Only Starts After Unplugging Then Plugging In ECU

Discussion in 'Mazdaspeed 3 Troubleshooting' started by Awines2326, Dec 3, 2024.

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  1. Awines2326

    Awines2326 Silver Member

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    Been doing a bunch of work to my car, finally got it all together and I have an ABS light on, I assume from changing all 4 calipers and the car recognizing ABS needs to be bled. But the issue is after I shut the car off it won't start back up unless I unhook the ECU and plug it back in. It cranks right up good to go. When I shut it off and attempt to crank it I get no starter...
     
    Awines2326, via a mobile device, Dec 3, 2024
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  2. Easter Bunny

    Easter Bunny Professional Engineer Motorhead Platinum Member

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    Are you getting immobilizer lights?
     
    Easter Bunny, via a mobile device, Dec 3, 2024
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  3. Awines2326

    Awines2326 Silver Member

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    The only light I'm getting is a solid ABS, my check engine flashes but nothing else I noticed. I connected FORSCAN and all the normal codes are there EGR VCTS, and 1 ABS for my steering wheel sensor being disconnected. It's always been a CEL and never popped the ABS light. The speed isn't supported on the FORSCAN ABS reset function. I can't find anyone who's had a similar issue, but I have to believe the ABS light and no crank are connected, right?
     
    Awines2326, via a mobile device, Dec 3, 2024
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  4. Awafrican

    Awafrican Moderator Silver Member

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    that's odd, have you tried rebleeding the brakes?
    all sensors connected? I wonder if fluid stuck in the abs module is causing a fault or you have a DOA caliper that's triggering and abs shutdown.
     
    Awafrican, via a mobile device, Dec 4, 2024
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  5. Awines2326

    Awines2326 Silver Member

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    So i got the car to start up and went for less than a 5 mile drive, used the brakes liberally and they felt good. I've been bleeding them with a hand pump and finally with the pedal for 2 days. They initially had a drop after and I threw a splash of fluid in. Mid drive the ABS light shut off, car starts every time now. Thanking God he solved that one for me. As weird as it might sound I think the clutch pedal had something to do with it. Idk exactly how the car knows you've fully pressed the clutch in order to start but it had a weird feel after the drive and I had to really stretch it to the floor. Back to normal now I guess. Still plan on doing an ABS bleed when a new scanner gets delivered this weekend to be safe with the ABS
     
    Awines2326, via a mobile device, Dec 4, 2024
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  6. Raider

    Raider Administraider Administrator Platinum Member

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    I wonder if the pedal is cracked.
     
    Raider, via an iPhone, Dec 5, 2024
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  7. Awafrican

    Awafrican Moderator Silver Member

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    OP did you bleed the clutch while you were in there? the clutch is fed by a small resovour in the back of the brake one and only fills up when the brake fluid is above the full line so you need to over fill it to properly top off the clutch fluid.

    If you're running dot 4 over 3 you'll need to full system bleed more often as it attracts water more. I find with dot 4 I'm bleeding my clutch / brakes every 3 years for best feel, I really notice it below -10c in that while car is cold I have to fully to floor and revs may drop a little when I clutch out on cold starts and then come back up seems to be alleviated by a bleed.
     
    Awafrican, via a mobile device, Dec 5, 2024
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  8. Easter Bunny

    Easter Bunny Professional Engineer Motorhead Platinum Member

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    The clutch switch is on the pedal.

    You need to bleed the clutch when you bleed the brakes they share a reservoir
     
    Easter Bunny, via a mobile device, Dec 5, 2024
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  9. Awines2326

    Awines2326 Silver Member

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    Yeah I actually replaced the full clutch line with a braided stainless line and bled it fully as well. I also do run DOT4 and try to exchange a chunk of it from the entire system every year. I'm wondering if I just didn't do a great job of bleeding the clutch line, or conversely I did a really great job and its super stiff now making be think I'm all the way down and I'm not. Either way I think it all falls on user error not a malfunction of any kind.
     
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