'06 Audi A3 2.0 Tdi 170 BMN P1269 Implausible Signal / P1266 Implausible Signal

[Crasher]

The first thing you must consider is that you cannot get a legal MOT with the car as it is so you need to deal with this before putting any more money into the car. Check the lift pump runs, delivers fuel and very importantly, the fuel lines are the correct way around on the sender top. I see this a lot and the key clue is it runs better with a full tank. Fed is black, blue is return, the sender top has annotation to show which is which.

[mcmurray]

So I've checked the lift pump, all seems well - I took it apart to clean and there was a bit of crud in there, not an excessive amount though and the fine gauze was pretty clean. It is a bit concerning it's running so well now just because it's got a full tank, the fuel filter has also been replaced recently by the way. So at the moment I've basically got a non turbo 2.0tdi, well that's what it drives like anyway. What's the first port of call for troubleshooting that on these? Is there something I can check with vcds?

[Crasher]

Yes, you can check the operation of the actuator movement and the N75 valve, the functions will come up in the menus of basic settings and output tests. Also apply a vacuum to the tandem pump servo hose connection 3mm pipe, you should not be able to draw air through this, it should hold a vacuum.

[mcmurray]

I've had a good look through vcds and can't find those functions - basic settings just gives me basic infomation about the actuator and when I turn the basic settings on the values just stay the same. On output tests it only lets me go through a series of sequencial tests, none of which are n75 / actuator related. Sorry for the lack of basic vcds knowledge but I'm fairly new to it. The tandem pump holds a vacuum.

[Crasher]

With it idling, go into basic settings group 011 if it will allow a direct number entry, if it works this should lift the idle to 1200 ish and cycle the N75 valve off and on about every 20 seconds so you can watch the turbo actuator lever.