I have a 1996 Volvo 960 and am getting a P0410 OBD2 code of p0410. I verified that when it is cold out and the injection pump runs air does channel through the SAS valve and when I pull the vacuum activation hose off of the SAS valve the air from the pump stops. From what I can tell everything is working OK.

I also noticed that before I use to get this fault, when the pump would run you use to hear what I would describe as the same pumping sound that a large air compressor would make. Now all you hear is the sound of the motor in the air pump running with out the “pumping” sound.

If any one has any suggestions I would appreciate any comments.

Thanks,
Bob

 

Pull the Valve off the back of the engine and inspect to Carbon cloggage and Put vaccum to it and make sure it opens.

 

Thanks to the moderator for replying.

I have verified that when a vacuum is put on the valve (mistakenly referred to it as a SAS valve, my manual refers to it as a PAIR valve) that the air from the pump flows through the valve, and when the vacuum is turned off the valve shuts and th eair stops. So up to the exit of the valve everything seems ok. The air then goes into a pipe that is under a plastic cover. I have not taken this cover off yet, but it is my understanding that it eventually gets into the exhaust. I am wondering if something is bad in this pipe?

Thanks,
Bob

 

If the pipe goes under the plastic cover in the top of the engine it goes back to the engine.
Follow and make sure all pipes are clear. Usually either the Air pump or Pair vavle is bad.

 

Hi Again:

Thanks for your last response, but I think I must have a different engine than you were referring to. I have a Volvo 1996 960. I have verified that when the vacuum is on the PAIR valve is active that air freely flows through it from the pump and when vacuum is removed the air stops.

I took the plastic cover off and the pipe goes into the center of the upper head, in between the coil packs. Since this internal passage way is now inside the engine I am clueless as to where it goes next. I thought the whole idea behind the secondary injection theory is that it is suppose to go to the exhaust manifold to provide air to the CAT. It is not clear to me how it gets there from the head unless there is some internal passage way in the head. When I start the engine with out the pipe connecting the PAIR valve to the head on I don't hear a loud exhaust sound which leads me to believe that it is not directly connected to the exhaust, unless there is a blockage inside the head.

Also it takes about 70 miles driving till the check engine light comes on after it is reset. Do you or possibly any one else have any ideas what the path of this tube is once it gets into the head?

Thanks,
Bob

 

Check your e-mail.

Also im going to move this post to the 960 section.