P2015 error code

[Roger Blassberg]

2010 2.0 litre TDi Highline, common rail engine code CBAB, plastic inlet manifold, showed P2015 error code.
I have replaced the swirl flaps manifold, the actuator motor with the add-on stop to prevent over rotation and the egr valve ( on the front of the engine without an integral cooler). Cleared the code but it keeps coming back. I am suspecting a vacuum leak somewhere. The brakes work perfectly well, so not a huge vacuum leak there.
The wiring loom connector to the swirl flap actuator looks ok despite its incredibly stupid twisted design ( do VAG do this built- in -fault stuff on purpose??).
All help would be appreciated.
I have had many VW cars, since 1981. This is by far the most badly designed ever for maintenance accessibility, eg you have to take off the bonnet slam panel to change the thermostat apparently.
And the front wings have a handy piece of foam plastic in the wheel arch to aid rusting through.