NOx sensor and Adblue faults codes

[superchargedpolo]

I'm starting a new thread to make it easier to search this issue.

I recently experienced the following problems with my van. It's a Euro 6 102bhp 2017 model.
Basically my mpg started to decrease significantly and my adblue consumption started to go through the roof, for no good reason. Eventually the engine management light came on and I did a scan with VCDS.

Address 01: Engine Labels: 04L-907-309-V2.clb
Control Module Part Number: 04L 906 056 KA HW: 04L 907 445
Component and/or Version: R4 2.0l TDI H02 4047
Software Coding: 00114010432501090000
Work Shop Code: WSC 02737 790 50316
ASAM Dataset: EV_ECM20TDI03004L906056KA 004003 (VN75)
ROD: EV_ECM20TDI03004L906056BF_004.rod
VCID: 76E82E43C941D5F6BB-8022

2 Faults Found:

33262 - Reductant System Performance Bank 1
P204F 00 [096] - Malfunction
Intermittent - Not Confirmed - Tested Since Memory Clear

31103 - SCR NOx Catalyst Bank 1
P20EE 00 [236] - Efficiency too Low
MIL ON - Intermittent - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 4
Mileage: 14818 km
Date: 2009.01.05
Time: 13:08:19

Engine speed: 2466.00 /min
Normed load value: 58.8 %
Vehicle speed: 104 km/h
Coolant temperature: 90 °C
Intake air temperature: 7 °C
Ambient air pressure: 990 mbar
Voltage terminal 30: 14.820 V
Dynamic environmental data: 20 96
Unlearning counter according OBD: 40
Air mass at air mass meter 1: 208.8 kg/h
Extern.temp.sens.1 bank 1: raw value: 6.0 °C
Mass airflow sensor 1 bank 1 airflow: raw value: 712.2 mg/stroke
Throttl.valve adapt. 1 bank 1: posit feedback - Act.value: 0.00 %
NOx sensor before SCR cat conv: offset correction factor: 0 ppm
NOx sensor after SCR cat conv: offset correction factor: 216 ppm
Reducing agent quality sensor: urea concentration: 0.00 %
Reducing agent quality sensor: raw temperature value: 0.0 °C


Readiness: 1 1 0 0 0

 

[superchargedpolo]

As you can see 2 fault codes were recorded. After a bit of research I was fairly confident that the second code - 31103 - SCR NOx Catalyst Bank 1 was related to a problem with the NOx sensor in the exhaust. This made sense as it might explain my increase in Adblue consumption. The van was booked into VW in Aberdeen, as it's under warranty. I gave them both of the fault codes and they ran their own diagnostics. After a couple of tests (one was to remove the adblue injector and measure the number of injections in a given time, the other was to check the adblue was not contaminated / the wrong stuff) it was confirmed that the NOx sensor was at fault. Surprise, surprise they had one on the shelf! It was replaced and a 30 mile road test conducted. No more engine management lights.

However, the technician working on my van knew I'm no muppet so decided to run their diagnostics once again before handing it back to me. This time the - 33262 - Reductant System Performance Bank 1 - code appeared again, but no engine management light. Apparently REDUCTAND = ADBLUE. The tech wasn't sure what this meant so decided to contact the mothership in Milton Keynes. They advised to fill the adblue tank and re calibrate the sensor to tell the ecu that it's full. He explained to me that there is no 'float' in the adblue tank, like a fuel tank. He wasn't exactly sure but called it something like a sound wave that bounces off the bottom of the tank and reflected off the top fluid level. I think the fault occurs due to the level being above the top of the tank, i.e. somewhere inside the filler neck. (sorry if this is not 100% correct but it was the best he could come up with). Anyway, it turns out that you can overfill the adblue tanks and the sensor can get all confused and needs a recalibration. I'm not sure if this can be done with VCDS and I'm not going to try it now my van is working as it should but it's handy to know. I asked how on earth you are meant to know if you have overfilled the tank and was told the owners manual details the filling steps. I had better break it open and have a read!

Anyway, I hope this helps anyone out there with a similar problem and gives a wee bit of an insight to potential adblue issues.

 

[Loz]

That’s why vw sell a filler hose that reaches down the filler neck to ptevent overfilling.

 

[Pauly]

If you overfill the adblue the upper level of fluid goes into the filler neck, whilst driving the engine requests adblue which is delivered as it should be but after a while of adblue usage the sensor doesnt recognise a drop in fluid level (as it cant see into the filler neck) and this leads to an error message as the van knows adblue is being used but cant compute the fact the level is changing.
It works in this way due to the corrosive properties of adblue, rather than an internal sensor (which would corrode/suffer damage) they use some form of sonic sensor to measure the level without contacting the fluid

 

[superchargedpolo]

That's exactly what I used when I filled mine, unknown to me that it could be overfilled. These fault codes don't relate to over filling an adblue tank, they are related to a faulty NOx sensor, just a bit of additional info that I thought might be useful

 

[Loz]

I think the sensor looks up from the bottom and also measures the density so you don’t try a fool it with just water..
Have a read of this SSP.

 

[Tinman1UK]

I think this is the same problem I have same symptoms and today the Adblue warning came up. Absolute pain.

 

[mmi]

Here is my contribution to the thread, a few similar faults recorded from my van (MY16, 150PS). They have not turned on check engine light, so without VCDS I would be just driving happily.

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_ECM20TDI03004L906056A_002.rod
VCID: 7BA0FD5D636C1E3F78B-802E

1 Fault Found:
31103 - SCR NOx Catalyst Bank 1
          P20EE 00 [039] - Efficiency too Low
          Not Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 20564 km
                    Date: 2014.01.29
                    Time: 08:47:48

                    Engine speed: 1563.00 /min
                    Normed load value: 65.9 %
                    Vehicle speed: 84 km/h
                    Coolant temperature: 91 °C
                    Intake air temperature: 2 °C
                    Ambient air pressure: 960 mbar
                    Voltage terminal 30: 14.812 V
                    Unlearning counter according OBD: 40
                    Air mass at air mass meter 1: 136.8 kg/h
                    Extern.temp.sens.1 bank 1: raw value: 1.0 °C
                    Mass airflow sensor 1 bank 1 airflow: raw value: 734.1 mg/stroke
                    Throttl.valve adapt. 1 bank 1: posit feedback - Act.value: 55.05 %
                    NOx sensor before SCR cat conv: offset correction factor: 0 ppm
                    NOx sensor after SCR cat conv: offset correction factor: 303 ppm

1 Fault Found:
31103 - SCR NOx Catalyst Bank 1
          P20EE 00 [039] - Efficiency too Low
          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

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: 34010 km
                    Date: 2024.01.13
                    Time: 08:24:29

                    Engine speed: 1558.25 /min
                    Normed load value: 65.1 %
                    Vehicle speed: 84 km/h
                    Coolant temperature: 90 °C
                    Intake air temperature: -6 °C
                    Ambient air pressure: 1010 mbar
                    Voltage terminal 30: 13.773 V
                    Unlearning counter according OBD: 40
                    Air mass at air mass meter 1: 147.6 kg/h
                    Extern.temp.sens.1 bank 1: raw value: -6.5 °
                    Mass airflow sensor 1 bank 1 airflow: raw value: 801.3 mg/stroke
                    Throttl.valve adapt. 1 bank 1: posit feedback - Act.value: 0.00 %
                    NOx sensor before SCR cat conv: offset correction factor: 0 ppm
                    NOx sensor after SCR cat conv: offset correction factor: 133 ppm
                    Reducing agent quality sensor: urea concentration: 145.92 %
                    Reducing agent quality sensor: raw temperature value: 0.0 °

And besides those above, a few similar ones without freeze frame data. A kind of interesting thing is that the freeze frame data set is not always the same. Of course the VCDS version has been kept up to date so it has been different on each of them. My understanding is that VCDS is not selecting what to extract from ECU, it just pulls out everything available so looks like ECU has decided to report different things.

Actually my faults are different variants than your fault P20EE 00 [236]. The code in [brackets] is different.
Unfortunately I don’t have the detailed coding what those bits […] indicate. Neither does the tool of VW dealer.
The common thing seems to be BIT 5 (of BITS 7..0 below) and BIT 4.

​

[032] 0010 0000​

[039] 0010 0111​

[096] 0110 0000​

[100] 0110 0100​

[236] 1110 1100​

A few thoughts about fault codes in your van:
1) The fault had happened four times. The mileage is for the last first one. The wrong date is just coding thing in the VCDS but you can count on mileage, and the time, too.
2) Your van reported “Reducing agent quality sensor: urea concentration: 0.00% which is different what I have had. May be it is worth to have a closer look at the AdBlue sensor at measuring values IDE10032 and IDE10039.

I have never seen 0.00% from Adblue quality sensor IDE10032 (25 measurements from last May till today). The only values I have seen are 145.92%, 177.92%, 209.92%, 273.92%. The values are interestingly spaced by 32 (64), which probably means just that the actual output is just a coded binary value.

Other measuring values that might be of interest:

​

IDE03142 Remaining vehicle distance until reducing agent deficiency 8314.220 km​

IDE10032 Reducing agent quality sensor: urea concentration 209.92 %​

IDE10039 Reducing agent quality sensor: validity valid​

IDE10247 Reducing agent tank volume: act. value calculated 15.335 l​

IDE10249 Reducing agent fill level sensor: act. value 117 mm​

The NOx sensor was also a suspect in the thread Multiple Engine Management Faults but to me it looks like that replacing it didn’t solve the issue.

A few observations of my NOx sensor (VCDS measuring value IDE09017):

The sensor reports back 0 ppm NOx for about 10-15 minutes after starting the engine and setting off. I discussed with VW tech about this and his thought was that the sensor probably needs to get up to proper temperature before starting to send out meaningful values – I could agree but exhaust temp at the sensor is hot and “stabilized” well before that time.​

Another thing that was discussed with VW tech that when auto-start-stop restarts the engine, the NOx sensor starts again from 0 ppm, and stays at 0 ppm about the same time as mentioned above.

The NOx sensor behavior above was verified to be the same on another van, so according to VW that proves the sensor can’t be faulty. Which is a kind of interesting procedure…

 

[mmi]

Another contribution to the thread:

I believe the trigger for this fault was "Reducing agent quality sensor: urea concentration: 34.56 %" because it is way below the values seen before (see my post above).

Probable cause was that it had been very cold (-25C) for a few days and AdBlue was definitely frozen. The van was driven only a few miles to a garage for a service and in the afternoon at fault point AdBlue most likely was still partially frozen and so the urea concentration was probably way out of the limits.

Because I do not get this fault when the van is in the cold and AdBlue is frozen, I would like to think that in this case the ECU thought it is warm enough (intake and reducing agent tank temperatures) to measure urea concentration.

No lights on dash.

Address 01: Engine       Labels: 04L-907-309-V2.clb
Control Module Part Number: 04L 906 056 KF    HW: 04L 907 445
Component and/or Version: R4 2.0l TDI   H02 3809
Software Coding: 0025401C437601080000
Work Shop Code: WSC 02737 790 50316
ASAM Dataset: EV_ECM20TDI03004L906056KF 004005 (VN75)
ROD: EV_ECM20TDI03004L906056BM_004.rod
VCID: 7BA0FD5D636C1E3F3D7-802E

1 Fault Found:

31102 - Reductant Quality Performance
          P207F 00 [032] - -
          Intermittent - Not Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 34412 km
                    Date: 2024.01.21
                    Time: 16:01:01

                    Engine speed: 0.00 /min
                    Normed load value: 0.0 %
                    Vehicle speed: 0 km/h
                    Coolant temperature: 88 °C
                    Intake air temperature: 35 °C
                    Ambient air pressure: 1000 mbar
                    Voltage terminal 30: 12.328 V
                    Unlearning counter according OBD: 36
                    Simulated particle filter surface temperature: 197.0 °
                    Reducing agent fill level sensor: act. value: 88 mm
                    Sensor for reducing agent tank temperature: temperature: 9.0 °
                    Calculated NOx concentration behind turbocharger: 0 ppm
                    NOx sens.dwnstrm.SCR cat conv: NOx conc.: 0 ppm
                    Reducing agent quality sensor: urea concentration: 34.56 %

 

[superchargedpolo]

Ouch -25c, that's the real deal. We only get about -5c, worst case, here on the NE Scottish coast.
My adblue seems to be behaving itself now and no more NOx issues, at the moment. I ran a scan yesterday and no fault codes.

 

[Tinman1UK]

Van has been back to VW 4 times in 3 weeks with engine and AdBlue warning lamp issues. After replacing sensor and injector they completing a complete test and rest, they are now looking to replace the catalytic converter. Problem is there are none available. Guess this is more wide spread issue than they would like admit.

 

[mmi]

Ouch -25c, that's the real deal. We only get about -5c, worst case, here on the NE Scottish coast.
My adblue seems to be behaving itself now and no more NOx issues, at the moment. I ran a scan yesterday and no fault codes.

Not helping in the case but a kind of related observations:

I have had a chance quite a few times to compare the fault codes reported by VCDS with fault codes reported by OEM VW tool at service point. A kind of interesting thing is that quite often the VCDS reports earlier/more faults.

It seems to me that to get comparable results with the VW tools, in the VCDS I have to turn off the aggressive mode. By default the VCDS seems to run in the aggressive mode but I can tick-off that (on fault code display) - which sometimes makes the faults to "disappear". At the moment I have 3 different faults in the engine when checked with VCDS aggressive mode, and none if in normal mode- so I'll keep eye on how things will move on.

I have also noticed that the fault associated freeze frame data fades away eventually (even in aggressive mode) but the fault oneliner stays on definitely longer.

Clearing the faults codes by OEM VW tool clears also these "hidden faults" - so probably would be a good idea to do a VCDS-scan before handing over the vehicle to any service.

 

[mmi]

I have never seen 0.00% from Adblue quality sensor IDE10032 (25 measurements from last May till today). The only values I have seen are 145.92%, 177.92%, 209.92%, 273.92%. The values are interestingly spaced by 32 (64), which probably means just that the actual output is just a coded binary value.

Other measuring values that might be of interest:
IDE03142 Remaining vehicle distance until reducing agent deficiency 8314.220 km
IDE10032 Reducing agent quality sensor: urea concentration 209.92 %
IDE10039 Reducing agent quality sensor: validity valid
IDE10247 Reducing agent tank volume: act. value calculated 15.335 l
IDE10249 Reducing agent fill level sensor: act. value 117 mm

The above was from a 150PS engine. Lately I have been exercising with a van having a 204PS engine and surprisingly the measuring values are something else:

IDE03142 Remaining vehicle distance until reducing agent deficiency 8851.74 km
IDE10032 Reducing agent quality sensor: urea concentration 0 %
IDE10039 Reducing agent quality sensor: validity invalid
IDE10247 Reducing agent tank volume: act. value calculated 15.044 l
IDE10248 Reducing agent supply pump: offset factor calculated 0.975
IDE10249 Reducing agent fill level sensor: act. value 110 mm​

The values above (the red) have been observed over 8 months and they have remained the same - no activity on them. I have checked these values also on another van with same engine type (204PS) and they are the same - 0%/invalid. No faults on either of them.

 

[mmi]

Besides the infamous 31103 - SCR NOx Catalyst Bank 1 P20EE 00 [100] - Efficiency too Low -fault I have been curious about stated AdBlue overfilling causing errors in T6 engine management. So with ”promise to rescue” from my VW garage I have been “overfilling” my AdBlue tank almost two years now.

The last refill was 3 months ago. On the MFD remaining AdBlue range was 6500km and requested refill was 3.25-3.50 litres. Actually it took 7.8 litres into the tank . As far as understand the sensor registered that correctly = showing in IDE10249 Reducing agent fill level sensor: act. value 136 mm (regular refill 120-125mm).

At the refill the AdBlue range on the MFD resetted to 9500km. In next 500 km’s it creeped up to 10500km. Since then the counter has started slowly come down (but slowlier than accumulated km’s). Today, since 5100 km from refill the remaining AdBlue range is 8400 km (fill level at sensor 105 mm) – thus predicting AdBlue range of 13500 km’s from a tank. So all this in temperatures well above AdBlue freezing point.

Admittedly the sample size (2 vans, 150PS and 204PS, accumulated 50.000 km) is not very big. Also the variety of different revisions of engine software might diminish applicability to all T6 variants. However I tend to think there is no inherent mechanism that would cause “over-filling” inevitably lead to engine fault.

Anyways, definitely not encouraging anyone to try the same.

 

[mmi]

Just a recorded observation from last winter (year ago). Engine CXFA - 110kW/150PS.

Initially thought this was because of cold weather (it had been around -20C for several days) because returned back to normal when warmed up. But during next cold period (down to -25C) the display just remained normal (with filling quantities+title). Normally quantities show up when remaining range about 6500 km.

So two peculiarities:

(1) Disappeared filling quantities
(2) Title missing "AdBlue".​

Immediately after switching Ignition ON.


After about 10 seconds - and remains till engine switch off.

 

[graffo]

I recently had the engine Amber light come on constant, stopped and called VW , they sent out AA and he found code 31103 but no info?
He suggested deleting the code, continuing on my journey (92miles) and take it in to VW to double check.
The fault hasn't returned, the adblue reads 1800m.
my question is, is it safe to reset this code and can it be reset by say carista?
or is there something else I can/should do?
cheers

 

[Muhammad khateeb]

I have vw sharan 2015 on dashboard yellow adblue sign came up. Which will cause engine stops after 300 miles. I visited to vw garage they said to me nothing coming up on their computer or software every thing is fine but yellow adblue sign is still on my Sharan dash.They advised me I need to change Catalytic converter which will cost me around £2500 and they still not sure or giving me guarantee this is the problem and sing will go off.
I'm wondering shell I carry on driving untill my vehicle stops?

If anyone have the same problem please let me know that will be helpful for me.

Kind regards
Muhammad khateeb

 

[Dellmassive]

I have vw sharan 2015 on dashboard yellow adblue sign came up. Which will cause engine stops after 300 miles. I visited to vw garage they said to me nothing coming up on their computer or software every thing is fine but yellow adblue sign is still on my Sharan dash.They advised me I need to change Catalytic converter which will cost me around £2500 and they still not sure or giving me guarantee this is the problem and sing will go off.
I'm wondering shell I carry on driving untill my vehicle stops?

If anyone have the same problem please let me know that will be helpful for me.

Kind regards
Muhammad khateeb

Third post !!!

 

[Danksy]

There's definitely a common thread here - which is the temperature. In the cases above it seems that the fault codes are being thrown when the temperature is below freezing, which may add some weight to the theory about adblue urea concentrations!

So here's my experience :-(

Yesterday when driving the ad blue warning came on indicating adblu was needed at 650 miles. This is the first time she's been used in the cold and she'd been sat in temperatures of -4 for about 48 hours before being used, with ambient temps not much above freezing all day.

The MIL came on and I carried on to my destination - when I restarted the addblu warning indicator had gone off - I checked by pressing the dash button and it had risen to 3500 miles - weird huh!

So VCDS out this morning revealed

Tuesday,21,January,2020,08:25:37:03003
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 10 x64
VCDS Version: 19.6.2.0 (x64) HEX-V2 CB: 0.4508.4
Data version: 20190930 DS308.0
www.Ross-Tech.com


VIN: WHYSONOSEY License Plate: Noseybugger



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


Address 01: Engine Labels: 04L-907-309-V2.clb
Control Module Part Number: 04L 906 056 KA HW: 04L 907 445
Component and/or Version: R4 2.0l TDI H02 4047
Software Coding: 00114014430401090000
Work Shop Code: WSC 02737 790 50316
ASAM Dataset: EV_ECM20TDI03004L906056KA 004003 (VN75)
ROD: EV_ECM20TDI03004L906056KA.rod
VCID: 76B5E4C258478607E3B-8022
2 Faults Found:

31153 - Reductant
P20E9 00 [232] - Pressure too High
MIL ON - Intermittent - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 4
Mileage: 6915 km
Date: 2036.01.10
Time: 16:09:39

Engine speed: 2086.50 /min
Normed load value: 69.8 %
Vehicle speed: 88 km/h
Coolant temperature: 88 °C
Intake air temperature: 7 °C
Ambient air pressure: 1030 mbar
Voltage terminal 30: 14.765 V
Unlearning counter according OBD: 40
Extern.temp.sens.1 bank 1: raw value: 6.0 °C
Reducing agent pump module relative press.: calculated: 9065 mbar
Reducing agent fill level sensor: act. value: 76 mm
Sensor for reducing agent tank temperature: temperature: 7.2 °C
Reducing agent system pressurization release conditions-Engine running: Condition not met
Reducing agent system pressurization release conditions-Press. enabled: Condition not met
Reducing agent system pressurization release conditions-Heat. strategy: enable: Condition not met
Reducing agent system pressurization release conditions-Depressurized min. time below limit: Condition not met
Reducing agent system pressurization release conditions-Catalyst temp.reached: Condition not met
Reducing agent system pressurization release conditions-Release due to jammed valve needle: Condition not met
Reducing agent system pressurization release conditions-Rinse function finished: Condition not met
Reducing agent system pressurization release conditions-Initial filling completed: Condition not met
Reducing agent system pressurization release conditions-Release via inducement: Condition not met
Reducing agent system pressurization release conditions: 255

31103 - SCR NOx Catalyst Bank 1
P20EE 00 [096] - Efficiency too Low
Intermittent - Not Confirmed - Tested Since Memory Clear


Readiness: N/A

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


Address 01: DTCs cleared

So the common denominator between our posts appears to be low temperature related? Even though the adblu in mine was 7.8C she'd been sat for a while at temperatures below freezing!

I've cleared the DTC and will wait and see what happens next!

Mines a 2016 MY with 102 PS (75 kW; 101 hp) - only 5k miles!

 

[Danksy]

Third post !!!

Hopefully mine is more helpful