I find it weird that volkswagen diagnostic shows P codes, lol. P codes are pretty much useless. The other code ie 19459, is the one you should look at. Google "ross-tech 19459"
That specific one doesn't yield any results, its the coolant glow plug relay likely. I have never seen a code for that nor should it effect anything unless your harness is all chewed up and that is where you're having all your problems. All these devices are tied into a common yellow wire which is +12v, Its possible there is corrosion somewhere causing issues - they get power from the plenum plugs near the drivers side.
I also find it funny that the VAG software is calling it a wastegate. And that it says glow plug #4. Your system doesn't have the ability to detect which glow plug is causing the fault. All it can do is see a difference in voltage drop across plugs 1&2 together vs plugs 3&4 together, even then it couldn't tell you anything. If you replace the plugs and still throws that code, I have the solution.
Also, if the fuel shut off solenoid opened while driving, the engine would die, not limp mode, but it would die.
With your hood open, you should be able to hear the solenoid click. It probably does since the car runs. It cuts off fuel to the plunger in the pump when power is removed from it.
lol I kinda wondered about EGR
its probably ASV that you're thinking of? Anti-Shudder Valve, its located in the EGR valve itself(flapper) and the solenoid is on the intake manifold. Do yourself a favor and replace the vacuum lines(use good OEM preferably, no flimsy lines!)
I just read back to the first post - 99.5 have hot start issues which is a simple fix included in every tune. You require ECU sockets(I do this) and chips for a tune vs a loader.