Citroen DS5 Exhaust Sensor Issue

Hello, I experienced something similar with my 2016 BMW 3 series. Same symptoms: check engine light, power loss, and increased fuel consumption. The error code also indicated a problem with the exhaust system. Have you checked for any signs of leaks in the exhaust system itself? That was the root cause in my case.

Thanks for the info. I haven't specifically looked for leaks, just focused on the sensor itself. Where exactly should I be checking for these leaks? Is there a particular area of the exhaust system that's more prone to failure?

In my experience, the area around the exhaust manifold and the flex pipe are common points for leaks to develop. However, without specialized equipment, pinpointing the exact location can be challenging. Given that you've already identified a faulty sensor and suspect exhaust issues, I would recommend a thorough inspection at a qualified workshop.

Took your advice and brought the DS5 to a shop. Turns out there was a small crack in the exhaust pipe near the sensor, causing temperature fluctuations and triggering the error. New sensor and a small welding job on the exhaust cost me 265€. Thanks for pointing me in the right direction!