DPF failing to regen and output gas temperature question

[Calvin]

I am so glad that I found out about the VAG DPF app, without it I would have no idea what was going on in my engine and I'd be totally at the mercy of the garages! That said, I'm looking for help in interpretting the data I'm seeing and 'guiding' the garage on what might be wrong with my VW transporter as their 'solution' so far has been a DPF clean which of course didn't actually fix the problem.
I'll probably post a full description of my problems later but the quick questions are:

1. During regeneratoin I'm seeing an input gas temperature of about 600C but an output gas temp of only 320C to 350C. This doesn't sound good to me but I don't have any data from a good engine to campar it with. Can anyone tell me what the output gas temp shoudl be during regeneration please?

2. Assuming that output temperature is too low what might be causing it?

Thank you in advance to anyone who can help with either providing 'normal' data or giving me ideas about what might be wrong.

[admin]

First we have to understand which is the right output gas temperature sensor read by the app, because in the exhaust line there can be many temp sensors and not always the same in between different engines. Usually I try to find the sensors as close as possibile to the DPF, but it couldn't be near the filter.
What engine group are you using and what's the engine code of your car?
I can try to find more information in some SSP document.

Anyway, 320-350° are lower than what usually see in my engine (DETA 2.0 TDI) that reaches 550-580 at the end of the regeneration.

[Calvin]

Oh, I'd not even thought that the app might be reporting from the wrong sensor! I have the app set to read the engine group from the ECU, is there a way to tell what it thinks the engine group is? (I do notice that the app shows fields for Oil Ash Residue and Low Press EGR which never receive any data - which might indicate that it isn't using the correct engine group).
All of the documentation I can find says that I have a 7HC / CCH 036994 engine. Resources online say that the CCH type engine is fairly common in a caravelle but I can't see which group that equates to in the app.
I'll try to get out to the van today and see if there are any visible markings on the engine which might help.

[admin]

It could be a sensor in a different position versus other engines and this can be the reason of lower values. But this is only an hypothesis, let me check if I have detailed information about your engine.

[Nikolay]

Hi,
When you have big difference in the temperature in front and at the end od DPF, this can mean only two things
1. Defect sensor
2. Clogged filter
Hope it helps

[Calvin]

Looking closely at the app I see that it reports the engine type which it reads from the ECU in the bottom right corner of the screen. Mine reads:

CCHA/2011
R4 2.0L EDC

So the app thinks it's a CCHA engine too, that's good news!