Possible source of dead 12-Volt for SubaruConnect users
This is an update to my original post here.
Four days after the first time the car was found dead, it needed a second jumpstart.
Today the car was at the service center for diagnosis. Too soon to tell if this will solve the problem but the long story short is if you have the SubaruConnect App installed on your phone, disable Background App Refresh for SubaruConnect (on iPhone it's in Settings/General/Background App Refresh) and delete the companion App that's automatically installed on Apple Watch if you have one. Check your phone's battery usage to see if the Subaru App has been burning battery on background activity. Limit location services to only when the App is in use for good measure.
Here's the longer version. There's a Subaru service information bulletin revised 06/29/26 (yesterday) that has a list of Apps suspected of frequently requesting updates from the car, keeping it awake and draining the battery. One on the list is the wearable companion app that's installed alongside the SubaruConnect App on Google Wear OS and Apple WatchOS. The documentation implies these wearable apps contain a setting to constantly update the vehicle status - we could find no such setting in the Apple Watch app - my only guess is they may be simply referring to the background app refresh toggle. But, hearing this got me thinking about unwanted background activity.
So, I checked my wife's iPhone (where the SubaruConnect App is installed) and found that in battery usage, the app's background activity was off the charts; on Sunday it burned 17% of her iPhone's battery spending 15 hours and 45 minutes being active in the background - despite her not actively use the app at all. The surrounding days were also very high, measured in hours (a typical heavily used app might have a few minutes of background activity in a day and for comparison the KiaAccess app for our other car uses so little phone battery that it doesn't even register in the activity). Saturday - the day it needed jump-starting, was the second highest day. I'll attach a screenshot.
I don't understand the electrical side of anything but for those that do - the service center documentation confirmed a draw between 90-180mA on the battery before they proceeded to reset the infotainment system and remove our connected devices; afterward the found the draw to be 17ma steady.
Again, too soon to tell if this solves it - could wake up tomorrow and the car is dead again. But I can't imagine the SubaruConnect app talking for hours in the background doesn't have something to do with the dead 12-volt - at least in our case.
