this is Park
    1F5 0F0F000200000300 - this is Reverse
    1F5 0F0F000300000300 - this is Neutral
    1F5 0F0F000400000300 - this is Drive

    I have heaps more info to share if anyone is interested.

  2. #2
    Tuner in Training
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    I have some logged data I can share. This is from a 2008 Pontiac Solstice GXP Manual Trans

    08_gxp.txt

  3. #3
    Tuner in Training
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    Quote Originally Posted by kgschlosser View Post
    I have some logged data I can share. This is from a 2008 Pontiac Solstice GXP Manual Trans

    08_gxp.txt
    Thanks for sharing. I'll take a closer look.

    Have you confirmed what any of the messages are related to?

  4. #4
    Tuner in Training
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    I have managed to get decoded partially the following ID's:

    0c9 -- RPM and throttle pedal % (missing other fields)
    4c1 -- ECT and IAT (missing other fields)
    4d1 -- Oil Pressure (missing other fields)
    3e9 -- Vehicle speed

    I am still looking for:

    In particular: Ambient air temp, baro pressure, manifold pressure.

    I am also looking for any info on the broadcast messages above to fill in the missing values, but also the below which I see in the data streams:

    0f9 (80Hz)
    1c3 (40Hz)
    1ed (80Hz)
    1ef (80Hz)
    1f5 (40Hz)
    2c3 (20Hz)
    3c1 (10Hz)
    3d1 (10Hz)
    3f9 (4Hz)
    3fb (4Hz)
    4c9 (2Hz)
    4f1 (1Hz)
    772 (1Hz)

    Any info to help fill in the details would be appreciated. Willing to share what I have as well.

  5. #5
    Tuner Joe6pt0's Avatar
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    Anybody have any updates to this? I'm looking for this info as well.

  6. #6
    Advanced Tuner
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    buy this https://global.ihs.com/doc_detail.cf...s_key=00443334

    it's the engineering standard docs from GM. it will have all of that info.

    example:
    0F9.PNG