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Thread: PCM Bench Harness Build

  1. #1
    Electronic Ignition!
    Join Date
    Sep 2019
    Age
    46
    Posts
    10

    Lightbulb PCM Bench Harness Build

    If anyone would like to share their experience with building one of these please by all means do.

    I grabbed a set of PCM connectors and an OBDII port at the salvage yard and I am going to build a bench harness.

    96 Grand Prix GTP-#16211539, with the 3.4L DOHC.

    Connector one PCM C1 BLUE
    PIN#19 Power Ignition (Pink) *Hot in RUN*
    PIN#20 Battery (Orange) *Hot At All Times*
    PIN#21 PCM Ground (Tan/White)
    PIN#59 DLC Class 2 Data (Purple)
    PIN#60 PCM Ground (Black/White)
    PIN#68 Power Ignition (Pink) *Hot in RUN*

    **May Not be Required**
    Connector two PCM C2 CLEAR
    PIN#21 PCM Ground (Black/White)
    PIN#60 PCM Ground (Tan/White)

    Two 12v switches w/LED, <=> 2Amp Fuse Holder <=> Connected to Bench Top Power Source @12V 1amp
    Switch (LED) #1 <=> 2Amp Fuse <=> PIN#20 (Hot at all times)
    <=> OBD2 Data Connector PIN#16
    <=> (To switch #2)<=>
    Switch (LED) #2 <=> PIN#19 (Hot in Run)
    <=> PIN#68 (Hot in Run)

    *All Grounds to ground of the 12v power supply.

    OBDII Data Connector
    PIN#2 <=> PIN#59 DLC Class 2 Data (Purple)
    PIN#4 <=> Ground
    PIN#5 <=> Ground
    PIN#16 <=> 12V 2Amp Fuse <=> Switch #1

  2. #2
    Fuel Injected!
    Join Date
    Dec 2013
    Posts
    85
    This is the Bench harness i use to read ALL 99 to 06 PCMs (Gen 3), 4Cil (ecotec Blue/clear), V6 (Blue/clear) and all V8 (Blue/Red, Blue/Green).

    Connector one PCM C1 BLUE
    PIN#19 Power Ignition *Hot in RUN*
    PIN#20 Battery *Hot At All Times*
    PIN#1 PCM Ground
    PIN#58 DLC Class 2 Data
    PIN#40 PCM Ground
    PIN#75 Power Ignition *Hot in RUN*

    OBDII Data Connector
    PIN#2 <=> PIN#58 DLC Class 2 Data (Purple)
    PIN#4 <=> Ground
    PIN#5 <=> Ground
    PIN#16 <=> 12V *Hot At All Times*

    That's it, Maybe you pcm different? or where do you get the diagram?
    Last edited by NISANDA; 10-03-2019 at 08:36 AM.

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