I recently had my 2015 Subaru legacy detailed. Now I'm getting the message
that the passenger side airbag is off. What did they do and how do I undo it? I
have found nothing useful in the manual.
Your passenger airbag has a sensor in the seat that detects weight. Set your purse over there and see if it comes back on. Let me know if it doesn't so we can look deeper into it.
By design, the passenger airbag will remain off if there is no passenger in the seat. If someone sits on the seat, this airbag will become active. The driver airbag is always active. do check with Subaru about the Takata recall; yours might be on the list.