DPF light on Audi A4 2.0 tdi 2008

DPF light on Audi A4 2.0 tdi 2008

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Pazman

Original Poster:

16 posts

62 months

Monday 22nd April 2019
quotequote all
Hi

I brought a 2008 57 plate Audi A4 2.0 tdi sline convertible 115k full service history , remapped last week , private sale so no warranty.
Drive 12 miles and got the dpf light on ffs.
Had at my local garage for a read which showed no faults .
He did a forced regen , he said it was only saying 6% soot before the regen .
two days latter the light came on again so I did a run down the m42 at 3k rivs until the light went off .
Another 100 miles I came on again so I replaced the dpf sensor with a new one .
I also removed the egr valve to check that , it was solid with soot and cleanly has not working for a very long time , strangely to error code for this or eml.
I cleaned it up like and new and refitted it and went for a spin , the car definitely drove different I could feel it was not pulling as much fresh air in as it was before , letting off the gas at speed the car would now still roll on with little difference , before it would pull back and slow when you take your foot off the peddle .
So I thought it was all fixed and running well until today , the felt sluggish like the turbo was not kicking in then the dpf light came on again .
20 mins down the m42 it’s off again for now but what’s next the try ????
Any help would be greatly appreciated.

shake n bake

2,221 posts

209 months

Monday 22nd April 2019
quotequote all
Probably something to do with the remap I’d imagine.

CoreyDog

717 posts

92 months

Monday 22nd April 2019
quotequote all
What are the readings on the DPF after a new sensor has been fitted?

It has all the symptoms of a blocked DPF. I went through a similar issue with a V50 a few years ago. Blocked DPF was changed but unknowingly had damaged the sensor at same time so within 500 miles, new DPF was also blocked. Needed another DPF and a new sensor. Since then no issues.


Condi

17,336 posts

173 months

Monday 22nd April 2019
quotequote all
Who remapped it? You can try and get it hot again to regenerate it, but sounds like something more than it just blocking up over time. 100 miles is not long enough for it to be sooting up.

Btw, you dont need to drive at 3000 revs to get it to burn, it should work perfectly well at 60-70mph in 6th, which is about 1800-2000 rpm.

E-bmw

9,324 posts

154 months

Tuesday 23rd April 2019
quotequote all
DPF issues should be quite easy to diagnose for a garage familiar with them.

1. Are the sensors working.

2. Take the DPF off & check it is in place & clear.

3. Find out where it was mapped & get the muppets that did it to remove it.

4. Check injectors/egr/breathers are all working correctly.

bearman68

4,674 posts

134 months

Tuesday 23rd April 2019
quotequote all
You'd have to say that a 2008 Audi, with (presumably) a PD engine and a DPF is a nightmare. IIRC the DPF sensor needs to be calibrated, and this is not a straightforward. The fact it's mapped as well makes it much more tricky, as it's hard to know what the software is doing.

stevemcs

8,717 posts

95 months

Tuesday 23rd April 2019
quotequote all
Did you buy it with the remap ? I'd be guessing someone has gutted the DPF and remapped after being told it needed a new DPF - it only it hasn't worked.

Pazman

Original Poster:

16 posts

62 months

Tuesday 23rd April 2019
quotequote all
Sorry guys the site would not let me reply until today .
Thanks for the info posted .
It’s been back to the garage today for another forced regen but he noticed the ecu doesn’t see the Dpf sensor , here is no reading from it at all .
This is a new sensor
I’ve also spoken to the remap company and there coming to put the original file back on the car at the weekend to se if that fixes the problem.

Condi

17,336 posts

173 months

Tuesday 23rd April 2019
quotequote all
Most sensors on that model need to be coded into the car - its not usually as simple as changing the sensor at home without having vagcom.

Although as someone else mentioned, has the car even still got a DPF, or has it blocked up and someone has simply removed it?

Pazman

Original Poster:

16 posts

62 months

Tuesday 23rd April 2019
quotequote all
So new sensor has to be setup within the ecu is that why the ecu is not showing any readings from it ?
My garage is using snap on unit to with on the car is that not able to pair the new sensor ?
It still has a dpf fitted the remap guy say he has not deleted the egr or dpf.

Condi

17,336 posts

173 months

Tuesday 23rd April 2019
quotequote all
I would think the new sensor would have to be set up, whether the garage's Snap On computer is able to do it I dont know. From your original post it sounded like you just replaced the sensor yourself, which I doubt would work.

The guy who remapped it probably didnt take the DPF out, but had the old owner already taken it out because it was blocked? You probably wouldnt know unless you looked.

stevemcs

8,717 posts

95 months

Tuesday 23rd April 2019
quotequote all
We use snap on and hella and snap on sometimes struggles to find things.

Has the garage tried unplugging the sensor to see if something changes, have they checked the wiring ? If a new sensor hasn't fixed the issue and it doesn't need coding either its a wiring issue or they are looking at the wrong sensor.

Pazman

Original Poster:

16 posts

62 months

Tuesday 23rd April 2019
quotequote all
Condi said:
I would think the new sensor would have to be set up, whether the garage's Snap On computer is able to do it I dont know. From your original post it sounded like you just replaced the sensor yourself, which I doubt would work.

The guy who remapped it probably didnt take the DPF out, but had the old owner already taken it out because it was blocked? You probably wouldnt know unless you looked.
I did it myself as videos on how to did it never said it would need setting up with the ecu .
The history of the vehicle unknown really , I was thinking a clean software install from Audi maybe better just Incase any previous previous software tampering has been done .
Im trying the obvious things first to Eliminate the problem.
next on the list is to get the new sensor setup with ecu
Then the remark removed .
Then burn the car out ;-(

Edited by Pazman on Tuesday 23 April 19:04


Edited by Pazman on Tuesday 23 April 19:40

Pazman

Original Poster:

16 posts

62 months

Tuesday 23rd April 2019
quotequote all
I just unplugged the sensor and started the car , no warning lights no eml the car drove just fine
What’s going on is that normal for this year of car ?
Surly eml should have come on.

E-bmw

9,324 posts

154 months

Tuesday 23rd April 2019
quotequote all
Pazman said:

Im trying the obvious things first to illuminate the problem.
here is the most obvious thing if you just want to illuminate the problem........



tumbleweed

Condi

17,336 posts

173 months

Tuesday 23rd April 2019
quotequote all
Not necessarily, if 'normal' is a 0 reading for the sensor then removing the sensor wouldn't necessarily show a fault.



Your best bet is to ask Audi if the sensor needs coding, if so get the remap removed and the sensor coded to the car, and then go from there. That might sort the issue, it might not, but at least you would know what situation you're working from. All anyone on here can do is guess because nobody has a clue what changes were made when it was remapped, or what work was done on the DPF before you bought it.

Pazman

Original Poster:

16 posts

62 months

Wednesday 24th April 2019
quotequote all
I had the car read by a guy with vcds software and he was able to see a fault from the old dpf sensor .
He deleted it , paired in the new one did another regen as the procedure says .
Hopefully this is now fixed , I should know by the weekend if not .

Pazman

Original Poster:

16 posts

62 months

Saturday 27th April 2019
quotequote all
And it’s back again FFS
Dpf light came on again today after 90 miles since the new sensor was coded in .

stevemcs

8,717 posts

95 months

Saturday 27th April 2019
quotequote all
When the sensor was coded was the soot content checked ? when was the last regen carried out ? You need to physically check the DPF hasn't been gutted too.

Pazman

Original Poster:

16 posts

62 months

Saturday 27th April 2019
quotequote all
No he did not check it .
The DPF is not very easy to get too , can it be check when still on the car ? Like removed the exhaust from it maybe