Sorry for the noob question but I'm sure someone can help me , it would be appreciated . Well to the point I'm trying to figure out what is the little cylinder shaped thing underneath the ABS module I Believe , that has one small hose with a blue line on it going to the top of I think is the suction thing for the throttle cable , well that's not the only hose it seems to me that there is suppose to be another hose coming out of the cylinder thing (bear with me) but it isn't there and I have no idea , I will upload a picture later to show what I am talking about . Please someone answer this I've looked everywhere online to see what it was . Thanks in advance

 

Car make 1999 Audi a4 2.8 btw forgot to mention can someone please respond or say some I thought this forum was a good resource really trying to figure this out .

 

Don't worry about guys I've figured it out , lol no one helped either way , but for anyones general knowledge , its a cruise control vacuum pump