My understanding is,

the SAS valve stays closed, except for a few seconds during cold startup, when it opens as the airpumps starts and blows air into it to help reduce emmissions during cold start.

When the valve fails, it usually fails in the open position, thus the combustion vapors condense into water and the fluid ends up in the airpump because of the lower location.

If the valve is the original or has not been replaced recently, and you are getting air pump codes, then I would just replace the valve since is not expensive like the pump, and you might be saving the pump from failure down the road.
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'88 240, '92 745, '98 v70 John, Tampa Bay