Accident damage has never been covered under the Subaru warranty. We can certainly discuss whether or not $100 is a reasonable diagnostic fee in this situation, though.
Most likely, there is something (broken pieces, a rock, debris, etc) jamming the AGAS shutter, preventing it from operating. That’s something you can probably check and un-jam by yourself.
Won’t work. The AGAS servo receives commands and communicates its status to the ECU via a dedicated, single-wire serial data bus. Some people have reported a successful work-around by simply detaching the servo motor from a damaged shutter assembly, which allows the servo to operate freely.
You can download a legal copy of the entire Subaru FSM, and a whole lot more, direct from the STIS web site for $35. It’s a bargain.
