Hey all, So I've had my 2006 A3 2.0 TDI DSG since August. It was serviced before pickup with water pump, cam belt kit and oil change. After purchase it went into limp mode. The following fault codes appeared 17507 (Glow plug) 17506 (Glow plug) 19559 (Manifold flap) 16618 (Overboost) The manifold flap was replaced with a new part (Part number S038128063L) along with 4 glow plugs. Fault codes cleared and road test performed. No problems. I've since done 4,000 miles and when I was on the motorway the other day it went into limp mode. First chance I got I went and got it fault coded as the emissions light came on and it kept going into limp mode after restarting. Only fault code thrown up was 16618 (Overboost). This was cleared and the emissions light went out. I will take it on the motorway later and see if it overboosts again but I get the feeling it will. Now I know this could be down to one of the following Hoses incorrectly connected, disconnected, blocked or leaking Boost Pressure Control Valve (N75) faulty Boost Pressure Sensor (G13) faulty Turbo Charger stuck/faulty I'm going to check for any boost leaks etc first, but has anyone got any idea of any other issues this could be caused by? I'd also want to try and replace items in a cost order as a new turbo is over Â£900 for the unit alone. Have people had more luck replacing the N75 or G13 components before a new turbo or am I looking at a turbo replacement? Car has 110k on it and has got decent service history.