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Thread: 2004 Cavalier with a L61 2.2 Ecotec - problems in reading the ECU

  1. #1
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    2004 Cavalier with a L61 2.2 Ecotec - problems in reading the ECU

    After playing with my various 5.3 LM7 engines, finally needed to play with my commuter cavalier. It is a CNG Bi-fuel but the tank has now expired (and will be removing that) and I just finished updating the broken timing chain and friends. Its back on the road. I have deleted the CNG fuel injectors (and sold them) and its intake manifold. Getting code P2665 which makes sense, as that is Fuel Shut off B control circuit open, and that part of the harness is now gone. So I want to first turn off that (and any other related) code.

    So this morning I whip out my HPTuners and read the image.

    I press "Gather info" and I get:

    VIN: 3G1JC52604S178363
    2004 Chevrolet Cavalier 2.2L 4 Cyl
    OS: 12596935

    okay, so good

    then press READ

    reads for some 5 seconds and then nothing. No further information, various boxes are emptym, no ECU information - nothing. Try several times, cycle the key, etc.

    SO I am not familiar with this ECU, so now is the time to learn. Therefore I am looking for more information on what happened. I know HPTuners says it supports 2004 Cavs, but does it handle the Bi-Fuel ECUs? Am I a one off, some other issue, I don't know.

    If I need to, I can order another ECU w/o Bi-Fuel. What is the GM part number for a 2004 Cav standard GAS ECU?

    I see on ebay some part numbers for 2004 Cavs: 12584709, 12579654

    thanks
    Last edited by dougbert; 02-01-2019 at 03:20 PM.

  2. #2
    Senior Tuner cobaltssoverbooster's Avatar
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    is there an option for you to read the ecu in low speed mode?
    rdrfabrication@gmail.com
    2016 GMC 3500 Denali Diesel
    2000 Ford Mustang - Top Sportsman

    Ecotec help can be found here:
    LNF-http://www.hptuners.com/forum/showth...357-LNF-Guides
    LSJ-http://www.hptuners.com/forum/showth...965-LSJ-Guides

  3. #3
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    ah, yes, the high speed is clicked. will turn it off.

    thanks for the prompt response

    looking forward to playing with this little 4 banger

  4. #4
    Senior Tuner cobaltssoverbooster's Avatar
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    if this doesnt work and you can connect to the ecu with the scanner software then while your connected you can pull an info log from the scanner software and send it to tech explaining read issues. they should be able to offer insight on os/hardware read issues or support.
    rdrfabrication@gmail.com
    2016 GMC 3500 Denali Diesel
    2000 Ford Mustang - Top Sportsman

    Ecotec help can be found here:
    LNF-http://www.hptuners.com/forum/showth...357-LNF-Guides
    LSJ-http://www.hptuners.com/forum/showth...965-LSJ-Guides

  5. #5
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    thanks for that

    I did the low speed, but it failed as well. I am used to the LS defaulting the ECU model (P01 or P59). I scanned the dropdown list and found a GM 2.2L P11 ecu and it did read the entire

    but in saving it got the checksum error and a request to to send in what the HPT was downloaded and the Suit Info log and sent to support.

    so I did and am awaiting their response.

    thanks for the help

  6. #6
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    Was this ever resolved?

    I just had two PCMs brick on me.

    Could not read in high speed mode (older MPVI1 NEVER had an issue reading/writing P11s in high speed mode.

    read successfully in low speed mode.
    When I attempted to write config, it failed.

    I attempted to write again in low speed mode, and it seemed to be working, then failed at the very end of the flash. Now PCM won't communicate.


    I ran to a junkyard to grab another PCM. Matched the PN and service number. Did a passlock relearn, car started and ran no problem.


    I drove home and decided to try this PCM with HPTuners MPVI2.

    High-speed read was no go.
    Low speed read worked (took forever).
    I manipulated that file slightly, then attempted to reflash.

    High-speed write config. Fail.
    High-speed write entire. Fail.
    Low-speed write config. Fail, triggered VATS.

    VATS relearn, car started again.

    Low speed write-entire. Failed during erase step.

    When this happened, the PCM would not respond to communication anymore.


    I'm pretty annoyed. I have a ticket already open.
    I purchased two more PCMs on ebay for a really good price luckily, but still pissed that a simple reflash turned into an all-day ordeal to try and get a handle on the problem.

  7. #7
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    Just to update this:

    After talking with Eric via support ticket, and his remark on how the signal was noisy, I experimented with two new PCMs I bought on ebay (same P/n same Service No.)

    Read entire worked no problem, high speed mode, no issues.

    When trying to write calibration, it will get to the erase step then freeze. Odometer would read "error" and the instrument panel gauges go dead (no needle activity).

    I then decided to unplug a PAC audio device that I have plugged in where my radio used to go. It interfaces with the class 2 serial in order to retain door chimes and most importantly to me, Retained Accessory Power. Features that disappear if you remove the factory stereo.

    After doing this, I tried a write calibration again and it worked in slow speed.
    After that, I tried a write calibration again in high-speed mode and it also worked.

    It seems the PAC device was interfering with the write-process. So either:

    1) Don't install one of these things -or-
    2) Unplug it/ power it down every time you flash the car's PCM.

    EDIT:
    Worth noting: Scanner works perfectly fine with the PAC device plugged in and operating. I can also read entire no problem with the PAC device plugged in and operating. It's only during the WRITE process that it messes stuff up.
    Last edited by DaFlyinSkwirl; 06-20-2019 at 07:20 AM. Reason: added stuff about the scanner

  8. #8
    Senior Tuner cobaltssoverbooster's Avatar
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    I usually get fucked by the anti theft or remote start upgrades. Occassionally a radio head unit, but a pac controller I haven't got one of those interfering yet. Glad you guys got it sorted out and can go back to work.