2023 BMW M340i — no crank with full dash power, then it starts later

Ask what changed right before it started. Capture voltage while the 2023 BMW M340i is actually failing — after it restarts you've lost the clue. That's the branch I'd chase this week. Learned this the expensive way on a previous car. That's coming from doing this as an owner, not a shop. No warning lights, which is why I'm documenting it.

Start with the test that can prove you wrong. Swap the cheap/easy piece first on the 2023 BMW M340i and see if the fault moves. Save the big job until that test fails. Write the result down so the next test isn't a repeat of the last one. Your commute and mine probably aren't the same, but the test still applies. I'll update if anything new shows up.

I wouldn't throw parts yet. Write temp, speed, and in-gear vs coast when the 2023 BMW M340i does it — then decide on parts. Don't erase codes until someone who can help has seen them. Write the result down so the next test isn't a repeat of the last one. Your commute and mine probably aren't the same, but the test still applies. Only after sitting overnight so far.

OP update: scanned the 2023 BMW M340i again and still only have the one pending code, no new lights. This is the version I'd tell a friend.

If it were in my driveway, write temp, speed, and in-gear vs coast when the 2023 BMW M340i does it — then decide on parts. That's the branch I'd chase this week. That's the whole play. I'd sleep better after that step, even if it finds nothing. Next check is the cheap one I can do in a driveway.

Update: the cheap test changed the symptom, so I'm not throwing parts yet. Heat soak after errands is the other window.

It did no crank with full dash power, then twice this week, both times after sitting. No change in mileage feel. If this is nothing, great. I want that in data.

This is usually cheaper to test than to guess. Two 2023 BMW M340is can feel identical and have different causes, so measure before you copy someone else's repair. You'll know quickly if you're on the wrong tree. This is from a 2023 BMW M340i in Northern Virginia with 57,500 miles. If it doesn't change the out-the-door or the repair estimate, it's noise. If that fails I'll eat the diagnostic fee.

Log the conditions before you spend. Two 2023 BMW M340is can feel identical and have different causes, so measure before you copy someone else's repair. You'll know quickly if you're on the wrong tree. On “no crank with full dash power, then,” that was the fork that mattered for me. That's the sequence I'd use. This is the filter I use when the thread starts repeating itself. I'm in no rush to be a hero on it.

Start with the test that can prove you wrong. If a shop can't duplicate it on the 2023 BMW M340i, bring a video plus freeze-frame data, not just a story. You'll know quickly if you're on the wrong tree. No need to make it theatrical. Trying not to diagnose from the couch.

If it were in my driveway, write temp, speed, and in-gear vs coast when the 2023 BMW M340i does it — then decide on parts. If the cheap test changes it, stop and reassess. If it doesn't change the out-the-door or the repair estimate, it's noise. If it repeats twice more I'll book time.