What do you check if a 1999 Mustang has a check engine light code P1413 SAI system monitor circuit low input?

Answer 1

If I'm not mistaken, the code you are refering to is for the Secondary Air Injection system. The system injects air into the exhaust if the car during the first few moments after you start the car. It's purpose is to assist in warming the catlyitic convertors to operating temperature. As this module is part of the emmissions system, you may be covered under Ford's emmissions warrantry. You will need to check with your local Ford service center to determine if your car still applies to this "Emissions Warranty." If you have any more questions feel free to ask.

I have been told that one of the two vacuum solonoids located on top of the EGR and regulator valve assembly are in line with the air pump. I haven't found out which one yet (I need to replace it and am doing on-line research to determine which one it is). If one of these solonoids is malfunctioning electrically, it could also cause the same problem. I paid $400 for a new air pump to be installed and still have the P1413 but the ford diagnostics say "change out the pump". So apparently something is awry here. The mechanic who changed the pump got advice from one of the mechanics at a different shop who is more of an expert, and I'm relaying what I was told here. I hope it helps both of us. I'm going to go to Ford and determine which solonoid it is and replace it myself. They are both "on top" of the pipe where the EGR 'master regulator' is, and have both vacuum hoses and electrical connections to them. One of these two is likely to be the cause.

there is also an electronic relay mounted to the side of the air pump. I had this problem, changed the relay out. However I still got 1 spurious P1413 after I verified the electric air pump would spin. So maybe there are multiple causes here. I took the precaution of using electrical contact cleaner on the wiring before I re-connected it also, just in case. But if there is a problem between the relay and the computer, I bet this would cause it as well.