Q7 Parking sensor wiring fault

[S3DUST]

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.

Cheers
Rich

 

[desertstorm]

Here is the wiring diagram off ELSAWIN. It seem the sensors all share a common connection for power and ground and then have individual feeds back to the module for the sense output.

Karl.

 

[S3DUST]

Perfect thankyou, I'll take a look in the morning when on the laptop.

Cheers Karl

 

[S3DUST]

I forgot to update this thread.... The problem was traced to the front wire harness. where the Front sensor harness plugs into the loom ( Front drivers side wheel behind wheel arch ) one of the wires had worn through around 1 inch from the connector. There was the smallest of broken insulation but enough where water had got in and corroded through the wire. Fix was simple, chop out broken wire, solder in new one.

Its been working for the past 3 months without fault

 

[desertstorm]

Thats my kind of repair, cheap and simple., well done for finding it.