Time for a DPF Clean?

2014 Audi A7 3.0 TDI 205k miles

All seems fine with the DPF regen’ing itself every 300 motorway miles and normal DPF pressure readings. I did a routine VAGCOM diagnostic with service and it says fault 5585 DPF blocked. I noticed the oil ash volume was 0.39L which I think is above the threshold hence the fault code?

My question is - do I need to remove the DPF to clean it or can I do an ‘on the car’ clean adding cleaner via the temp sensor port? Do any of the of the shelf cleaners work or do I need to take it to a specialist DPF cleaner?

many thanks for any advice.

Attachment 39441

Here’s a pic of the fault code:
Attachment 39440

I would like to know also
Your different pressure is at 8hPa, i hear this should be <5 at tick over and less than 50 at 3kRPM? to be confirmed.
I believe, but again don't know for sure - the cleaners will sort the soot out but not the ash?

Yeh mine is normally 5 at tickover and about 35 at 3000 rpm. It hits about 200 at full power in sport mode which I try to avoid. I’ve noticed it varies with the engine loading (going uphill or accelerating) as the fuel flow increases which I guess makes sense.

What is strange is when it regens the soot never drops to zero but stops at about 4g (not sure how it calculates it) - I was wondering if this represented the oil ash / soot it can’t burn off as I assume it can’t actually measure it but just calculates an estimate based on useage?

So finally got round to removing the DPF and getting it professionally cleaned. Removing it was ok apart from the one exhaust nut that has to be accessed from below - this bit was a 2 man job really as one to hold the socket onto the nut on the lower DPF flange and one underneath the car to undo the nut. I had to use 2 long extensions and a universal joint but it worked - definitely not a nut to round off as can't see how you could recover as no access.

The results from the DPF clean was:

Before:
Flow rate: 222 m3/h
Back pressure: 34 m/bar

After
Flow rate: 415 m3/h
Back pressure: 6 m/bar

The DPF had done 200K so the before results were not surprising and a Lot of ash was removed (lots of motorway miles and shows good regens apparently).

Anyway refit it today so it will be interesting to see what vagcom says.

Do a service regen when it is back on.

So all seems good. Did a DPF reset after refitting DPF to clear the computed Ash value. After this it said it needed a regen so took it for a drive and regen'd fine. Thanks for the tip on service regen Crasher :beerchug:, it reduced the remaining measured soot value to zero and calculated soot to 4g (assume this is normal - not sure why the difference between calculated and measured?). Temps got high (620 deg c and some very hot smells from the exhaust - thought I was going to melt the tarmac!!). Anyway DPF pressure now reads 2 to 3 hPa on idle. Long motorway drive tomorrow, so will be interesting if MPG etc improves.

I'm also pleased I managed to retrieve with a magnet the 12mm socket that dropped into the v when removing the DPF!!