Model S

2015 Model S 85D - "May Not Start" and "Acceleration Reduced" warnings, etc

Just took delivery this week of a 2015 S 85D - 68k Miles in private sale. I was able to have it for the weekend prior to deciding and do some good driving with it and all seemed very well!

Same for the first few days - but then I saw the "May Not Restart" warning once or twice but not always. Then the screens won't always come on or boot slow. Now today - Same with the screens, the "BMS_w172 May Not Restart" will not go away and I also have the persistent "BMS_u008 Acceleration and Top Speed Reduced" warnings. This obviously kicks out the regen as well. It also has a charge door sensor fault CP_w043 and the car thinks the charge door is open pretty much all the time, even though it seems to operate correctly.

Sigh... Off to the SC. I hope this doesn't hurt too bad. I'm thinking in needs the MCU2 upgrade for the screen issue. I've read anything from the 12v battery to the DU to the Battery Heater Unit..... We'll see I guess. My first Tesla (and I understand it's used...) and I am really impressed with it. I'm certainly hoping the fixes make it reliable.

Comments

  • > @NSAS said:
    >I'm thinking in needs the MCU2 upgrade for the screen issue. I've read anything from the 12v battery to the DU to the Battery Heater Unit.....

    If it is the MCU it's not necessary to do the MCU2 upgrade, it can be fixed with a memory daughterboard replacement which is being covered under warranty. From your symptoms, it does sound like a battery heater, about 800 bucks.
  • > @GHammer said:
    > If it is the MCU it's not necessary to do the MCU2 upgrade, it can be fixed with a memory daughterboard replacement which is being covered under warranty. From your symptoms, it does sound like a battery heater, about 800 bucks.

    Daughterboard replacement would be nice under warranty. Seems there was some discussion on MCU2 upgrades if it needs it on warranty. Not sure I want that upgraded or not.

    But from other reading it sure does sound like the Battery Heater is a good possibility. Sigh.
  • Well, I got an estimate tonight for a Battery heater. Looks like the charge door will be replaced for that alert as well. I'll certainly be asking them to check over everything else and look for any other concerns. Fairly impressed with the SC at this point, I hope to feel the same way after the work! :)

    No mention of MCU1/2 or issues but that they will diagnose it. We'll see if they come back with anything there.
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