With Inspection coming due next month I decided to dig into my P0410 secondary air injection problem. Removed the air pump, took it apart, tested, all good, vacuum diaphragm tested and cleaned, all good, vacuum solenoid checked, all good.... fuses, good... check valves good... getting a little ticked off...start looking for broken wires... nothing... just happened to be putting the battery back in and noticed a connector disconnected next to the pcm... plug it in everything works perfectly.... dangit... had this problem since we swapped the engine, must have disconnected it then and never reconnected.... total cost $0 and 3hrs of labor.....

 

Sorry hit the button too soon. I had same problem but the previous owner connected the coolant reservoir overflow tube to the air pump intake. What a dipstick but thanks for the info