Originally Posted by liberalswine
Awesome, that was one of my theories. Are these the same valves notorious for sticking due to water corrosion? Seems like the delete would be most efficient in eliminating any possible future problems. Doesn't make sense to replace the unit if the valve could possibly get stuck/fail again
The air pump & valve system is on the 2006 and newer WRX and 2007 and newer STI.
On the 2006 model, both valves are clustered next to each other, under the TMIC on the driver's side.
On the 2006 model, you can unplug both valves and have the CEL shut-off by a tuner thus allowing you to fully remove them as well as for the air-pump. On 2007 and newer models, you have to leave one of the valves plugged in because it acts as an atmospheric sensor. You still however need a tuner to shut down codes permanently.
An air pump lists for approximately $654 and the valves list for approximately $314 each.
On the 2006 model, one valve is easily removed. The other is mostly tucked under the intake manifold. There is also an air-feed tube from the valve that is under the manifold that runs along the rear top of the engine and then over to the passenger's side head, and terminates at the head behind the uppipe. The driver's side tube is easily removed to install a block-off plate.
The passenger's side requires the removal of the exhaust uppipe to access the air-feed tube. If you would be able to remove the air-feed tube then installing the block-off plate is easy. My solution was to cut the head off of the air-feed tube and leave the rest in place. I also left the other valve in place because I had no patience in trying to remove it from under the intake manifold.
Also, read this thread: http://forums.nasioc.com/forums/show....php?t=1209260
FWIW, I don't think that water is actually infiltrating the hose/valve and getting in. I think that the water is a natural byproduct of the emissions process. Regardless, water can and may be in the first valve, causing it to corrode and fail. That's what happened to mine and along with it, it would cause the valve to stick open allowing exhaust to feed-back through the system mimicking an exhaust leak.