T-Roc Exhaust Problems: EGR & Cat Symptoms Guide

Had a very similar issue with my 2019 T-Cross last year. I have some experience working on cars, but this was definitely a job for professionals. The symptoms you describe match exactly what I experienced, engine light, rough running, and that distinct exhaust smell. In my case, the oxygen sensor (lambda sensor) was failing, which caused incorrect fuel mixture readings and affected the exhaust system performance. The workshop diagnosed it using their diagnostic equipment and found the faulty oxygen sensor was sending incorrect readings to the ECU. They also checked the NOx sensors and exhaust pipe for any related damage, but fortunately everything else was fine. The repair took about 2 hours and cost 375€ including parts and labor. Before suggesting anything specific for your case, could you share: Current mileage? Any previous exhaust system repairs? Does the rough running happen more at idle or while driving? Have you noticed increased fuel consumption? These details would help determine if your issue is similar to what I experienced or if it might be something else in the exhaust treatment system.

Thanks for sharing your experience. My mileage is at 89147km and last service was done just 2 months ago. The rough running happens mainly while driving, especially during acceleration. Since the issue started, fuel consumption has increased by about 20%. Have not had any exhaust system repairs before this. The mechanics initially suspected the catalytic converter but could not confirm without further testing. I have also noticed black smoke occasionally, which might point to an EGR valve malfunction. Really hoping its not both components needing replacement, as I know these repairs can get expensive.

Thanks for those details. That additional context really helps, and the symptoms you describe are quite different from my T-Cross case, especially the black smoke which I never experienced. The combination of black smoke, increased fuel consumption and rough acceleration points more toward an EGR valve malfunction rather than just an oxygen sensor issue like I had. The particulate filter might also be affected if the EGR isnt working properly. In your case, I would strongly recommend getting the EGR system checked first. When my oxygen sensor failed, I never had black smoke, and the rough running was consistent rather than mainly during acceleration. While the repair cost for my oxygen sensor was 375€, an EGR valve replacement typically runs between 400-700€ with labor. If the catalytic converter is also affected, you might be looking at an additional 800-1200€. The engine light combined with these specific symptoms suggests its more complex than my issue was. Given the mileage and that its your first exhaust-related problem, I would focus on the EGR valve first before replacing more expensive components.

Based on your diagnostics and explanation, I think youre right about checking the EGR valve first. The black smoke during acceleration does seem to point in that direction more than a catalytic converter issue. I scheduled an appointment for tomorrow morning to get it properly diagnosed. The workshop mentioned they will do a full exhaust system inspection, including pressure testing for any exhaust leaks. They quoted about 90 minutes for the diagnostic work. Really hoping we can isolate the problem to just the EGR valve. The 400-700€ range for that repair is much more manageable than having to replace both the EGR and catalytic converter. The DEF fluid level is good and was topped up during the last service, so at least that part of the exhaust treatment system should be fine. Will update once I get the diagnostic results and know exactly whats causing these issues. Thanks for helping me narrow down the likely causes.