I have a 99 SC2, it recently threw the po410 secondary air sensor code. I browsed all the threads about this topic and troubleshooting the issue. When I went to remove the silver pipe which runs from the diverter valve into the exhaust manifold to check for carbon build up, I noticed that the connection between the diverter valve and the pipe has a metal plate blocking it off, and the end where it attaches to the exhaust manifold isnt connected to the manifold, and another metal plate has been put over the hole in the manifold where the pipe would connect. Is this common? Could this be causing the code? Thanks in advance!

 

I am another sure why there is a differance between your 99sc2 and my 99sc2 but I don't even have a tube going to the exhaust manifold the only thing going into the manifold on mine is an o2 sensor. But if yours has a tube and it has been blocked off it sure could throw emission codes.

 

Does yours have a secondary air injection pump? Here is the picture of what I'm talking about. That silver pipe I'm pointing to, it isn't connected on the manifold end. And where it would connect to the manifold the hole has a metal plate blocking it. And on the opposite end where it connects to the diverter valve soda can looking thing, there is another metal plate blocking off the air flow.

 

I dunno. Maybe take the metal plate off and connect it there?

 

I agree take the plate off and hook it up.
Mine does not have that yours might California emissions. Or somebody took mine off before I got it.

 

sounds like it's been fussed with

was the car purchased from a location where emissions inspections were not required?

 

I bought it from a guy here in PA. As far as I know it came from Ohio. I don't know much about secondary air injections but with that silver tube not being hooked up it is going to throw a p0410 code no matter what correct? Because the guy I bought it from said it had no codes. I have a feeling he disconnected the battery before me test driving it to clear the SES light....

 

there are many counties in ohio that do not require emissions inspections.
He was probably having trouble with it and just capped off the ports and cleared the codes before you bought it.

Musta been pretty motivated to make custom plates to cap off the system unless someone on ebay sells them..............

not a lot of harm in hooking it back up....you need it for emission insp in PA so just note how it's capped off then hook it up and prepare for the possibility that your car may not run in top form until you solve the problem

 

That's what I was thinking.. I just don't see why he would cap off the ports, instead of just leaving the system how it was.. working or not. Now I supposed I need to find the connectors to attach that pipe back up to the manifold and try to get it working.

 

Maybe car runs like crap with it in.

ah pisser you will likely need to get them from a GM dealer or maybe an exhaust shop if they'll sell you the parts in order to assure the connection is made properly and no threads (if there are any in the manifold) are stripped