DPF problems limp home

[Adhal]

Last week when the cold weather really kicked in I started to get a flashing glow plug light but thought nothing of it as it went off after it got warm. Then strangely the DPF light came on midweek on the way home from work which is a 15 mile 50+mph route (usually comes on at weekend when driving around town). The next morning I drove to work expecting the light to go off and it didnt and I noticed I had reduced power too and I couldnt rev over 2500rpm. This was closely followed by the EML.That night I had to force a regen through VCDS which worked, but I'm now back to square one as the DPF light came on again yesterday and after trying for an hour to get it to regen I got the reduced power and rpm again. The EML is not on yet but I imagine it will be if I drive it further.

So basically there seems to be an underlying issue that's not allowing the car to regen itself. I do know that it has a fault code stored which I'll post later, but can anyone help with where to start?

[Adhal]

This is a copy of the VCDS log from Saturday when I got it scanned. This is few days after the forced regen had been done. 2 fault codes present.

Address 01: Engine Labels: 03G-906-018-BMN.clb

Part No SW: 03G 906 018 EL HW: 03G 906 018 EL

Component: R4 2.0l PPD1.2 G 9802

Revision: --H42--- Serial number: SKZ7Z0G4543053

Coding: 0000072

Shop #: WSC 73430 790 00000

VCID: 73EED50012AA24802C7

2 Faults Found:

008194 - Particulate Trap Bank 1

P2002 - 006 - Efficiency Below Threshold - Intermittent

Freeze Frame:

Fault Status: 00000001

Fault Priority: 5

Fault Frequency: 2

Reset counter: 32

Mileage: 201729 km

Time Indication: 0

Date: 2000.00.00

Time: 22:38:40

Freeze Frame:

RPM: 0 /min

Torque: 0.0 Nm

Speed: 0.0 km/h

(no units): 1.0

Lambda: 124.0 %

Pressure: 0.0 mbar

Time: 918.5 s

012600 - Intake Manifold Runner Control

P3138 - 006 - Regulation Deviation - Intermittent

Freeze Frame:

Fault Status: 00000001

Fault Priority: 5

Fault Frequency: 1

Reset counter: 35

Mileage: 201859 km

Time Indication: 0

Date: 2000.00.00

Time: 10:05:16

Freeze Frame:

RPM: 2048 /min

Torque: 0.0 Nm

Speed: 49.0 km/h

Mass Air / Rev.: 528.6 mg/str

Mass Air / Rev.: 534.1 mg/str

Lambda: 6.3 %

Text: Kein Messwert verfuegbar

Readiness: N/A

-----------------------------------------------------------------------------

[kris1]

Could it be an exhaust sensor rather than the dpf?

[mattcut]

I would suspect the exhaust pressure sensor as suggest above

[Adhal]

Could it be an exhaust sensor rather than the dpf?

Can I ask what makes you think that and is there any definitive way to check it.

[silver1011]

The exhaust gas pressure sensor is a well documented weak point.

Check behind the sensor, if it has 'Made in US' on it then it is likely to be faulty.

The later and improved version has 'Made in Malaysia' on it.

I had a duff sensor with no lights, it eventually meant that the DPF wasn't regenerating properly which kept throwing up the DPF light.

Eventually the sensor completely packed up and brought on the EML light.

I got it swapped out before I reached the glow plug light and limp-home mode.

[silver1011]

See here for more info and lots of pictures...

http://www.briskoda.net/forums/topic/237798-dpf-light-on-no-town-driving-pd170-vrs/page__hl__%20eml

[Adhal]

So consensus is that the sensor could be the underlying problem as to why the DPF is not regen'ing.

Just to clarify the EML came on after the glow plug and limp home mode started. I see my original post is a bit misleading.

The glow plug light flashing has been intermittent, mainly coming on when its seriously cold outside i.e. less than 5degrees. It just flashes for a while then turns off. The DPF light turned on around Tuesday last week and didnt go off and by Thursday the car entered 'limp home' on the way into work. At this point the EML had not illuminated. When I started the car after work the EML was on. Forced a regen on Thursday night which lasted till Yesterday. Didnt regen all yesterday and 5 mins from home it entered limp home. I've not driven it since yesterday but I imagine if I do the EML will turn on. Hope this is a bit clearer.

Edited 18 December, 2012 by Adhal

[silver1011]

I'm not 100% sure on the sensor, If I remember correctly it has a specific fault code which doesn't appear in your earlier list.

All I know is that my sensor started playing up well before I saw any lights / symptoms / fault codes.

[James I]

I had an Audi A4 that had a dodgy sensor, car went into limp mode and lights etc, Audi assist came out, and told me to follow him to a dealer, car still in limp mode, half way to the dealer, lights went out and car drove fine.

Audi had the car for two days and confirmed a sensor was changed.

DPF relies on the sensors telling it what and when to do a regen. My money is on the sensor too.

[Adhal]

Managed to force a regen again and the lights have gone off. I will be visually checking which sensor is fitted tommorow (hopefully the made in us one).

Is a software update required if a new sensor is fitted?

Edited 21 December, 2012 by Adhal

[Anddenton]

Managed to force a regen again and the lights have gone off. I will be visually checking which sensor is fitted tommorow (hopefully the made in us one).

Is a software update required if a new sensor is fitted?

It's the made in Malaysia one you want, the US ones were the dodgy ones.

No software but the sensor will need to be adapted to the car

[Adhal]

Can it be adapted through vcds?.

[Anddenton]

Can it be adapted through vcds?.

Not done it myself but yes I believe so

[Adhal]

It looks as if I have the later sensor already installed. Just checked the fault codes and the following has reappeared:

012600 - Intake Manifold Runner Control

P3138 - 006 - Regulation Deviation - Intermittent

So I went for a run to see if it would regen and after 20mins of driving in 4th at 2200rpm, the DPF load increased from 12% to 17% with no signs or indication of it attempting a regen. One thing I have noticed is that the ross-tech wiki states the temp before turbo should be greater than 700c for a regen, but at no point does it reach that, even with hard acceleration it ranges from 200-450.

So what else could it be?

Edited 22 December, 2012 by Adhal

[silver1011]

The temp will only increase for an active regen with the intervention of the CANBUS through the injection of additional fuel.

Longer steady runs are better for the initiation of a regen, not repeated hard and fast acceleration.

The soot load needs to reach 24 grams before the DPF light will illuminate and at 40 grams you get the DPF light, glowplug light, EML and limp-home mode.

At 45 grams its game over for the DPF.

As the fault code suggests the intake manifold I'd be tempted to look here first, may be the DPF light is a consequence of an issue else where?

[Adhal]

Does VCDS display the soot load in grams, as it reads 17% not 17g?

Also is there anyway to view the ash content of the DPF?

[silver1011]

Not sure about the percentages but the dealer can check the ash level.

Skoda UK had to tell my dealer how to do it though!

[Adhal]

Well the reason I ask about the percentages is that both times I have forced regen via VCDS, the particulate filter load was over 115%!

The intake manifold fault seems to coincide with the glow plug light flashing (which I only get when the weather is REALLY cold).

[silver1011]

[Adhal]

Interesting find, so if when it hits 24% I get the DPF light I'll know grams = %, which is gonna mean £££'s!

[gtamax22]

Last week when the cold weather really kicked in I started to get a flashing glow plug light but thought nothing of it as it went off after it got warm. Then strangely the DPF light came on midweek on the way home from work which is a 15 mile 50+mph route (usually comes on at weekend when driving around town). The next morning I drove to work expecting the light to go off and it didnt and I noticed I had reduced power too and I couldnt rev over 2500rpm. This was closely followed by the EML.That night I had to force a regen through VCDS which worked, but I'm now back to square one as the DPF light came on again yesterday and after trying for an hour to get it to regen I got the reduced power and rpm again. The EML is not on yet but I imagine it will be if I drive it further.

So basically there seems to be an underlying issue that's not allowing the car to regen itself. I do know that it has a fault code stored which I'll post later, but can anyone help with where to start?

Yes have a possible fix for symptoms these videos!!

Very informative material was found here on a fix

some variations to parameters but basically the same procedure for other manufacturers that have DPF filters fitted with pressure sensors

DPF FIX PART 1 http://www.youtube.com/watch?v=QMf4m946aKA

DPF FIX PART 2 http://www.youtube.com/watch?v=TXLZEG6It8o

[scumspawn]

In VCDS check field 68 block 2 (in VCDS measured values in engine) gives you the level of blockage of the filter (ash mass). For the BMN engine 60 grams is the max.

Feild 75 block 3 will give you the soot loading.

The soot loading will give the following sequence:

Operating Status System Response

45% DPF Load Level 1

- Normal Regeneration

50% DPF Load Level 2

- Regeneration at maximum exhaust

temperatures

55% DPF Load DPF lamp

Regeneration from 60 km/h

onwards

("See operating manual")

75% DPF Load DPF, SYS and MI lamp

Torque limitation, EGR

deactivation,

Regeneration via VAG tester only

95% DPF Load Replace the DPF Unit

Hope this helps.

[Adhal]

scumspawn, where did you find that?

Thanks for that info as it puts it all into perspective now. Both times I forced the regen, the DPF load was over 95%! Can forcing it to regen above 95% cause damage, the only thing I was aware of was a possibility of a 'burn down'.

[scumspawn]

Hi info was from the files attached. One file is a VCDS file for the BMN (PD engine) which lists all the field and block info and the other is DPF regen info from VAG.

170pd.txt

DPF_regen_info.txt