Your Scion tC comes with an optional cabin air filter that filters fresh and recirculated air. Problem is, it is not offered standard or as a Scion option, nor is it even mentioned in an owners manual.

Located behind the glove box is the air conditioning fan plenum box. In the picture you can see the passenger front airbag assembly above and the ECM to the right. The long rectangle cover panel is located in the middle.

The cover panel is spring clipped in place. To remove, just squeeze each end simultaneously while pulling rearward. This provides access to the filter slot.

Order Toyota P/N: 885685201083KJF3 It should be the correct P/N for 2005 and up tC's.

The cover plate is actually an one assembly that the filter installs into. Be sure to install the P/N's up. Doing so will have the pleats up and the filters seal lip on the bottom. Make sure to install the seal lip under all of the small fingers on the assembly.
SquallLHeart has this helpful tip well.. if you don't wanna fork up the stupid price that dealerships want for their part,
the best thing you can do is head to a store and purchase a house air-filter (which are fairly big).. and they cost maybe like $5-10 or so and can cut alot of small filters from them.
it'll last you awhile that way
