Peugeot 508 injector fault

The error code you're seeing, coupled with a rough running engine and the check engine light, strongly suggests an issue with your fuel injection system. Have you noticed any changes in your fuel economy recently? It might also be beneficial to check airflow sensor readings via an OBDII scanner to eliminate false positives.

Thanks for the reply! Fuel economy does seem a bit worse than usual, now that I think about it. Where exactly should I be looking for the airflow sensor readings? Are there specific values I should be seeing?

A decrease in fuel economy further reinforces the plausibility of a defective injector. While I cannot provide specific sensor values due to variations between diagnostic equipment, access to live data via an enhanced scan tool will allow scrutiny of the mass airflow sensor readings. Given the complexity, and the nature of the reset quantity drift compensation error, I strongly recommend seeking assistance from a qualified workshop. This likely requires specialized diagnostic equipment to properly assess.

Thanks so much for the advice. Took it to a shop, and you were spot on. Turns out an injector was faulty and screwing everything up. Quoted me 515€ for the repair. Ouch, but at least it'll be running smoothly again soon!