VW Amarok NOx Sensor Issues & Exhaust System Fix Guide

I had a very similar issue with my 2013 VW Touareg diesel last year. With some experience working on VW diesels, I recognized these symptoms immediately. The check engine light combined with exhaust issues pointed to a sensor failure in the emissions system. After scanning, it turned out the nitrogen oxide sensor had a damaged wire connection. The air-fuel ratio was completely off because of this faulty connection. Took it to my regular workshop where they diagnosed the exact same problem, a loose connector was causing the NOx sensor to send incorrect readings to the ECU. The catalytic converter was actually fine, though they checked it thoroughly given the symptoms. The fix was straightforward, they repaired the wiring connection and reset the system. Total cost was 95€ and the car was ready in about 2 hours. No issues since then. Before suggesting specific fixes for your case, could you share: Current mileage on your Amarok, Exact error codes from the diagnostic, Any performance changes (power loss, rough idle), When did the symptoms first appear This will help determine if your issue is similar or if there might be additional components affected.

Thanks for the detailed description. Just had my service last week at 143393km, and this issue emerged shortly after. In my case, the exhaust system actually shows visible damage near the sensor mounting point. The engine is running noticeably rougher than usual, especially when cold. My error codes specifically point to the emission sensor circuit, which aligns with your experience. However, the physical damage to the exhaust near the sensor suggests this might require more extensive repairs than just fixing a connection. I will double check the air-fuel ratio readings, but based on your feedback, I should prepare for a potential sensor replacement rather than a full catalytic converter job. This gives me more confidence heading to the workshop.

Looking at your description, this sounds more severe than my initial sensor issue. With visible exhaust damage near the mounting point, you are dealing with a compound problem that needs immediate attention. After dealing with my sensor connection issue, I learned these diesel engines can develop more serious problems if the exhaust system integrity is compromised. The rough running, especially during cold starts, strongly suggests the air-fuel ratio is being affected by both the sensor failure and the exhaust leak. In your case, the repair will likely require: Complete NOx sensor replacement (not just rewiring), Repair of the damaged exhaust section, Full system diagnostic to verify no catalytic converter damage My repair was simple because it only involved the wiring. Your situation with physical damage will need welding work on the exhaust system. When my workshop did a similar repair on another vehicle, it took about 4-5 hours and cost roughly 450€. The good news is that catching this shortly after your service means other components should still be in good condition. Once fixed, make sure they perform a complete sensor calibration to restore proper air-fuel mixture control. Worth asking the workshop if the exhaust damage could have been missed during the recent service, as this might affect warranty coverage.

Appreciate your thorough insights on this. The situation does sound more complex than a simple wiring fix. The physical damage to the exhaust system near the sensor definitely changes the scope of repairs needed. The rough cold start behavior matches what I am experiencing, and your explanation about the air-fuel ratio being affected by both the sensor and exhaust leak makes perfect sense. A compromised exhaust system combined with faulty pollution control components would explain the symptoms. Your repair cost estimate of 450€ helps set realistic expectations. Good point about questioning why this wasnt caught during my recent service, I will definitely bring this up with the workshop. The fact that this started right after service seems more than coincidental. I will schedule the repair next week and make sure they do a complete inspection of the catalytic converter while fixing the exhaust system and replacing the nitrogen oxide sensor. Better to address everything properly now rather than risk further damage. Thanks again for sharing your experience, it has helped clarify what I am dealing with and what to expect from the repair process.