Three problems related to alternator/generator/regulator have been reported for the 2015 Subaru Outback. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2015 Subaru Outback based on all problems reported for the 2015 Outback.
Parasitic battery failures: multiple events between July 2018 and January 2021. Battery & alternator were consistently found to be working correctly. Battery was replaced three times. One event had excessive battery percolation. The problem was caused by an after-market hum speed & location monitoring device placed in January 2018 and partially removed in October 2020. We did not know about the hum attachment to the obdii port. The problem was finally fixed when an astute mechanic recognized that the failures were likely due to the remaining hum part attached to the obdii port. Logical it would draw down the Outback undersized battery, which is well documented. Advice to owners: do not attach after-market devices to your Outback. Remove connections like phone jacks as needed when the car is parked. And, if you have an unexplained dead battery problem, check the obdii port & remove any foreign devices or have your mechanic do so.
Battery suddenly went dead shortly after driving when it should be charged. After investigating, I found that the ecu cycles the alternator off and on to try to increase fuel mileage. This has twice resulted in battery failure, not starting and leaving me stranded. I've had to buy new batteries twice in five years.
Vehicle would not start. After jumping the battery vehicle started, aaa performed roadside testing and determined the battery and alternator are working properly and are sufficiently charged. Car would not start for unexplained reasons. Previous service history leads me to believe there is an ongoing electrical issue with this vehicle. Previously the airbag light would frequently illuminate. Dealership stated it was due to electrical interference and that nothing was wrong.