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Thread: "new" PCM/TCM in vehicle = no crank

  1. #1
    Potential Tuner
    Join Date
    Sep 2020
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    2

    "new" PCM/TCM in vehicle = no crank

    Let me preface this by saying, I only do a limited number of LS based stuff every year. Recently I've been asked to do more and more, so I'm on a steep learning curve.

    Customer has a 2008 TBSS with some 3rd party software on the PCM. Customer installs supercharger and requests I tune it (at this time, the vehicle will start and run). When I arrive the PCM and TCM are locked and I can neither read nor write to either unit. GM technician attempted to wipe them clean and could not. Customer sourced a new PCM and TCM from junkyard from a 2008 Malibu. I licensed a stock 2008 TBSS file from the repository and was able to write to both the PCM and TCM. I was sure to swap vins and disable VATS. After completing the flash, the truck will not start (starter does not engage). Did I do something wrong? Are the two PCM's incompatible/have different pinouts despite being the same type and year? Any help would be appreciated. Both files are enclosed below (hopefully).


    Malibu ripped ROM.hpt

    Stock TBSS rev2.hpt

  2. #2
    Advanced Tuner
    Join Date
    Oct 2013
    Posts
    550
    Quote Originally Posted by dux10 View Post
    Let me preface this by saying, I only do a limited number of LS based stuff every year. Recently I've been asked to do more and more, so I'm on a steep learning curve.

    Customer has a 2008 TBSS with some 3rd party software on the PCM. Customer installs supercharger and requests I tune it (at this time, the vehicle will start and run). When I arrive the PCM and TCM are locked and I can neither read nor write to either unit. GM technician attempted to wipe them clean and could not. Customer sourced a new PCM and TCM from junkyard from a 2008 Malibu. I licensed a stock 2008 TBSS file from the repository and was able to write to both the PCM and TCM. I was sure to swap vins and disable VATS. After completing the flash, the truck will not start (starter does not engage). Did I do something wrong? Are the two PCM's incompatible/have different pinouts despite being the same type and year? Any help would be appreciated. Both files are enclosed below (hopefully).


    Malibu ripped ROM.hpt

    Stock TBSS rev2.hpt

    Specific language is always beneficial ...

    PCM = Powertrain Control Module (controls the engine and automatic transmission).

    ECM = Engine Control Module (controls the engine only).

    TCM = Transmission Control Module (controls the transmission only).

    Locked ECMs are just that - you generally cannot reprogram them, even with GM software.

    If you are going to do tuning for others (and charge them a fee), then you need to invest the time to self-educate. There are many threads on this Forum, that clearly tell you that you cannot use the method that you did, to reprogram a Gen 4 ECM.

    The 2008 Malibu E67 ECM must be initially programmed with GM software using a Tech 2 / MDI / etc. with a VIN based TBSS calibration. Tuning software cannot accomplish this task.

  3. #3
    Advanced Tuner
    Join Date
    May 2006
    Location
    Seattle, WA
    Posts
    538
    What Jon said, you need to flash the Malibu ECM with a factory calibration from GM's SPS so the DBW segments will be updated.
    ~Erik~
    2013 Sonic RS - manual, CGM, 6M, sunroof, mods in process
    2008 TrailBlazer 3SS AWD LS2, loaded, dropped, modded, SE22 Performance tuned. And then some...
    2002 TrailBlazer LT 4WD 4.2L I6, lifted, tires, exhaust, SE22 Performance tuned