Jaguar S Type NOx System Failure Causing Multiple Issues

I experienced similar symptoms on my 2006 Jaguar XJ6 diesel. The rough running and increased fuel consumption paired with exhaust leaks pointed to serious emission control issues. The automotive repair revealed multiple problems in the exhaust system. The main culprit was a failing catalytic converter combined with deteriorated gaskets between the exhaust manifold sections. The nitrogen oxides readings were way above normal limits, indicating the NOx catalyst was no longer functioning properly. What started as a minor exhaust leak turned out to be a significant issue affecting the entire emissions system. The repair required replacing the catalytic converter and all connecting gaskets to restore proper exhaust flow and emissions control. The fuel efficiency improved noticeably after the fix. For your S Type, have them specifically check: Exhaust manifold gaskets, Catalytic converter condition, O2 sensor readings, Exhaust pipe connections, NOx catalyst efficiency These components work as a system, so one failing part often leads to others being affected. Best to have a complete diagnostic done rather than replacing parts individually. The replacement catalytic converter needs to meet exact specifications for these engines to function properly.

Thanks for sharing your experience with the XJ6. My S Type had very similar problems and the car diagnostics showed the same NOx emissions issues. I ended up having most of those parts replaced too after discovering multiple exhaust system leaks. Did you keep track of your total repair costs? Also wondering if youve had any other emissions-related problems since the repair was done? My fuel efficiency is still not quite where it should be, and I want to know if I should expect more issues down the road.

After getting the repairs done on my XJ6, the total came to 265€ for fixing the exhaust system leak. The mechanic found the NOx storage catalyst aging was causing most of the problems, but once they addressed that the car runs much better now. The emissions system has been working perfectly since the automotive repair was completed. No more NOx emissions issues or check engine lights in the past months. My fuel consumption returned to normal levels shortly after the fix, so if yours is still high, you might want the mechanic to double check the catalytic converter settings and oxygen sensor readings. These diesel engines are actually quite reliable once the emissions control components are properly maintained. Just make sure to use high-quality parts for any future repairs, especially when it comes to the NOx catalyst and related components. The initial investment in good parts pays off through better performance and fewer repeat issues.

After dealing with the check engine light and emissions system problems on my S Type, I finally got it fixed last week. The mechanic found multiple issues just like you mentioned. The NOx catalyst was completely shot and there were several exhaust leaks around the manifold gaskets. The car diagnostics confirmed high nitrogen oxides readings, which explained the rough running and poor fuel economy. Total repair came to 1200€ including parts and labor. They replaced the catalytic converter, all gaskets, and had to fix some corroded exhaust pipe sections. Just picked up the car yesterday and the difference is night and day. No more check engine light, engine runs smooth again, and the exhaust leaks are gone. Fuel consumption already seems better but will monitor it over the next few tanks. Really glad I got a proper diagnostic done instead of trying quick fixes that would have wasted money. This mechanic actually took the time to show me all the failed parts and explain how the emissions system works together. Much better experience than my previous repair attempts. Will definitely stick with them for future maintenance.