HOWTO: Replace front outer parking sensor(s)
 

Here is a quick guide for replacing the front nearside parking sensor, it should also work for the offside but you'll need to remove the airbox (possibly more) to get access. The inner sensors may require bumper removal, so these are not covered here.

On the D3 all the parking sensors share the same part number, and are supplied unpainted when new, the part number you need is: 7H0919275

Some of this can be done from above if you have small hands, by reaching down below the headlight, once you work out how the sensor is attached to the car its a piece of cake to remove. The sensor is not a twist remove, its literally a push in fit with some a couple of plastic tags which hold it in place at the back. Removing the foglight grill and foglight makes disconnecting the wiring 10x easier as you can poke the sensor down into the opening.

The foglight grill is held in place by clips and can be removed reasonably easily, basically grasp the inner most part of the grill and apply a lot of downward pressure and then pull towards you, and work your way along the top edge. Be very careful when you get to the foglight hole otherwise you may crack the grill. Gently work around this area, there are no clips on the top/bottom of the foglight but several where the grill meets the front wing. Once the top is clear the grill should just lift out of the bottom clips.

Foglight is held in by 3x screws

Wiring from the sensor points towards the centre of the car.

Basic process to follow.
1) Remove foglight grill
2) Remove foglight, disconnect its wiring and place carefully to one side.
3) Working from above, use your left arm and reach down below headlight and you should be able to locate the rear of the sensor. The sensor retaining clips are top and bottom.
4) Release the sensor, easily done with your finger, apply gently downward pressure on the bottom clip and upwards on the top clip. I used my thumb and forefinger to prise them apart, use your spare hand to gently push on the front of the sensor at the same time and it should pop inwards and release from the bumper.
5) You should now be able to manoeuvre the sensor to the foglight opening.
6) Disconnect sensor and discard
7) Connect new sensor, and test it before assembly. Just leave it dangling, get in the car, switch on ignition and select reverse. The flashing green light should be solid and chances are it will be beeping telling you that you are close to an object.
8) If all OK, reassemble as above.
9) When done, and refitting the grill make sure its properly aligned before pusing it back in. Make sure the outer clips of the grill go in before fully home as they are a pain otherwise.

And thats it, all done.

I know Manny is no longer on the site but thought I'd have a go at his guide, bloody hell a lot harder than I thought gave up after trying to bend my hand backwards though the fog opening and up to unclip the outer sensor. Tried I did but failed miserably, the outer rear however are a piece of cake, might have to get the bumper off to get the outer front one fitted what a sod they are!

This is the point where I've just realised he says working from above, use your left arm and reach down below headlight and you should be able to locate the rear of the sensor.. doh 2nd try tomorrow

Timely thread bump. I have this exact sensor out too, ha ha.