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Thread: NEED Tech Help. 0411 Swap, PCM locked after third flash??

  1. #1
    Electronic Ignition!
    Join Date
    Apr 2022

    NEED Tech Help. 0411 Swap, PCM locked after third flash??

    IDK if this is the right topic forum or not, but I'm looking for tech help. I bought a junkyard 0411 PCM out of a 02 Express v6(according to the tune file I pulled from it.) I was able to find a 02 Express 5.7 tune and segment swap a s10 4l60e 4x4 trans segment in. I disables VATS, removed some Emissions reporting CELs, disabled EGR, that kind of thing, but left tune nearly stock using TunerPro. On my bench harness, ran a couple flashes onto the PCM with PCM Hammer and OBDlink SX cable, no Problem. Finally was able to do the swap into my 99 OBS suburban, all good(needs some tuning, but that's another issue). I only had one set of PCM plugs, so my bench harness was then used to install the PCM into my truck. I had to make some tweaks and reflash again in the truck through the obs port, all went well. I went back out to reflash another tweak, and now PCM Hammer says it can't unlock the PCM for the flash??? I was able to open the PCM and ground out the pin allowing my to read and flash it, but this shouldn't be needed every time, because no matter what I do, It stays locked. I didn't set a lock on it, and it has worked fine until now. I did move the PCM Hammer file folder on my PC from one spot to another, but that shouldn't effect it I think. I checked the tune's VIN(generic vin with 00000 for the build #), So just in case it looked invalid, I changed the VIN to a valid matching vin I found online for a 2002 Express 5.7 1500, it took the change, but still locked. I set PCM hammer to have a user created Lock and flashed it, it refused the user lock code, and remained locked. I am racking my brain to try and disable to lock so I can go back to using my flash like normal, is there something I have missed or overlooked? My PCM isn't bricked, it will flash with a ground pin bypass, but this is crazy to have to do every time.

  2. #2
    Fuel Injected!
    Join Date
    Nov 2019
    Bossier City, Louisiana
    Are you flashing a file that has checksum errors?

    1970 Chevy El Camino, LM7 Engine, 4L60E - Two 896 and two 0411 PCM's

  3. #3
    Electronic Ignition!
    Join Date
    Apr 2022
    No, I don't think so. I am using the 12212156 02 Express Van tune from "LS_Based_Engine_Repository-master" zip as my base. Using the correct 12212156 xdf from the repository zip and imported the checksum plugin from that zip as well into my TunerPro Files(documents\TunerPro files\Plugins). Before moving the plugin to my Tunerpro Files, I did get a notification of checksum error, but once I moved the plugin over I did not get any checksum errors when saving my tunes. Just for giggles, I guess I can grab the 100% stock Express l31 tune and the 'stock' trans segment swapped tunes and flash those on to see if they lock up as well.

  4. #4
    Electronic Ignition!
    Join Date
    Apr 2022
    Figured it out... Through an afternoon of splicing tunes, flashing, and reading the PCM, I found that the 02 Express L31 tune I used as a base was somehow corrupted? If flashed on fine and edits in TunerPro fine, but once you flash it on, PCM does not respond to unlock so it can't be read or flashed again. Long story short, during the flashes, I would see that if the OS was the read as the same in PCM Hammer, it wouldn't re-write that section, which made me think to try a different OS tune, just to see if it would unlock after that. Yep it did, Put on a 01 s10 tune, unlocked NP. Went back to the unmolested 02 Express L31 2wd I started from, and won't unlock again... Went to a 02 Express 2500 L31 4l80e 2wd Tune, and PCM Hammer shows that one section of the OS is different, even though both are 12212156. Strange Right? Anyway, that tune unlocked fine. So I have to go back to the beginning and Segment swap my 4x4 4l60e section into the express 2500 tune. Flashed that in and All Good! Runs(enough) like its supposed to, and now will unlock for tuning when I get that far along. Thank for the help!

    PS the corrupted Tune I used was titled "2002 Chevrolet Express Van Automatic L31 5.7L 4L60e 2wd (12212156) Lean Cruise" In the "LS_Based_Engine_Repository-master" zip, just in case anyone else has similar issues.

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