2010 XC70 failing to start intermittently, throwing weird messages

[Banka1948]

My 2010 XC70 has about 145k miles now and FWIW I live in a warm, dry climate in Arizona. I've been running into an issue where, after the car is not driven for at least 24h, it has a problem starting up. It normally happens first in the morning however I've noticed this problem never happens when the car is used in the afternoon the day prior. It's only when the car hasn't been started since the prior morning or longer.

The typical sequence of events is I put my foot on the brake, push the on/off button, and I can hear it attempt to crank once or twice, and then it stops. Lights, radio, AC turn on, but engine doesn't turn over. When this happens, I get the weirdest messages on the dash usually it's "DTSC Temporarily OFF" but less commonly I get messages about the immobilizer or just today "Rear child lock activated". I usually wait 30 seconds and try again, and I usually get the same problem. But on the third or fourth try the car will successfully turn over. Usually it does this and then revs for about 4-5 seconds and dies (video below). But on the next start after that it will stay on no problem.

Any ideas what this might be? I'm not too concerned as it's not a major impediment to using the car, usually only a 1-2 minutes inconvenience in the mornings. But it's really starting to bug me as it's been happening for a couple months now. I was thinking it's likely a battery issue as I do have a Chinese dashcam always plugged into the 12V cigarette socket. However I just tested the battery with my multimeter and it came out at 12.44V and it's only 28 months old so I'm not so sure. I might try swapping the battery with another car to see if I still have the problem.

Thanks for any input y'all can provide. It's much appreciated!

Imgur link to video

[MoVolvos]

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Yesterday I saw an excellent video while doing research on transmission issues. It was long, very thorough and the short of it was that the battery was not being charged fully and it kept throwing transmission codes and affected the solenoids during shifts. Wasn't sure it was common enough and useful so didn't Bookmark it.

Try a fresh battery or unplug the cam for a day or two or both. Wouldn't hurt to have the alternator checked also. Youtube .
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