VW Lupo Catalyst Failure & Exhaust Leaks Fix Guide

Recently dealt with similar NOx catalyst issues on my 2005 VW Polo TDI. The symptoms matched exactly, check engine light, exhaust noise, and catalyst-related error codes during car diagnostics. The automotive repair revealed multiple problems: a cracked exhaust manifold causing leaks and a failed NOx catalyst. The nitrogen oxides readings were far above acceptable limits. This is actually a serious issue that needs prompt attention, as it affects both emissions compliance and engine performance. The repair required: Complete catalyst replacement, New gaskets and mounting hardware, Exhaust manifold repair, Full emissions system testing The work took 2 full days at the shop. Worth noting that running the car with a failing catalyst can damage other components like oxygen sensors and the EGR system. When the NOx catalyst fails, it often indicates the exhaust system needs a thorough inspection. For the Lupo, the repair process should be similar. These symptoms typically dont improve on their own and get worse if left unaddressed. Best to have it checked soon to prevent additional damage to the emissions control system.

Thanks for sharing your Polo experience, it helps a lot. The symptoms and error codes you described match my Lupo perfectly, especially the exhaust system issues and NOx problems. I am planning to take it to a shop this week since the nitrogen oxides emissions are likely way off. Would you mind sharing how much the full repair cost in your case? Also, have you had any other issues pop up since getting the NOx catalyst replaced? I want to make sure I budget properly and know what to watch out for going forward.

Had the repair done last month and glad to report my NOx storage catalyst aging issue was fully resolved. The car diagnostics confirmed the exhaust system leak was successfully fixed for 265€, which included parts and labor. The automotive repair went smoothly and no other problems have appeared since. The check engine light has stayed off and emissions are now within normal range. Air quality readings from the latest tests show everything working as it should. Your Lupo seems to have very similar symptoms to what my Polo had. The investment was worth it, the engine runs much cleaner and quieter now that the exhaust leak is sorted. Just make sure they do a complete system check while they have it up on the lift to catch any other potential issues. Regarding ongoing maintenance, a yearly inspection of the exhaust system components is recommended to catch any problems early. This helps avoid more expensive repairs down the line.

I took my Lupo to the repair shop yesterday after reading your helpful responses. The mechanic confirmed exactly what you mentioned, failing NOx catalyst and exhaust leaks. The car diagnostics showed high nitrogen oxides levels, just as expected. The total repair came to 290€, slightly more than your case but still reasonable. They completed everything in about a day and a half: New NOx catalyst installation, Fixed the exhaust leaks, Full emissions system check, Replaced worn gaskets The difference is remarkable. The engine runs smoother, no more warning lights, and the exhaust noise is gone. The air quality readings are now within spec. The mechanic also showed me the old catalyst, it was completely shot. Going to follow your advice about yearly inspections to keep the emissions system in good shape. Really glad I got this sorted before it caused more damage. Thanks again for helping me avoid another bad repair experience.