Malfunctions and faults within the secondary air system can be identified using an on-board diagnostic system (OBD). The diagnostic trouble codes P0410, P0411, P0412, P0415, P0413, P0416, P0414, P0417, P0418 and P0419 indicate faults in the secondary air system. You can find out which components are affected by the different diagnostic trouble codes and how you can check them here.