Normal. Sometimes it will turn on again after driving a bit to test the OBD 2 system.

Sounds like a quiet vacuum cleaner.

There is a screen on the bottom / back , just have a loot to see if it is grease covered.

There is a valve between the two exhaust manifolds, this is operated by a vacuum solenoid at the front of engine ( under the black plastic cover ) . Make sure you are getting vacuum at the manifold valve when the pump is running.