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"Car may not restart" - just ignore it

Actually she said "If the car doesn't act strange and you don't get the message again I'm sure there's nothing to it. If it shows up again let us know."

This happened to us before when we were in the middle of New Mexico. Went to Salt Lake City where they gave us a nice loaner and we spent a couple extra days while they put in a new Drive Unit. The guy on the phone originally told me it sounded like a high-voltage battery issue. But that was a year ago.

So, has anyone else had multiple occurrences of this error but no apparent problems?
I had a series of similar messages.

I would get to the car in the morning and get the message then it would go away. Tried hard reset, came back a few days later and took it to ta service center to be looked at. They, presumably, checked the error messages and said not to worry and ignore it. The next day I got the same message in the morning and when I returned to the car in the evening, it wouldn't start.

Had it towed from the third floor (tow truck could barely fit... they had to bring a special small one) to the same service center (Palo Alto, CA) and had to wait 5 days to even have it diagnosed (they need to hook it up onto a simulator and there were several cars ahead of mine). Turned out to be one of the high capacity wires failing and not recharging the 12v battery (I guess it's the EV equivalent to an alternator).

It took another two weeks to get the part and they replaced the battery as well, under warranty (2016 car). I'm not happy that I had brought it in and they sent me back on the road. I'm also no happy on how long a fairly simple repair took. It has been working well since however (happened in March).

This is the service invoice info:

Concern: Around 7:30 AM & 4:00PM 3/1 & 3/2 "Car needs service. Car may not restart"
Alert started appearing, other than the alert, vehicle was not exhibiting any other symptoms.
3/2 around 11am screen rebooted by itself while he was getting into the vehicle. 12v battery
needs to be replaced alert appeared also appeared shortly thereafter. 3/5 Vehicle would not
go into gear, alerts appeared. "12v battery needs service alert" & "car needs service may not
Cause: Multiple HV external isolation faults found in logs. (SEE CAUSE NARRATIVE)
Repair Plan: Perform dummy plug isolation test to determine source of isolation. Repair as

Pay Type: Warranty
Corrections: Battery - Auxiliary - 12V - 1st Generation (Dual Motor)
Confirmed concern.
Performed diagnostic on all HV components and HV harnesses.
Confirmed HV harness is causing alert.
Replaced HV harness and 12v. battery.
Performed extended road test and confirmed no alerts present and proper operation at this

Part Quantity
Battery, 12V, DCS33-UNCR, MS (1083774-

HV HARN,FJB-FDU,MS2 (1055875-10-E)
  • Informative
Reactions: Ken43
I recently had this message, and was told it could be the "Battery Heater", as in the winter they work harder to keep the batteries warm. Well took it to the service center today and they said it is a bad "Drive Unit"...so glad I took it in and glad it is under warranty. I have a 2014 MS85. First drive unit since I purchased it CPO at about 20,000+ miles since I purchased it. So that is in 7 months I have driven 20,000+. I think these drive units aren't as bad as the press makes them out to be, but I hope they upgrade my so I can go another 100,000 miles.

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