Ascent Catalytic Converter Causing Exhaust Leaks

Having dealt with similar symptoms on my 2020 Subaru Outback, I can relate to your exhaust system concerns. The symptoms you describe strongly suggest a failing catalytic converter or damaged NOx catalyst assembly. Last month, car diagnostics revealed my exhaust leak was occurring at the connection point between the catalytic converter and the exhaust manifold. The scan showed similar error codes related to NOx emissions. The issue turned out to be more serious than expected, as the internal honeycomb structure of the catalytic converter had partially collapsed, causing restricted exhaust flow. The repair required replacing the entire catalytic converter assembly and reinforcing the mounting brackets. While the car was driveable, continuing to run it with these symptoms risked damaging other components of the exhaust system and could lead to increased fuel consumption. Key warning signs to watch for: Rattling noise under the vehicle, Drop in power during acceleration, Sulfur smell from exhaust, Increased engine temperature Getting this checked promptly is important since catalytic converter issues can cascade into more extensive exhaust system damage if left unaddressed.

Thanks for that detailed reply about the catalytic converter failure. Your experience with the NOx catalyst issues sounds very similar to what I am dealing with. The automotive repair shop I contacted mentioned they need to do thorough car diagnostics first, and I am a bit worried about the final cost. Would you mind sharing how much you ended up paying for the full repair? Also, has everything been working properly since the replacement, or have you noticed any new issues with air quality sensors or engine performance?

After getting car diagnostics at the shop, they found the issue was indeed similar to what you described. The emissions system check revealed a leak in the exhaust system near the NOx storage catalyst. The repair cost came to 265€, which was less than expected since theyaged to fix the aging catalyst rather than replacing the entire assembly. Since the repair three months ago, the catalytic converter and emissions system have been working flawlessly. The engine performance is back to normal, and there have been no more error codes or issues with the nitrogen oxides sensors. The exhaust leak noise completely disappeared, and fuel efficiency has actually improved slightly. Getting professional diagnostics early helped prevent more extensive damage to the exhaust system components. The initial symptoms you described match what I experienced, so having it checked now is definitely the right move to avoid more costly repairs later.

Thanks for the input. I finally got my car checked at a repair shop and wanted to share my experience. After comprehensive car diagnostics, they found multiple issues with the NOx catalyst system. The automotive repair cost ended up being 1850€ for replacing the catalytic converter and fixing some related exhaust components. The process took about 4 hours. They showed me the damaged parts, including the deteriorated catalyst material and cracked housing. Since the repair, the exhaust leak noise is completely gone and the check engine light hasnt returned. The air quality sensors are now working correctly and engine performance feels noticeably better. While the cost was higher than I hoped, addressing the problem early prevented additional damage to the exhaust system. The mechanic explained that waiting longer could have led to more extensive repairs. Now the car runs smoothly with no emissions issues.