I've got an '01 996TT and a few days ago got the secondary air injector error codes: P1411/P0410. I've scoured the message boards and found some great info - including this thread
https://www.6speedonline.com/forums/...ml#post2333373

Question that I have is how to diagnose which valves might be bad? Looks like either the divertor valves or check valves are usually the culprit. I've listened and confirmed that the air pump itself is functioning. I've also located the diverter valves, but don't know how to tell if they are bad? Any suggestions before I just start replacing parts one by one?

Thanks in advance.
Dave