NOx Signal Low: Troubleshooting Guide

Could someone please explain the error to me?

Code:

Adresse 01: Motorelektronik Labeldatei: DRV\059-907-401-V2.clb Steuergerät-Teilenummer: 4G0 907 589 F HW: 4G0 907 589 B Bauteil und/oder Version: 3.0BTD EDC17 X23 0008 Codierung: 122A403A257603030000 Betriebsnummer: WSC 92521 052 00000 ASAM Datensatz: EV_ECM30BTD0114G0907589F 001008 (AU57) ROD: EV_ECM30BTD0114G0907589F_001.rod VCID: 377B45848EC48F2933-8062 1 Fehler gefunden: 9691 - Geber für NOx (G295) P1033 00 [10101111] - Signal zu klein Warnleuchte EIN - bestätigt - geprüft seit letzter Löschung Umgebungsbedingungen: Fehlerpriorität: 2 Fehlerhäufigkeit: 1 Kilometerstand: 123985 km Datum: 2024.06.04 Zeit: 06:16:18 Motordrehzahl: 1386.00 /min Normierter Lastwert: 91.0 % Fahrzeuggeschwindigkeit: 86 km/h Kühlmitteltemperatur: 93 °C Ansauglufttemperatur: 14 °C Umgebungsluftdruck: 980 mbar Spannung Klemme 30: 14.380 V Verlernzähler nach OBD: 40 Luftmasse: Istwert (mg/Hub): 473.6 mg/stroke NOx Emission NOx-Sensor 2: 132 ppm NOx Emission NOx-Sensor: 41 ppm Berechnete NOx-Konzentration hinter Turbolader: 172 ppm Ventil für Abgasrückführung: Istwert: 86.51 % Mittlere Einspritzmenge: 24.31 mg/stroke Außentemperatur: 11.0 °C Readiness: 1 1 0 0 0

Hello,

Did the error occur after a long journey (over 100 km) with very little load, for example, driving on the highway at 90 km/h?

I'm experiencing a similar issue with my T6, but I haven't yet found a definitive cause. My suspicion is that it might be related to soot buildup/low temperature of the NOx sensor, or simply its aging.

I would first fill the SCR tank, clear the error codes, and see if the error reappears.

Best regards, Rainer.

The error is recurring, and it initially appeared after about a week, but now it appears after only a day since cleaning the sensor. Since the time interval has shortened after each cleaning, I suspect a defect in the sensor and will have it replaced.

top55 wrote:

The error is recurring, and it initially appeared after about a week, and now, after cleaning the sensor, it appears after only a day. Since the time interval has shortened after each cleaning, I suspect a defect in the sensor and will have it replaced.

Thanks for the information. Feedback on whether that was the issue is very welcome!

The weasel had gnawed on the cable at the front sensor, causing the error .

Where is the front sensor located on your vehicle? Is there actually a NOx sensor in front of the AdBlue injector?

If no cost-saving measures were implemented, there are at least two sensors. Otherwise, it's only possible to check if the system is working using the estimated value and the value after the AdBlue injection. The front sensor, located under the water tank in the A6 Competition, measures the raw exhaust gas.

Currently, after reading the log, I have a better understanding of the situation, and it's quite clear what's happening. Since the second sensor measures more than the first, it's likely the first sensor that's the problem, because the NOx value cannot be higher at the rear than at the front, especially since the calculated value behind the turbocharger is higher than the actual value measured at the rear .

dieselschrauber wrote:

Where is the front sensor located on your vehicle? Is there actually a NOx sensor in front of the AdBlue injector?

As of my knowledge from 2022, only one truck manufacturer, as well as Venturi Motori with some RDW 3.0-liter diesel engines, omit the front sensor.

When purchasing a replacement, it's important to pay attention to the correct part number, because even though the NOx sensors may physically fit, they operate on different CAN node numbers and/or SPNs (Standard Parameter Numbers).

Regards,

Okay, please provide the German text you would like me to translate.