BBV should be open at idle yes.

Its open The lever pointing UP at idle and highway driving for more air circulation in the LIM to improve fuel economy. It closes under BOOST so all the air is deflected into the rotors to make the boost. Once your out of boost, it opens it back up. When your engine is off, it closes.

Testing...start your car, and give it some engine revs. Some short heavy throttle engine bursts will cause it to close, then reopen right away.

~F~