NOx sensor and Adblue faults codes

[mmi]

They tried updating software,

Tried? I read this the update was not done?

Can you find with your tool what software you are running now? Look for strings 04L056056xx H02_xxxx
What's the engine code - CXFA or CXHA? (on sticker under dash)
I assume your VIN begins with WV1? Otherwise the van would have been called in for a mandatory update.

always the same error - the top one, and sometimes others.

The others - any notes what they were?

I wonder if we have people here who sorted the problem out definitely.

I've been tracking the Forum and this far the software update has cured the (false alarms of) faults P20EE and P204F. On mine those haven't surfaced any more - for 17 months/14000 miles now.
Some more here:

AdBlue Issue after software update

You may have read, that last Saturday while having the van serviced at VW, they installed a software update for the AdBlue on my Van. Well this morning after covering a further 900 miles (busy week) the AdBlue 1400 mile message popped up on the display, now while this wouldn't normally be a...

www.t6forum.com

 

[superchargedpolo]

I used to get the P20EE quite regularly but after hounding VW to get the software update I haven’t had any further fault codes relating to this. That’s been over a year now.
My van is a 2017 102ps 5 speed. Its be remapped to circa 150ps for well over 1.5 years now

 

[Spaghetti]

I used to get the P20EE quite regularly but after hounding VW to get the software update I haven’t had any further fault codes relating to this. That’s been over a year now.
My van is a 2017 102ps 5 speed. Its be remapped to circa 150ps for well over 1.5 years now

I presume you had to pay for the new software? What did they charge you please?

 

[superchargedpolo]

It was under warranty. There is no way I’d be paying for VW’s mistake! They tried hard to fob me off though but I was persistent and knew exactly what I was talking about.

 

[Spaghetti]

It was under warranty. There is no way I’d be paying for VW’s mistake! They tried hard to fob me off though but I was persistent and knew exactly what I was talking about.

That’s a result. I used to get the ‘low flow’ error on the EGR and subsequent AdBlue error but just self diagnosed and replaced the EGR at £1100. Been good for over a year now.

I called them before (called two dealers) and they insisted that there were no relevant updates for my van. Grrr.

 

[Robert]

I used to get the P20EE quite regularly but after hounding VW to get the software update I haven’t had any further fault codes relating to this. That’s been over a year now.
My van is a 2017 102ps 5 speed. Its be remapped to circa 150ps for well over 1.5 years now

So your remap is gone?
Which one was the most recent, remap or VW software update?

 

[superchargedpolo]

Still have the remap. It wasn’t disturbed by the software update. I thought it might be but all is well.
Just shows, it would have been the perfect get out of jail for VW if they had paid a bit more attention

 

[Robert]

Still have the remap. It wasn’t disturbed by the software update. I thought it might be but all is well.
Just shows, it would have been the perfect get out of jail for VW if they had paid a bit more attention

How did you verify that?

 

[Unimog]

I'd like to disagree with the Twitter support.

The engine software yours (below) is the original one from factory.
---------------------------------------------------------------

01 Engine​

System description: R4 2.0l TDI​

Software number: 04L906056KA​

Software version: 4047 ​

Hardware number: 04L907445​

Hardware version: H02​

---------------------------------------------------------------
The current engine software is the following:
---------------------------------------------------------------

01 Engine​

System description: R4 2.0l TDI​

Software number: 04L906056KA​

Software version: 6163​

Hardware number: 04L907445​

Hardware version: H02​

---------------------------------------------------------------
However, for N1 class (basically VIN WV1....) the update has not been classified as mandatory (as it was for passenger carriers) but should be done if faults (especially) P204F, P20EE show up.
A related thread --> AdBlue Discussion and Issues

How do you identify the vw software version with VDCS, I can’t see it listed in the text on my scan data?

 

[mmi]

How do you identify the vw software version with VDCS, I can’t see it listed in the text on my scan data?

In the VCDS scan it's marked as below (snipped from your scan):

Address 01: Engine (2D2D2-CXHA)​

Part No SW: 04L 906 056 KJ HW: 04L 907 445​

Component: R4 2.0l TDI H02 6167​

​

where

software number = 04L 906 056 KJ​

software version = 6167​

The same logic applies to other controllers too.

 

[Unimog]

In the VCDS scan it's marked as below (snipped from your scan):

Address 01: Engine (2D2D2-CXHA)​

Part No SW: 04L 906 056 KJ HW: 04L 907 445​

Component: R4 2.0l TDI H02 6167​

​

where

software number = 04L 906 056 KJ​

software version = 6167​

The same logic applies to other controllers too.

 

[Unimog]

In the VCDS scan it's marked as below (snipped from your scan):

Address 01: Engine (2D2D2-CXHA)​

Part No SW: 04L 906 056 KJ HW: 04L 907 445​

Component: R4 2.0l TDI H02 6167​

​

where

software number = 04L 906 056 KJ​

software version = 6167​

The same logic applies to other controllers too.

Thank you. My van has been in the Vw workshop recently, is 6167 a recent update?

 

[mmi]

Thank you. My van has been in the Vw workshop recently, is 6167 a recent update?

Yes, correct. Before the update the version was 3770.

If interested the ECU flash status (reprogramming counter etc.) can be seen by VCDS > Engine > Advanced ID.

 

[Greybeard]

Hi all

I’ve read relevant posts until me eyes wouldn’t focus and would like to share (some of) my issues….

I would really appreciate some sage advice, please.

A little background to maybe help;

Sept ‘19 Bought my pre-registered 2018 150bhp DSG Kombi with 47 delivery miles.

Oct ‘20 VWVC 1st service @ 3.5k miles

Dec ‘20 EML light came on.
VWVC plugged into HQ and updated engine S/W to ver 6168

Mar ‘21 Towbar fitted and coded by local specialist

Aug ‘21 Prior warranty end;
Scanned Bus with OBDeleven prior fitting TP HQ LED DRL headlights.
No EML lit, but had one error;
9870km 01 Engine fault P20EE00 SCR NOx Cat Eff below threshold - Intermittent

Early Sep ‘21 1st MoT, brake fluid service and interim oil/filter change at local highly recommended VW Specialist (Master technician and connected to VW HQ etc)
Discussed OBDeleven fault and advised to book in with VWVC for attention, as still under warranty.

VWVC checkup. No fault found.

Back home rescanned and same fault shown.

Mid Sep ‘21 Updated OBDeleven to latest iOS version.
Now 3 faults, including 2 new;

01 Engine P20EE00

03 Brakes U112200 Database implausible message - Intermittent (from service?)

13 Adaptive Cruise Control U112300 - Intermittent
Odd, as Bus has standard cruise, not adaptive.
Subsequently explored OBDeleven History to find ‘ADC’ date of last coding was the day the Bus was coded by the towbar guy.

Nov ‘21 Long trip, Wiltshire to Yorkshire.
Stopped for coffee at M1 services. As left noticed EML back on.

Rescanned with OBDeleven;

Now 5 faults, as per printout below;

OBDeleven vehicle history log
Date: 2021-11-29 17:02:09
VIN: WV1ZZZ7HZJH1xxxxx
    Car: 
    Year: 2018
    Body type: Van
    Engine: CXHA  kW ( hp) l
    Mileage: 13310 km
---------------------------------------------------------------

Full scan
    Control Units: 14
    Fault count: 5
    Control Units:

    09 Central Electrics
    System description: BCM PQ25 Max4
    Software number: 7E0937090C
    Software version: 0752
    Hardware number: 7E0937090C
    Hardware version: H82
    Serial number: 4000 123180258

    Faults:
    No trouble codes found

    19 Gateway
    System description: GW-K-CAN TP20
    Software number: 7E0909901
    Software version: 0752
    Hardware number: 7E0937090C
    Hardware version: H82

    Faults:
    No trouble codes found

    61 Battery Regulation
    System description: Batt.regelung
    Software number: 7E0907534
    Software version: 0752
    Hardware number: 7E0937090C
    Hardware version: H82
    Serial number: 4000 123180258

    Faults:
    No trouble codes found

    01 Engine
    System description: R4 2.0l TDI
    Software number: 04L906056KG
    Software version: 6168
    Hardware number: 04L907445
    Hardware version: H02

    Faults:
    P204F00 - Reductant System Performance Bank 1
    Intermittent

    P20EE00 - SCR NOx Catalyst Efficiency Below Threshold Bank 1 Catalyst 1
    Intermittent
    Priority - 2
    Malfunction frequency counter - 32
    Unlearning counter - 255
    km-Mileage - 12520 km

    Unknown ambient data - 1E05906A8233652F3D712096283F6507BC4454006444C921B244A715105821000000005822000000BD58B2000041E30000

    date - 2039-01-31 09:22:56

    U101900 - Instrument cluster control module
    Missing signal oil level/temperature
    Intermittent
    Priority - 6
    Malfunction frequency counter - 1
    Unlearning counter - 255
    km-Mileage - 12464 km

    Unknown ambient data - 00000000732F653160712096273F6500003F6403E8446AFEE344A7000020290000F40B652097000041C80B41C90B41C70B

    date - 2039-01-31 08:26:09

    08 Air Conditioning
    System description: Climatic-T5
    Software number: 7E0907047AC
    Software version: 0708
    Hardware number: 7E0907047AC
    Hardware version: H22

    Faults:
    No trouble codes found

    04 Steering Angle Sensor
    System description: LENKW.SENSOR
    Software number: 6R0959654
    Software version: 0070
    Hardware number: 6R0959654
    Hardware version: H07

    Faults:
    No trouble codes found

    10 Parking Assistance
    System description: PARKHILFE 8K
    Software number: 7E0919475AA
    Software version: 0212
    Hardware number: 7N0919475
    Hardware version: H06
    Serial number: 28231811703862

    Faults:
    No trouble codes found

    25 Immobilizer
    System description: IMMO
    Software number: 5K0953234
    Software version: 1107
    Hardware number: 5K0953234
    Hardware version: H03

    Faults:
    No trouble codes found

    02 Transmission
    System description: DSG DQ500-7F
    Software number: 0BT300046J
    Software version: 5301
    Hardware number: 0BH927711G
    Hardware version: H11

    Faults:
    No trouble codes found

    15 Airbag
    System description: VW10Airbag021
    Software number: 7E0959655J
    Software version: 0018
    Hardware number: 7E0959655J
    Hardware version: 010
    Serial number: 003EK00195LU

    Faults:
    No trouble codes found

    17 Dashboard
    System description: KOMBI
    Software number: 7E0920970S
    Software version: 1107
    Hardware number: 7E0920970S
    Hardware version: H03
    Serial number: 00000000000000

    Faults:
    No trouble codes found

    5F Multimedia
    System description: MU-S-ND-ER
    Software number: 5C0035680G
    Software version: 0472
    Hardware number: 5C0035680G
    Hardware version: H41
    Serial number: VWZAZ2U0743188

    Faults:
    No trouble codes found

    13 Adaptive Cruise Control
    System description: ACC Bosch PQx
    Software number: 7N0907572C
    Software version: 0211
    Hardware number: 7E0907572
    Hardware version: H03
    Serial number: 0205180453A0D8

    Faults:
    U112300 - Databus error value received
    Intermittent
    Priority - 6
    Malfunction frequency counter - 1
    Unlearning counter - 43
    km-Mileage - 10749 km
    date - 2037-12-26 16:17:39

    03 Brakes
    System description: ESC
    Software number: 7E0907379P
    Software version: 0133
    Hardware number: 7E0907379M
    Hardware version: H06
    Serial number: 61208000002125

    Faults:
    U112200 - Databus implausible message
    Intermittent
    Priority - 2
    Malfunction frequency counter - 1
    Unlearning counter - 43
    km-Mileage - 10749 km
    Freezeframes - C000801832080006C60700F60079FFD7FF780800000000
    date - 2037-12-26 16:17:39

 

[mmi]

9870km 01 Engine fault P20EE00 SCR NOx Cat Eff below threshold - Intermittent

Early Sep ‘21 1st MoT, brake fluid service and interim oil/filter change at local highly recommended VW Specialist (Master technician and connected to VW HQ etc)
Discussed OBDeleven fault and advised to book in with VWVC for attention, as still under warranty.

VWVC checkup. No fault found.

What was the mileage at VWVC checkup? The fault doesn't stay active very long (less than 500 km) without reoccurence - thus VW diagnostics doesn't bring it up any more.

VWVC checkup. No fault found.

Back home rescanned and same fault shown.

OBDeleven reads and reports faults from history log, as long as they aren't explicitly cleared. Thus OBDeleven can report even ancient faults, or just glitches which were caught by engine's self diagnostics.

13 Adaptive Cruise Control U112300 - Intermittent
Odd, as Bus has standard cruise, not adaptive.
Subsequently explored OBDeleven History to find ‘ADC’ date of last coding was the day the Bus was coded by the towbar guy.

Besides Adaptive Cruise functionality controller 13 is used also for Front Assist. VW calls it by more general name "Control Unit for Distance Control".
The fault U112300 tells us only "Databus error"

---

Anyways re the fault P20EE00

P20EE00 - SCR NOx Catalyst Efficiency Below Threshold Bank 1 Catalyst 1
Intermittent
Priority - 2
Malfunction frequency counter - 32
Unlearning counter - 255
km-Mileage - 12520 km

The above suggests that the fault has occurred 32 times since mileage 12520 km, and as the scan was made at

Mileage: 13310 km

Thus during 790 km (490 miles) the NOx threshold was exceeded 32 times. Do you know how many times (approx.) the engine was started between mileage 12520 km (7800 miles) and 13310 km (8300 miles)? I'm a bit puzzled of that many "bursts" over such a short distance.

Have you cleared the faults, when?

 

[Greybeard]

Oh wow @mmi.

Thank you so much for responding and your step by step analysis.

I will check all mileages and distances etc in the morning and respond.

In the meantime, unlike many people and easy option hints from OBDeleven, I haven’t, so far, deleted any errors.

Have a good evening
Andy

 

[Greybeard]

Hi @mmi

1. The mileage at VWVC checkup was around 6300 miles/10,080km.

I don’t recall being given paperwork for this visit, as no fault found.

2. Thank you. Should/can I clear fault?

3. Should I be concerned about this?

4/5. I checked my diary regarding engine starts, journey numbers, distances and timings from 12520 - 13310 km.

It does indeed indicate 32 starts. This has been an exceptional time, helping others and needing to make about 28 journeys of 15 minutes or less.

After about 10 short journeys, followed by a 150 mile/240km motorway drive and a short break, was when the EML came on.

I recalled and last night reread your post #8 in this thread which mentions NOx sensor reporting 0ppm for first 10-15 minutes.

I do not normally make journeys this short. Indeed, if one is required, I will happily turn it into a longer ‘joy ride’.

6. I have not yet cleared any faults. Should I and can/should I clear the EML warning?

A couple of other points; I keep diesel level above 1/4 full and refilled AdBlu when level was indicated low enough to add a full 10 litres from a new, sealed RedEx container.

Could you please advise what I should do.

Thank you again
Andy

 

[mmi]

9870km 01 Engine fault P20EE00 SCR NOx Cat Eff below threshold - Intermittent

Do you remenber (or in OBDeleven history log) was there an associated mileage reading for the fault? If not, it's a definite sign that the fault has "expired" - doesn't show any more on VW's diagnosis. (See the fault P204F00 in your log - no mileage = an ancient fault = not detected by VW.

1. The mileage at VWVC checkup was around 6300 miles/10,080km.

This was 210 km after the 9870km fault reading - so possibly the fault had expired (see above).

2. Thank you. Should/can I clear fault?

3. Should I be concerned about this?

Yes, I would clear the faults. Currently the old/intermitent/expired faults just create confusion. At the moment I don't see any concerns here.

4/5. I checked my diary regarding engine starts, journey numbers, distances and timings from 12520 - 13310 km.

It does indeed indicate 32 starts. This has been an exceptional time, helping others and needing to make about 28 journeys of 15 minutes or less.

After about 10 short journeys, followed by a 150 mile/240km motorway drive and a short break, was when the EML came on.

Thank you for checking your diary. Well, this a kind of suggests/confirms that fault frequency counter is stepped up only once per driving cycle.

Anyways, here's my guess what were the contributing factors to turn on the emission light. Your van had fallen doing active DPF regenerations during the 10 short journeys - probably the regen was split over several short journeys. During the regen the NOx levels were above threshold too long and that have triggered the fault count to step up.
Eventually accumulated threshold crossings (within certain time/mileage) triggered the emission light.

Based on measurements on "non-updated" engine software there seemed to be a tendency to get this fault logged during high speed long journey very soon after engine finished active DPF regeneration. Now (afterwards) it's fairly obvious it was triggered by significantly elevated NOx levels during the DPF regeneration. Anyways, even with the updated software the NOx levels are higher during DPF regen than during "normal" drive, although not that extreme as before the update. I believe that your motorway drive (probably did then also another DPF regen) was just the straw that broke camel's back.

I recalled and last night reread your post #8 in this thread which mentions NOx sensor reporting 0ppm for first 10-15 minutes.

Thanks for reminding - need to check how quick it starts reporting on cold engine performing a DPF regen. I would guess much faster - as soon as hot exhaust gases has heated it up.

I do not normally make journeys this short. Indeed, if one is required, I will happily turn it into a longer ‘joy ride’.

6. I have not yet cleared any faults. Should I and can/should I clear the EML warning?

I'm assuming that clearing the faults would return the engine's internal emission etc. "counters" back to square one. Thus no real need for a joy ride. However, clearing the faults also means that engine's "Emission readiness" status would be cleared, thus would not pass MOT (if checked in the UK). To re-establish the readiness status the engine needs to run certain amount of time/distance - thus a good excuse for a joy ride.

I would clear the faults - (1) to clear the ancient ones, (2) to get a fresh start.

 

[Greybeard]

Hi again @mmi

The scan at 9870km did not show an associated mileage for the Engine fault P20EE00 fault.

For your info;
On checking Google maps I have realised that some of the short trips before and all of those after the EML came on on my trip up to Yorkshire were actually only around 1km.
So the engine would have had no chance to warm up properly.
I hope this is of some help.

This morning I carried out a further Full scan and Backup.
I then deleted all faults and was pleased to see the EML went off.
Afterwards I went for a 50km joyride, taking it gently until temperature gauge showed normal running temp.
The rest of the trip was a little more fun, with DSG in Sport.
When I returned I switched off the engine.
I was pleased to note the fans were not running on as if it had been partway through a regen.

Then I did another scan to find a fresh NOx fault.
No other faults. So I have only copied in the relevant part.
The EML light has not returned.

Could you please advise whether this could be normal behaviour, or whether further investigation is required, as it’s now worrying me.

Regards
Andy


OBDeleven vehicle history log
Date: 2021-12-04 13:14:18

VIN: WV1ZZZ7HZJH1xxxxx

Car:
Year: 2018
Body type: Van
Engine: CXHA kW ( hp) l
Mileage: 13360 km

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

Full scan
Control Units: 14
Fault count: 1
Control Units;
01 Engine
System description: R4 2.0l TDI
Software number: 04L906056KG
Software version: 6168
Hardware number: 04L907445
Hardware version: H02

Faults:
P20EE00 - SCR NOx Catalyst Efficiency Below Threshold Bank 1 Catalyst 1
Intermittent
Priority - 2
Malfunction frequency counter - 1
Unlearning counter - 255
km-Mileage - 13344 km

Unknown ambient data - 1A7A8A5E82306239B5712096283F65069C4454004B44C9212344A70C8F58210000000058220000015358B2000041E30000

date - 2040-01-16 12:38:57

 

[mmi]

The scan at 9870km did not show an associated mileage for the Engine fault P20EE00 fault.

Ok, this explains why at VW no faults were present - the fault was "expired" already at 9870 km.

date - 2040-01-16 12:38:57

Do you have an idea what kind of driving you were doing at 12:38:57 - at the moment of the fault surfaced.

Below a sample of my fault log & snapshot of recorded engine parameters at the moment of the fault. I believe this kind of data is in the "Unknown ambient data" of the OBDeleven log. Just a note that the date is not decoded correctly below nor in OBDeleven log, however the time and mileage are correct in the logs.

Just an observation - in several fault logs there seems to be a correlation between the fault P20EE triggering and either high speed or high engine load (in the log below normed load value). All my faults (25+) were logged at speed above 85 km/h, however they never surfaced as emission light.​

Address 01: Engine (2D2D2-CXFA) Labels: 04L-907-309-V2.clb
Part No SW: 04L 906 056 KF HW: 04L 907 445
Component: R4 2.0l TDI H02 3809
Revision: 23002001
Coding: 0025401C437601080000
Shop #: WSC 02737 790 50316
ASAM Dataset: EV_ECM20TDI03004L906056KF 004005
ROD: EV_ECM20TDI030_004_VN75.rod

1 Fault Found:
31103 - SCR NOx Catalyst Bank 1
P20EE 00 [100] - Efficiency too Low
Intermittent - Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Mileage: 22931 km
Date: 2016.01.23
Time: 19:32:28

Engine speed: 1973.25 /min
Normed load value: 64.3 %
Vehicle speed: 107 km/h
Coolant temperature: 90 °C
Intake air temperature: 14 °C
Ambient air pressure: 990 mbar
Voltage terminal 30: 14.593 V
Dynamic environmental data: 20 96
Unlearning counter according OBD: 40
Air mass at air mass meter 1: 147.6 kg/h
Extern.temp.sens.1 bank 1: raw value: 13.5 °C
Mass airflow sensor 1 bank 1 airflow: raw value: 630.5 mg/stroke
Throttl.valve adapt. 1 bank 1: posit feedback - Act.value: 58.98 %
NOx sensor before SCR cat conv: offset correction factor: 0 ppm
NOx sensor after SCR cat conv: offset correction factor: 69 ppm
Reducing agent quality sensor: urea concentration: 145.92 %
Reducing agent quality sensor: raw temperature value: 0.0 °C

I was pleased to note the fans were not running on as if it had been partway through a regen.

Perhaps you could even check by OBDeleven when the engine finished it's last DPF regeneration - Control units > Engine > Live data.
Just curious if/how it correlates with the mileage 13344 km?

Could you please advise whether this could be normal behaviour, or whether further investigation is required, as it’s now worrying me.

My understanding is that this is normal (and correct) behaviour - the faults in memory (+associated counter) are a kind of intermediate result or early warning. Emission warning light on dash eventually is result of long term poor emission conditions. Actual malfunctions of emission control system would manifest themselves with other fault codes and .
In my opinion there is no need to investigate this any more although the P20EE probably will come and go in fault memory (if you'll keep eye on that). Certainly repetitive short journeys would challenge the system. Anyways, the emission light alone is just "informative", indicates that emission control system is just "underachieving".

---

Below an example how recorded fault events in my engine would be seen by VW diagnostic tool (above) and when used more "aggressive" diagnostics capability of VCDS (and OBDeleven) (below).