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How do clear "replace 12v battery" warning?

Discussion in 'Model S: User Interface' started by efusco, Feb 12, 2018.

  1. efusco

    efusco Moderator - Model S & X forums

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    For background, see this thread: Blackvue 750 causing 12V battery warning?

    Obviously, the easiest way would be to replace the 12v battery, but if you read the thread above you'll see why I'm skeptical that the 12v actually needs replacing. So I'd like to be able to experiment and see if unplugging the Blackvue will prevent the warning from coming back on.

    I did a hard reboot of both the center display and the dash display, but that did not clear the warning.

    Does anyone know how to clear that?
     
  2. Exiom

    Exiom Member

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    AFAIK once the warning appears... you need Tesla to reset that code... whether you replaced the battery or not

    or their software to reset that code... if you can get your hands on it... I think some states in the US can for a fee?
     
    • Informative x 1
  3. efusco

    efusco Moderator - Model S & X forums

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    Thanks, was afraid of that.
     
  4. apacheguy

    apacheguy S Sig #255

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    It is either a DTC (which Tesla will need to reset) or an alert which can often be cleared by rebooting the gateway.
     
  5. efusco

    efusco Moderator - Model S & X forums

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    Not sure what "the gateway" is, but I did reboot the center and dash displays and it did not clear.
     
  6. apacheguy

    apacheguy S Sig #255

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    GW is an RTOS computer mounted on the MCU and it provides the CAN link “firewall” between the Ubuntu systems and the embedded controllers.
     
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  7. Terra117

    Terra117 Member

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    I got the warning. The battery was fine. It was caused by my car being in a sleep state for a long time. Since the battery wasn't being charged, the voltage dropped below some threshold. Once that happens you need to have the service center do the reset.

    They advised me that when I'm away from home for long periods of time I should periodically wake the car up by turning on the climate control. Now when I'm away, I turn on the climate control at least once a week. Everything's been fine ever since.
     
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  8. efusco

    efusco Moderator - Model S & X forums

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    I suspect that's what's going on here. It's just been 13 months since it was replaced, but my service advisor says it needs to be replaced...no warranty, but he's gonna try to keep the cost down for me. Frustrating b/c I suspect the battery is fine.
     
  9. Tripple_T

    Tripple_T Cincinnati Member

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    The warning will clear when the battery is replaced. There is not a code that needs to be reset. In my experience the system is looking at the voltage of the battery on a few cycles and sees when the voltage comes up. That is my best guess to how it is fixed.
     
  10. efusco

    efusco Moderator - Model S & X forums

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    It isn't so much the act of replacing the battery that clears the code, it's the disconnection of the HV connector that completely shuts down the car. Learned this just yesterday. If you simply disconnect the 12v and reconnect it will not clear the code.
     
  11. apacheguy

    apacheguy S Sig #255

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    Well, if you disconnect the 12 V supply, the contactors will open, disconnecting the HV pack. Is that what you mean?
     
  12. efusco

    efusco Moderator - Model S & X forums

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    Well, that's not what the tech showed me...but I see what you mean, it seems that would do the same thing.
     
  13. Exiom

    Exiom Member

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    Because it has been reported by others that, changing their own 12V battery does not clear the warning so thus...
    This doesnt work? Because to replace it you have to disconnect it.

    So would disconnecting the First Responder Loop achieve the goal? Would you please kindly share some more info? so those of us who wants to replace our own battery can do so
     
  14. efusco

    efusco Moderator - Model S & X forums

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    Yes, it was the first responder loop that he showed me.
     
  15. msaficionado

    msaficionado Member

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    If you pull the first responder loop and 12v power, the alert should go away. I heard this is hard on the contactors, though.
     
  16. apacheguy

    apacheguy S Sig #255

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    You can wait until the contactors open by going to power off vehicle on the CID and then pulling the 12V.
     
  17. AWDtsla

    AWDtsla Active Member

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    If disabling the 12V opens the contactors, what else could opening the first responder loop do? The car is already without any power.
     
  18. apacheguy

    apacheguy S Sig #255

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    Correct. There is no point to disconnecting the first responder loop if 12V is disconnected. However, the service manual definitely recommends it.
     
  19. JCBX

    JCBX Member

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    I have been driving for 3-4 month now with the 12V service needed alarm on

    today I disconnected the "frl" alone .... and that didnt do it ...

    then I did disconnect the "frl" again and the negative on the 12V battery

    I measured 12.75V on the battery disconnected

    put all back again and the alarm was reset

    time will tell if it last :)
     

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