If you are getting a P2102 error code associated with "Engine Fault, Workshop!" on the display, then there is most likely something wrong with the throttle valve.
The throttle valve and EGR valve can get gummed up or filled with engine oil causing them to fail:
Replacement of the throttle valve involves:
Installation is the reverse procedure.
If you're throttle valve has lots of oil deposits, then it may be worth removing the EGR valve and giving it a clean as well. Mine had lots of oil buildup in various stages of hardness.
Here are some pictures of my failing throttle valve. Lots of oil deposited inside:
Lots of liquid oil inside throttle valve mechanism:
I cleaned my throttle value of its oil deposits and liquid oil in the mechanism but it still generated an intermittent P2102 fault code. As a result, I had no choice but to replace it with a new item. My version was 03L 128 063 B. It has since been superseded with revisions C, D and E. The replacement from VW was 03L 128 063 E. The revision E part has a plastic butterfly flap. The B revision was metal.