Q7 Parking sensor fault


Just add boost :D
Hi All I have a 2010 Q7 and have been having intermittent problems with my parking sensors...

When putting the car in reverse you get a long beep and the rear camera displays for a few seconds then disappears!

I have scanned with VCDS and get the following fault:

01628 - Sensor for Parking-Aid; Front Mid-Left (G254)
009 - Open or Short to Ground
Freeze Frame:
Fault Status: 01101001
Fault Priority: 3
Fault Frequency: 1
Reset counter: 187
Mileage: 79857 km
Time Indication: 0
Date: 2015.04.06
Time: 16:44:22

So i have had this sensor out and swapped with the center right and the fault still remains i have also put the left in the right connector and it works using the measuring blocks in VCDS.

I then decided to try and trace the wiring back to see where its connected but this is almost impossible without stripping the car down :( i opened the fuse/replay compartment under the passenger side windscreen and wobbled a few wires around and suddenly i started to get a reading for that sensor in question.

It was at this point that i thought i had traced the problem to a bunch of black wires that looked like they had been joined together. Everytime i moved these i went from from no reading on the sensor to reading as it should. So i secured theses wires better with cable ties and thought i had solved the problem ! unfortunately i was wrong as the symptoms reappeared shortly after :(...

So i had another mess around in that compartment again today and can not get the sensor to come into play. Im now thinking that it was just a coincidence when moving things around in there.

I got the multimeter out and compared each pin on the loom connector where the sensor doesn't work to one that does. There are 3 pins on each connector and it is pin 2 (center Pin) that has no reading so must be open circuit. i guess by wobbling things around i must of made the broken wire connect back together for a short time :s

Now my question is does anyone have a wiring diagram for the front parking sensor harness ?

I need to work out in what area the wire is broken between interconnects. In the fuse box there is hundreds of wires and i have no idea what connectors the wires from the sensor harness connect too. If i could work this out then i could just run a new wire from pin 2 to the point where it interconnects....

Any help or experience would really be appreciated.