2.0 TDI not starting to regen the DPF by itself

Tavi19195

New member
Joined
Jan 11, 2025
Location
Romania
TDI
2.0 TDI CBAB
Hello everyone, I have an Audi A3 2.0 TDI 104kw 140HP engine code is CBAB.

I got a weird issue where the DPF started to accumulate 20g of soot and the ECU never started the regen process it was usually doing that as soo as it reached >=17g of soot, usually 300-400km I knew it has to make is regen cycle and it never started. Happened twice already the first time I just started a regen and the residual left was 5g of soot.

Now it happened again, I usually track my regens, I was at 500+ km and no regen, plugged my VCDS and soot was 25g, I was like *** this is wrong!

What I did this time is to completely reset the DPF data (see picture) and then did a regen while doing 40mph everything went well and now values are ok again.

Differential sensor looks all good, idle at 5-10mBar and that is within specs. (while accelerating it goes up indicating is all ok), offset is 0mBar, again in specs.

Pictures before and after the regen + delete DPF data from ECU:




TLDR: My DPF was usually starting to regen at 17g of soot, now it exceeds 25g and still it does not start to regen by itself! Why does it do that? All sensors are ok! checked with VCDS.
 

lina87

Member
Joined
Jul 13, 2022
Location
atlanta
TDI
2015 Mk7 Golf Sportwagen TDI
Check the sensor readings regularly during typical rides, and make sure its variations follow expected behavior. If the readings become erratic, it may be worth testing or replacing this sensor.

 
Last edited:

Mozambiquer

Vendor , w/Business number
Joined
Mar 21, 2015
Location
Versailles Missouri
TDI
2004 VW Touareg V10 TDI, 2012 Audi Q7 V6 TDI, 1998 VW Jetta TDI. 1982 VW Rabbit pickup, 2001 VW Jetta TDI, 2005 VW Passat wagon TDI X3, 2001 VW golf TDI, 1980 VW rabbit pickup,
Make sure the coolant temperature is staying above 87°C during drives. If it drops below that it won't Regen. Are there any codes thrown?
 

Tavi19195

New member
Joined
Jan 11, 2025
Location
Romania
TDI
2.0 TDI CBAB
17g always triggered mine, I know that for sure.

Right now the car is in the shop for a subframe alignment... The only way to adjust caster and camber LOL
 

TurboABA

Top Post Dawg
Joined
Jul 24, 2010
Location
Kitchener, ON
TDI
RIP-2010 Jetta 6spd 2014 Touareg Execline '14 A6 Technik S-line
Let's see a full VCDS scan. There's also a MVB for average distance between regens (I think... it's been a while since I've played with a 2L)
 

Tavi19195

New member
Joined
Jan 11, 2025
Location
Romania
TDI
2.0 TDI CBAB
Alright guys, good news, it was the differential pressure sensor. Car just did a regen as normal, when reached 17-19g.

I had no errors whatsoever, the way I diagnosed this is looking at the values in VCDS.
 
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