When installing your Single vanos you can easily check your setup to ensure it's allowing the full amount of travel. Measure the distance between the edge of the chain tensioner and the notch on the cam position wheel using calipers. Take one measurement with the cam fully retarded, then again fully advanced. You will need to manually rotate the intake cam with a 24mm wrench clockwise until it stops (full vanos advance). Make sure the exhaust cam does not move when rotating the intake cam. You can use one of the cam locking blocks to hold the exhaust cam in place.
The difference between the two measurements will generally be around 10mm, but 8.5 is the minimum. Any less and you have likely set up the vanos and/or cam gears incorrectly. If you're unable to rotate the intake cam at all then you've likely set up the thrust washers incorrectly on the intake cam.
If everything looks good and the computer is still showing the 'stuck vanos' fault code then you may need to do some slight modifications to the cam sensor wheel.
How to Fix A Stuck Vanos Code