VR6 solenoid valve to throttle body - do i need it?

Quick question - do i need the solenoid valve that goes to the lower connection of the VR6 throttle body. Someone's told me it can be blocked off as it's for the carbon cannister and it won't effect performance, idle, etc etc. Can anyone confirm it's role and tell me whether it's needed for sure?

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Thanks

 

I left it connected, but plugged the valve (with the connector attached, just so i didnt have any random unattached connectors) and cable tied it out the way.

 

I did the same, as baz has said, hasnt it got something to do with the carbon canister?