My check engine light came on the other day, the car started and continued to run fine. I just got the code read and it came back PO 413, secondary air injector valve. Does anybody know what this is, and is it something I can fix myself?
(The check engine light has not come back on after I erased the code).

 

I'd forget it until it came back.

Go to section 25 - page 30 AIR INJECTION in the 2004 Service Manual and read about the system, the valve is mentioned a couple of pages later.

 

I found the problem, the part is a small valve on the left front of the engine, right above the belt. It has 2 small wires going in to it & somehow those wires got cut, it looks almost like someone took a knife to them. It doesn't look like the wire was close enough to the belt to be cut by it, but that is the only explanation I can think of. At least it doesn't look like it is too hard to replace the part.