code po410 secondary air injection

Hey whats i have been having a problem with my suburban. I cant smog it due to check engine light on. I have tryed to clear it but same code comes bak on within 40 miles. PO410 secondary air injection faluire.
I have replaced my egr valve(new). and checked all vacuum connection they all seem to be okay no leaks detected. I can use some help if anyone has any info to give me thanks