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  1. #1
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    Need help clearing brain fog

    Issue is I'm killing batteries. No draw, nothing unusual.

    I'm leaning towards PCM as sometimes when I crank it, I only see 13v in the EVIC, but I haven't ruled out the alternator yet either.

    My question is, if I pull the alternator to have it tested, how will it be determined to be bad with the VR located in the PCM?

    How would I determine if it IS the PCM?

    I have probably over thought myself into a tizzy, but I can't clear my brain to figure it out.

  2. #2
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    Nov 2011
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    How quick are you going thru batteries? Have you done actual in-depth parasitic draw tests? Gone through wires you can get at to check for bad grounds, +s, etc? Maybe spend an hour at the dealer to have them diagnose it with good proper equipment?

  3. #3
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    Quote Originally Posted by IcarusLSC View Post
    How quick are you going thru batteries? Have you done actual in-depth parasitic draw tests? Gone through wires you can get at to check for bad grounds, +s, etc? Maybe spend an hour at the dealer to have them diagnose it with good proper equipment?
    If you knew my build you'd thump yourself in the sack for even thinking about me taking it to a dealer lol.

    I spent 5 days tracing wiring, draw testing and eliminating everything except those 2 items.

    I've put 4 batteries in it in as many years. It's doesn't kill them with ANY sort of regularity, I'll just go to start it one day and go, "Welp, that ain't happening".

    I'm leaning towards the PCM. I bought it from a forum member and had it written for my car. IIRC that's about when the problem started and was well before the build.

    If it IS the PCM, I have my stock one I can have unlocked or I could buy another alternator if that's the problem. I'm just trying to figure out which one without doing both.
    Likes DBL.DWN liked this post

  4. #4
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    Maybe check the voltage with the engine running. Then, turn everything on, lights, stereo, heater blower etc and check the battery voltage again. That might give you an idea about how the alternator is working.

  5. #5
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    NVM. I found my answer on Allpar.

    Thanks guys.

    I know what I'll be doing tomorrow.
    Likes diboblo liked this post

  6. #6
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    Quote Originally Posted by punisher69 View Post
    NVM. I found my answer on Allpar.

    Thanks guys.

    I know what I'll be doing tomorrow.
    And the answer was?

    Sorry I don't know your build. With my memory I'm lucky to remember what my build is let alone someone else's
    Last edited by IcarusLSC; 04-19-2021 at 04:20 PM.
    ·Ï¢årµ§·

    2014 CHRYSLER 300C 5.7L AWD
    Thanks Combatvet thanked for this post

  7. #7
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    Quote Originally Posted by punisher69 View Post
    NVM. I found my answer on Allpar.

    Thanks guys.

    I know what I'll be doing tomorrow.
    Share with the class!


    Sent from my iPhone using Scat Pack Forums

  8. #8
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    Do you still have the battery sensor hooked up to the negative lead at the battery?

  9. #9
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    Quote Originally Posted by DBL.DWN View Post
    Share with the class!


    Sent from my iPhone using Scat Pack Forums
    Charging system diagnostics: battery, alternator, and related systems | Allpar Forums

    Big help right there!
    Thanks POWERMAN thanked for this post
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  10. #10
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    Quote Originally Posted by IcarusLSC View Post
    Do you still have the battery sensor hooked up to the negative lead at the battery?
    Nothing is unhooked. All connections are tight and clean. It's either the alternator or the PCM. I'll get it sorted out when I get back from NC.

  11. #11
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    Quote Originally Posted by punisher69 View Post
    Nothing is unhooked. All connections are tight and clean. It's either the alternator or the PCM. I'll get it sorted out when I get back from NC.
    Try changing the batteries in both of your key fobs with new panisonic ones, my car was doing this and kept killing the battery in the car i ended up buying a new battery and same thing wouldn't auto start because battery was too low, think its something to do with the transponder trying to connect to the key fob or something i don't know but it fixed by dying battery issue.

  12. #12
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    Quote Originally Posted by chrisstevens View Post
    Try changing the batteries in both of your key fobs with new panisonic ones, my car was doing this and kept killing the battery in the car i ended up buying a new battery and same thing wouldn't auto start because battery was too low, think its something to do with the transponder trying to connect to the key fob or something i don't know but it fixed by dying battery issue.
    I have passive entry turned off and my fobs are nowhere near the car.



  13. #13
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    Its the PCM. Try putting back your old one and see how it goes

    Sent from my SM-G965U using Tapatalk

  14. #14
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    Quote Originally Posted by punisher69 View Post
    I'm leaning towards the PCM. I bought it from a forum member and had it written for my car. IIRC that's about when the problem started and was well before the build.
    Did you get it from DiabloSport or HemiFever? I'm having a similar issue, that's why I asked. Right now, I have it hooked to a Battery Tender to keep it happy.

  15. #15
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    Quote Originally Posted by vbt View Post
    Its the PCM. Try putting back your old one and see how it goes

    Sent from my SM-G965U using Tapatalk
    I have to have the stock one unlocked and my tune loaded to it before I can do that.

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