I had the same observations when I was troubleshooting this issue. Valve actuated no problem with no end of wiggling wires from me. Monitoring the pressures when the pump/valve are on/actuating, they seemed pretty constant, which suggested to me no leak or anything like that.I've been dealing with a P0413 for a few months now. It would come and go randomly. I finally took a look at the combi valve last weekend and ran tests through OBD11. Both the solenoid and pump tests worked everytime no matter how much I wiggled the cables / connector. Only been a week but It hasnt come back yet despite ~500 miles and multiple redline pulls. Like you said maybe my connector or sensor was just loose. Probably unrelated, but I also cleaned my air intake filter and SAI filter the same time I played around with the Combi valve connectors.
Knowing my luck it will come back this afternoon because I wrote the post.
I hate parts-cannoning things but that's what I did and bought the 06K131097AA kombi valve and it's seemed to have done the trick. I have the old one sat in the basement and thinking about dissecting it, but really I don't expect to see anything glaring.
In your case, if it's not coming back relatively quickly, I'd think that the connector may have been loose??