The blind spot monitor has been into the Subaru dealer three times and each time it works for about a day then the error comes up again. The system was first calibrated and lasted a couple of days then went out again. Went back to the Subaru dealer again. They replaced left master sensor. Again lasted for couple of days and went out again. The Subaru dealer said the right sensor was out of spec. Again re calibrated. Went out a day later and it out again. I like to use it when I am going to pass but now i can't trust it any more. What a bummer.Sounds like some engineering needs to be done. I have read about some 2015's have voltage drop during engine cranking. I don't believe it.

Blind spot monitor light on passenger side mirror works intermittently. Dealer was finally able to reproduce the problem but no fault codes and they cannot find out what is wrong or how to fix it. Subaru corporate was made aware of it and said they have not been aware of this as a recurring problem. I am waiting for them to get enough complaints to see if they can come up with a fix. This is not an issue where a car/truck of a certain size or relative speed/weather issue keeps the light from alarming, because when it goes out we can drive for hours on the interstate and nothing in the right lane will trigger the alarm. I don't know if it is just the light or if the audible alarm would sound if I tried to merge into the right lane with somebody there.