View Full Version : Parking sensor fault finding
I have a 2015 A6 Avant C7 (facelift ) and the front-left sensor gives No-signal/Communication according to VCDS.
I've swapped the sensor from the opposite side of the car and get the same error.
I then tried a spare sensor and get short to positive, so can only assume the spare is not the correct part.
Next I got out the multimeter.
I get continuity from the yellow/black and blue/purple wires from the sensor connector to the loom connector bottom left/ bottom middle pins.
The brown/white pin doesn't get continuity to any of the pins in the loom connector, so assume there is a break in the loom?
Would you guys agree, or am I misdiagnosing?
(photos attached)
Many thanks!
Brown is generally ground on Audi.
In the case of the G255 front left sensor it goes from the sensor to the '348' parking aid ground connector first (in the front bumper wiring harness) then to the X65 connector in the front bumper wiring harness.
Whereas the other 2 wires go directly to the X65 connector which is where I assume you are checking continuity.
The brown white wire then also changes colors at the T8 connector pin1 to brown/green and makes a stop at the B741 main wiring harness before continuing onto the control module connection.
Sadly I do not know where the '384' parking aid ground connector is located...you might have to trace the wire.
What I find interesting is only the left front sensor does this.
All the other sensors brown/white wires stop at the '348' ground connector.
You could try tracing the brown/white wire from another sensor to confirm where '348' is and then your issue may be isolated from '348' to X65.
I honestly don't know if this would work and don't even really recommend trying, but maybe if you can put the brown/white wire directly to any ground in the car as a test to see if the sensor works again then you know for sure there is a break in your ground wire for that sensor location.
Hope that helps. Cheers
Brown is generally ground on Audi.
In the case of the G255 front left sensor it goes from the sensor to the '348' parking aid ground connector first (in the front bumper wiring harness) then to the X65 connector in the front bumper wiring harness.
Whereas the other 2 wires go directly to the X65 connector which is where I assume you are checking continuity.
The brown white wire then also changes colors at the T8 connector pin1 to brown/green and makes a stop at the B741 main wiring harness before continuing onto the control module connection.
Sadly I do not know where the '384' parking aid ground connector is located...you might have to trace the wire.
What I find interesting is only the left front sensor does this.
All the other sensors brown/white wires stop at the '348' ground connector.
You could try tracing the brown/white wire from another sensor to confirm where '348' is and then your issue may be isolated from '348' to X65.
I honestly don't know if this would work and don't even really recommend trying, but maybe if you can put the brown/white wire directly to any ground in the car as a test to see if the sensor works again then you know for sure there is a break in your ground wire for that sensor location.
Hope that helps. Cheers
Thanks, I tested continuity from brown on sensor plug (front-left) to brown on centre-left plug and it fails.
I’ve just fixed it!
Replaced the parking sensor front loom (£69) as I found previous owner had it trapped in undertray and likely broken it.
Managed to fit it without having to take off the front bumper too!
I just removed both lower vents for access, plus the centre-front engine cover.
20minute job to remove, replace and test. Very happy!