D3 4.2TDI DPF Pressure Sensor
 

Apologies for my first post being a request for help but I have been a lurker for a while and an A8 parts customer :)

I have a 2005 A8 4.2 TDI, circa 125K miles on the clock and it has just started showing an amber engine warning light, I have checked with VCDS and the following error is showing. Clear the code, the light goes out for a day or so and then returns.

Google suggests that I need to replace G450 or possibly G451 sensor? Has anyone come across this before or can you give me any tips? Is the part something that is best from a dealer or elsewhere and where will I find the sensor on an 8?

Thanks in advance +++

Paul

It could be the filter is choked, there are products available to clean them out

I think the DPF is okay in itself, I think the sensor is the problem given the "Implausible Signal". I have found the code for other VAG engines and the fix seems to be to change the sensor, just not sure where it is on A8 :hammer:

I found the number G524 for bank 2 sensor and G505 for bank 1 sensor

See attachments for location of connections and sensors

Hope this helps

I agree with your thoughts, I'm sure the DPF will be OK it is just the Pressure Difference sensor that is unable to calculate the difference in pressure before and after the DPF therefore it cant decide how clogged or not-clogged it is.

Note that while it is broken it wont try and do any re-generation of the DPF so I would suggest a replacement sooner rather than later. I had to change the one on our Crafter for the same reason, easy job, and afterwards I used VAS to force a regeneration although I dont think that is vital - once fitted it should sort itself out.

We can get hold of one from TPS if you need, just let us know via email or a call on Monday morning.

If it is expensive, I would put the money towards having the filters taken out of their boxes and trashed and then ECU reflashed sans DPF.

I had mine taken out at 175,000miles due to blockage and it is much better without. You have two and it costs about £2400 to replace them!

What a great forum!
 

Ah, okay so looks like I need a G524 then :) Shame it looks a bit of a pain to get too "on gearbox rear" but I will give it a go!

I was working form what I could see in this doc http://www.volkspage.net/technik/ssp/ssp/SSP_365.pdf but the info posted above looks more specific to my car so many thanks 47p2 +++

David, I will send you an email shortly and would be very appreciative if you could source the part for me +++ Will try and get it fitted ASAP and post back how I get on.

Thanks to all :cheers:

Bank 2 looks to be sensor G505, double check numbers before ordering!!!

Also see attachment for sensor G450 which is the exhaust pressure sensor

Well guys, having been under the car and re-acquainted myself with ELSA I am now wondering who in their right mind in Germany decided the est place to mount the sensor was on the TOP of the gearbox!?

£60 for a part, I suspect it will be a lot more in labour as lowering the subframe isn't something I want to try on the drive with a trolley jack and stands :mad:

Will call around tomorrow and hope that the actual labour involved isn't as bad as it sounds! Thanks for the help thus far +++

I am glad I was sat down when I called my local dealer for a quote, 7.5-8 hours @£145 per hour +VAT, so over £1,300 in labour, oh and £47.86 for the actual part :ROFL:

Actually it was worse than that, their tech suggested it was actually the lambda sensor as "your car doesn't have a DPF sir"! When I explained that it clearly did have TWO of them and maybe he should check they spoke to the master tech who advised that apparently they need to "remove the gearbox", which is weird because that's not what ELSA says but what do I know!? :Confused: In any case, not very confidence inspiring!

Now awaiting a call back from a couple of indi's who hopefully will know their arse from their elbow! :D