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Thread: What does this wire do?

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    What does this wire do?

    Hi,

    I have an 06 GTO LS2 with the E40 PCM. I'm trying to figure out the function of a wire in C101. C101 is the connector at the front of the engine that powers the coils/injectors, reverse lockout and skip-shift solenoid. I know what pins 1-5 do, but pin 6 isn't clear. The schematics say it's PK/BU, but it's actually dark green. They put it on circuit 339, Ignition Voltage, the same as pin 5, so it needs power. When I give it power, the throttle body clicks very loudly; throttle opening I guess. With no power it still clicks, but softly. The loud click makes me worried that it's getting too much power. The engine seems to run the same either way, at least up on blocks. It does not power the reverse lockout and skip-shift. Those are pin 5. Pins 2 & 3 are the coils/injectors. So I can't tell what pin 6 does. I can't find it on any schematic that I have. Any ideas?

    C101.gifC101-1.gif

    Thanks,
    Jon
    Last edited by Calparts; 04-24-2017 at 11:35 AM.

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    Registered Member fitz's Avatar

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    Quote Originally Posted by Calparts View Post
    Hi,

    I have an 06 GTO LS2 with the E40 PCM. I'm trying to figure out the function of a wire in C101. C101 is the connector at the front of the engine that powers the coils/injectors, reverse lockout and skip-shift solenoid. I know what pins 1-5 do, but pin 6 isn't clear. The schematics say it's PK/BU, but it's actually dark green. They put it on circuit 339, Ignition Voltage, the same as pin 5, so it needs power. When I give it power, the throttle body clicks very loudly; throttle opening I guess. With no power it still clicks, but softly. The loud click makes me worried that it's getting too much power. The engine seems to run the same either way, at least up on blocks. It does not power the reverse lockout and skip-shift. Those are pin 5. Pins 2 & 3 are the coils/injectors. So I can't tell what pin 6 does. I can't find it on any schematic that I have. Any ideas?

    C101.gifC101-1.gif

    Thanks,
    Jon
    From the diagram, scan 4, which connector are you referring to? C101 does not carry the signals you describe as shown in scan 5. Both signal sets go back to the ecu ON C1 AND C2

    Scan0004.jpgScan0005.jpg

    Almost forgot, there are 297 splices shown in the wiring for the 2006 GTO. 37 of them are in the engine harness itself. Other than the engineer who designed that harness who knows how many places "Ignition Voltage 1" is spliced to? I surely don't; but my 1991 NA has a 2006 GTO engine & T56 trans and ir runs like a stabbed rat.
    Last edited by fitz; 04-25-2017 at 01:40 AM.

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    Quote Originally Posted by fitz View Post
    From the diagram, scan 4, which connector are you referring to? C101 does not carry the signals you describe as shown in scan 5. Both signal sets go back to the ecu ON C1 AND C2

    Scan0004.jpgScan0005.jpg

    Almost forgot, there are 297 splices shown in the wiring for the 2006 GTO. 37 of them are in the engine harness itself. Other than the engineer who designed that harness who knows how many places "Ignition Voltage 1" is spliced to? I surely don't; but my 1991 NA has a 2006 GTO engine & T56 trans and ir runs like a stabbed rat.
    A stabbed rat. lol
    I don't think C101 is in scan 4. C101 is at the front of the engine. It is on a section of harness that also has the connector to the MAF on the air intake. (I wish I had a picture, but I'm having trouble getting pics from my phone to my computer.)
    Your scan #5 shows C101. Pin 5 powers the skip shift and reverse lockout. We confirmed that. Without power to pin 5 they don't work. The diagrams for their connectors also show a PK/BU Ignition 1 Voltage wire on circuit 339. So that's pretty certain. Pin 6 definitely affects the throttle because when I give it power, the throttle clicks much louder than without. That's the green wire I have in pin 6 instead of a PK/BU wire. SO that's what I'm trying to sort out.
    On the diagrams I have, there is no circuit 339 going into the PCM on any connector, nor is there a PK/BU wire. Where on C1 and C2 do you see them, which pins?

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    Registered Member fitz's Avatar

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    Quote Originally Posted by Calparts View Post
    A stabbed rat. lol
    I don't think C101 is in scan 4. C101 is at the front of the engine. It is on a section of harness that also has the connector to the MAF on the air intake. (I wish I had a picture, but I'm having trouble getting pics from my phone to my computer.)
    Your scan #5 shows C101. Pin 5 powers the skip shift and reverse lockout. We confirmed that. Without power to pin 5 they don't work. The diagrams for their connectors also show a PK/BU Ignition 1 Voltage wire on circuit 339. So that's pretty certain. Pin 6 definitely affects the throttle because when I give it power, the throttle clicks much louder than without. That's the green wire I have in pin 6 instead of a PK/BU wire. SO that's what I'm trying to sort out.
    On the diagrams I have, there is no circuit 339 going into the PCM on any connector, nor is there a PK/BU wire. Where on C1 and C2 do you see them, which pins?
    C101 is the 6 pin connector which plugs into the throttle body on the front of the engine as shown in the scan of the service manual. Pin 5 & Pin 6 are PK/BU shown in the other attached scan. That signal 'Ignition Voltage 1' goes back to C1 pin 14.

    Engine showing C101.jpgC101.jpg

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    Correct, except my pin 6 wire is dark green. I don't care about the color so much as what it does. That's what I can't find anywhere. The only thing that I can tell is that when I apply power to it, the throttle clicks very loudly when ignition is on.

    I saw that pin 14 is Ignition 1 Voltage, but the circuit number and wire color are different... Circuit 339 vs 439. Pink/blue vs just pink. So I'm not 100% sure it goes there. But I don't think that matters. Either way it needs ignition voltage. The lingering questions remains: What is it used for? What is it doing with the throttle? Why does the engine seem to run the same with or without power to it?

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    Registered Member fitz's Avatar

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    Quote Originally Posted by Calparts View Post


    The lingering questions remains: What is it used for? What is it doing with the throttle? Why does the engine seem to run the same with or without power to it?
    Beats me! Doesn't match my manual.

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    I've found a couple of threads that say it's for the AC compressor clutch. I know that the throttle is being affected by it. Maybe it engages the ac compressor and opens the throttle a little at the same time to compensate? I don't have AC at this time. I still need to build that.

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    Registered Member fitz's Avatar

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    Quote Originally Posted by Calparts View Post
    I've found a couple of threads that say it's for the AC compressor clutch. I know that the throttle is being affected by it. Maybe it engages the ac compressor and opens the throttle a little at the same time to compensate? I don't have AC at this time. I still need to build that.
    The A/C compressor clutch connector is the two wire plug shown in the attached scan of the 2006 GTO service manual:

    Scan0004.jpg

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