2017 BEV partially reset itself? Cosmic rays?

I parked my 2017 non-REX i3 tonight, walked away for perhaps 10 minutes, and came back to find that the trunk wouldn't open with Comfort Access. Then the driver's door wouldn't open. When I opened it with the physical key, the alarm went off (expected, I suppose), and only stopped when I started the car with the key pressed to the steering column. I subsequently discovered that the TPM system wouldn't connect, and it had lost contact with all four tires, suggesting a central failure. Drove home, replaced the fob battery (it was at 2.9v, so probably dead), but that didn't change its inability to interact with the car. Tried the spare key fob, fresh battery inserted, with the same lack of any action. Then I noticed the heating system had changed to show Fahrenheit instead of Celsius temperatures on the adjustment knob.

So, clearly some variety of reset happened, but I have no insight into what it might have been. The car is driveable, as long as I'm willing to lock and unlock the door with the physical key, but this suggests there may be other shoes preparing to drop.

I replaced the 12v battery a year or two ago, and have gotten no warnings about it being low (which I had gotten before the swap). It went a little haywire at that battery swap, but I was eventually able to get it smoothed out (no memory of what all I had to do, but I waited too long, and the system lost its mind when the 12v petered out, and took coaxing to bring back), and it's been working perfectly since then. No indications of HV battery problems, no indications of 12v battery problems, no indications of infotainment problems. It was working perfectly before all this happened. I had just charged it a day or two before this, and it was around 90% charged when the reset happened.

I'm thinking maybe a cosmic ray flipped a really vital bit, or some kid with a magnetron and a deathwish was spraying EMP energy nearby, or something. Anyone heard of anything like this happening before? The obvious searches here didn't turn anything up.

Amusingly, I checked this morning, and the Comfort Access system is working properly, and the car gives no signs it had any problems. We'll see if the TPM system comes back or not, but I suspect it will. My best guess for what went wrong is low 12v battery voltage, and if that's the case, then I should see these symptoms (or weirdness like them) come back soon. I called the local dealership and they basically said, "dunno, let's get it in for diagnostics and maybe a firmware update." This is, naturally, a $215 minimum-one-hour appointment. That'll be option #2 or 3 after I get a chance to get probes on the 12v battery terminals and look around for obvious problems like rodent-chewed wires.

one of the "obvious" problems may be that the bolt(s) holding the terminal adapters down on the battery may have loosened over time. If you are checking the voltage at the terminals, I would check the posts as well to see if they are loose at all.

EvanstonI3 said:

one of the "obvious" problems may be that the bolt(s) holding the terminal adapters down on the battery may have loosened over time. If you are checking the voltage at the terminals, I would check the posts as well to see if they are loose at all.

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Well, your suggestion wasn't obvious to me However, several i3 owners have reported loose 12 V battery cable clamps, so I think yours is an excellent suggestion. I have found a loose battery post as well. The bolt that attaches these posts should be tightened as well as the clamps.

Good thought, I'll check that as well. Thanks!

It's odd to me that the computer repaired itself overnight, though, and loose terminals should be most apparent when driving, not when sitting still. Ah well, I'll be curious to see what's hiding behind the frunk.