Disconnected sensor and a loose wire. IS this right??

[Nathan 9⁵]

Hey gang! I was changing the filter on my sister's '04 Arc 2.0T today, and noticed there was an unplugged 3 pin sensor, and a dangling 2-pin connector. The sensor is next to the manifold pressure sensor, and looks like it's an atmospheric or barometric pressure sensor. I've looked all over, and there is are no wire connectors dangling naked that would fit this sensor. I did however find one two-pin connector neatly gathered and zip tied to a hose next to the TCM. There is no CEL on, and no stored or pending codes. Any ideas on this abandoned sensor and unconnected, uncapped wire harness would be appreciated! Thanks! -Nathan

Pic below shows unplugged 3pin atmospheric/Barometric sensor:



Pic below shows dangling, unplugged and uncapped 2 pin wire harness:

[Nathan 9⁵]

After going through the WIS for a few minutes, I found this:



I guess this car didn't use the sensor, but decided to bolt it on anyhow! I find that very odd. I wonder how many engines were produced like this.

[nordwulf]

I wonder what this sensor is/was used for. My best guess is for some kind of fuel/air mixture adjustment depending on the elevation.

[Nathan 9⁵]

I'm guess the same. I took it off and tossed it into my box of misc. Saab parts. I wonder why so many things changed between '03-'04.