1.4 TDI: Faulty EGR Valve & O2 Sensor?

Hello everyone!

My Polo has recently started displaying the engine check light.
The error code read from the diagnostic system was:

Code:

Sonntag,05,November,2017,11:57:07:25065 VCDS -- Windows-basierter VAG/VAS-Emulator läuft auf Windows XP x86 VCDS Version: RKS 17.8.0.1 Datenstand: 20170809 DS276.3 http://shop.dieselschrauber.de Fahrzeug-Ident.-Nr.: WVWZZZ9NZ8B0xxxxx   KFZ-Kennzeichen: A- Kilometerstand: 388250km   Reparaturauftrag: Winterreifen+Fehlermeldung -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- Fahrzeugtyp: 9N (9N3 - Polo) Scan: 01 03 08 09 15 17 19 25 44 46 76 Fahrzeug-Ident.-Nr.: WVWZZZ9NZ8B0xxxxx   Kilometerstand: 388250km ------------------------------------------------------------------------------- Adresse 01: Motorelektronik        Labeldatei: DRV\045-906-013-BMS.clb    Teilenummer SW: 045 906 013 E    HW: 045 906 013 E    Bauteil: R3 1,4L EDC G000SG  4271     Revision: --H03---    Seriennummer: VWZ7Z0G5933092    Codierung: 0003071    Betriebsnr.: WSC 49000 143 80495    VCID: 112F82EC0B0893CE15-5120 2 Fehlercodes gefunden: 001027 - Ventil für Abgasrückführung (N18)                P0403 - 000 - Fehlfunktion - Sporadisch              Umgebungsbedingungen:                     Fehlerstatus: 00110000                     Fehlerpriorität: 1                     Fehlerhäufigkeit: 1                     Verlernzähler: 255                     Kilometerstand: 388010 km                     Zeitangabe: 0              Umgebungsbedingungen:                     Drehzahl: 0 /min                     Geschwindigkeit: 4.0 km/h                     Tastverhältnis: 0.0 %                     Spannung: 12.46 V                     Luftmasse/Hub: 0.0 mg/H                     Tastverhältnis: 17.0 %                     Binärwert: 00110000 008598 - Bank 1 Sonde 1                P2196 - 000 - Signal zu fett - Warnleuchte EIN              Umgebungsbedingungen:                     Fehlerstatus: 11110000                     Fehlerpriorität: 2                     Fehlerhäufigkeit: 1                     Verlernzähler: 255                     Kilometerstand: 385052 km                     Zeitangabe: 0              Umgebungsbedingungen:                     Drehzahl: 1785 /min                     Geschwindigkeit: 74.0 km/h                     (keine Einheit): 99.0                     Temperatur: 47.7°C                     Druck: 958.8 mbar                     Spannung: 0.584 V                     (keine Einheit): 0.09 Readiness: 1 2 0 0 0

Do you have any suggestions on how I can narrow down the cause of the error/defect?
I think it would be a bit premature to buy a new EGR valve and/or oxygen sensor just yet...

Deleting the errors only provided a temporary solution; the errors keep reappearing.

Thank you very much!

Regards,
Volker.

Hello Volker,

A too rich fuel mixture can be a consequence of a malfunctioning EGR valve that is no longer closing properly. Therefore, I would recommend repairing the EGR valve first.

Best regards, Rainer.

Keep an eye on the DPF as long as you're driving with the EGR error; in some cases, regeneration doesn't occur if the EGR isn't working.

dieselschrauber wrote:

Hello Volker, A too rich fuel mixture can be a consequence of a malfunctioning EGR valve that is no longer closing properly. Therefore, I would recommend repairing the EGR valve first. Best regards, Rainer

Hello Rainer,

Thank you for the tip!
I will look into the AGR and report back!

Best regards, Volker.

chli1976 wrote:

While you're driving with the EGR error, keep an eye on the DPF. In some cases, regeneration may not occur if the EGR is not functioning properly.

Wow, you might be right! If I think about it carefully, he hasn't "rumbled" in a long time...

Thank you!

I'm currently thinking about something.
In the VW Polo 9N3, the EGR valve is located so far behind the engine that it's difficult to access without disassembling half of the engine.

stolley wrote:

I'm currently thinking about: In the VW Polo 9N3, the EGR valve is located so far behind the engine; is it even possible to access it without disassembling half of the engine?

Hello everyone, and a happy new year to all!

Regarding my Polo:
To access the screws on the EGR valve, you need to remove the front cover.
However, I wasn't able to remove one of the screws from the EGR valve; the Torx screw was too shallow and stripped.
Then I just put everything back together – I didn't feel like it anymore!

What problems should I expect if I leave the EGR valve as it is? Regeneration is actually happening, contrary to my initial impression. The emissions test at TÜV was passed thanks to the error code being cleared beforehand! However, it was quite a hassle: the engine had to be revved up to its maximum RPM for the first time! Ugh...

Hi,

I would fix it. A faulty EGR valve can cause a loss of power at the most inconvenient times, such as when overtaking.
If you have retrofitted a DPF (Diesel Particulate Filter) to your vehicle, it is likely an open system without pressure sensors, temperature sensors, or other related components.
You will never encounter "regeneration problems" here because the engine control unit cannot initiate an active regeneration process and does not measure anything related to it. In case of doubt, the system will simply become "inactive" over time.

The main problem with your car will likely be accessing the necessary screws; otherwise, removing and installing the AGR (selective catalytic reduction) system is quite straightforward.

Best regards, Rainer.

dieselschrauber wrote:

If you've retrofitted a DPF (Diesel Particulate Filter) to your vehicle, it's likely an open system without pressure sensors, temperature sensors, or other related components. You will never encounter "regeneration problems" here because the engine control unit cannot initiate an active regeneration process and does not measure anything related to it. In case of doubt, the system will simply become "inactive" over time.

Hello Rainer!

Thank you for your reply!

"Of course, the car comes standard with a DPF, but that certainly doesn't change my recommendation, right?"

I will probably try to remove the EGR valve, including the connecting piece.

Regards,
Volker.

P.S. Do you know why I'm not receiving notifications about new forum posts?

stolley wrote:

The good one actually comes with a DPF as standard - but that certainly doesn't change your recommendation, right?

045 906 013 E -> EDC17U01

Okay, I had overlooked that. The engine was also available with EDC15 without a DPF. So you have a closed DPF, which is also recognizable in the measured values due to the exhaust temperature sensors and the differential pressure sensor. However, this does not change my recommendation.

Best regards, Rainer.

Hello everyone!

I have now replaced the AGR (Abgasrückführung - exhaust gas recirculation system).
To do this, I removed the valve cover and unscrewed the EGR system along with its connecting pipe from the intake manifold.

After driving approximately 70 kilometers, I read the error memory again. Unfortunately, there was still ONE entry recorded – although (so far) without a warning light illuminating.

Code:

Sonntag,14,Januar,2018,21:15:02:25065 VCDS -- Windows-basierter VAG/VAS-Emulator l‰uft auf Windows XP x86 VCDS Version: RKS 17.8.0.1 Datenstand: 20170809 DS276.3 http://shop.dieselschrauber.de Fahrzeug-Ident.-Nr.: WVWZZZ9NZ8Bxxxxxx   KFZ-Kennzeichen:  Kilometerstand: 396670km   Reparaturauftrag: -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- Fahrzeugtyp: 9N (9N3 - Polo) Scan: 01 03 08 09 15 17 19 25 44 46 76 Fahrzeug-Ident.-Nr.: WVWZZZ9NZ8Bxxxxxx   Kilometerstand: 396670km ------------------------------------------------------------------------------- Adresse 01: Motorelektronik        Labeldatei: DRV\045-906-013-BMS.clb    Teilenummer SW: 045 906 013 E    HW: 045 906 013 E    Bauteil: R3 1,4L EDC G000SG  4271     Revision: --H03---    Seriennummer: VWZ7Z0G5933092    Codierung: 0003071    Betriebsnr.: WSC 49000 143 80495    VCID: 112F82EC0B0893CE15-513C 1 Fehler gefunden: 008598 - Bank 1 Sonde 1                P2196 - 000 - Signal zu fett              Umgebungsbedingungen:                     Fehlerstatus: 01110000                     Fehlerpriorit‰t: 2                     Fehlerh‰ufigkeit: 1                     Verlernz‰hler: 255                     Kilometerstand: 396610 km                     Zeitangabe: 0              Umgebungsbedingungen:                     Drehzahl: 1596 /min                     Geschwindigkeit: 53.0 km/h                     (keine Einheit): 90.0                     Temperatur: 14.4∞C                     Druck: 958.8 mbar                     Spannung: 0.438 V                     (keine Einheit): 0.01 Readiness: 0 0 0 0 0

Can someone tell me how to interpret this error message? Will the warning light come on if the error occurs more frequently?

Thank you very much!

Hi,

Check if you have a leak in the charge air system, which could be causing necessary combustion air to escape into the atmosphere. This would then result in a lack of air during combustion.
I assume the oil consumption and oil level are normal; otherwise, you would have definitely told us.

Best regards, Rainer.

dieselschrauber wrote:

Hi, Check if you have a leak in the charge air system, which could be causing necessary combustion air to escape into the atmosphere. This would then result in a lack of air during combustion. I assume the oil consumption and oil level are normal; otherwise, you would have definitely told us. Best regards, Rainer

Hello Rainer,

Yes, the oil level and consumption are normal. More specifically, there's a slight tendency for diesel to contaminate the oil. I've already had the PD injectors sealed. That's why I change the oil every 15,000 km.
I suspect the leak is most likely at the transition point between the rubber and aluminum parts, which are simply connected. I'll order a new seal for that area.

You're welcome!

The leak reveals itself through oil mist/oil residue at the leaking point.

dieselschrauber wrote:

The leak reveals itself through oil mist/oil residue at the leaking point.

Thank you for the tip, Rainer!
I was unable to find such a spot, but the intake manifold on the Polo isn't really easy to see either.

Would it potentially make sense to log any kind of metadata (MWB) in order to gain further insights?

Best regards,
Volker.

So, a visual inspection to ensure all individual components are securely fastened should always be performed first. The diagnostic process only begins after that.