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  1. #1
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    1995 LT1 Flashing Issues EEHack

    Hello guys,

    I hope someone can help me out.
    I'm trying to flash a 95 ECM on the bench using EEHack, but i´m getting an error when doing the flash and i'm not sure what i'm doing wrong...
    If someone can see the pictures and help me with this i would be very thankfull....
    ECM: 16188051

    Thanks
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  2. #2
    LT1 specialist steveo's Avatar
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    i did just answer this in a PM but just in case anyone else is reading:

    VPP voltage if you aren't aware is a signalling voltage to the EEPROM in a state where it can be erased/reprogrammed. without VPP it's 'safe' to twiddle any pins without actually damaging information on the EEPROM, we need to supply voltage to that pin to do any damage to it.

    unfortunately that flash routine built into eehack does not tell you why the VPP apply routine failed, it just gives up. my new flash tool will tell you but it's not quite ready yet.

    if you are really curious why its failing, open eehack's debug log and check the 'verbose' box it will dump all of its bus messages. right after it fails it'll probably spit out a short message containing a return code, which i could use to tell you why its failing.

    the VPP apply routine first checks the IGN voltage (it has to be 10.8 to 16 volts so that's unlikely to fail) but then it tries to apply VPP voltage and tests its output, which will fail if input voltage is insufficient. it must be in a very narrow range, so if your input voltage is too low, it'll fail. usually 11.5-13.5v of clean input is fine, though.

    what is the ignition voltage in eehack if you just run a datalog for a few seconds?

    be very careful flashing until you find out whats going on, a small failure might brick that ecm.....

  3. #3
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    Quote Originally Posted by steveo View Post
    i did just answer this in a PM but just in case anyone else is reading:

    VPP voltage if you aren't aware is a signalling voltage to the EEPROM in a state where it can be erased/reprogrammed. without VPP it's 'safe' to twiddle any pins without actually damaging information on the EEPROM, we need to supply voltage to that pin to do any damage to it.

    unfortunately that flash routine built into eehack does not tell you why the VPP apply routine failed, it just gives up. my new flash tool will tell you but it's not quite ready yet.

    if you are really curious why its failing, open eehack's debug log and check the 'verbose' box it will dump all of its bus messages. right after it fails it'll probably spit out a short message containing a return code, which i could use to tell you why its failing.

    the VPP apply routine first checks the IGN voltage (it has to be 10.8 to 16 volts so that's unlikely to fail) but then it tries to apply VPP voltage and tests its output, which will fail if input voltage is insufficient. it must be in a very narrow range, so if your input voltage is too low, it'll fail. usually 11.5-13.5v of clean input is fine, though.

    what is the ignition voltage in eehack if you just run a datalog for a few seconds?

    be very careful flashing until you find out whats going on, a small failure might brick that ecm.....
    Thanks for the quick answer...
    I saw your PM now.
    I will do some tests on the afternoon / night and see if i can get that Log messages and let you know...
    Questions: from the USB-TTL adapter, do we need to connect the VCC to anything?
    I just have the GND, RX and TX connected...

  4. #4
    LT1 specialist steveo's Avatar
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    Quote Originally Posted by boxsport View Post
    Thanks for the quick answer...
    I saw your PM now.
    I will do some tests on the afternoon / night and see if i can get that Log messages and let you know...
    Questions: from the USB-TTL adapter, do we need to connect the VCC to anything?
    I just have the GND, RX and TX connected...
    nope, just rx/tx and ground.

  5. #5
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    Quote Originally Posted by steveo View Post
    nope, just rx/tx and ground.
    Ok, so i just tried again and still same error...
    I'm uploading here the log you mention to do and also the picture of the "Stability Test" so that you can see that i got no errors...
    Doing the flash, im using both "Skip Unused Regions" and "Insert Patches" options activated (not sure if this is the way).
    As i remember i also read with those options activated...

    Can you take a look at the log and see if there is anything i can do to solve this?
    Also, about the voltage, when i tried this minutes ago it was giving me 13.6V.
    I also made the test using 12V showing on EEHack and still same problem...
    By the way, i tried to change VIN and it worked. I made the VIN change without any problems...
    Can this be related to the COM por configurations? i have it setup with "1" in latency and speed with 9600 (Default)

    Thanks
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    Last edited by boxsport; 04-03-2020 at 05:34 AM.

  6. #6
    LT1 specialist steveo's Avatar
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    yeah the vpp voltage isn't sufficient, maybe its the power supply or a connection. check all your connections and power the ecm from a charged battery rather than your power supply to see if that works.

  7. #7
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    What is the purpose of that blue box between the pcm and power supply?

  8. #8
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    Quote Originally Posted by kur4o View Post
    What is the purpose of that blue box between the pcm and power supply?
    if your asking about the blue PCB were the cable go conneted, its and OBD2 adapter / PCB so that i can connect ECM/ECU, Dash, Immo box, etc for some bench tests...
    In this case, i´m just using it to supply voltage and ground to the ECM, because it has several pinouts / connections that makes bench tests easier for me...
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