How serious is this and what is cost to fix?

[The Radium King]

well, he has the exact same symptoms as me (mine went to 16 iirc) and that is a pic of my solenoid. from what i could determine the solenoid retracts when activated so at idle it should be extended (but isn't when it fails).

regardless the test is the same - drain oil and look for debris. if debris is the ramps then it will be hard brown plastic in the sump. having said that i'd suggest that ramps failing to the point that deviation went to 16 would mean chains running on metal which would present as a whole lot of sound and fury.

also, if your mechanic has a porsche system tester he can do driveline actuations wihich include testing the actuators..