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Thread: PCM and BCM Swap possibility???

  1. #1
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    Default PCM and BCM Swap possibility???

    Hi guys,

    I was wondering if its possible to swap my PCM and BCM with the intention of the GM dealer flashing from an 02 trailblazer I6 to an 03 trailblazer I6
    s Vin OS while at the same time pass the state car inspection with a different Vin number not matched to my registration card? The addin features from an 02 to an 03 trailblazers are about the same so I dont think I will have any electrical problems.

    Since I do not think it is possible for efilive to add the feature to adjust the Fuel Gauge amount on the pcm, my intention was to swap to a 03 Vin so that I can obtain the extra fuel package that the 03 trailblazer has that no 02 will ever have. Has anyone with a different Vin ever pass the state inspection?

    Thanks
    2002 4.2L I6 Trailblazer LTZ

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    Hate to say it, but why not just use the other software and full flash an 03+ OS into it? If its really in the PCM, that will do it. If not, then change your VIN to an 03 one and have a dealer flash the BCM. Once they flash you'll have to use that VIN otherwise I dont believe the VATS will let the engine start.
    ~Erik~
    2013 Sonic RS Manual - 1.4L I4T E78, starting the mods
    2008 TrailBlazer SS 3SS AWD Summit White - LS2 E67/T42, bolt ons, suspension, etc.
    2002 Chevy TrailBlazer LT 4X4 Summit White - 4.2L I6 P10, lifted, wheels, etc.

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    Quote Originally Posted by ScarabEpic22 View Post
    Hate to say it, but why not just use the other software and full flash an 03+ OS into it? If its really in the PCM, that will do it. If not, then change your VIN to an 03 one and have a dealer flash the BCM. Once they flash you'll have to use that VIN otherwise I dont believe the VATS will let the engine start.
    Thats a good idea but will I be able to pass the state inspection with a different Vin number?
    2002 4.2L I6 Trailblazer LTZ

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    Quote Originally Posted by goldbergv95 View Post
    Thats a good idea but will I be able to pass the state inspection with a different Vin number?
    Have to check with your local DMV to answer that one, I dont even know what the rules are in Washington and Ive lived here my whole life.
    ~Erik~
    2013 Sonic RS Manual - 1.4L I4T E78, starting the mods
    2008 TrailBlazer SS 3SS AWD Summit White - LS2 E67/T42, bolt ons, suspension, etc.
    2002 Chevy TrailBlazer LT 4X4 Summit White - 4.2L I6 P10, lifted, wheels, etc.

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    Quote Originally Posted by ScarabEpic22 View Post
    Have to check with your local DMV to answer that one, I dont even know what the rules are in Washington and Ive lived here my whole life.
    Hmm Ill have to ask the dealer later.

    I was thinking of purchasing the Tech 2 program. Will this beable to flash the bcm and the pcm?
    2002 4.2L I6 Trailblazer LTZ

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    Yes, I believe you need a yearly subscription to GMs SPS service and its not cheap. I want to say $1000+ a year but its probably more.
    ~Erik~
    2013 Sonic RS Manual - 1.4L I4T E78, starting the mods
    2008 TrailBlazer SS 3SS AWD Summit White - LS2 E67/T42, bolt ons, suspension, etc.
    2002 Chevy TrailBlazer LT 4X4 Summit White - 4.2L I6 P10, lifted, wheels, etc.

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    Well, I talked to the state inspector and they said this wont be a problem since they dont check the pcm.

    But Erik even if I did flash the pcm from an 02 to an 03, the OS would be the same. The updated OS on an 02 is completely different from an 03. I seem to lost the site where they can disclose the pages of OS if the pcm or bcm needs update. Do you remember the site?
    2002 4.2L I6 Trailblazer LTZ

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    Quote Originally Posted by goldbergv95 View Post
    Well, I talked to the state inspector and they said this wont be a problem since they dont check the pcm.

    But Erik even if I did flash the pcm from an 02 to an 03, the OS would be the same. The updated OS on an 02 is completely different from an 03. I seem to lost the site where they can disclose the pages of OS if the pcm or bcm needs update. Do you remember the site?
    Good to hear, non-issue then.

    If you changed the VIN, the OS would be the same. If you upgraded the OS to an 03 one to get the fuel tank calibration, then the OS would be different. Do you know for sure the fuel tank calibration is stored in the BCM or is it stored in the PCM? Figure that out first, then determine if you need to flash the BCM or upgrade the PCM OS to an 03 (go to 05 if you're going to do it).
    ~Erik~
    2013 Sonic RS Manual - 1.4L I4T E78, starting the mods
    2008 TrailBlazer SS 3SS AWD Summit White - LS2 E67/T42, bolt ons, suspension, etc.
    2002 Chevy TrailBlazer LT 4X4 Summit White - 4.2L I6 P10, lifted, wheels, etc.

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    Quote Originally Posted by goldbergv95 View Post
    Well, I talked to the state inspector and they said this wont be a problem since they dont check the pcm.

    But Erik even if I did flash the pcm from an 02 to an 03, the OS would be the same. The updated OS on an 02 is completely different from an 03. I seem to lost the site where they can disclose the pages of OS if the pcm or bcm needs update. Do you remember the site?
    http://tis2web.service.gm.com/tis2web
    Is this what you want?

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    Quote Originally Posted by Jedi_Jr View Post
    YES!!! perfect!!! Thanks a lot!


    Quote Originally Posted by ScarabEpic22 View Post
    Good to hear, non-issue then.

    If you changed the VIN, the OS would be the same. If you upgraded the OS to an 03 one to get the fuel tank calibration, then the OS would be different. Do you know for sure the fuel tank calibration is stored in the BCM or is it stored in the PCM? Figure that out first, then determine if you need to flash the BCM or upgrade the PCM OS to an 03 (go to 05 if you're going to do it).
    Yeah the gm tech 2 is about 2 grand but I heard the software updats is only free for the first 5 months. I might get it since nowadays gm dealers have been pretty busy lately.

    Didm't you say the fuel change is stored in the PCM? Regardless, I have to reflash the bcm if I change to the 03 vin or else i would get electric problems. But something still bugs me. Even if I changed the Vin is there a way also change the OS based on the 2003 tbs? Or will I have to get a flash from the dealer.

    BTW, I would do a 05 swap but 05s have air bag and other features that 02s and 03s dont have which might fail the state inspection. Plus I saw an additional wire that is connected to a connector located on the exhaust manifold that 02s and 03 dont have.
    2002 4.2L I6 Trailblazer LTZ

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