I found this on a google.
The secondary air injection pump pumps air into the exhaust to help heat the catalytic converter at cold start. This lowers the emissions at an otherwise high emission time.
A malfunction means that computer has registered either a pump failure (common on some models), fuse blown, or improper catalytic converter function.
http://www.autoshop101.com/forms/h65.pdf has a diagram of this part, how it works etc.
It may shed some light on thee subject, let me know how it goes.