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Erroneous "Key battery needs replacing" message

Discussion in 'Model S: User Interface' started by dweeks, Jun 30, 2018.

  1. dweeks

    dweeks Member

    Joined:
    Aug 26, 2014
    Messages:
    221
    Location:
    Flagstaff, AZ
    I've started getting a constant "Key battery needs replacing" message on the center cluster, along with the alert at the top of the MCU. This is in a 2017 S100D.

    This came AFTER I changed the battery on the fob. The battery is known good (brand new out of the box).

    I've rebooted both the MCU and center instrument cluster, and then also did a complete power-down, but am still getting the message.

    I also changed the battery in the spare FOB and the car shows the "needs replacing" message with the spare fob.

    Both fobs function properly.

    I'm fresh out of ideas. Any suggestions would be welcomed.
     
  2. boaterva

    boaterva Supporting Member

    Joined:
    Apr 2, 2016
    Messages:
    5,385
    Location:
    Northern Virginia, USA
    There’s a couple of these threads, because i added to an old one. :D Basically the problem and solution is this is why Tesla does this at annual maintenance. A real pain. I think it helps to change both batteries and change them in the car but it’s too late now for you. I had the exact same thing happen, called national support, they said some mumbo-jumbo about the ‘immobilizer’ and I had to take it to the SC to have them reset it.

    There is some database in the car that isn’t getting updated and the fix is to really cold-start the car (all the way down to the gateway), from what I recall. We can’t do that, unless you know more about it than the average owner.

    The SC also said they have been seeing more of this recently (from something in recent firmware?).

    I’d call national support, perhaps early tomorrow AM before all the Teslas in California start calling road service, and have them verify it can’t be fixed remotely. Then they can make you a Service Center appt. (And the first thing I did was same as you, change the other one also with no luck.)

    Let us know how it goes!
     
  3. mkspeedr

    mkspeedr Member

    Joined:
    Jun 14, 2015
    Messages:
    565
    Location:
    Santa Clara, CA
    I have the same issue. I replaced the batteries but I cannot get the warning to clear.
     
  4. dweeks

    dweeks Member

    Joined:
    Aug 26, 2014
    Messages:
    221
    Location:
    Flagstaff, AZ
    The car is going to Scottsdale service on the 5th, for this and the "clunk" from under the front suspension. I'll report back on what was done for the keyfob issue.
     
  5. mkspeedr

    mkspeedr Member

    Joined:
    Jun 14, 2015
    Messages:
    565
    Location:
    Santa Clara, CA
    I went to the service center and they gave me a free replacement 3.0V battery that measures 2.5 volts. I bought a new battery (after I went to 4 stores who do not carry the X battery). The 5th store had it but it does not fit - it is the right battery but shaped differently.

    I hope there is an easy solution.
     
  6. dweeks

    dweeks Member

    Joined:
    Aug 26, 2014
    Messages:
    221
    Location:
    Flagstaff, AZ
    Followup:

    One fob had gone bad. The other got a new battery (after my new one) and worked fine, so the message went away.

    The front-end "clunk" was fixed by this:

    upload_2018-7-10_9-13-7.png
     
  7. Unpilot

    Unpilot Active Member

    Joined:
    Dec 2, 2017
    Messages:
    1,383
    Location:
    Illinois
    I have got a "Key not is car" message before and if I move the fob that goes away.
    I wonder if this means my fob battery is getting low?
     

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