Aveo 2009 throttle body issue

[drmagieed]

Hi Everyone:
I cleaned my throttle body and used tech2 in idle reseting. I noticed that the hose # 4 in the attached photo evacuate air after shuting down the car. The air make the throttle opened little bit. The mechanics here told me that this is normal. Is it?
Thanks.

[drmagieed]

I will change the question. What is the function of hose # 4? And what it's name? And who I know that it is work properly? Thanks.

[drmagieed]

are there any answers to my question?