Cadillac 2009 CTS Owner's Manual page 332

3. Disconnect the electrical connector from the air box.
4. Loosen the screw on the clamp holding the air
outlet duct in place. Do not remove the clamp.
Move the duct aside.
5. Remove the hose from the air cleaner housing
mounting arm. Move the hose aside.
5-26
6. Remove the three air cleaner housing cover
screws.