Hi!

I am looking at the wiring diagram, and according to it, from the ECU, a wire goes from the ECU to the MAP, which is L/W in color. This splits out to a plug to the gauges, which comes out to the Miles sensor no 2... that does not need a MAP sensor reading at all, I don't see why it is stated as such, but that is the only wires that can be for the turbo pressure gauge is that wire.

 

The wiring diagram you are using does not have a Pressure Sensor for the turbo model so it is wrongly depicted.

 

It is the only I can find that one for S5, but those seem to be the correct wires, as they come from the pressure sensor via the ECU

 

They were correct. The gauge seemed to be accurate compared to my mech gauge, BUT, since it is electrical, it got a fair bit of delay.