Peugeot Expert warning light and DPF issues

Sounds familiar. I had similar issues with my old Opel Astra a couple of years ago. Warning lights, performance issues... Did you check the sensor itself for any visible damage or loose connections?

I visually inspected it, and nothing seems obviously wrong. Could a faulty sensor genuinely cause all these symptoms? I'm not very experienced with vehicle diagnostics.

Yes, a faulty exhaust back pressure sensor can definitely cause those problems. It happened to me, too! I would suggest you go to the workshop to get it checked properly before you spend a lot of money. It may save you a lot of headache.

Thank you for the advice. I took it to a workshop, and indeed the exhaust back pressure sensor was defective. The repair cost 245€, and all the issues are now resolved.