I still have emission items on my 2001 trans am. I have a SES light on for secondary air circuit codes P1416. I tried cleaning the check valves with carb cleaner, def dirty but light still on. If I buy new check valves how do I get the old ones off the a.i.r. pipes? They seemed to be part of the entire part, nothing that you can just rotate off.

 

They just screw off - disconnect the hose/clamp side, then use 2 wrenches - one to hold the air pipe steady and the other to unscrew it. P1416 is the passenger side. GM PN is 12565503 (same for either side).