Peugeot 208 Rail Pressure Sensor Issue

Check engine lights are the worst! Sounds like that sensor could be the problem. If it's not sending the right info, the car's computer probably freaks out and doesn't know how much fuel to pump in. Did you try wiggling the wires going to the sensor? Sometimes it's just a loose connection. Also, has the fuel filter been changed recently? A clogged filter could maybe put extra strain on the fuel system and mess with the sensor readings.

I checked the wiring and connections; they look good. The fuel filter was replaced about 15000 km ago. Could the filter be clogged already, and would that affect the sensor signal?

Good job checking the wires! And 15000 km... hmm, probably not the filter then, unless you've been driving through seriously dusty conditions. Honestly, it really does sound like that sensor is the problem. I'm no expert, but based on your symptoms and what the computer is telling you, I'd bet money on it. Maybe it's worth taking it to a shop to confirm? They have fancy tools to really test these things.

I consulted a technician who confirmed it was a defective rail pressure sensor. I had the sensor replaced, and the issue is now resolved. The repair cost 240€.