How to clear a blocked diesel particulate filter

[Matty1234]

I've just picked up a second hand A4 S line 2007 tiptronic that has been limited to occasional very short trips (total mileage 10K kms at 2 years old). Took it for its first long run on the weekend and got the warning light for the particulate filter. Following instructions, I ran it hot (above 60kph in 4th and 5th) for the best part of an hour with no change. On the way back home the following day the coil warning light came on and the engine went into some sort of 'safe' mode that wouldn't get the revs over about 2500 or speed more than 100kph. Its at the garage now and the mechanic assures me that its just a computer issue but as I'm in Sofia Bulgaria, I've been looking for advice/comments/thoughts on the issue. Other forums seem to think this is a more substantial issue than 'just drive the car fast for a while'.

I'd appreciate your thoughts

[dantdi]

Ive be told from audi that the sensor for dpf is normaly the fault not the dpf it's self.
Not sure how true it is but worth looking into it maybe.

Dan

[Matty1234]

thanks!

[dantdi]

Let us know how you get on with it mate.

[devonmikeyboy]

Just get it remapped to delete the DPF as it will be a pain all it`s life. With a remap and DPF delete you should get 210 bhp + and never have any DPF issues again.

[Matty1234]

So it was the sensor, not the DPF. Replacing it cost around 100 euro. Thanks for the advice, which I passed on to the mechanic and may have saved a lot of time and expense.

[ladyvic]

Had to reply to this one as this is causing me a total nightmare...

Just replaced my A4 cab 56 plate petrol with a Diesel 09 A4 cab. I live in London so dont get out on the open road much, after its deleivery from the north on the motor way ( so a good burn) the particualet filter light came on then the engine went into safe mode. It was in the garage for a week having full diagnostics, came back to me, and was driven on the motor way so not just town driving. The light came on AGAIN, did exactly as it said in the manual ,cleared after 15 mins, next day light came on again, after driving the car fro 22 minutes!! I have had numerous dealings with Audi who say it my style of driving(!!) and not a problem with the car! This is apparently a "feature" of the car!!

I was not going to go out of my way to drive at 60k for 15 min in S as I have neither the time nor the inclination to drive more than I already do! So yesterday, one week after I drove it on the motor way the engine went in safe mode yet again. When Audi recovery service arrived the filter was 90% blocked.

Needless to say the car is going back and I wont be driving another diesel in london. Audi still wont accept responsibilty. Very very dissapointed with them, I have been a loal customer but am now worried about my driving style...not!!

Good luck on the short journeys

[Matty1234]

Well my saga continues to run and (not) run - I took the now repaired Audi for a long trip around SE Europe. At the very start of the trip the DPF light came on but an hour blasting the hell out of it seemed to work. It drove without problems for another 1000kms but once I started moving through slower traffic the warning light came on after an hour. It wouldn't clear and went into safe mode. Audi in Split (Croatia) said they couldn't find a fault. The diagnostic said change the filter but there was nothing wrong with it. In the end they cleaned the soot from the pipes leading to the sensors. Everything worked fine for the next 1500 kms but as soon as I had driven for 40 mins in city traffic when back here in Sofia (after 900kms on the motorway), the light has just come on again.

Tomorrow morning, it goes onto the forecourt. I'm buying a Mercedes. Petrol.

[Matty1234]

Being unwilling to bite the financial bullet in these difficult times of dumping the price to get rid of my Audi (and having 2 potential buyers get the DPF warning light come on during test drives) I have persevered with trying to convince Audi that their product is faulty. The DPF light now comes on every 300kms or so of open road driving, but seems to go off easily enough - if I'm on the open road. If I'm in town, I'm doomed. After one 'fix' after another (at my expense and with the caveat from Audi that 'we don't know whether this will work'), Audi have finally agreed to replace the whole DPF and cover 70% of the cost themselves. Perhaps my note to Audi Germany explaining that I bought their product because a) I thought it would work and b) if it didn't I thought the main dealer would be able to fix it, might have made an impact.

Fingers and toes crossed......

[Matty1234]

Well, the new DPF did not resolve the problem - warning light came on after 174kms of highway driving.