I have a 2015 equinox and I have been receiving the P0411 (that advanced auto gave me). Today I got a blue tooth OBDII tool and it is also giving me P0412 which is "secondary air injection system Switching Valve "A" Circuit" Steps I have taken so far have been removing air pump and hooking power up to it and it works fine. I tested 2 relays and a fuse in the fuse box and they seemed good. I removed the check valves (they are pretty carboned up) I cleaned them the best I could. I also did the seafoam into the throttle body. I guess my main question is where should I go from here? Is the switching valve the same as the air injection check valves, or is there some other solenoid or electrical thing i need to be looking at? I dont want to spend $270 on 2 check valves if it is just a wiring harness or solenoid issue. On a side note when I change the oil I am missing 2-3 quarts of oil. Not sure if that is related to anything or not.

Thanks for the help