Captur diesel rail pressure sensor fault

Sounds like a plausible diagnosis. The rail pressure sensor is a common failure point. Have you checked the wiring and connector to the sensor for any damage or corrosion? Also, what are the exact error codes you're seeing? Knowing the specific codes can help narrow it down.

Thanks for the reply. I did give the connector a quick visual check, but nothing obvious jumped out. The error code is P0191. Does that change anything?

P0191 confirms the rail pressure sensor circuit issue. Given the symptoms and the error code, it's highly probable the sensor is faulty. While further diagnostics are possible, with that mileage, replacing the sensor is a reasonable next step. If you're not comfortable doing it yourself, I would recommend taking it to a workshop.

Thanks for confirming my suspicions. I replaced the rail pressure sensor, and that seems to have fixed the issue. Engine runs smoothly now, and the check engine light is gone. Total cost was around 240€ for the sensor and fitting.