Parking sensor failure

[fat controller]

It would appear that one of my parking sensors has turned its toes to the sky - - got into the car this afternoon to reverse out of my parking space at work, and the front one on the drivers side of the grille appears to be shorting or at least the display is saying that it can 'see' something immediately in front of it when there is nothing (long continuous tone from the front only);

So, two questions really - are these difficult to replace (I can easily feel the wiring at the back just by putting my hand under the front bumper), and do they cost arms and legs?

[Guest 2]

don't think they're much, just get the part number off your current or just do an ebay search.

something like this "should" fit but obviously it will need painted but check first and the connection plug is the same.

Original Audi Parking sensor PDC A3 A4 B8 A5 Q5 Q7 New | eBay (http://www.ebay.co.uk/itm/Original-Audi-Parking-sensor-PDC-A3-A4-B8-A5-Q5-Q7-New-/400523202592?pt=UK_In_Car_Technology&hash=item5d410b1020)

not too hard to get the bumper off, I have a walkthrough I can send if it helps any :o

[fat controller]

Thanks Chris :)

It won't even need painting - its the plain plastic one at the front of the grille (at least that is the one that is showing as permanently 'stuck'

Would I need to remove the bumper, as I can feel the back of the thing without really trying just by putting my hand under - wondering if I could swap it out by jacking the front end up? I have a good hydraulic trolley jack, axle stands and a nice flat driveway?

Also, if I disconnected it, would that make it go open circuit and at least silence it to eliminate that it is actually that part that needs replaced?

[Guest 2]

Ah, I was reading that as the very outer one, sorry!

You could try that, if you have smallish hands I'm sure it would be possible, I'll have a look and see if its possible to get the grille out without the bumper.

Yep, everything else should still work, but you still could get the beeep but no harm in trying. I'll send you that guide within the next 30 mins ;)

[fat controller]

Thanks mate - no rush :)

I am half tempted to unplug and switch it with its neighbour and see if the fault moves position on the screen, its about the only way I can think of eliminating the faulty part properly.

I'm lucky in that I have a VW dealer right next to my work, so I am sure if I went to them armed with a part number that they would oblige.

[fat controller]

Well, I tried getting the front part of the undertray off to get in from underneath, and it wouldn't budge; then I took the lock carrier cover off to see if I could get at it from the top - I could feel it, but couldn't see it; then, just when I was on the verge of taking the bumper cover off, I decided to try sticking my phone through the grill and video-ing the back of the sensors so that I could see how they were held in.

They are simply held in by plastic tabs top and bottom, so pushing the bottom one down with a finger whilst pushing the round part of the sensor in toward the car, and then doing the same with the top releases it fairly easily - it can then be dangled through one of the grill holes quite easily, and then unplugging it is child's play.

Now, the good bit - I firstly disconnected the one suspected of being faulty and then started the car and put it in reverse - - it didn't like that, and threw a hissy-fit giving me a constant tone and flashing the light on the button by the gear stick. So, I then swapped the one from the nearside of the grill with the suspected duff one, and it is now working fine! I have had the car on and off a few times, and even got my daughter to walk round front and back at varying distances from the car and it is spot on in every way. I can only assume that it was a cruddy connection somewhere that I have resolved by unplugging and re-plugging?

I'll post a photo of the sensor later on this evening, just in case it helps anyone else.

Thanks again for your help Chris - you are a true gent.

[fat controller]

Sorry for the delay in posting - anyway, the picture showing the sensor in situ isn't great as it came from a video, but hopefully you will get the idea:

http://i182.photobucket.com/albums/x7/fatcontroller_2007/VIDEO0020_0000017900_zps79195676.jpg

This is looking at it from the inside, so you will have to put your fingers through the grill and push the wee clips whilst pushing on the round centre part of the sensor and it will just pop out.


Part number appears to be 420 919 275 on both of them; no idea what they cost, as so far mine are behaving again:

http://i182.photobucket.com/albums/x7/fatcontroller_2007/IMAG0439_zpsfe0f6ac8.jpg

[Guest 2]

Hi Russ,

That sensor is actually from an R8 so your car has sporting credential! ;)

£35 for a brand new genuine sensor if you're that bothered - Genuine New AUDI A3, A4, A5, Q5 & R8 PARKING SENSOR 420919275GRU | eBay (http://www.ebay.co.uk/itm/Genuine-New-AUDI-A3-A4-A5-Q5-R8-PARKING-SENSOR-420919275GRU-/281055029786?pt=UK_In_Car_Technology&hash=item41702f6a1a)

Or £20 for a used genuine - VW VOLKSWAGEN AUDI SEAT SKODA REVERSING PARKING SENSOR 420 919 275 420919275 | eBay (http://www.ebay.co.uk/itm/VW-VOLKSWAGEN-AUDI-SEAT-SKODA-REVERSING-PARKING-SENSOR-420-919-275-420919275-/161022287015?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item257dad1ca7)

[fat controller]

:biglaugh:

That sensor and the four rings on the nose are about the only thing shared with an R8, sadly

I'll probably go for a new one if it plays up again, but so far so good. They are so easy to pop out, at least the ones in the grill are, I am tempted to whip them out, clean them up and give them a smearing of vaseline on the outer cover before winter.

The bad news is that doing this wee job today, I noticed a crack in the chrome ring that runs around the grill, as well as a wee dent at the top of it - - starting to think about replacing the grill on it now. :1zhelp:

[Guest 2]

They seem to be fairly common on ebay, just search for that 420 part number.

Grilles seem to be quite dear, I'm not sure if the sensor one is different to the non sensor, are the sensors actually attached to the grille or are they a separate part?

I ask because all the grilles on ebay seem to be non-sensor and the sensors are a separate part.

If that's the case you can get a grille for £45 ;)

Audi a4 b8 grille | eBay (http://www.ebay.co.uk/sch/i.html?_odkw=Audi+a4+b8+grille&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0&_nkw=Audi+a4+b8+grille&_sacat=0)

[fat controller]

Oddly, this one (http://www.ebay.co.uk/itm/Audi-A4-B8-8K-Saloon-Avant-Grille-S-Line-S4-optic-look-07-12-8K2-8K5-/330966487043?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item4d0f23d003) is the only one that looks like it has the wee holders for the sensors to clip into - whether they could be transferred over, I have no idea. I'd say that there would certainly be a problem with the honeycomb style grills as there is nowhere for them to go.

I'll try and get a closer picture of the arrangement tomorrow and will post back.

Looking at a couple of the grills in there, they have blemishes or cracks the same as mine, so I just need to stop being a picky sod :biglaugh:

[Guest 2]

You see I saw this one - Audi A4 B8 original S-line S4 front grille Grill with PDC | eBay (http://www.ebay.co.uk/itm/Audi-A4-B8-original-S-line-S4-front-grille-Grill-with-PDC-/400476585835?pt=Motors_Car_Truck_Parts_Accessories&hash=item5d3e43bf6b)

And you can see the little sensor holders separate to the grille, but I'll have a looksy online sometime tomorrow and see what the score is.