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ECM / PCM (Computer)

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 87K54WD, Nov 6, 2001.

  1. 87K54WD

    87K54WD 1/2 ton status

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    General question here about on-board computers in a vehicle. Is the PCM separate from the ECM or is the PCM inside the ECM. If so, you would get a new/rebuilt PCM if you were to get a new/rebuilt ECM?
     
  2. Burbinator

    Burbinator 1/2 ton status

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    That depends on the vehicle. They are usually separate stand alone boxes.

    That's because most automakers usually offer the same vehicle with different trans/engine options while the trans/engine remains the same, or the powertrain is used in multiple platforms. It wouldn't be cost effective to have 5 combos of computers for every platform sharing powertrain components.

    The learning curve is a toll road...ride with someone who has already paid!
    <a target="_blank" href=http://photos.yahoo.com/abshort1>U.S.S. Nimitz II</a> <P ID="edit"><FONT class="small">Edited by Burbinator on 11/06/01 05:04 PM.</FONT></P>
     
  3. K5 NUTT

    K5 NUTT 1/2 ton status

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    Where do i start....your 87K5 has an ECM...can also be called an ECU....Pn#7747...stand alone with two chips.... a main prom...and a calpack. When you get into PCM's (Powertrain Control Modules)....your are talkin late model stuff. Some gm units run twin and some even 3 ecu's (cadillac) to get the job done. What they do is use one main ECU to control the engine..then they use another for ABS...and one more for controlling active suspension...fan control...a/c outputs etc. Thankfully any 87 up K5 will only have 2....the main ECM...and one for the ABS if so equipt. When you purchase any reman ECU it comes without chips...normally you pull out you calpak and main prom and transfer them to the new ECM....in my case at work (Freightliner) ECM's come blank.....and i program in the pertinant HP ratings per application with a lap top...and then reset the customers own special parameters...but thats another story all together. And as a side note....more than half the automotive ecm's changed out where not the problem to begin with....

    Azblazer

    1979 K5 350 TBI
    1976 K5 Chalet
    If it ain't got arizona pinstriping.....you ain't wheelin the pee outa her!
     

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