Help with Electrical fault

Here again....fault is back.
Looking at circuit diagram the 5V is connected to:

ECU T60 pin 25 colour Yellow Blue
1 - Engine Speed Sensor G28 pin 1 colour Yellow Blue
2 - Position sender for charge pressure positioner G581 pin 3 colour Yellow Blue
3 - EGR Potentiometer G212 pin T6y/1 colour Yellow Blue (part of EGR N18)
4 - Fuel Pressure Sender G247 pin 3 colour yellow grey (not sure why wiring diagram shows different colour)
5 - Throttle Valve Potentiometer G69 pin T5q/1 colour Yellow Blue (I'm guessing G69 is part of Throttle Valve Module J338 ?)

So plan to change them all except EGR as they are connected to 5V from ECU T60 pin 25. Will ring them out too and check for short to 0V when all sensors unplugged and ecu unplugged.

Question. I need to look but is it straight forward to change these. G28 already replaced.

Thats a bitch! Same fault code?

Yes
Only Fault Found:
4124 - Sensor Reference Voltage B
P0651 00 [032] - Open Circuit

And a genuine VW ECU?

Yes....did not know there were others?


No time to look at it at the moment. Using wifes car so it will have to wait as busy.

Are the circuit diagrams correct?
Am I right thinking its one of the sensors or the wiring.
Could it be interrupted supply to ecu? i.e. ignition switch.....though I'm thinking engine would cut out if power to ecu lost.

So all I'm left with is fault is either a sensor I mention above or a short on 5V from ecu, or sensor lost earth (maybe wiring fault) or ecu lost signal (due to wiring fault) from sensor.
Does that exhaust everything?

Might be after christmas before I have time to check all these things.......