2015 BMW 335i — service lifetime transmission fluid or leave it alone?

This is usually cheaper to test than to guess. Get a real battery/charging test on the 2015 BMW 335i, not just resting voltage, before blaming a module. That's the branch I'd chase this week. I'd want that in writing, not as a promise. Happens in gear, not in park, for what that's worth.

Log the conditions before you spend. A pressure test beats staring at a dry driveway if the 2015 BMW 335i is losing coolant with no puddle. You'll know quickly if you're on the wrong tree. On “service lifetime transmission fluid or leave it,” that was the fork that mattered for me. Run the total, not the monthly, before you commit. Climate here is different, so treat that as a local data point. Checking again after work.