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Thread: LS1B Bricked?

  1. #1
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    Default LS1B Bricked?

    I flashed in the custom os for my 2005 silverado because I'm preparing the truck for boost. Then flashed in the cal file. Truck started and ran so i read the file and saved it so i could change all the values to prepare for boost. I decided to flash the stock tune and stock o/s back in so i could drive the truck later. Right when i started flashing the truck i realized the key wasn't on so i made the dumb mistake of cancelling the flash. EFI live cancelled the flash but now i can't communicate to the ecm. When i hit auto-detect it doesn't detect the ecm. I tried pulling the negative battery cable and pulling ecm fuses. Also tried resetting the computer but i still can no connect to the ecm. From research on here it seems like i bricked the ecm. Thoughts?

  2. #2
    EFILive Developer Site Admin Blacky's Avatar
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    If it was only a cal-flash then the PCM should be fine. However it will be in dead-poll mode. That is a state where it has no calibration and cannot "identify" itself to EFILive so the auto-detect does not work. You should be able to just restart the flash process and it should recover the PCM.

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    Paul
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  3. #3
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    It was a full flash. I was going from a custom o/s back to the regular o/s.

  4. #4
    EFILive Developer Site Admin Blacky's Avatar
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    If it was a full flash then yes it is probably bricked. It can be recovered by removing the flash chip from the main circuit board and reprogramming the flash chip in an external flash chip programmer. I believe SoCal Diesel offer that service.

    One way to know for sure is after hooking up FlashScan, watch the orange LED second from the right. If it blinks rapidly (4 times per second) all the time, then the PCM is in dead-poll and should be recoverable. That contsant blinking is the PCM "asking" any connected tool for a new calibration. If it blinks just a few times and then stops then it is bricked, in that case the initial burst of blinking is attempting to contact the PCM.

    Regards
    Paul
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  5. #5
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    Thank you for the reply Paul. I'm sure it is bricked, and i learned an important lesson from this. I sent it out today to PCM Calibrators to reflash the chip and get me back on the road.

  6. #6
    EFILive Developer Site Admin Blacky's Avatar
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    We've all done it at least once, some more than once

    In future if you ever do interrupt a full-flash (before it's about 15-20% done), keep power supplied to the PCM as long as possible and keep restarting the flash process until it completes successfully.

    During a full-flash the EFILive software sends up a custom piece of software (called a boot loader) that is placed in the PCM's RAM* and executed. The boot loader takes control of the PCM and is responsible for communicating with the EFILive software and reprogramming the PCM with the data that EFILive sends to it. So long as power is maintained to the PCM, that boot loader will continue to run in the PCM's RAM - waiting for another full-flash attempt. Once a full-flash is complete the boot loader terminates and returns control to the PCM.

    Obviously if the flash does not complete at least the first 15-20% and power is removed/restored, then when the PCM powers up there is not enough of the operating system in the PCM to be able to communicate with FlashScan (or any other tune tool) effectively bricking the PCM by preventing it from communicating with the outside world.

    * Random Access Memory or volatile memory, memory that is lost when power is removed (i.e. not flash memory which is where the OS and calibrations are stored).

    Regards
    Paul
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  7. #7
    Joe (Moderator) joecar's Avatar
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    Very good refresher course (on full flash, don't remove power, just try flashing again), thanks Paul.


    If it was a cal-only flash, then I take it the PCM is using its own loader (i.e. resides in the non-cal part of flash)...?


  8. #8
    EFILive Developer Site Admin Blacky's Avatar
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    Quote Originally Posted by joecar View Post
    If it was a cal-only flash, then I take it the PCM is using its own loader (i.e. resides in the non-cal part of flash)...?
    Correct, the GM VPW comms code is in the operating system. During a full-flash the operating system is also erased which means the GM VPW comms code is erased. The only way to communicate with the ECM after the full-flash is erased is via the EFILive boot loader running in RAM. If power is removed that boot loader in RAM is gone and the PCM is a brick. The full-flash boot loader will continue to run forever so long as power is maintained to the PCM.

    Note: that is different to the cal-flash boot loader which will eventually self terminate if FlashScan is no longer communicating with it. But a failed cal-flash is always recoverable.

    Regards
    Paul
    Before asking for help, please read this.

  9. #9
    Lifetime Member Tre-Cool's Avatar
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    I killed my 1st ls1b the other week myself on the bench. efilive itself froze and since i had no idea at what stage it was at, made the mistake of turning the ecu off

  10. #10
    Lifetime Member GMPX's Avatar
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    GM did things better after the LS1 PCM by putting a bootblock in the ECM that never needs to be erased or programmed, this way if the OS and cals are erased the ECM still has enough in there to be able to communicate with a reflash tool. You can't blame them though as these PCM's weren't designed to be flashed multiple times per day, just a couple of times at the dealer in the life time of the car was probably what they designed them around.
    I no longer monitor the forum, please either post your question or create a support ticket.

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