1.6 FSI: Single fault code 16523 that recurs

U

unipower

Member
Hi All
This seems a relatively rare single code - a Search of A2OC shows one occurrence back in 2013. The title on that thread wasn't clear and there was no outcome reported, so I have started this one.
Yellow engine light comes up and stays on - no change in performance or economy that I can detect.
Using my simple Gendan VAGScanner fault code reader it shows the single code 16523.
This is diagnosed as:-
16523 - Oxygen (Lambda) Sensor B1 S2
P0139 - 35-10 - Response too Slow - Intermittent

B1 = Bank 1 and S2 = Sensor 2 (Previous poster took this to be Post cat).

If I erase the code the light goes off but it reappears after about 500 miles with the same fault. It's done this several times. Car (2004 1.6 FSI) has done 120 000 miles.

Does anyone else have experience of this fault, please?

The advice for rectification is to check for wiring and exhaust leak problems before replacing the sensor. Assuming it is the post cat one, it's not so easy to find (apart from going back to Audi). Euro Car Parts only lists the pre cat sensor.

Regards
Mark
 
I had that on a FSI and it was indeed an issue with the post Cat sensor. A2steve may well have one at reasonable cost to try. It plugs into the unit under the passenger floor (near the ECU and CCCU).

They are mega expensive new and possibly not worth that sort of expense.

Steve B
 
Quick, helpful responses - thanks the 2 Steves!

A2Steve: At this stage I would prefer to try a replacement lamda/Nox sensor (post cat) from you, please. The car had a comprehensive overhaul of the manifold flaps, sensors, actuators and injectors at A2 Cars MK in 2016 (50 000 miles ago).

I'm in North Kent, so it would have to be posted. Could you let me know the cost, please, and payment arrangements? There's no hurry for it to be sent.

Thanks
Mark
 
Hello kind and learned folks of A2OC.

After a protracted break from resolving issues on my 1.6 FSI, I finally got the battery reconditioned, and 15 minutes to run the Colour DIS diagnostics.

I have got this error message running my standard (non-Pro Boost) ECU:
1000054281.jpg


I know from @A2Steve comment above, reinstallation of the Proboost would mean the sensor is no longer required, but I am keen to iron all the niggles out using knowledge and parts sourced here and then the skills of one of the recommended specialists in the South East. Probably http://www.bfautos.co.uk/ as they are closest to me.

So, what are the chances of getting a replacement Lambda/Nox sensor (post cat) OEM for a reasonable price? Anyone got any spares?

I will attach other error codes in threads which relate to the codes, as I hope this bolsters information available to other users of the forum. Please learned admins, let me know if another approach is preferable.

Thanks as always for sharing your wisdom.
 
Last edited by a moderator:
No issues with this approach but perhaps an advert in the wanted section for the sensor may be an option. 👍
 
Last edited:
jaffa_jim said:
Hello kind and learned folks of A2OC.

After a protracted break from resolving issues on my 1.6 FSI, I finally got the battery reconditioned, and 15 minutes to run the Colour DIS diagnostics.

I have got this error message running my standard (non-Pro Boost) ECU:View attachment 115737

I know from @A2Steve comment above, reinstallation of the Proboost would mean the sensor is no longer required, but I am keen to iron all the niggles out using knowledge and parts sourced here and then the skills of one of the recommended specialists in the South East. Probably http://www.bfautos.co.uk/ as they are closest to me.

So, what are the chances of getting a replacement Lambda/Nox sensor (post cat) OEM for a reasonable price? Anyone got any spares?

I will attach other error codes in threads which relate to the codes, as I hope this bolsters information available to other users of the forum. Please learned admins, let me know if another approach is preferable.

Thanks as always for sharing your wisdom.
Click to expand...
@jaffa_jim I have a question, and depending on the answer, maybe a huge favour too.
The question is, did you scan with VCDS, and if so, did you use the new BAD Engine .lbl available on here?
The reason for the question is that if the new .lbl file is not used, the scan does not, (I think), recognise the NOx sensor as separate from the post cat Lambda.
If you didn't use the new .lbl file, could you add it to the label folder in VCDS, and repeat repeat the scan, and post both reports for comparison please?
This would, I hope, help fill a gap in our FSI knowledge. If I can help in any way, please PM me.
If you are able to use VCDS Measuring Blocks, Groups 030, 031, and 150 with the new file, would be even more helpful.
Mac.
For convenience, I've PM'd you the new file. Change the file type from .txt to .lbl before adding it to VCDS.
 
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Dave M said:
No issues with this approach but an advert in the wanted section for the sensor may be an option. 👍
Click to expand...
Yeah, will wait to see what opinions are proferred here before I decide on making the wanted advert. I wonder if there are oem sensors a acva
PlasticMac said:
@jaffa_jim I have a question, and depending on the answer, maybe a huge favour too.
The question is, did you scan with VCDS, and if so, did you use the new BAD Engine .lbl available on here?
The reason for the question is that if the new .lbl file is not used, the scan does not, (I think), recognise the NOx sensor as separate from the post cat Lambda.
If you didn't use the new .lbl file, could you add it to the label folder in VCDS, and repeat repeat the scan, and post both reports for comparison please?
This would, I hope, help fill a gap in our FSI knowledge. If I can help in any way, please PM me.
If you are able to use VCDS Measuring Blocks, Groups 030, 031, and 150 with the new file, would be even more helpful.
Mac.
For convenience, I've PM'd you the new file. Change the file type from .txt to .lbl before adding it to VCDS.
Click to expand...
I am not using VCDS. I am simply using the default settings of the colour DIS installed by @timmus . I am unsure of how to update the firmware or indeed add additional files.

I am keen to learn and I'd be happy to guided through the process of updating the colour DIS diagnostics files, if possible.
 
This is (from memory) the code that I've got. Certainly sounds like the same thing, no detectable symptoms from the driver's seat, you clear it and it's back within a couple of hundred miles. ProBoost sadly isn't a solution for this one as my FSI is running it. I've had the pre-cat sensor replaced at WOM, it looks like replacement of the expensive post-cat/NOX sensor is the only way forward.
 
Proghound said:
This is (from memory) the code that I've got. Certainly sounds like the same thing, no detectable symptoms from the driver's seat, you clear it and it's back within a couple of hundred miles. ProBoost sadly isn't a solution for this one as my FSI is running it. I've had the pre-cat sensor replaced at WOM, it looks like replacement of the expensive post-cat/NOX sensor is the only way forward.
Click to expand...
Are you thinking about getting one via Heritage, or would you just make a beeline for WOM amd have them order it?.
 
I'd let WOM order it, since they'd be fitting it. It'd probably be coming from the same place (they have an EORI number for Audi Tradition to be able to export to).
 
Slow response of a Lambda sensor seems to be down to contamination of the sensor.
Do you run the car on top quality, 98/99 octane, E5 fuel, (Shell V-Power is my FSI's tipple)? These have "detergents" that can minimise the build up of contaminants, and reduce existing build up, (I believe).
A good long blast, to get the exhaust really hot, may also help.
If, once cleared, the EML stays out for 500 miles, I'd think the fail condition was marginal.
If the Lambda element of the NOx Sensor failed, so would the NOx Sensor, as the NOx controller uses the Lambda value to monitor the efficiency of the Nitrous Oxides removal process.
Mac.
 
I certainly run mine on V-Power. Darren before me would definitely have used E5 Premium, I'm sure Jeff before him would also have provided the correct diet. That's most of the last 10 years taken care of, but only about 15k of its 40k miles.
 
Proghound said:
I certainly run mine on V-Power. Darren before me would definitely have used E5 Premium, I'm sure Jeff before him would also have provided the correct diet. That's most of the last 10 years taken care of, but only about 15k of its 40k miles.
Click to expand...
Just looking for possible causes, and possible recovery/avoidance strategies really.
I do think a clean and check of all the connections, between the sensor and the NOx controller and out of the controller to the ECU would be a good idea.
Mac.
 
jaffa_jim said:
Here's the block data for this issue.
View attachment 115776
Click to expand...
The CDIS shows Engine Group 001, which is general engine data.
1,Engine Speed.
2,Coolant Temperature at Radiator Outlet, (G83). *See Note
3,Lambda Control.
4,Conditions for Basic Setting.
*Note: I think the CDIS is showing ECU Group 001, so the coolant temperature displayed, is not going to be representative of the engine temperature, This is because it's from a sensor located at the radiator outlet, not the engine outlet.
The FSI has two engine temperature sensors.
One is at the Engine Outlet, (Actual Engine Temperature G62), while the other is at the Radiator Outlet, (G83).
The Actual Engine Temperature, (G62), is available in Group 130, Block 1.
We need a CDIS Guru to check this out, as it's FSI specific. In other engines, there is only one temperature sensor,so coolant temperature will represent engine temperature.
Mac.
 
I also think that if you have a marginal fail condition on a Lambda sensor, it would be well worth running Basic Settings, which is an adaptation, to allow for lambda sensor ageing. For Bank 1, Sensor 2, it's Group 043.
The Cat must be Hot for the test to run.
The new .lbl file must be used.
@Andrew has posted the version for full VCDS, I have a version for VCDS LIte, Please PM me for a copy.

Basic Settings, Group 043,0, Lambda Sensor Ageing (Sensor 2)
>Activate basic setting
>Press the brake and accelerator pedal together and hold down
The engine speed is automatically increased
> Field 4 = Test ON
Wait until Field 4 displays "B1-S2 OK"

The Fields, (Blocks), will display during the test: Field 1, Engine speed, (G28). Field 2, Cat Temperature. Field 3, Voltage,Sensor 2.
Field 4, Test ON/Test OFF/B1-S2 OK/B1-S2 Not OK

No guarantee, but much less expensive than a new sensor.
Mac.
Edit: If sending me a PM requesting the Lite version of the FSI lable file, please make the Subject BADLite. Help me keep track of who has it, and means it is A2OC members only.
Mac.
 
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PlasticMac said:
I also think that if you have a marginal fail condition on a Lambda sensor, it would be well worth running Basic Settings, which is an adaptation, to allow for lambda sensor ageing. For Bank 1, Sensor 2, it's Group 043.
The Cat must be Hot for the test to run.
The new .lbl file must be used.
@Andrew has posted the version for full VCDS, I have a version for VCDS LIte, Please PM me for a copy.

Basic Settings, Group 043,0, Lambda Sensor Ageing (Sensor 2)
>Activate basic setting
>Press the brake and accelerator pedal together and hold down
The engine speed is automatically increased
> Field 4 = Test ON
Wait until Field 4 displays "B1-S2 OK"

The Fields, (Blocks), will display during the test: Field 1, Engine speed, (G28). Field 2, Cat Temperature. Field 3, Voltage,Sensor 2.
Field 4, Test ON/Test OFF/B1-S2 OK/B1-S2 Not OK

No guarantee, but much less expensive than a new sensor.
Mac.
Click to expand...
I may get a chance to do that in the next week or so, thanks Mac 👍
 
PlasticMac said:
The CDIS shows Engine Group 001, which is general engine data.
1,Engine Speed.
2,Coolant Temperature at Radiator Outlet, (G83). *See Note
3,Lambda Control.
4,Conditions for Basic Setting.
*Note: I think the CDIS is showing ECU Group 001, so the coolant temperature displayed, is not going to be representative of the engine temperature, This is because it's from a sensor located at the radiator outlet, not the engine outlet.
The FSI has two engine temperature sensors.
One is at the Engine Outlet, (Actual Engine Temperature G62), while the other is at the Radiator Outlet, (G83).
The Actual Engine Temperature, (G62), is available in Group 130, Block 1.
We need a CDIS Guru to check this out, as it's FSI specific. In other engines, there is only one temperature sensor,so coolant temperature will represent engine temperature.
Mac.
Click to expand...
My apologies - I'll see if I can find G62 information. I had assumed that 108-110 temperature *was* the actual engine temp. No idea who might be a CDIS guru other than @timmus (though I know he's a diesel owner, so likely hasn't had the opportunity/inclination to go down this rabbit hole).
 
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