VW Up Flashing CEL & Exhaust Leak Symptoms Decoded

Had a similar situation with my 2015 VW Polo TSI. The check engine light started flashing due to exhaust system issues. Car diagnostics revealed multiple error codes related to NOx emissions and catalytic converter efficiency. The leak was occurring where the catalytic converter connects to the exhaust manifold. This affected the air quality readings and triggered the engine management system. The mechanic found cracks in the heat shield and deteriorating gaskets, allowing exhaust gases to escape. This required urgent attention since exhaust leaks can lead to: Higher nitrogen oxides emissions, Reduced engine performance, Potential engine damage if left unchecked, Failed emissions tests The repair involved replacing the catalytic converter, gaskets, and heat shield. The entire job took about 5 hours. After fixing, the check engine light cleared and exhaust readings returned to normal. Given your similar symptoms and mileage, I suggest getting a comprehensive inspection focusing on the exhaust system components. Make sure they check all connections and gaskets around the catalytic converter area.

Thanks for sharing your experience with the Polo. My Up had very similar issues and the flashing check engine light was definitely nerve-wracking. Would you mind sharing what the total repair cost was? My catalytic converter also needed replacement to address the NOx emissions problems, and I am curious how costs compare. The fuel efficiency is much better now after the fix, but I noticed the engine sounds a bit different under heavy acceleration. Have you experienced any changes or new issues since the repair?

Thanks for asking about the costs. After taking my Polo to the mechanic, I got the exhaust leak fixed for 265€, which included addressing the NOx storage catalyst aging. Much more reasonable than I initially feared. The cost covered both parts and labor for sealing the connection points and replacing worn gaskets. Your observation about engine sound changes is interesting. After my repair, the engine actually became quieter during acceleration since the exhaust gases were properly flowing through the system again. If you are hearing unusual sounds, it might be worth having the automotive repair shop check the mounting brackets and connections. Sometimes they can become loose after exhaust work. The emissions system has been working perfectly since the fix. The car diagnostics show all readings are now within normal range, and I have not had any warning lights reappear. Fuel economy on my Polo also improved notably after the repair, similar to what you experienced with your Up. My only suggestion would be to have them verify all exhaust connections are properly torqued if you notice any continuing sound changes under load. This is usually a quick check and can prevent future issues.

Thanks for sharing that insight about the Polo repair costs. After my recent experience with the Up, I can relate completely. I finally took it to a reputable automotive repair shop last week. The total came to 750€ for a new catalytic converter plus labor, which was more than your repair but necessary to fix the NOx emissions issues. The mechanic found significant deterioration in the emissions system components. They showed me the old parts, the catalyst was completely clogged and there were multiple exhaust leaks. The nitrogen oxides readings were way off the charts. The repair took about 6 hours but made a huge difference. The check engine light is gone, fuel economy is better, and the engine runs smoother. That different sound I mentioned during acceleration actually went away after they adjusted some mounting brackets that were slightly loose. Really glad I got it properly diagnosed and fixed this time. The exhaust system is working perfectly now and I just passed the emissions test with flying colors. Definitely worth the investment even though it cost more than I initially hoped.