Can you tell me what this is?

[03greenZ71]

Can someone tell me what the name of this part is and what it does? Located on the brake booster. 2003 Tahoe z71 5.3 flex fuel.

Thanks

 

[corvette744]

Can someone tell me what the name of this part is and what it does? Located on the brake booster. 2003 Tahoe z71 5.3 flex fuel.

Thanks

View attachment 275769

https://www.carid.com/acdelco/gm-or...JDQeK90u8vaiXO7N7gvwDIk8i9N-KyUBoCL4kQAvD_BwE
89058946 gm part number but looks discontinued good luck finding it.