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Thread: 98 C5 pcm brick precautions

  1. #1
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    98 C5 pcm brick precautions

    I?ve done plenty of tunes on plenty of cars but this 98 C5 has me worried.
    I?m hoping for a check list of precautions that helps it go like all my others.
    I?m just making a few minor changes to the original factory tune.
    Thanks for the help, guys.

    Doug

  2. #2
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    bump for a little advise?

  3. #3
    Tuning Addict 5FDP's Avatar
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    You can't really mess things up if you read what you are changing.

    Some tables will clearly state that you should not change them because it could render the PCM useless. Some of the electronic throttle controls and such.

    Also any OS change under the OS requires a write entire and not a write calibration. Make sure your battery is in good condition and that the laptop is in good working order.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

  4. #4
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    My searching has indicated the Y body 97/98 is more prone to bricking than the 0411 that started in 99. Also more prone than other LSx platforms of the same years.
    As far as I can tell these are the necessary precautions:
    1: Vehicle battery fully charged even to the extent of being on an active battery charger.
    2: Laptop fully charged and unnecessary laptop programs closed.
    3: Doors closed and DO NOT open until totally done with session.
    4: Stereo off, HVAC off, interior lighting off. Electrical system as stable as possible.
    5: Engine temp nowhere near triggering cooling fans to activate.
    6: Pull fuse/relay for DRLs.
    Any other suggestions welcome.

    Doug

  5. #5
    Tuner in Training novaman996's Avatar
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    If you do all of the above you should have no problems. I never do a write on the side of the road when street tuning. I do it in my driveway..Its only a push away if i run into problems...Flat bedding a corvette is a pain in the ass...
    Thanks Richard

  6. #6
    Senior Tuner Russ K's Avatar
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    If you add the 2 bar OS, make sure you select write entire the first time you flash. If you don't, you will brick the PCM.
    This only applies to the 1997-98 PCM's.

    But if you're not adding the 2 bar OS, then just select write calibration.

    Russ Kemp

  7. #7
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    I've flashed my 98 probably 500 times. Never write entire unless you are going SD. Write calibration...works every time, side of the road, laptop on it's own battery, sometimes headlights on.

    After 500 flashes, you'd think I had it dialed in by now...nope!! lol still logging and changing!