Seat Cordoba NOx Catalyst Concerns

The symptoms you describe are indeed indicative of potential issues with the NOx catalyst. I encountered a similar problem with my older Volvo some time ago, though the brand is obviously different, the underlying principles remain the same. Have you performed any car diagnostics, specifically checking for error codes related to nitrogen oxides or catalytic converter efficiency? A leak in the exhaust system, as you suspect, could certainly impact the catalyst's performance and fuel efficiency.

Thank you for your reply. You mentioned a similar issue with your Volvo. Could you elaborate on the specific error codes you encountered during your car diagnostics? I am curious if they align with the codes I retrieved, which point towards NOx catalyst aging. Also, did your Volvo exhibit any noticeable exhaust leaking, or was it a more subtle issue?

Indeed, the error codes I observed on the Volvo were directly related to the efficiency of the catalytic converter, specifically concerning nitrogen oxides reduction. The exhaust leaking was not immediately obvious but became apparent upon closer inspection of the exhaust manifold. Given the symptoms you describe and the error codes you have retrieved, it would be prudent to have a qualified technician examine the exhaust system for leaks and assess the overall health of the catalytic converter. It might be time to visit the workshop.

I appreciate the information you provided. It seems my suspicions were correct. I took the Seat Cordoba to a certified workshop. The diagnosis confirmed a leak in the exhaust system, contributing to the NOx storage catalyst aging. The exhaust system has been repaired, and the check engine light is now off. The overall cost amounted to 265€. Thank you again for sharing your experience.