Just went and looked at an 01 s40 for sale. I cant get the image to upload but on the drivers side near the firewall there is a port on a line with a spring sitting there. I think it may have been a location for some sort of sensor ? Any ideas. Also check engine light is on for bank one rich. If it is a sensor could that be the issue?

 

https://goo.gl/photos/mb5mF3mNsVpe5rDP9

 

The brake vacuum switch is broken. The rest looks like it is sitting beside the spring (2 wire brownish orange connector)

This can cause a vacuum leak and set that fault code.